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9 Laws of Physics That Don't Apply in Hollywood
Ant writes "Neatorama lists nine laws of physics that don't apply in Hollywood (movies and television/TV shows). In general, Hollywood filmmakers follow the laws of physics because they have no other choice. It's just when they cheat with special effects that people seem to forget how the world really works..."
The "Hollywood special" from a few moths back.
It seems that we have discussed this kind of things so many times. Hollywood are not meant to learn about real world. It is about entertainment.
-- tinyhack.com
I've always enjoyed intuitor dissect movie physics for some of the more popular movies.
http://www.intuitor.com/moviephysics/
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True enough, radioactivity isn't contagious. Remove the source of radiation, and with any luck, the body will heal. But certain types of radioactive materials DO glow without phosphorus- which in and of itself is a mildly radioactive material. Remember all of those green glow-in-the-dark mechanical clocks from the 1920s to the 1970s? Radium paint is what made them glow. And since light is in the electromagnetic spectrum- just about anything that glows without a power source is indeed "radioactive" to some extent. (note, this doesn't mean all "glow in the dark" materials, just some).
SJW: a person who perceives an injustice, and while correcting it, commits a greater injustice.
This list reads like a combination of 'well duh' and 'seen it on Mythbusters'... I'm glad they had to remind us that thunder does indeed follow lightning. Yawn
You don't see people's skeleton glow when they are being electrocuted.
That being said:
In most instances that come to mind, the director takes care of this problem by zooming you in on the Volcano, shell explosion, or baseball hit. Once you hear the sound at the source, the director usually cuts away to the actors after the sound has arrived. (As can usually be surmised by the ash and dirt flying at the camera.)
To the human ear, they are effectively simultaneous if the lighting crack is close enough to the observer. Considering how LOUD the director usually chooses to make the thunder, I don't think it's that bad of a summation. How about we start worrying why the actors aren't taking shelter?
This is actually incorrect. Radioactive "things" can emit light through two other methods:
1. They grow physically hot enough to glow red-hot or white-hot.
2. They heavily ionize the air around them, creating pretty streaks and rainbows.
However, the green-glow often seen in movies and cartoons does usually require the presence of phospher.
Or... the kicker could be properly grounded. If the kicker is properly braced against the ground, it's not impossible to send an unbalanced opponent off his feet. The fact that you can pick an opponent up and toss him in a single motion demonstrates that. That's not to say that the exact situation of many fights isn't ridiculous (excuse me, rediculous), but the physics of the situation don't prevent a kicker from delivering a blow hard enough to knock someone off their feet. Perhaps even to the point of sending them flying. (Though it's unlikely that it would be to the point of many kung-fu movies on strings. There's only so much structural capacity in the human body. After that, you start breaking your own bones.)
:-P
Now when they miss their target and don't go flying across the room...
Unless, of course, there is some sort of incline for a takeoff (ever notice how the Duke boys always manage to find that conveniently placed incline?) or the second section is lower than the first, thus allowing for the jump to complete depsite the drop in altitude. (As the camera appeared to make the situation in Speed.)
Smash cuts don't exist in real-life, either. Yet we don't complain about those. Slow motion is an entirely artistic thing, and is not related to the physics of the situation. At all.
Pretty much the rest of his arguments
Javascript + Nintendo DSi = DSiCade
Human cloning/duping is possible, unless your on Slashdot
How about the fact that there is no such thing as a perfect vacuum?
Hollywood movies suck so much it seems like they violate this one.
blah blah blah
With the string of new kung fu films out (they run the gamut from The Matrix to Charlie's Angels), you just can't escape the small matter of bad physics. Yeah, the action scenes look great and all, but in reality momentum is conserved, such that every action has an equal and opposite reaction. So, when you see a gal kick someone across the room, technically, the kicker (or holder of a gun) must fly across the room in the opposite direction - unless she has a back against the wall.
If I punch a punching bag, the bag moves but I don't. That is because my fist has the energy which transfers to the bag. I don't go flying backwards as the article suggests.
today is spelling optional day.
I'm guessing it's more realistic since it , six years ago.
Time is rarely shown as continuous, forward moving, and in real time.
They are always using edits, skipping stuff and even going backwards and forwards. Really makes it hard to enjoy a film with your sense of reality totally shattered.
If you're going to write an article about the laws of physics, shouldn't you actually understand the laws of physics? "Equal and opposite reaction" doesn't mean that when I kick someone and they go flying in one direction, I must go flying in the opposite direction at the same speed, unless I had no momentum toward them before impact. In which case, umm, it would be kind of hard for me to hit them.
Don't blame me; I'm never given mod points.
Sure, they apply to Hollywood... they just don't get accepted. Not glamorous enough.
"...the truth is that the most common forms of radioactivity will make you radioactive only if the radioactive particles stick on you. Radioactivity is not contagious. If a person is exposed to the radioactive neutrons from a nuclear reactor, then he can become slightly radioactive, but he certainly won't glow."
True, most cases of "people being radioactive" are the result of contamination with radioactive substances. True, you won't glow (and if you ever do, you won't live long enough to worry about it). True, neutron activation is the only way to make you slightly radioactive without actually contaminating you with radioisotopes.
But in an article that otherwise does a good job in debunking Hollywood misperceptions that lead to scientific illiteracy, I'm not gonna "radioactive neutrons" slide. What he meant is not what he wrote. (But in the blogger's defense, I've seen "highly-charged neutrons" in print, so it could have been worse :-)
That one bugged me about a recent Battlestar Galactica, as well. Inside the room, the characters were freezing because the air was leaking away. (Thus cooling the room.) I can accept that. But once they're blasted into space? Not a chance of freezing. No air for cooling == no loss of heat. (Actually, you can still lose it slowly through black-body radiation, but that's another topic.) Human skin is pretty good at holding pressure, so the big things are:
- Don't hold your breath (unnecessary internal pressure)
- Close your eyes (they're more susceptable to decompression)
See the research into the Space Activity Suit for more info.
Javascript + Nintendo DSi = DSiCade
radium paint didn't glow because radium did... not in that concentration, or in those colors. the radium was mixed into a heavy coat of standard enamel with a whole bunch of phosphorescent pigments, which glowed.
until they burned out. old WWII radio dial markings from military gear have a lot of brown markings. they are radium paint with the phosphors all burnt out atomically, like a ghost image on a burned-in computer screen or monitor screen on an ATM. still radioactive and dangerous if ingested.
radium, polonium, radiocobalt, and other strong alpha emitters will emit a Czerinkon glow of blue when in the presence of hydrogen or water, which may be what you are thinking of. the blue glow is that of ionized hydrogen from the alpha hits, however, and should be thought of as a form of phosphorescence.
if this is supposed to be a new economy, how come they still want my old fashioned money?
One word: dramatic.
TLF
I do not respond to cowards. Especially anonymous ones.
I've got two complaints about #4.
1) The point of the Matrix was to bend the laws of physics. It was rather explicit.
2) The author obviously never watched Bruce Lee in action. If you plant yourself correctly you can send people flying across the room without moving an inch yourself. However, if you're in midair you certainly can't without the mentioned conversion of momentum.
Also concerning #5.
1) If it's a hole with level ends on both sides, it is entirely impossible to jump it on car without a ramp or other device to add a vertical component to velocity. However, in the event of a bridge being raised for a boat, the angle can potentially allow a vehicle to "jump" the gap. Is it likely or feasible? Not particularly, but it is possible.
2) This could have been expanded to include the "Bombs do not drop straight down" category of gravitational violation. A plane flying at high horizontal velocity v over a stationary target is not capable of dropping a bomb without horizontal velocity. Unless it fires the bomb backwards at a relative velocity -v, in which case we can have a semantic argument over whether the bomb is being dropped or fired.
Thunderclone: ONE MAN ENTERS! TWO MEN LEAVE! ONE MAN ENTERS! TWO MEN LEAVE!
Is the availability of parking spaces actually controlled by the laws of physics?
- - Sha la la la . . .
Fast paced music doesn't really play when something exciting happens. Not everyone in real life looks like a hollywood actor. If people speak in a foreign language, you don't actually see an English language translation at the bottom of the screen. I tend to be pretty easy going on most non-realism since it is just there to tell a story. If the plot relies on a complete failure to grasp some basic fundamental of physics, (e.g. The Day After Tomorrow), I tend to be a lot more critical.
1. They are called Sound Suppressors not "silencers". They do not "silence" the sound just diminish it.
2. They do not really suppress the sound the way movies put it (I am looking at you Mr. Bauer). Motion pictures have produced the common misconception that sound suppressors ("silencers") completely silence the weapon's sound, or reduce it to a quiet whistling sound, which is in most cases very far from the truth. In fact, the emergent noise can still be heard from a fairly large distance. The quiet whistling sound associated with silencers is more attributable to the noise made by air guns 3. (And the most interesting for me) They are good just for a small number of shots (Yeah, again looking at you Mr. Bauer) Very effective suppressors either involve a large total suppressor volume, a moderately large volume plus many baffles, or wipes. It is possible to design a very small and compact suppressor with wipes which effectively silences a pistol; these suppressors have a lifetime of as few as 4-5 shots and typically no more than a few magazines of ammunition. Larger wipeless (baffle only) pistol or rifle suppressors may be nearly as effective for long lifetimes (hundreds or thousands of shots) but are relatively bulky, clumsy, and heavy.
Ubuntu is an African word meaning 'I can't configure Debian'
I often wondered whether if you were in a vacuum you might even overheat? Since theres no air convection taking heat away from your body and any sweat would immediately vapourise as it came out your pores so it wouldn't have a chance to spread over your skin and cool you.
I am a firm believer in the ability to break the law of gravity.
I was out surfing and paddled into a wave. When I jumped up to my feet, I missed the sweet spot of the wave and ended up on the breaking part instead (ie. not a good location). To this day I swear the wave dropped out from under me followed by the board while I hung there in midair. Misquoting Douglas Adams, "gravity finally looked my way and wondered what the hell I was doing" and down I went. The couple of people who saw it were sure I was surfing a board made by "Acme".
It was a really bizarre physical sensation I have not been able to adequately explain. (or recreate).
--Keith
They missed out a pretty good one. Near the start of some Bond movie (possibly Goldeneye?) there is a plane travelling straight down a cliff with it's engines on full power. James Bond jumps after the plane, falls faster than the (more aerodynamic, even ignoring engine force...) aircraft, catches up with it, gets into the cockpit and gains control just in time...
# cat
Damn, my RAM is full of llamas.
The radium in those clocks only glowed because the radiation excited a zinc based compound mixed with the paint. However, #3 is incorrect due to the phenomenon known as Cherenkov radiation, which is caused by electrons (beta particles) emited from radioactive (or really, any other source) travelling faster than the local speed of light. This is why spent fuel rods stored under water glow blue - cherenkov radiation given off by electrons that are moving faster than the speed of light in the water. However, cherenkov radiation in air is much less common.
I can handle sound in space, sound from distant events being simultaneous with their appearance, and even gunshots that blow their victims backwards.
But what's really started bugging me lately, are explosions. Real high-explosion explosions look dramatically different from movie explosions, where they're generally simulated with drums of gasoline and detcord. This generates a big lovely plume of burning gas and black smoke, which is usually filmed at high speeds and then replayed in slow motion.
But when real high explosives go off, you don't get that kind of sustained burn, since detonation velocities are much faster. You get a shockwave, and sometimes no noticable flamefront at all. But the important thing is the shockwave. I'm pretty sure we've reached the point at which a realistic-looking explosion can be made with CGI, but they still keep using drums full of gasoline, even though it looks shitty. Probably the worst example I can think of is Pearl Harbor. Granted, there were so many things wrong with that movie that harping on the explosions on Battleship Row is probably a bit silly, but it illustrates my point.
If Hollywood were only to depict reality, no one would go see movies. Reality is too boring. People want to see intergalactic space flight, time travel, dragons and people with super-human strength. If I want reality, I'll switch off the computer and go outside.
Any sufficiently advanced bug is indistinguishable from a feature.
I lived in Fremont, CA when "Terminator II" was being filmed. For the Cyberdyne office building to be blown up, the crew put something like a hundred gallons of gasoline on the roof and ignited it. The result is a big fireball, which for viewers equates to "big explosion," but it's not, really. Most explosives don't produce flames. A hand grenade, for instance, makes a little whiff of black powder, no flames, but I guess movie directors and most audience members expect to see flames shooting out all over the place.
Oh, yeah, it's not easy to pad these out to 120 characters.
basically because the western has been out of favor for a long time.
I refer, of course, to the infamous 250-shot revolver.
basically, back in the black and white days, nobody EVER reloaded their guns.
you never saw any recoil, either, but that's because those movies were made when men were MEN and sheep ran scared, and those actors were truly made of steel, riding horses at a full gallop and able to hit a bad guy in the back of the head from 300 yards with a pistol with a four-inch barrel. and their arms never moved when the revolvers and rifles fired.
and the scenery along the trail repeated itself every 60 yards or so, but then we're not going for the top 2,000,327 movie lies here, are we?
if this is supposed to be a new economy, how come they still want my old fashioned money?
Sunshine has all manner of things wrong with it, but it's still probably headed to this years scifi blockbuster.
I resent any film that says "Re-ignite the Sun".
I am becoming more convinced that people watch series like 24 or The Unit and are mistakenly under the impression that they are accurate representations of US capability. Vast computing power at everyones fingertips, satellites retasked at a moments notice for real time video, instant communication anywhere in the world, highly sophisticated gadgets that never fail in the field and of course clairvoyant and all knowing agents. No surprise the US has been so gung-ho lately.
Do not try to read the dupe, thats impossible. Instead, only try to realize the truth
What truth?
There is no dupe
People Don't Explode in a Vacuum
Some SciFi is getting better at this, e.g. the new Battlestar Galactica, but it's still a staple of Hollywood effects.
Normal Guns Don't produce Huge Muzzleflash
Muzzle flash is bad for all kinds of reasons, e.g. It gives your position away. Yet, whenever someone fires a gun on TV there is a huge flame-thrower effect coming out the front. Real weapons tend not to do that, but they probably just look pathetic on film.
Didn't I see this voted down all the way to black in the Firehose? Yesterday? What the hell do they do with that thing, anyway?
Movies' Physics is way ahead of the other Physics.
...is when a hero leaps out of a plane in an effort to catch something that's been thrown out of the plane several seconds earlier. And he catches up with it.
--I'm so big, my sig has its own sig.
-- See?
When you sweat, the fluids come from inside your body. Since they're already heated, they will carry away some of the heat when they vaporize. So you'd probably die of other causes long before you overheated.
In the Space Shuttle, however, the bay doors are opened for heat rejection when in flight. Unlike the "cold" problem we see in Star Trek whenever they lose power (e.g. TNG: Booby Trap), they're far more likely to overheat due to the heat rejection systems being inoperable. (Presumably, a ship like the Enterprise would have a circulatory system that would pump heat from the inside of the ship to the outer skin, where it would be rejected as black body radiation.)
Javascript + Nintendo DSi = DSiCade
One of the liberties Hollywood takes with physics that amuses me is how lasers and other energy weapons tend not to propagate at c, but rather at the speed of conventional projectile weapons or often slower. You can see the beam flying across the screen, and sometimes the hero even has time to dodge them. Since all guns in movies can be fired as many times as is convenient before reloading, it would seem the only advantage energy weapons offer is that their projectiles give off a pretty glow.
Could someone point out a movie to me where an Astronaut is exposed in space and yelling at someone else? I know of none. They're always in a suit, theres air in the suit, and assuming they have some kind of microphone/walkie-talkie setup, their partners will hear them speak.
Seriously... how dumb of a point is that? What they should've pointed out was explosions etc in space, even then though I think you could argue if the camera is set up in a ship, another ship explodes, you might hear a rumble as the shockwave hits the ship with the camera in it.
But astronauts talking? Never, ever have I seen a movie with two astronauts unprotected and talking in space.
Between this selection and the Nature article from 2000... time to close /. until tomorrow.
DB connection timing out, boy that didn't take long. Anyone got a mirror or text capture to repost?
$ man woman *
-bash:
They seemed to think that the moon has zero gravity. Inside the dome, you floated. Once you went outside, you could walk.
It just made me stare at the screen and go "Wha?"
Nice writeup here.
An imperfect plan executed violently is far superior to a perfect plan. -- George Patton
1 Law of Computers That Doesn't Apply in Hollywood: Computer passwords cannot always be guessed in 3 tries.
"It's the height of ridiculousness to say for those 9 lines you get hundreds of millions."
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they can stop a plane feet from the ground.
Do we really expect an industry that is out of touch with copyright and the Internet to follow the laws of physics? In all fairness a little embellishment in movies makes it more fun. That's why we watch movies, real life can be boring.
- None can love freedom heartily, but good men; the rest love not freedom, but license. -- John Milton
If you can't kill him with five shots, then you shouldn't be doing the job in the first place.
Don't forget that you want to use a lower grain count in your rounds, to reduce muzzle velocity. The last thing you need is the "pop" of a supersonic bullet giving you away. To compensate for the reduced muzzle velocity, use a bigger caliber to get the same stopping power.
So: large caliber, reduced power round, flash/sound suppressor on the barrel.
The man who does not read good books has no advantage over the man who cannot read them. - Mark Twain
... is why you can always see the complete action of each shot from a handgun. When one shoots a semi-automatic handgun the whole bullet/slide action/reload thingy happens REALLY fast. So fast that it would almost always happen between the individual frames. How do they catch that on film? My brother went to film school and he never learned how that's done.
Dirt doesn't need luck.
The article says that the frequency of middle C is 256 Hz. Sorry, no, it's approximately 261.6Hz. Analysis: the article is quite flat.
There probably are movies that committed these physics faux pas for narrative, but while reading the article, I immediately think of two or three recent movies that did "do it right" for most of the things on the list, and the list falls flat.
I've seen lists like this before that were a lot more amusing in presentation..
Actually, fluid in space freezes because much of it quickly evaporates when it hits a vacuum, which chills the remaining droplets below the freezing point. This is similar to the way they make dry ice by letting compressed CO2 flow out of a nozzle.
On a related firearms note, they always f*** with the depiction of double action revolvers. When the actor checks to see if it's loaded, they release the catch and swing the cylinder out. They always spin it, and they always dub in the clicking sound of spinning the cylinder of a single action revolver (think cowboy Colt Peacemaker, where the cylinder doesn't swing out). In real life, they don't make any sound when you do that.
Some mornings it's hardly worth chewing through the restraints to get out of bed.
I wonder if these people also complain when the camera has an overhead shot, since in real life people always see things at eye level.
It's a matter of perspective. In a movie, the perspective is mutable. Don't think two asteroids colliding makes a sound? Try living inside an asteroid.
"Sound doesn't travel through a vacuum!" and "Sound doesn't occur when things happen to objects which are in a vacuum!" are two different and unrelated concepts.
-- 'The' Lord and Master Bitman On High, Master Of All
"In fact, the emergent noise can still be heard from a fairly large distance."
Depends on the gun, suppressor and ammunition. With a locked bolt and subsonic ammunition, it can produce as little noise as a faint click.
Certainly there are plenty of things wrong with the portrayal of 'silencers' in movies, but those comments aren't exactly correct either.
It's just when they cheat with special effects that people seem to forget how the world really works
Some people, for me it kind of ruins the movie, especially when its real obvious. Its ok for Sci Fi like the Matrix at least its explained. Has anyone seen Transporter 2? Its almost a comedy.
Libertarian Leaning Political Discussion Forum.
Do you know the Klingon proverb that tells us revenge is a dish that is best served cold? It is very cold in space!
but my favorite from personal observation is:
objects have inertia orders of magnitude larger than their mass would indicate
that is, when a cartoon character starts running madly, his feet need to build up enough momentum before his body actually starts moving. hanna barbera cartoons like the flintstones, scooby doo, etc. were especially good at this gaffe/ enhancement
intellectual property law is philosophically incoherent. it is your moral duty to ignore it or sabotage it
Now you're going to tell me the science behind Armagedon wasn't accurate ... There goes my hope for saving the human race from the /. story just after this one ... ;)
Bark less. Wag more.
-Eric
SJW: Someone who has run out of real oppression, and has to fake it.
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In what movie did this ever happen? People talking to each other without communications equipment in the vaccuum of space?
Modern copyright is theft of culture from everyone and it retards the progress of the useful arts and sciences.
No one in Hollywood has Caller ID
-- www.globaltics.net
Political discussion for a new world
Then what did I put in my time-traveling delorean this morning? Uh-oh!
I suppose next they'll tell us that time-traveling deloreans don't really come back iced-over, they come back hot.
stuff |
Why no mention of that classic of science fiction, the ability to somehow break or bypass the laws of physics and travel to other planets, without taking decades or centuries to do it? Whether it be through warping space, creating wormholes, entering some sort of hyperspace, 'jumping' between two distant points, or perhaps just running really really fast, many sci-fi films stretch the known laws of physics for this sort of travel. Admittedly, many of these sci-fi films wouldn't be nearly as interesting if the took place in only one star system, so as a plot device such conceits are necessary. But it's still against the laws of physics.
And then there's time travel; if true time travel were possible, chaos theory would say that even the slightest changes in the past would have immense changes in the present, such that paradoxes (ala Back to the Future) would be inevitable. That is, unless it's impossible to change the past; but then again, that would mean one could go to the past and predict exactly what would happen. And if *that* were possible, I could say whether or not Schroedinger's cat was alive or dead or some other obvious breach of quantum mechanics, so that form of time travel is out too. The book/novel Timeline gets it at least somewhat right by having them travel not back in time, but to alternate universes that are time-shifted from our own; at least that doesn't create paradoxes or violate quantum mechanics. Again, such conceits can make for a great movie, but they still break every known law of physics.
I think when we see the tanker truck blow up, the Power Rangers jump-kicking someone in the chest, or Neo fly through the air like Superman, we understand it's fiction. It's called "suspension of disbelief." It's what makes movies enjoyable. No one is really going to think that these things happen as regularly (or at all) in real life as they do in the movies.
But the power rangers were established as having super powers, and superhero stuff generally gets a pass and sits more in the fantasy realm anyway. Neo did most of his tricks inside a virtual reality where the laws of phsycis are defined by the programmer and redefined by the hacker.
Lots of artistic things are done to improve the quality of the movie that don't necessarily translate to real life.
Agreed here. Too many film geeks complain about "innaccuracies" when what really happened was artistic license. The orientation of moon phases is a common one. Even "2001" gets dinged for that.
So, like you and the two responses above me, I was really skeptical of this "freezing in space" idea. I even told a student that a reference they had cited was wrong in claiming that you would freeze to death in the Sun's corona, the argument being that you wouldn't freeze for the same reason you wouldn't burn: no particles to transport heat.
But I recently found out, from a colleague over beer, that loss of heat from blackbody radiation is actually much faster than I thought. In the old days, in non-cold places, some people (ancient Egyptions among others) would actually make ice, basically by letting water in a deep, dark place radiate it's heat away. Sure it took hours, and it had to be already pretty cold outside, but considering that the water was also being continually warmed by all the air around it, that's pretty impressive for "only" blackbody radiation.
It's pretty easy to calculate heat loss. According to this, in our 293K atmosphere we lose 95W. In a 2.7K vaccuum this translates to 640W, due to us not getting any energy back from the atmosphere. With an average human body heat capacity of 3470 Joules per Kelvin per Kilo, a 70Kg person will drop to the freezing point from 305K in less than 3 and a half hours.
Ok, so that's pretty slow. Damn those movies suck.
Actually, I disagree. I find real life to be MUCH more interesting than fiction. I've seen, heard, and experienced things in real life that I could *never* have imagined, and have never seen in a movie. Watch some good documentaries. I guarantee that you'll see stuff that you've never seen in Hollywood movies. Sure, in movies, you have space ships and supermen, but they're silly ideas used to dress up stories and characters that would completely bore you to tears, otherwise. Heck, watch "American Movie" or "Brothers Keeper" or "Jesus Camp", and tell me that real life isn't more interesting than fiction.
I don't respond to AC's.
If you've ever used a gun of any kind, you'd at least know that the sound of "racking" is quite loud, and even if you could remove the muzzle-sound, you'd still hear the mechanism.. unless this is what you mean with a locked bolt, which i assume it is, but in that case, you'd have to reload after each shot..
i find your lack of faith in science disturbing!
The story is slash doted so I did not RTFA.
:)
Come on, It is a movie. Movie physics can be explained with a simple question.
Is it in the script?
If the answer is Yes, then "Make it so number one!"
Now this must be real because I found it on the internet. http://www.theatrecrafts.com/humour_darksuckers.ht ml
Suppressors for .22 rimfires have the best 'Hollywood sound', especially with a fixed bolt gun. They are quiet enough that my dog doesn't recognize the sound as a gun shot and go looking downrange for something to retrieve.
.22 rimfire, as they are nothing at all like Hollywood. More like a muffled shot, but you still recognize it as a shot.
Most people are suprised by the high sound level of a suppressor with anything larger than a
With the US military using a lot of 5.56x45 rounds there has been a lot of effort into designing better suppressors for military applications. One of the companies I take pictures for, Surefire, started selling them over the last couple of years. I have been to some of their promo events and have seen their products withstand several hundred rounds of continous 5.56x45 firing without much change in sound levels, yet are small enough to mount on an M4 rifle intended for close quarters use. All of their products are 'dry', meaning they use baffles, rather than 'wet', indicating wipes.
To add even more convolutions to the topic, in a lot of the gangster movies you will see a guy pull out a silenced pistol and assassinate someone on the sly. Presumably a suppressed 22 rimfire would be quiet enough, if it weren't for first round pop, which plagues all dry suppressors.
"Sacrifice for the good of The State" - The State
People want to see intergalactic space flight, time travel, dragons and people with super-human strength.
You've just described "speculative fiction." Speculative fiction is at its best when it is completely plausible, and adheres to the laws of Physics, as it's only then the speculation seems both fantastic and makes the viewer say, "maybe that could happen."
At the very least, stories are things where we watch identifiable characters get into, and out of, bad situations creatively. Is a story interesting when the character whips out "shark repellent spray" or a "magical remote control that makes the badguys go away?" Then why is it interesting when the character escapes by driving across a ditch or shouting instructions across the vacuum?
from the relativity-also-out dept.
On the contrary, my pastor has done several sermons about the cultural relativity of liberal Hollywood.
Step into a huge movement. Don't Tread In Me.
god damn people - Learn to use Mirrordot / CoralCache / Google Cache / WHATEVER
MIRROR
Actually, sweat works because the evaporation process is endothermic. When water turns from liquid to gas it consumes heat. That's why you can cool down to 98.6F even when its 105F outside. That's also why a room with a "cool mist" humidifier consisting of a fan and a sponge-like filter will cool down several degrees.
Moderating "-1, Disagree" is simple censorship. Have the guts to post your opinion.
Eventually, but the ice would have to sublimate, which is a much slower process than liquid evaporation.
The latent heat energy of evaporation, which is what would drive the process, is much greater than the heat energy of temperature differences in the liquid. The initial temperature wouldn't matter that much.
The discussion wouldn't be complete without a reference to the Cartoon Laws of Physics.
My favorite is image zooming, in many TV shows and movies. CSI has extended this to the outer limits..
You cannot zoom - you just cannot extend the information beyond its limits. Not even with your favorite filters.
"unless this is what you mean with a locked bolt, which i assume it is,"
Um, yes.
"but in that case, you'd have to reload after each shot.."
Well, you have to manually cycle the action to load the next round. But if you're using that kind of gun you're probably expecting to kill your target with one shot anyway.
But with subsonic ammunition, even the silenced MP5 firing full auto isn't horribly loud. You'd hear it from a reasonable distance away, but probably wouldn't even realise it was a gun until you saw bullet-holes appearing in people. With supersonic ammunition the sonic boom from the bullets would certainly make it obvious, but the low noise from the gun would still make it difficult to spot.
According to the commentary on the Battlestar Galactica Miniseries DVD, they originally tried to have no sound in space sequences, but it didn't work. For one thing, the producers said that the transition between sound inside the ships and no sound outside was too jarring.
What annoys me is how the rocket engines are continuously firing as if they operated like jets. In space, the combination of weightlessness and being in a vacuum means that the engines do not need to be continuously firing to maintain momentum in any particular direction - only if they need to change direction should they be fired. It makes no sense for a spacecraft "fighter" to look like a traditional jet-like design.
~Religion is O.K., as long as it gets you laid.
Wrong. As you sit in front of your computer, you exchange heat with your environment in three ways simultaneously: (1) conduction, (2) convection, (3) radiation.
The part you are referring to is heat transfer mechanism (1), conduction, as your body heats cooler air molecules around you. Mechanism (2), as occurs when those heated air molecules rise toward the top of the room making room for cooler ones, also requires air.
However, mechanism (3), the most effective of the three, does not require any medium at all. You, like all baryonic matter, emit electromagnetic radiation with frequencies and intensities as described by blackbody radiation, dependent on temperature. An object twice as hot gives of 16 times as much heat in radiation per unit time.
Normally, when sitting in front of your computer, you are radiating like mad, and so losing heat. However, so are the walls of your apartment. Those walls, being nearly the same temperature as you are, heat you to a large degree, making up for the heat that you are losing to radiation. Hence if, on a cold night, you are walking down a hallway in which one wall has a fireplace behind it, you immediately notice how warm the wall is without coming anywhere near it.
Considering that the "walls" in space are the 2.73K cosmic microwave background radiation, and that a person's temperature is more like 300K, you would radiate 10^8 times more energy than your receive. You'd freeze in a hurry.
Now, if there's a star heating you from one side, this can partially make up the difference. You still get the one-side-super-hot and one-side-super-cold problem, then, like the surface of Earth's moon writ small.
Set your phasers on "funky"!
Do they have car tyres squealing everywhere, even on sand at 5mph?
Get your own free personal location tracker
There are 3 thing on a semi-automatic* firearm that make noise:
.22 caliber pistol. The addition of a sound suppressor baffle to the barrel absorbed 90% of the noise. William Joseph Donovan, Director of the OSS, demonstrated the pistol for President Roosevelt while visiting the White House. Donovan fired ten shots into a sandbag without interrupting the President as he dictated a letter."
.45 ACP load is subsonic--230gr @ 870fps, if memory serves. 9mm comes in supersonic and subsonic varieties--subsonic loads are usually 147gr @ 950fps. (Speed of sound = about 1100 fps.)
.22s can be made pretty close to silent. Larger rounds, not so much.
1) the sound of the gunpowder burning
2) the crack of the bullet as it breaks the sound barrier
3) the sound of the weapon's action cycling (i.e., the part that ejects the empty shell casing and loads a fresh round into the chamber)
Silencers (yes, properly called 'supressors') only deal with #1. True, most don't totally silence the weapon, but silencers are still useful if they make it quieter overall, and the muffled sound is also harder to localize--i.e., hard to tell where the sound came from. They were originally developed by the same guy who invented mufflers for cars just to make the hobby quieter. Fun note from the Wikipedia page you mention: "The suppressor was first introduced into the United States Army Air Forces before World War II. Office of Strategic Services agents during World War II favored the newly-designed High Standard HDM
#2 can be addressed by using subsonic ammunition. It's easy to use a lighter charge and/or heavier bullet to reduce the final speed. The traditional
Specially-built pistols address #3. Pistols exist with an 'action lock' which prevents the weapon from cycling normally. This increases the interval between shots (the pistol must be unlocked, cycled, and re-locked) but the result is a very quiet weapon, when combined with a suitable load and good silencer.
I've only fired one--a silenced Beretta 92FS with supersonic ammunition at an indoor range--and while it wasn't totally silent, it was noticeably quieter than a normal Beretta. I just heard a 'crack-thwack' which was a combination of all the noises plus the bullet hitting the backstop 50 feet away. I'd love to fire one, with proper ammo, outdoors, into a soft backstop. YouTube has lots of videos of silenced weapons. Of course, a typical camera can't capture a regular weapon's noise accurately in the first place, but you can watch a few and get an idea of what real silencers do. One thing is for sure--most don't make the 'kshew' noise heard in movies.
Long story short:
* revolvers can't be silenced due to the gap between the cylinder and barrel. #3 doesn't apply to single-shot, bolt-action, or pump-action weapons.
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No, I really didn't want to start the flame war about artificial gravity generators (not the centrifuge kind of spaceship). I was thinking more of scifi movies and the occasinal STTNG where someone can move thru solid matter because of some sort of quantum or temporal phase shift. So, if he can walk thru walls, how come the deck holds him up?
https://app.box.com/WitthoftResume Code: https://github.com/cellocgw
All ideas^H^H^H^H^Hprocesses in this post are Patent Pending. (as well as the process of patenting all postings)
I've done that once or twice. I think I've left claw marks on waves as I've gone over.
Best Slashdot Co
Lets put objects falling through the air on a scale based on their drag.
Bowling Ball-=============-Feather
Less Drag-==========-More Drag
Of course, in a vacuum everything would accelerate at the same speed and your complaint would be valid, but as long as the object falling is more to the right of the human being on the drag scale, given enough distance, the person would catch up to it.
The person catches up to the object
BB-====Human Being=====Object from plane====-Feather
The person does not catch up to the object
BB-======Object from plane====Human being====-Feather
Is that more clear?
Out of modpoints but really liked a post? 1BDkF6TtmmeZ3yqXbz9yhdYVqRYnwFoXDj
I guess I assumed that most people knew this already. Nobody can shoot someone in a restaurant without anyone turning their heads, I don't care what kind of silencer you have.
On a more interesting note, one of the better silencers you can use is a 2 liter pop bottle.
You seem to forget that:
a) The body continues to generate heat that more than makes up for the black body radiation loses.
b) Losses are significantly reduced by any insulating clothing worn. Even your standard shirt and pants provides fairly decent insulation. In the work suits worn on the Battlestar Galactica episode, the characters would have been more than protected.
To actually lose more heat than you generate, you need to look to an active cooling solution rather than a passive one. Conduction (and by extension, convection) are the ones that cause the body to lose heat faster than it can produce it. Since there's no conduction in space, you're not going to lose heat faster than you can generate it.
That's why I mentioned black body radiation in passing. It just doesn't matter to this discussion.
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That's technically accurate.
Some of the fluid evaporates quickly because of the vacuum, the rest is cooled by evaporative cooling to the freezing point. They've had problems in the past on Shuttle with ice buildup on waste dump ports.
The phenomenon has been known and routinely observed by astronauts since the 1960s.
-- Alastair
What bothers me the most is the convention (frequently seen in the Star Trek Universe) that species evolving separately on different planets can interbreed! Or even be attracted to each other! I mean, come on... I may be desperate, but I really draw the line at dating outside my species!
Unless something is really wrong with the powder charge you're using in the gun, there shouldn't really be any "sparks" coming out of the end of the barrel, at least with modern smokeless powder.
The muzzle flash that comes out of a gun is superheated gas, the product of the powder's rapid combustion; a "spark" would indicate some form of burning / incandescently-hot large particles, and there really shouldn't be anything that big left after combustion. If there are big (enough to be visible) chunks of burning powder coming out the muzzle of your (modern) gun, you have some sort of problem. I'm not sure whether you'd even technically call a real muzzle flash a "flame," since it's not really burning anymore; the majority of the chemical reaction that launched the bullet, ran to completion in the first few fractions of a second after the primer detonated. On weapons with short barrels, the muzzle flash is visible because the exhaust gases exit the muzzle out into the atmosphere before they've had a chance to cool below the point of incandescence. I don't think there's really anything in the way of actual 'combustion' still going on.
Muzzle flash is another thing that Hollywood tends to exaggerate; although it's definitely an issue in real life, it's more difficult to see on a bright, sunny day than you'd expect from watching action flicks. FWIW, I think that they simulate muzzle flashes by using propane or methane, particularly for automatic weapons, in movies.
"Ladies and gentlemen, my killbot features Lotus Notes and a machine gun. It is the finest available."
This entire post is based on an incorrect assumption.
Radiation is the least effective of the three methods of heat transfer in normal situations. When you're sitting in a cold room you're losing almost all of your heat to convection/conduction, and basically nothing to radiation.
Try two experiments. Go outside on a very hot night and see if you become cold. You don't, even though half of your surroundings are open to space and therefore to radiative heat loss. Now go outside on a very cold day and see if you become cold. You do, even though you're being directly heated by the Flame Orb and the entire sky is filled with scattered radiation from same.
If you were in space with some way to keep breathing but no heat-rejection system, you would begin to overheat. However, I don't understand the grandparent's complaint about Battlestar Galactica because, if it's the episode I'm thinking of, the characters were only exposed to a vacuum for a few seconds.
I know most threads have been about how the postulated laws are broken, but there's a bigger question to be asked in this - do people, who go to the movies, want the laws of physics to be obeyed? I think the film industry has actually done it right - we go to the movies to, quite literally, be fooled. There's a reason sci-fi films end up being blockbusters. People are so fed up with the mundane, they want to see something extraordinary, even if it is something infinitesimally trivial as a simple bullet spark. It draws a person into the film with the appeal of the extraordinary, and gives them what they paid for - an escape from reality, even if they don't realize it.
No air for cooling == no loss of heat.
Two words: evaporative cooling.
That's how the Space Activity Suit keeps you from overheating while working against its resistance.
-- Alastair
Quite obviously aliens were involved. You were probably nearly abducted. Scary but the most likely explanation.
http://www.youtube.com/watch?v=3Gg1Avygqso
Very much like this poor cow I should think.
PS: For the humorless - I'm joking. It's just that someone's been boring me tears about aliens at work all day. Oh I want to believe but I can't.
spoonerize "magic trackpad"
... that the Law of Slashdotting remains in effect.
Which was considered "severe exposure". A few seconds exposure to vacuum is very far removed from "extreme exposure". Much less enough to cause them to freeze as they go flying out the side of the ship. In reality, the rescuers would have had a good chance of retrieving living (possibly quite healthy) people, even if they were exposed for as long as a minute.
Javascript + Nintendo DSi = DSiCade
Bullets in the vicinity of Jack Bauer silence themselves for fear of attracting his attention.
Avoid Missing Ball for High Score
You can't go from body temperature to freezing within a minute just by sweating. Your body will close the pores on your skin and prevent the loss of sweat until your body is restored to operating temperature. You could lose some moisture through your mouth, but without any air to breath, you're not going to lose too much.
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It should probably be pointed out for those who have not handled firearms before that a .22 is not a certain kill, even at close range. They certainly can kill, but the movie weapons are often shot from across the room where -- were I a professional killer -- I would not trust to be a kill shot, let alone a clean "drop him" shot. Birds, squirrels and paper targets are a better bet.
"$30 for the One True Ring. $10 each additional ring!" -- JRR "Bob" Tolkien
Silent shotgun shells are much more effective and economical than noise suppressors. Not so good for sneaking up on people in crowds I suppose, but they are very effective (quieter than the mechanical noise of the action) and add no limitations to manually operated shotguns.
I would add that the author of TFA doesn't understand the physics of hand to hand combat very well. It is true that targets will not fly accross the room when kicked. In fact the better targetted the kick the less they will recoil. However, when kicking you are accelerating much of your body (hip, leg, foot) toward the target. The reaction has to overcome this momentum. Furthermore, if you use orthodox technique you have a connection to the ground specifcally designed to transfer the reaction through my musculo-skeletal structure into the earth (the emphasis on this base varies from style to style, but it always exists). In movies people are always jump kicking, but in real life that is of limited utility. You don't want to lose that connection to the ground unless absolutely necessary.
It is cowardly, and a betrayal of whatever it means to be a Jew, to act as a white man
-James Baldwin
... is when a director puts Mel Gibson or Tom Cruise in a movie and attempts to make them seem normal.
art is science made clear. -cocteau
#1. Rarely do actors pause in mid conversation, after a meal, or during their entire (movie) life-time to go to the washroom.
#2. Entire weeks, months or years can pass without the main character being seen eating any food.
#3. A 1/2 litre sheep-skin sac of water is all you'll need to cross any desert.
#4. After you faint in the desert sun from dehydration & tiredness, you will wake up many hours later somewhat refreshed and able to carry on. Either that or you'll be found against all odds... EVERY time!
#5. Enemy bullets always hurt less than your bullets hurt the enemies.
#6. Nobody ever catches diseases in movies where blood spils over the main characters every other minute (horror/war/action movies).
#7. Heros never grow old
#8. Often the ugly guy, still gets all the hot chicks (by force, or by sympathy).
#9. Any ignoramus can survive by eating random leaves and miraculously bacteria free water in any jungle... and find his way out of course.
#10. The wound of a hero, no matter how long it bleeds, never results in death. This is because no hero's would ever gets infected.
Adeptus
No trees were killed in the making of this post; however, many trillions of electrons were horribly inconvenienced.
Yeah baby, yeah!
I think the ammo you're talking about is not jacketed in steel, but cased in steel. And yes, some people believe it to be significant rougher on guns than conventional copper-cased stuff, but not because of the bullet going down the barrel proper, but due to the damage that the steel case may be doing to the chamber during loading and extraction.
.223 Remington chamber, as opposed to the 5.56mm "NATO Chamber" or the compromise "Wylde Chamber").
You used to find this stuff under the "Wolf" brand name, and it was mostly made in Russia and some other ex-WP countries. I think Wolf may be trying to move upmarket and has ditched the steel-cased stuff, recently though.
At any rate, the bullets in that stuff were pretty standard at least that I ever saw, but instead of using a brass case, as is used in most Western countries' ammunition, they went with steel cases, covered in some sort of paint and lacquer (assumedly for rust-proofing). There were a number of issues with it, particularly in close-tolerance weapons. First was just the threat of damage to the chamber because it's a harder metal (although I have doubts about this), more significantly was that if you blasted a bunch of it off rapidly, you could get the gun's chamber hot enough to start melting the lacquer off of the cartridges, and over time, build up a layer of lacquer inside the chamber, that would change its dimensions, and lead to feed problems, particularly if you switched back to other types of ammo.
I know a number of people who got burned by the lacquer-buildup problems, because they had AR-15 style rifles with tight-tolerance chambers (the
"Ladies and gentlemen, my killbot features Lotus Notes and a machine gun. It is the finest available."
It's called propaganda. And we all soak it up whether we want to or not. It takes conscious effort to defuse the meanings absorbed especially as we watch TV in a realaxed and passive mode sometimes similar to a state of hypnosis. The average /.'er probably finds it easier than most due to scientific training to put these ideas away, the rest of the population less so.
spoonerize "magic trackpad"
This is my favorite. Explosions tend to be hypersonic, so the heros would have to be going faster than about 700mph to out run an explosion.
I do however take issue with the Matrix reference. In the matrix, you can 'bend' the laws of physics, so to me this is kosher.
putting the 'B' in LGBTQ+
Film would have you believe that radioactivity is contagious and makes you glow in the dark. Where did this idea come from? The Simpsons?
Even the Superman shows in the 50s had this affect.
These ideas are old indeed.
Have you read my journal today?
Should read:
I think the ammo you're talking about is not jacketed in steel, but cased in steel. And yes, some people believe it to be significantly rougher on guns than conventional brass-cased stuff, but not because of the bullet going down the barrel proper, but due to the damage that the steel case may be doing to the chamber during loading and extraction.
My bad; I edited and didn't proofread. Modern fixed ammunition usually has bullets made of lead, jacketed in copper, with cases made of brass. Duh.
"Ladies and gentlemen, my killbot features Lotus Notes and a machine gun. It is the finest available."
That's bothered me for a long time, too.
PHEM - party like it's 1997-2003!
In the old days, in non-cold places, some people (ancient Egyptions among others) would actually make ice, basically by letting water in a deep, dark place radiate it's heat away.
I call shenanigans. You can't make ice that way unless the temperature of the surrounding air is below freezing anyway.
Yes, deeper in the ground it's cooler, but it's not enough to get freezing temperatures in Egypt.
our bodies are set up to equalize atmospheric pressure. so without that pressure on us we start to bloat up pretty fast from the swelling. our fluids try to go from the now high internal pressure to lower pressure outside.
Its common practice to "cheat" on these laws in order to maintain the audience's attention and keep them hooked on the storyline. Ironically though, depending on how savvy the audience is, some things do exactly the opposite. For example, as an effect, thunder and lightning coincide in in order to maximize its effectiveness. In contrast, some "real world" rules, when broken, completely break this suspension of disbelief because its so commonly done on screen -- ie. how all telephone numbers have 555 in them; or how everyone still uses those old fashion mini cassette answering machines; or how rain always appears to fall straight down and in torrents. The problem here lies in how hollywood has become so damn lazy and pathetically uncreative. But the sad thing is that they need not be imaginative -- the audience is much too naive to even care. "....that's entertainment" indeed.
I dont watch a TV show or a movie to get a dose of reality. I can leave the TV off and get that right in my living room, or at work.
I watch movies & such to be entertained. A break from reality is the whole point. It drives me nuts when people cut apart a movie (usually while watching it) because something "wouldnt happen that away."
Large objects can remain suspended in air indefinitely. Just takes a little nip, tuck and some silicone.
Most insulative materials (such as clothing, blankets, mineral wool, etc) work by trapping air. If there's a vacuum, there's no air to trap, so I doubt normal clothing would insulate much.
On the other hand, if there's a vacuum, you don't need that kind of insulation, because you're not loosing heat through conduction anyway. A "space blanket" might help retain radiative heat, though, so please bring your tinfoil hat if you're ever worried about freezing to death in vacuum.
I worked at Lam Research in Fremont. The building used was one of our assembly buildings for plasma etchers. We had a few pics of Ahnold up at the time.
God, you bring back bad memories. How dare you, sir!
Politics is the art of looking for trouble, finding it everywhere, diagnosing it incorrectly and applying the wrong fix.
I spent many years as an army reservist. Every so often we would head out into a training area to live fire our personal and unit weapons (both at night and during the day).
It is true I have never seen a spark during the day.
At night, I have seen rounds from machine guns (7.62mm and .50 cal) spark on rock, not metal. Especially with the .50's (larger round) you get sparks every time you hit rock at night.
Most of the story is ridiculous. It's not like anyone thought it was true and is shocked to find out it isn't. Perhaps a better title would be nine fantasies accepted in US-based movies.
Or, the Nine Things that don't apply to Slashdot comments.
1. Those Explosive Comments
2. Moderations that Move at the Speed of Light
3. Everyone is Illuminated: The Myth of Big-Brother
4. Upgrades and Kung-Fu Make Computers Fly and Zoom
5. Hacker-Legends will never Fall
6. The omniscience of Science
7. Shell Shock! Finding out that money actually does make the world go round.
8. The Silver Bullet
9. Comments Travel outside of Slashdot
Have you read my journal today?
a 70Kg person will drop to the freezing point from 305K in less than 3 and a half hours.
No they wouldn't. If we're talking about someone in a vacuum, they will soon freeze to death and stop heating themselves. (Well, first they'll probably go into shock/dive reflex and stop heating anything but their brain, and then they'll die and stop heating anything. OTOH, who knows if that works in space?)
That's assuming they have some sort of air, of course. Like a scuba tank or something.
And your '305K' is goofy. At that temperature, someone would already be dead. You can't walk around with a body temperature that low.
Starting with 310K, how long would it take for them to drop to, oh, 305K to die, and then how long would it take a dead person to drop to 2.7K?
Oh, I see where you got 305K, as the skin temperature. That is useful for knowing the amount of radiation a normal living person exchanges with the environment on earth, but not that applicable to space, where a dead body's temperature would quickly average itself out over the entire thing.
If corporations are people, aren't stockholders guilty of slavery?
While cooler, "real explosions" with interesting shockwaves are extremely dangerous.
Gasoline and detcord are safer, known quantites that stuntmen and techs know how to work around. Film at the right speed, add some black powder charges to send debris flying, it'll look like what movie-goers expect without being deadly to those involved in the already expensive process of production.
THIS THING CAN TURN ON A DIME, MACROSSZERO STYLE ALSO FUCK BETA, ~NYORON
My problem is the faux historical works that attempt to legitimize themselves by intermingling actual people and events. Writers will always have to do things like fabricate dialog, but it irks me when they start playing with real events. Martin Scorsese is horrible about this (I'm not talking about a director's interpretation of history). He screwed up events in the Aviator and just BSed the biographies of real figures in "Gangs of New York." All for the legitimacy of the "based on a true story" label.
I swear to God...I swear to God! That is NOT how you treat your human!
In the episode I'm thinking of, they did retrieve living and quite healthy people, so we must be thinking of different ones.
In any case, any exposure to vacuum is dangerous, just not because of heat and cold. You start to rupture things right away, although if you're picked up quickly you'll probably just have superficial internal bleeding. The major problem is that you'll black out after about 15 seconds and after about 60 seconds you'll start to lose brain cells due to oxygen deprivation.
All of the freezing will happen beforehand, as the air leaks out and the temperature drops due to the decreasing pressure. It doesn't really matter whether it's the leaking air or the vacuum that causes freezing, you'll get just as cold either way.
This is true. However, it does take time for the fluids to move outward and the capillaries to start bursting. More time than the characters on the show were exposed to vacuum. (If you can even call their exposure a true vacuum. They caught them while they were being carried by the air-blast, for crying out loud!)
Javascript + Nintendo DSi = DSiCade
yeah...or the fact I'm in MOTHERF*CKIN SPACE!
Your in space, why would sweat leave your body?
It would just cling to your body.
The Kruger Dunning explains most post on
So, when you see a gal kick someone across the room, technically, the kicker (or holder of a gun) must fly across the room in the opposite direction - unless she has a back against the wall.
Not only that, but it fails to take into effect the masses of the two individuals. Just like I could push, kick, or punch a ball away from me, a person with enough mass can in fact repel a person of smaller mass over a certain distance. Perhaps not across the room and partway through a wall, but most people could already figure that part out.
Still, whether it's a person or any other object, it all comes down to friction, angle, and mass. I semi travelling at decent speed can send a small car flying, especially if it manages to "scoop" it with a certain angle. A mid-sized person braces right can propel another person away, and a larger person (well, more massive) can do so to a greater extent.
As to the shotgun blasts blowing someone across the room, I've never shot anyone or anything at close range with a shotgun, but it might work against a smaller person/animal. With a really big gun held by a really massive person (properly braced) it would possibly stagger the shooter while propelling the shootee...
You'd be amazed at how much it blocks Black Body Radiation.
Article
Piccy
Notice that the areas producing the most infrared energy are the areas of exposed skin.
Most insulating materials are composed of empty space, because empty space is the best insulator. (Vacuum is the absolute best, but an low-density oxygenated environment will work in a pinch.) However, the insulating material is intended to capture some of that heat, and transfer it back to the body through either conduction through air, or contact with the skin.
Javascript + Nintendo DSi = DSiCade
Comment removed based on user account deletion
Yes, I think that movies could get by just fine by doing this one realistically.
In "Terminator 2," remember the scene where the kid teachers Ahhhnold to check the sun visor for keys first?
The same could easily enough apply to computer hacking
Hacker: [enters password]
**INVALID PASSWORD - 2 Retries Remaining**
Hacker: [tries another]
**INVALID PASSWORD - 1 Retries Remaining**
Hacker: [checks under the keyboard, finds the sticky-note with the password, and uses that]
root@agency:~$
Alternately, they could switch the "This is Unix, I know this" (or whatever the line from Jurassic Park) for "Hmmmm, a linksys router with default ESSID... the default login for these suckers is 'admin' and 'admin'"
For those that are regular patrons of slashdot, you may remember an article that mentioned where various banks had forgotten to change some of the default admin passwords on their ATM's... stupid on the part of the banks, and stupid on the part of the ATM supplier (for not requiring a password-change for the machine to become usable). But if banks (which supposedly represent slightly higher-end information security) screw up like that, think about all the other cases of default passwords, hidden default backdoor passwords, sticky-notes and other things.
Maybe I'm misunderstanding the initial paragraph but you would certainly burn up in the Sun's Corona as the Sun is emitting heat constantly. The heat does not have to be transmitted by air otherwise we would not feel it on Earth.
Science teacher did an experiment for us in junior high, some 40 years ago. Took a petri dish full of water, put an apparatus over it and induced a vacuum. As the pressure lowered, the water bubbled violently - loss of surface pressure. As it hit vacuum, the remaining water froze. When the apparatus was removed, the ice remained, was cold to the touch and melted slowly.
Yeah, and they're called "automobiles" not "cars." The term "silencer" may not be as precise as you like but it is just as valid a term as "suppressor."
They do not really suppress the sound the way movies put it (I am looking at you Mr. Bauer).There are a lot more variables here than you are implying. I have some first hand experience with home-made silencers from my nonstandard youth. A .22 caliber is the most commonly suppressed round historically and used for assassinations. With a dry suppressor made in the basement, a .22 semi-auto will make the typical action noise and you can hear the bullet hit the target, but the sound of the bullet leaving the barrel is negligible. With a bolt action, you hear a sound like a pebble being thrown against your target and that is about it.
They are good just for a small number of shotsThis is true with some sound suppressors, but not all. There are a variety of home made one shot suppressors you can build yourself and there are commercial, "wet" suppressors that have a limited number of effective uses. There are also traditional baffle suppressors that are just as effective for 100 shots as for 2. The relative size of the suppressor is dependent upon many factors, but you can certainly build a dry suppressor about 8 inches long that would make a .22 caliber pistol with subsonic rounds pretty darn quiet.
Please read something about black bodies before you expose us to more of your ignorance :o)
You can absolutely make ice when the surrounding air is above freezing.
This link is more colloquial/easier to read than the wiki entry:
http://www.kilty.com/freeze.htm
This reminded me of a argument I once saw on a BSG forum. It was about the episode where they are rescuing the people from New Caprica. In it they jump one of the battlestars (I don't remember if it was Galactica or Pegasus) into the planet's atmosphere and it begins dropping quickly. They then jump it back out into space right before it hits the ground.
The funny thing is the argument was about whether the people inside the battlestar should have been floating weightless or not. People started bringing up all sorts of stuff the learned in high school physics about air resistance and gravitational forces. However no one made the obvious point that in most of the show they are in space and all of their ship's have gravity suggesting that they must have some gravity generating equipment, making the whole argument moot.
I'm a firm believer in the philosophy of a ruling class. Especially since I rule. -Randal, Clerks
Actually, it's not technically blackbody radiation.
Blackbody radiation implies that the radiator is a blackbody. A blackbody is an idealization that describes a surface material that absorbs all EM radiation which hits it, regardless of frequency and angle of incidence. Furthermore, radiation coming off of a blackbody follows Planck's law and is uniform in all directions. There's no such thing as a real blackbody, and the closest we've ever been able to get in a lab is a tiny hole into a large dark cavity, in which the imaginary surface of the hole acts a lot like a blackbody surface.
Radiation coming off of real objects, such as human skin, is very, very different from radiation coming off of a blackbody. The first, and most noticeable difference is that real surfaces have an emissivity coefficient, which is the fraction of blackbody radition they give off. The emissivity coefficent can itself be a function of direction, temperature, and wavelength... and usually it is.
While my point was just that 'blackbody radiation' implies radiation under a very specific set of idealizations, I did notice someone else responding to your post mentioned that the human body would lose heat very fast in space because of radiation. This is not necessarily true, because human skin probably is a very ineffective radiator. While a blackbody is a very efficient radiator, most real surfaces are not, and even with the 'cold' surfaces of space (effectively radiating to 0K) not all materials will lose heat quickly. Someone who knows an approximation for the emissivity for human skin will have to speak up here.
black body radiation losses are still quite substantial, in the abscence of insulation (unless my math is wrong). . .
Radiation loss = (SurfaceArea) x (Stefan-BoltzmannConstant) x (emissivity) x (Ts^4 - To^4)
Assume human has a surface area of 2 square-meters, an emissivity of 1, a surface temperature (Ts) of 300Kelvin, and space (To) is 0K.
That gives about a radiation loss of 920Watts, which is significantly higher than average human metabolism (~120W).
Of course, since it takes approximately -1500kJ to cool a 70kg man (mostly water) by 5 degrees Celcius (severe hypothermia), you still have plenty of time. . .
Wouldn't it be more likely to "boil off" due to the really low pressure?
Yes, I messed up on the 305K body temperature. But using a more accurate temp of 310K would only increases the time to freezing by 6%.
But why do you say they would soon freeze to death in a vaccuum? The whole point of this thread (and why space movies are dumb) is that they wouldn't freeze to death, at least not quickly. The only mechanism for heat loss is from blackbody radiation which, as I calculated, will take a several hours to drop a person to the freezing point. Dropping the person's temp to 305K would only take half an hour. But it doesn't matter if they die before reaching the freezing point. A living being won't be able to "heat themself" anymore than a dead one. They will both lose energy at the same rate, excluding all the heat loss from breathing that the living person is doing.
So, the end result is that if you are some amazing person that can survive the extremly low pressure and lack of oxygen of a vaccuum, you will die in half an hour from low body temperature, and your body will reach the freezing point in 3.5 hours. This is still a far cry from some movies where they instantly turn to ice pillars, and is also much slower than if you just step outside naked in the winter (where I'm from).
Aiming for center of mass, this is quite true; a .22LR might not do that much (immediate) damage in the torso. However, at most close ranges, a .22 has more than enough energy to poke a hole in the human skull if it doesn't hit obliquely, which is probably going to be fatal. (Particularly if it enters but doesn't exit, and dissipates all of its energy into the brain by bouncing around in there.)
.22 isn't that much of a stretch, if the target is stationary.) But with a moving target, or someone who isn't intimately familiar with the weapon, or has years of conventional shoot-for-CoM training, forget it.
.22LR isn't the lowest-energy cartridge commonly found in handguns, IIRC that dubious honor goes to the .32 Auto -- which is particularly interesting, because it was the gun of choice for Ian Fleming's original James Bond. The 32 Auto also has a bigger cross-sectional area, so its penetration is lower, so given the choice between a hot 22LR and a standard 32 Auto, you might be better with the 22. (Unless you're James Bond, in which case you can just shoot people in the eye.)
So, I suppose if you were going to try and use one, you'd best be aiming for the head; while a difficult shot, certainly not impossible if you were an assassin who'd spent a lot of time training with a particular weapon. (A head-sized target at 50' with a
OT: Interestingly, at least when loaded "hot," a
"Ladies and gentlemen, my killbot features Lotus Notes and a machine gun. It is the finest available."
Why in the blue blazes anyone would equate reality to film is beyond me. It's FILM. You know? Willing suspension of disbeleif and all that crap...
There's something wrong with either your calculations or Wikipedia's. The Wikipedia article computes about 95 watts for the average human.
Linky
95 watts is commiserate with the energy produced by the human body. If you were really dumping 920 watts through black body radiation (which will NOT be significantly impeded by an oxygenated environment) where is the missing 800 watts coming from?
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Yeah, I didn't agree with that part of the student's reference either. The argument must have been in the absence of the tremendous amount of radiation coming from the sun. So just considering the temperature and pressure in the corona.
This is a big one. The computer guy is at his console and has a frame from a camera and his boss says "enhance that." Suddenly a low-res pixalted image gains fine detail and resolution. Impossible!!!
The matter is very simple: according to the Stefan-Boltzmann law, power of radiation per area emitted by a black body (only depends on its temperature, nothing else) is \sigma \times T^4 (\sigma being the Stefan-Boltzmann constant). If the body isn't illuminated by a star or some form of radiation: A simple calculation yields 459 W/m^2, the area of a human body being circa 2 m^2, this gives about one kW of energy emitted per second, which is about 14 kcals per minute. The energy one person gains from food is about 2000 kcals in one day, so subjecting your body in space may make you feel cool for a while and, as the body temperature lowers, you will be feeling warmer, all the time losing energy though. The cloth you may wear is irrelevant, unless it traps most of the radiation from your body and that until it is heated up, at which point it will be radiating your energy away, just like without it (actually a bit more). Sweating will make you cold faster, though not freeze. I hope this helps.
It seems to me that "Legend of the Fall" was not really a myth. An object only falls about 2 inches during the first 1/10 second of its fall from rest. A vehicle moving at 70mph can travel about 10 feet in that amount of time. With a rear wheel drive vehicle such as a motorcycle the front wheel can actually lift off the ground when rapidly accelerating, in which case there would just be a 2 inch impact on the rear wheel as it lands on the far side of a 10 foot gap.
There are times when crashing cars will explode - typically, a front/side crash or rollover won't, but if the gas tank is impacted it could.
I remember reading about this happening accidentally in the first Beverly Hills Cop movie. At the beginning there's a chase with a semitrailer going through neighborhood streets, clearing parked cars out of the way. For the stunt, the cars were all supposed to have empty tanks, but one didn't. When the truck hits it in the back corner, it explodes. No one was injured, the shot was completed...and it made it to the final cut of the movie.
Who put this thing together? Me, that's who.
You won't freeze solid, no. You might well get frostbite.
-- Alastair
What? No mention of motorcyclists outrunning shock waves?
Shock waves in the air travel at about 330 m/s or 7oo miles/hour, fast even for a Hollywood stunt rider.
Never mind that the first shock to hit would have travelled through the ground. The speed of that depends on the types of rock underneath, but it's on the order of 4000 miles/hour. That bike better be tuned up.
Everyone knows you can only survive in the vacuum of space for 30 seconds!
That whole Star Trek is plausible if can go 1000 the speed of light with zero relativistic effects? Ok
And time travel? No problems there.
Hmmm. I wonder if there will be sufficient slashdot effect on creamer purchases after that post to justify purchasing stock options in however owns Carnation (General Mills?).
There is no right to feel safe thru security vaudeville at the expense of everyone's freedom, privacy and tax money.
Braking in space.
If they'd turn their brakes around backwards, they would work better than their dang warp drives.
The episode of Cowboy Bebop with the eyeball drugs comes to mind... the dog chase at the end.
Hmmm, let me think: Tits don't sag. Bimbos become celluloid icons. Outdoors has five shadows. People can be perfectly heard in clubs/restaurants etc. Movies are ranked by inflated millions of dollars rather than seats actual sold. Jane Fonda looks 50. Hollywood is a place which cannot be defined by Cartesian boundaries. You can have no vocal skills and still sing in a movie. And, of course the ever-present parking spaces!
*** Don't be dull.***
When playing both Descent and Descent Freespace, I had to find a reference direction of "Up" and assume that it's really up, not because the ship needed it, but because I needed it.
We still think more or less in 2D, for positioning and stuff.
We are Turing O-Machines. The Oracle is out there.
Why oh why does it still take 2 minutes to trace a phone call back to the source? Haven't anyone heard of caller id lately? The days of relay boxes have been over for over 40 years! It doesn't take minutes to triangulate your mobile phone either.
I'd be more worried about suffication and having my blood boil due to the drop in vapor pressure. Maybe you are right about the temp issue but you be dead anyway.
It is by the juice of the coffee bean that thoughts acquire speed, the teeth acquire stains. The stains become a warning
The most often broken law in Hollywood:
Stupid people don't die.
Aah, change is good. -- Rafiki
Yeah, but it ain't easy. -- Simba
It does not. Does anyone pay any frickin' attention around here? TWO SEPARATE POSTERS said the exact same thing before you. TWO SEPARATE TIMES I pointed out the flaws in their calculations and logic, linking to an article with actual information. (1: The human body emits ~95 watts which is consistent with the ~100 Watts produced, 2: Where would the other ~300 watts come from if the body doesn't produce it?) Hello!?! McFly?!!?
Cripes. I'm not a fan of violent games, but I suddenly have this overwhelming urge to perform MK Fatalities. Grr...
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At least theydid not try to make it a nice round number, but thing the author cared about
Your link is way too colloquial, despite your assumption about my ignorance. Regardless, the GGP refers to a "deep, dark place", which IS completely wrong. Your link says "by exposing a shallow earthen dish of water on a high piece of ground to a clear, dry, night-time sky", which I can believe. Deep underground, it absolutely will not work -- the radiation from the walls of the enclosure will tend to bring the water into thermal equilibrium with said walls.
they forgot my favorite, which is related to the conservation of momentum one. this is the one that says, no matter how fast you are going, as long as you are caught, you will be ok. in reality, the catch wouldn't do you any more good than slamming into the ground, unless the catcher slowly decelerates you, which still probably won't be enough, since they will be limited by the height of their arms off the ground. another good one is in matrix revolutions, where neo catches trinity, he's clearly travelling at a few 1000 mph, so she might as well have gotten hit by a train. and of course, for every action there is an equal and opposite reaction, so the catcher is going to get hit just as hard, too.
Frostbite from sweating? No. As I said, your body will immediately react, and close the pores. Your body will stop losing heat through any means other than black body radiation. No frostbite, sorry.
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IMHO, most of Hollywood's output is generally crap. Pulp that will sell well for a few days, for its skin/shock/sfx value, but after that die off. They stayers - the stuff that actually entertains, and keeps entertaining for decades - is not necessarily more realistic. Some of it is highly fantastic. But it is invariably stuff that is "internally" realistic (a sub-creation, Tolkien called it) and has a power that suspends nothing - it grabs you by the cortex and stuffs you into the writer's world - that really lasts.
It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
You sig, quote: There are A kinds of people in the world: people who understand hexadecimal and 9 other kinds.
Let me guess, you never made a grade less than an 'A', say a B,C,D,E, or F. *wink*
I only look human.
My mother is a halfling and my dad is an ogre, so that makes me an Ogreling
but think of "Pulp Fiction", it wouldn't have been the blockbuster it is had it not employed this technique...
the significance of a signature is insignificant
A Scanner Darkly has the best homemade silencer scene EVER.
True, astronauts can't shout and expect to be heard, but they most likely have this little thing called a "radio" in their helmets.
Funny thing, even real-life astronauts have them!
General Relativity: Space-time tells matter where to go; Matter tells space-time what shape to be.
Note, for a suppressed round, usually it is subsonic and has a lot less energy. I also saw an interesting x-ray of a guy shot in the forehead with a .22 where the bullet put a groove into his skull as it moved all the way around the outside somewhat contained and directed by his scalp to exit at the back of the head, resulting in an entry wound at the front and an exit wound at the back, but no actual penetration of the skull. Finally, for short range I'd like to mention mercury rounds, which are copper jacketed rounds with mercury inside and result in a splatter effect, rather than just fragmentation (as well as being toxic). They have been used in a few, rare assassinations.
If you have ever driven on L.A. freeways, you probably would think it quite possible to jump a bus without a ramp - what with all of the horrendous patchwork and potholes.
All this means is that the clothes will cool down to a very low temperature first, before you do. Then you'll be radiating to them instead of to space. Like another poster suggested, the best solution would be a space blanket, which has a very low emissivity and high reflectivity. Hence the whole "space" blanket thing.
Invariably, discovery of fucktardedness is preceded by denial, often verbally, especially in the form of "There's no way anyone could be that stupid." Fucktards do not just defy common sense, they are pathologically incapable of recognizing the obvious, and are space-and-time bendingly stupid.
Come on... this is Slashdot! Reading articles just takes time away from posting comments!
But I recently found out, from a colleague over beer, that loss of heat from blackbody radiation is actually much faster than I thought. In the old days, in non-cold places, some people (ancient Egyptions among others) would actually make ice, basically by letting water in a deep, dark place radiate it's heat away. Sure it took hours, and it had to be already pretty cold outside, but considering that the water was also being continually warmed by all the air around it, that's pretty impressive for "only" blackbody radiation.
Here's another way of looking at it.
The only way the Earth as a whole loses heat is by radiating it. And, since the Earth stays mostly the same temperature on average, there is an equilibrium between radiation absorbed and radiation emitted. So the rate at which a square meter of the Earth's surface radiates [infrared] light should be comparable to the rate at which that square meter absorbs [infrared+visible] light from the Sun. (Averaged over 24 hours of course. To be safe, might as well average it over latitude and longitude as well).
I do make some assumptions which are not totally justified, e.g., that the atmosphere is mostly transparent to the frequencies of light emitted by a black body at that temperature. But for the Earth I think it is approximately true.
Never mind. I see the problem with my own response. The delta of space (as much as 300K delta) results in a greater loss of black body radiation. Assuming no insulation, of course. (Such as clothes, which provide a great deal of radiative insulation.) So if you're naked in space, you could lose as much as 523 watts. (e=1, T=310K) Since you're likely to be wearing insulation, you'll lose a lot less than that, though it's difficult to compute how much. Obviously, the insulation is good enough that astronauts don't need heating packs, and the Space Activity Suit needs cooling via sweat.
:-/
That being said, it would be nice if this could have been kept in a single thread (perhaps poking a reverse hole in my own logic) rather than three people responding the same thing while ignoring each other's posts.
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Children of Men was a very underhyped recent movie that had an extremely "real" feel to it largely due to its staying with the protagonist's point of view for the entiritey of the film. Seriously some of the best continuous action shots ever. Highly recommended.
I'm sure no one will see this as it's much too late. But most of the modded-up posts I see aren't looking at the primary heat loss you'll experience in space, or in a vacuum of any kind. Water evaporation. If you take a jar of water and put it into a vacuum it will freeze over very quickly, because of the heat of evaporation, the same way sweat evaporation cools the body. Since our bodies are basically bags of water, if you put us in space unprotected, that water will promptly be sucked out of us by the near-zero pressure, and the evaporation will leave us frozen solid. The same thing applies to any fluid leaking from a spacecraft. It will probably rapidly form small ice spheres, which will then rapidly sublimate into vapor, depending on its characteristics.
It's reassuring to know some things in life are constant, like GNAA fp's and Zonk's failure.
And since the thread deals with body heat and freezing to death... One thing that I've always been interested in seeing, would be a zero-G fire. Like a camp fire, not so much an explosion.
This sig isn't original enough, it's time to come up with something witty...
Yes. At that low a pressure, your sweat will vaporize instantly as it comes out of your pores. As will any surface moisture on your skin the moment you're exposed to vacuum. You'll be quite dry, and I expect rather cool too.
"Convictions are more dangerous enemies of truth than lies."
No really! ok forget all about the virus, the BFG, and all that other made up stuff - for the first time ever - a guy in an action movie needs to take a dump!
You know that link is to the weapons guide for a role-playing game, right?
Is the discrepancy due to Wikipedia using an ambient temp of 293 Kelvin, whereas the parent poster supposed a vacuum and used 0 Kelvin?
"The fluid promptly freezes because, as we all know, outerspace is really, really cold."
Well water would most likely be non liquid very fast in a vacuum of space. Not sure what the effect would look like.
If you put a beaker of water in bell jar on earth and pump out the air it will boil and quickly freeze solid. So cooling won't be merely black body radiation, but state change as well and that can be very fast indeed.
I don't know about anyone one else, but as a martial artist I see a serious problem with #4. While movies do exagerate how far someone will get thrown, the kicker definitely doesn't bounce off and go flying in the opposite direction. While I havent kicked someone across the room, ive definitely kicked someone into the air at least a few feet, and I wasnt thrown backwards. The way I see it, as long as you're rooted to the ground by one foot, the opposing force is tranferred along that leg and into the ground. For a jump kick, the impact just slows you down, you dont stop spinning mid-air and suddenly start flying back across the room.
Neatorama lists nine laws of physics that don't apply in Hollywood (movies and television/TV shows).
The Law of the Slashdot Effect is still shown to be inviolable.
If my grammar and spelling are off, I am [distracted/tired/careless] (take your pick)
I believe that they are saying that you do not radiate that much on earth because all of the other radiation sources around you impinging you with their waste heat. The (Ts^4 - To^4) part of the equasion mentioned earlier, I think. You're 300k (Ts) and the surroundings are 295k (To) therfore the radiated amounts are much much lower. This actually only applies if you are far from a star. Depending on where you are and your (lack of) rotation you could have one side (sunward) cook while the other side (deepspaceward) would freeze.
What do you propose? Space operas would be seriously limited if have no faster than light travel or have to heed relativistic effects.
You are mistaken; my assumptions, calculations and result are indeed correct, as can be evidenced by any reference on astrophysics and thermodynamics. The 100W value you give is clearly incorrect, as this value is the energy difference that is emitted *on earth* with an atmosphere temperature of ~300K. Do the calculation yourself, if you don't believe me. It is funny, though, that the link you give points to a PDF file, which on page 12 verifies my claim (TMG reflective garment to avoid radiation cooling). If the energy due to radiation is restrained in the suit, as the article suggests, and the man eats nothing in the mean time, the suit will slowly start radiating as its temperature rises, and after quite some time (I don't know how long a human can last in these conditions), the human will have certainly died and frozen, until he has come into thermal equilibrium with the space, which (the cosmic background radiation) has a temperature of about 2.7K.
Maybe the problem is that the freezing won't happen instantly, as some have suggested, but will take a large amount of time, just as you mention in the initial post.
By the way, a man takes 2000 kcal per day from food, which is 8000 kj, which further supports my results (1 W = 1 j/s).
I hope this helps.
So you would feel better served by a link from a gun nut site? OK, here you go.
It is cowardly, and a betrayal of whatever it means to be a Jew, to act as a white man
-James Baldwin
radioactive particles from an object can be very contagious. I recall doing experiments in a nuclear reactor as an undergrad and my partner and I were reprimanded for wandering around. There was a lot of irradiated material around (like steel plates) that if we touched could have contaminated us (radioactive rust). Not curl up and die stuff, no, but not something to ingest either.
Yeah, I'm always forgetting the real laws because of movies. Why just today when I was flying to work...
How about the water at your skin's boiling away because of the low pressure? Wouldn't that take heat away?
Cripes. Not again. You're again three posts too late, and adding nothing to the discussion. Dude, look two posts up. Thank you, have a nice day, please drive through.
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Deep!=underground. But deep does stop outside ambient light from getting to the water.
> Middle C, for example, is 256 vibrations per second
Gee, now I'll have to get rid of all my instruments which are tuned so that middle C is about 262 cycles per second.
"I'm more concerned that people watching 24 will believe that terrorists are that capable. Seriously, I've heard people say that 24 shouldn't be aired because it will give terrorists working ideas on what to do. It's also sad that people believe there are an endless stream of highly skilled mercenaries and inside-men in the U.S. willing to murder thousands of innocent people for a million dollars."
There aren't thousands of skilled mercenaries/inside men in the US willing to murder thousands of innocent people for a million dollars? Damn, there goes that employment plan. I thought it was simple:
1). Get an H1B/Green Card (I am Canadian)
2). Get into a position of influence, preferably in the Los Angeles branch of the CTU - since all Terrorist related activities seem to focus on Hollywood (which in and of itself probably wouldn't be a bad thing) and not say, New York, 9/11 not-withstanding.
3). Get suborned by extremely rich terrorists for at least 1m dollars US.
4). Move to the Bahamas and live off my illict wealth.
Now, I admit there are a few problems with this plan. The first one is I have no desire to help terrorists. The second one is I have no useful knowledge to get me into CTU. The third is I highly suspect CTU doesn't exist and if it does under that name, not in LA. The fourth is I have no desire to live in the Bahamas. Still it seemed like a good plan when I thought of it...
Seriously, I am suprised that 24 is as popular as it is, given how *extremely* right-wing it is, how casually torture is accepted, and how predictable the plot is...
"The first time I got drunk, I got married. The second time I bought a chimpanzee, after that I stayed sober" Arian Seid
are always billowing clouds of fire and smoke. Doesn't it require air pressure to cause those roiling shapes? What should it look like, a fleeting sphere of convection distortion/magnification?
Water being frozen in "deep dark places", isn't from black body radiation (some things emit and other things absorb would tend to equal things out) but rather kinetic energy reduction through evaporative process of water. (unless you're talking about ground freeze and thus conductive heat transfer?) You'll achieve better results with that level of technology using a porous material container (clay pot) through which some water can evaporate overnight cooling the container down during the process (i.e. insulator and evaporation chill layer). Better is probably the container in a container method with continually dampened sand between the containers to cool the inner one while insulating it at the same time and giving a bonus that the stuff you're storing in there remains dry without rigging.
As for freezing in space, if you're a dandy and wore a thinly layered gold body suit then that would reduce radiation emissions and incoming radiation. In a sense this converts you into a half Thermos (tm) with an unneeded secondary layer since there is already a near vacuum outside. Your suit reflectivity also helps with radiation based heating of an infrared emission source like the sun.
1. You can enlarge the eye of someone in a photo, or a video, and get a good full-size image of what they are looking at.
2. If you find a single hair at a crime scene, it always will be from one the criminals, not any of the hundreds of other people who walked through the place recently.
3. If you run out of bullets, you are requirecd to throw your gun at your foe. You will also never be able to hit him with it.
4. Searching for a fingerprint in a computer database requires that every fingerprint in that database be displayed on your terminal. Also, when trying to break a password, you must display every single password being tried.
Who would win this election: Andrew Weiner vs Andrew Weiner's weiner.
Dunno that they do...
Some ass-holes probably do love their guns just like some ass-holes like to make comments like "Why do assholes love their guns??" or "best head can be had from a fresh marine".
Go figure.
Your thin skin doesn't make me a troll
It should read 24.75.0345.200 -- Owned by Comcast Cable. :-D
You get it wrong, he gets it right, but you realize your own stupid mistake before he responds. Just apologize and stop being an asshole.
I'll point out that none of Einstein's theories prevent apparently-faster-than-light travel, such as warp drive or wormholes, nor time travel.
Vintage computer games and RPG books available. Email me if you're interested.
And what's wrong with that?
"If you were really dumping 920 watts through black body radiation (which will NOT be significantly impeded by an oxygenated environment) where is the missing 800 watts coming from?"
Masturbation.
For those who remember, the Pinto tended to explode during rear-end collisions due to a rupture in the fuel system. Ford discovered this flaw during early crash tests, but decided not to fix the design flaw.
As Lee Iacocca was fond of saying, "Safety doesn't sell."
Anyhow, great example of how cars can explode during accidents.
They don't grade fathers, but if your daughter's a stripper, you fucked up. --Chris Rock
On the other hand, my old 1967 Pontiac Catalina station wagon launching from a slightly shallower angle (the top of Ott's Chapel Bridge) and accelerating until the rear wheels left the ground (roughly 105 mph) hit fairly flat, with a dramatic roostertail of sparks from the thick steel plate protecting the oil pan, and much adolescent squealing and whooping.
So I'd say that while flying cars will generally tend to hit nose first, weight, speed and type of vehicle (front
Oh, and repeatedly flying a 2-ton vehicle through the air eventually breaks the shock mounts.
-ccm
Too much Law; not enough Order.
I can't speak to the no vapor, but craft that make urine dumps in space produce, well, urine crystals. One source.
I even told a student that a reference they had cited was wrong in claiming that you would freeze to death in the Sun's corona, the argument being that you wouldn't freeze for the same reason you wouldn't burn: no particles to transport heat.
That's a pretty disturbing mistake to make if you're teaching. If there were no mechanism for heat transfer in a vacuum, how do you expect the Earth is heated by the sun? If you think it takes an atmosphere, or an active inner core, take a look at planet Mercury.
These posts express my own personal views, not those of my employer
A vacuum will "pull" fluid and blood from your skin. That's how one of those "natural breast enlargement" processes works. A large suction cup is placed over the area, air is sucked out which causes swelling. Over time the flesh and skin expands.
Ok, so this is just a blatant attempt to work breasts into the conversation...
09F91102 no, 455FE104 nope, F190A1E8 uh-uh, 7A5F8A09 that's not it, C87294CE no. Ah! 452F6E403CDF10714E41DFAA257D313F.
It would also be due to the same effects that divers experience when depressurizing too rapidly... the bends. Gasses in their blood coming out of solution due to the rapid drop in pressure.
"Democracy is two wolves and a lamb voting on what to have for lunch. Liberty is a well-armed lamb contesting the vote."
If you want really ridiculous Battlestar Galactica, you need to watch the original.
...
Everyone's a fighter jock, so of course they use those little fighters for everything. One time there's a fire on the Battlestar. Those little twerps get into their fighters and strafe the ship with fire retardant of some sort to put out the fire. Of course this is all happening in space.
Anyway, I haven't seen that episode in about 30 years, so the details are vague
BSG actually handled that scene pretty well IMO. They stated up front that while the decompression would suck, people had been known to survive hard vacuum for a minute or two. That said, I did take one issue with how the depicted the aftermath of hard vacuum. While your body won't burst, you WILL burst every single capillary on the surface of your skin. That isn't lethal, but it certainly would be unpleasant. More to the point, it would leave you with a giant body wide hickey. Think of what an overly enthusiastic kiss on your neck can do with that minor vacuum. Now imagine exposing your entire body to a near perfect vacuum. You might live, but you would look funny for a little while.
The other thing that nobody seems to be addressing here is the Heat of Vaporization.
While I cannot speak to whether the "sweat" would have a chance to spread, it would still cool you _very_ fast. The sweat would effectively boil off your body because of the vacuum, and your body would be the heat source for that boiling.
More explicitly (though I don't have the math here, but http://en.wikipedia.org/wiki/Heat_of_vaporization does) as pressure decreases, the boiling temperature of water (etc) drops. But regardless of the boiling temperature, the total amount of energy it takes for the liquid to become a gas is fixed by volume. This is why sweat can "keep you cool" when the ambient temperature is higher than your body temperature. The Heat of Fusion is why we add salt to ice to make the ice cold enough to freeze the cream to make ice cream.
The danegeld must be paid and you do sweat, _lots_ of cold to be had there.
So, for instance, in the Battlestar Galactica episode referenced by someone else I was like "dude, piss on a rag and stuff it in the hole!" Both media were available in the scene, the evaporating urine from the hole would have super-cooled the rag and frozen it solid and then the ice chunk would last until the ice sublimated, which would have easily been long enough to re-pressurize the bay.
Innocent people shouldn't be forced to pay for inferior software development.
--"Code Complete" Microsoft Press
Actually outer space is really hot, temperature wise.
Temperature is a measure of how fast particles are moving. In the near vacumn of space the few particles there are, tend to be moving very fast.
Of course there isn't much heat which is a measure of the quantity of those particles. No matter how fast the particles move there just aren't that many of them.
> I'd be more worried about not being able to breathe.
At least breathing out shouldn't be a problem...
(Initial Aside: the one thing nobody is considering in these comments about freezing in space is the Heat of Vaporization. The sweat boiling off your body would freeze you damn skippy. Look here http://en.wikipedia.org/wiki/Heat_of_vaporization and consider that that energy has to come from somewhere, while the reduction of pressure will lower the boiling point very very far, it costs a fixed number of calories for that boiling to effect a change in state of the water.)
Things that Bugged the snot out of me about that episode:
1) at the rate the air was leaking, there was no way enough cooling was taking place to make them cold like that. (My excuse for them: stress and shock related changes in the extremity.)
2) If one of them had pissed on a rag and stuck it in the hole the episode would have been over. Even if the rag didn't freeze into a solid plug (which it would, given that the Heat of Vaporization would have acted very fast such a rag in space) a wet rag is a _really_ good gasket for preventing the flow of air.
3) They are a space-faring race. This wouldn't be "unheard of scenerio X" it would be in the operations binder of every ship as "jammed door leading to occupied but slowly depressurizing compartment, scenarios 1 through 100, 101 and above continued in next manual."
4) These space superstars apparently haven't invented "the tent", you know, that air-tight plastic wrapping you glue to the side of a ship to hold in the air while you work on the hull. Or, you know, the tent we could attach to the outside of the big door and pressurize so that when we opened the door we could walk in and hand them some space suits. (Or for that matter the flat piece of plastic we could slip two space suits under and then glue/melt around the edge of the door and pressurize so that we can pass in two space suits.
5) We an put people in space, in ships, and suits, but we cannot give them a caulking gun to fill a quarter sized hole in a known and accessible location.
6) The chief has a pressure patch, which he uses, and which is apparently designed with the structural integrity of play-dough since it clearly cannot hold in one bloody atmosphere of pressure.
7) The chief has a tool kit, and it _doesn't_ contain any of: Duct Tape, Bubble Wrap, Caulk, Plumbers Putty, etc, etc, etc.
And now, for my single favorite mistake in every science fiction movie ever:
Commander: "What about the manual override?"
Worker: (pushing _button_ for damn sake) "It doesn't work."
(WTF?)
By definition, the _manual_ override wouldn't be a button. A button would be an electrical override.
The manual override would be a Lever, or a Crank, or a Wheel (or a chuck one would fit a wrench too) that one operated with one's hands, directly at the point of attachment. Hence "manual".
All that being said, the performances in the episode were excellent and, once turned off the "you have to be kidding" part of my brain, I found the episode to be "pretty good". (It didn't bare a second watching because then I was all MST3K on its ass... 8-)
Innocent people shouldn't be forced to pay for inferior software development.
--"Code Complete" Microsoft Press
Just as your skin and extremities will cool down before your core. You'll cool down eventually; clothing just adds one more layer of insulation.
Besides, I don't think anybody has been suggesting these things would keep you alive in space. If you wind up in an environment without air and pressure, you're sill screwed.
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No, that's completely wrong. Even deep in a pit doesn't work. You need as much of an angle on the sky as possible.
Did it ever occur to you that not everyone obsessively refreshes Slashdot every few minutes to check for new posts?
Sibling poster is right: stop being an asshole. When you find yourself in a hole, stop digging.
"Wet" and "dry" have nothing to do with baffles. "Wet" indicates grease.
My favorite is when they put silencers on revolvers. They don't do it so much these days but even the older Bond movies are covered up with that flaw. Reality is, silencers and pillows ONLY work when all of the exhaust gases can be channeled through the silencer; which means out the barrel. On revolvers, the gases are simply going to exit the gap between the revolver's cylinder and barrel.
.44 mag revolver. Wait for night fall. Shoot it. You'll observe a nice 3+' flame out the front and a 1-2' flame on each side. It's all very fun to watch. Hint, hint...for a silencer to be effective, you should not see flames anywhere except the front of the barrel.
For homework, get a
My other pet peeve is the size of silencers they use in movies. The size of your typical silencer in the movies is simply not effective. An effective silencer is measured in 8-36 inches in length, depending on the weapon. The movie silencers which was one or two inches in size may help shave a couple db, but it certainly won't prevent someone from hearing it...and it certainly will be MUCH louder than the "psssz" noise you hear. Not to mention, the action on the gun is NEVER silenced. And heck, the action alone is often several times louder than the noise they make in the movies. Hint, you know the classic, "shoock-shoock" noise guns make when cocking in the movies...that noise doesn't go away just because a silencers is on it.
The guy who started this meme is tops on my list of CGI "artists" I'd like to throttle. Automatic 1/2 point off my grade for a movie on a 1-4 scale.
A movie does doesnt have to be a real physical point of view. We see fast cuts all the time where the camera changes its location ten times a minute which no real object can. Cameras pan and zoom and sometimes even go through walls. Speed change; time is not montonically sequential (flash back and flash forward).
Novels and paintings are the same. A writer can jump from mind to mind, place to place, time to time no physical person can do. A painter or comic book artist can use impossible persepctive at will.
If something can move parts of itself independently it can impart momentum to itself. Ever been on a swing? You're not pushing off of anything, but swinging your legs imparts momentum to you and the swing.
"Sic Semper Tyrannosaurus Rex."
So what about that whole flying machines thing? How is that plausible? People can't fly; everyone knows that. It's impossible.
A few hundred years ago (before the invention of the balloon), if you suggested that people would be able to fly in the future, you'd be laughed at. What makes you think faster-than-light travel isn't possible?
Havent they played with their balls and strings? http://billysardar.tripod.com/sitebuildercontent/s itebuilderfiles/shinycool.jpg
Physics? Ok, nerds. Here's some movie laws of sociology that do not apply.
1. Nerds are not good looking
2. Nerds are not cool with the ladies
3. Nerds do not "get the girls"
4. No hot babe is gonna have a "moment" when you stare into each other's eyes and fall in love with you. As you lean in, she'll go "ick" and put up the palm of her hand. As if!
5. If a nerd actually saves the planet in reality, the hot girl will still go with the hairy, sweaty janitor.
6. If you finally get so ticked off you take a swing at the big bully, he beats the crap out of you again, anyway.
7. The hot girl laughs at you and starts giving the bully head while you cry and crawl off in search of pr0n.
(-1: Post disagrees with my already-settled worldview) is not a valid mod option.
Well actually the sweat/water would boil at first; and it takes 510 calories to boil a gram of water so you would get cold pretty quickly. Now the Hollywood version of people boiling inside their skins and exploding isn't going to happen, but a ruptured lung wouldn't surprise me. All that stuff in movies where the astronaut instantly ices up when is face shield cracks isn't going to happen either
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Well there are stars, which put out a lot of highly energetic partials and atoms. Highly energetic partials and atoms are what most of us would call hot, they have a high temperature, what outer space doesn't have is density and a few partials at a high temperature in a large space results in very little heat.
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A living being won't be able to "heat themself" anymore than a dead one.
Um, why not? People normally heat themselves just fine. Or are you one of those cold-blooded humans?
Considering the most important requirement for space suits is getting rid of heat, I think it's entirely possible that humans would generate enough heat to keep themselves entirely warm. I don't think it's likely, I have a feeling too much would radiate, but their body's heating would, in fact, slow the process down.
So, the end result is that if you are some amazing person that can survive the extremly low pressure and lack of oxygen of a vaccuum, you will die in half an hour from low body temperature, and your body will reach the freezing point in 3.5 hours. This is still a far cry from some movies where they instantly turn to ice pillars, and is also much slower than if you just step outside naked in the winter (where I'm from).
What's really dumb is that people can survive longer, temperature-wise, in any environment for longer than it would take to run out of air. You can be dumped into below-zero salt water and you'll drown before you'll freeze to death, and that transfers energy much better than a vacuum, so the entire idea is silly. I know we're talking about someone with an air supply, but in movies, they almost always don't have one, and yet 'freezing' is the danger.
If corporations are people, aren't stockholders guilty of slavery?
It doesn't matter that suppressed movie guns are quieter than real life, because they make up for it by adding that rattle-click noise whenever the guns are lifted.
This space intentionally left blank.
They showed that low-powered firearms do penetrate water. It was the progressively higher powered rifles that they fired that broke up upon entering the water. They didn't say that all bullets are harmless in water. But if you're a few feet under water and someone fires a high-powered military rifle at you, you're probably not in too much danger (until you need to breathe).
The divers blood under goes some very severe pressure changes, how every the people exposed to vacuum are in a very different situation because the skin and blood vessels are elastic the body will always be under some pressure. consider this normal systalic blood pressure is 1.76 psi, and the partial pressure of oxygen in the atmosphere is only 2.94 psi, it may be possible to put on a pressured helmet, and inflated bladder on your torso and spandex elsewhere and be able to function on 5 psi O2 without a full pressure suit!
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Why is it that Superman is able to pick up, and even fly with an entire house, and yet the weight of the house is only supported by the surface area of his hands? Must be a helluva strong building!
Politics according to Hollywood:
1. Better stop global warming. Today. Otherwise the aliens who appreciate our earth more than we do will take over tomorrow.
2. Raising minimum wage, absolutely and under any circumstances, will never result in inflation.
3. It's okay to steal from the rich and give to the poor.
4. It's okay to steal in general, particularly from wicked people like the Russians and casino owners.
5. It's okay to be "green" and still spend $30k/year in gas/electric bills.
6. Social means not-voluntary and Security means there's no real money backing it.
7. The Family Unit should be defined as sleeze in your bedroom for a week. Honestly I can't watch romantic comedies anymore because they all have a live-in.
8. Farmers, eh, we don't need them.
From the article:
Re bullets:
Some bullets (cheap furrin import. Novosibirsk LVE, anyone? Norinco?) are (or have been in the past -- not sure of their current legal status here in the United State) steel core, and has been known to spark.
No matter. Gun handling and gun effects in movies is routinely horrendously wrong. Click-click-click on an empty chamber in a Glock? WRONG! Can't happen. And get your idiot finger off! the trigger! Rant rant rant .....
"So, when you see a gal kick someone across the room, technically, the kicker (or holder of a gun) must fly across the room in the opposite direction - unless she has a back against the wall."
I think the author is confusing conservation of energy with conservation of momentum. In an elastic collision, in which energy is conserved, two people of equal mass will head in opposite directions. In reality, both the kicker and the kickee will absorb some of the energy of the kick, thus resulting in an inelastic collsion.
"For instance, in space the hero shouldn't be able to shout out instructions to the other astronauts from a spot several yards away."
That's what radio transmitters are for, and if you're wearing your helmet, you probably have a radio.
Explosions are what are particularly interesting. You will hear something as particles from the explosion collide with the hull of your ship, but it probably won't sound like an explosion.
And of course, High Noon ran in real time as well.
1) the sound of the gunpowder burning
2) the crack of the bullet as it breaks the sound barrier
3) the sound of the weapon's action cycling (i.e., the part that ejects the empty shell casing and loads a fresh round into the chamber)
You forgot primer detonation.
To be more specific, the sound from item 1 is generated when the gases created by the burning powder creates a pressure wave in the ambient air. The "silencer" diminishes this sound by slowing the gases and reducing the impact of the pressure wave.
LK
"Hi. This is my friend, Jack Shit, and you don't know him." - Lord Kano
Which is why the scene in the bar in Desperado was so cool when the guns kept running out of ammo or were empty when picked up. Finally, it was realistic to some degree. Good God, did I just use the word 'realistic' to describe "Desperado?"
This is stupid. People are going on about black body radiation. People certainly do NOT count as black bodies - you don't have an infinitely tiny hole through which you lose your heat, you radiate it from your body in every direction, and you exhale it in your breath. Having no atmosphere is why space might not *feel* cold, but it also stops you from warming your immediate surroundings to prevent loss of heat. Believe me that after a short while you will be freezing in space, assuming of course you aren't in direct sunlight and closer to the sun than, say, Jupiter.
It's OK Bender, there's no such thing as 2.
Don't forget that streets at night are always wet. Always. Even in lengthy tunnels where no rain can get (i.e. Back to the Future Part II).
All of their products are 'dry', meaning they use baffles, rather than 'wet', indicating wipes.
That is misinformative. A typical suppressor uses baffles and can be fired dry or wet (by adding water/oil/grease/solvent/whatever). Wipes are an entirely different matter altogether.
From wikipedia:
"Wipes are inner dividers intended to touch the bullet as it passes. Wipes are typically rubber or plastic or foam. They may have a hole drilled in them before use, or a pattern cut through at the point the bullet will strike them, or they may simply use the bullet's energy to punch a hole.
Wipes typically last for a small number of firings, perhaps no more than 5 before their performance is significantly degraded."
AND... for all you folks throwing out dubious and subjective claims about sound levels, see here for actual dB levels.
from the article: Various minor problems (sunburn, possibly "the bends", certainly some [mild, reversible, painless] swelling of skin and underlying tissue) start after ten seconds or so. I certainly agree that labeling 20 seconds to be "extreme exposure" is a tad.... well, extreme, and hopefully nobody tried to hold their breath, but we're talking about no protection at all and explosive decompression.
When it's all over, that's why they call it science fiction.
"Democracy is two wolves and a lamb voting on what to have for lunch. Liberty is a well-armed lamb contesting the vote."
Although I'm all for reducing public fears of radiation (its everywhere!), the message of Myth 3: "Everything is Illuminated: The Myth of Radioactivity" is somewhat flippant; as other posters have said -- radioactivity can be dangerous. But also, radioactivity CAN cause things to glow in weird, unexpected ways -- which is downright creepy. For example, the water shielding this reactor gives off a Pretty Blue Glow from Cherenkov radiation (radiation emitted when a charged particle is going faster than the speed of light in a particular medium -- sort of a luminal "Mach cone" effect). I had a lot of water between me and the hard radiation, so could take the photo in reasonable safety. If the effect occurs in your eyeball fluid, that's probably something to worry about.
i\hbar\dot{\psi}=\hat{H}\psi
Did you forget about Wag the Dog? I'll bet that's what's up right now, but not as much as the movie portrays, since we have soldiers shooting dogs and such with practice rounds on youtube and liveleak, etc.
They seem pretty fucking bored, right now.
Still waiting on Serviscope_minor to wake up to fucking reality and realize that Jessica Price isn't going to fuck him.
When Worf had his suit punctured by the Borg on the outside of the Enterprise, he certainly didn't seem to freeze! He even tied a Borg cable around his leg to stop the pressure loss, leaving the rest of his leg exposed to space!
:)
I'm joking but it seems appropriate given the explanation.
Still waiting on Serviscope_minor to wake up to fucking reality and realize that Jessica Price isn't going to fuck him.
Dude, quit obsessing! You're at +4 on my customized comments page, and you're showing up every other time and stressing! Go smoke a joint, if it's legal where you live! You've said your fill, why bother trying to preach to the ignorant and unobservative? They're going to be stupid, regardless.
Still waiting on Serviscope_minor to wake up to fucking reality and realize that Jessica Price isn't going to fuck him.
>Believe me that after a short while you will be freezing in space
Depends on how fast the human body radiates heat in a vacuum. Has anyone ever measured it? I would imagine it would be the same as standing in a breeze with air at body temperature so it takes away any heat you generate but at the same time doesn't start to cool you down nor does it heat you up.
Probably right, only you couldn't measure it that way because perspiration would throw things out. Come to think of it, perspiring in space would be another big way to lose your heat. I would imagine either you end up covered in ice crystals, or you spew out water vapour into the vacuum.
This is why we *have* to get into space en masse - to put all this uncertainty about what happens when you get sucked out the airlock to rest.
It's OK Bender, there's no such thing as 2.
YES!
Thanks for the concern, but don't worry. In the spirit of breaking up a problem into smaller parts, I discussed the radiative effects with them afterwards. That you think a teacher (not that I really am one, the uni makes me do it) could be so ignorant is also pretty disturbing.
Best illustration I ever saw for these was in high school. Someone had drawn a picture of a cooker with a pan on the hob, labelled "conduction"; a joint of m**t in the oven, labelled "convection"; and something under the grill, labelled "radiation".
Je fume. Tu fumes. Nous fûmes!
Only 9?
Since we're doing so well at mocking combat and/or Mr Bauer in this discussion, let's not forget the classic "automatic weapon that has no recoil even when unloading an entire magazine in 2 seconds", or Jack's trademark "mobile phone with infinite battery life". I never quite mastered the martial arts of Ang Lee, either. ;-)
Though on a related note, TFA is wrong about kicking/shooting someone through the air without taking off yourself. This certainly can be done under some circumstances, given that you're standing on a floor and have both upward resistance from the floor and friction on your side.
If you disagree, post your argument. (-1, Overrated) isn't your personal censorship tool for views you don't like.
Maybe most movies occur in a place where the majority of buildings and cars gastanks are made of flint and the bullets are made of steel = instant fun.
..........FULL STOP.
Red Dawn is one of the few movies I can think of that obeys the speed of sound. In the movie there are many explosions that are at a distance from the camera and you see the flash first, then several seconds later you hear the sound. It adds an authenticity to the movie that is more disturbing and impacting with realism, than any special effect.
"it takes 510 calories to boil a gram of water so you would get cold pretty quickly"
At sea level. The temperature at which water boils depends on pressure: in a vacuum, it boils at at any temperature above 0C (ice doesn't boil) without the need for any external energy input, whereas deep under the sea around the "blue smokers", it boils at around 400C. Pressure cookers are an example of a simple piece of technology that allow food to be cooked more quickly by using increased pressure to raise water's boiling point.
I'm not going to change your sheets again, Mr. Hastings.
"but we're talking about no protection at all and explosive decompression"
The dangers of explosive decompression are greatly exaggerated, at least for pressure drops of one atmosphere, which the human body has been demonstrated both in controlled laboratory tests and actual high altitude accidents to handle with ease. Lung damage is the only real danger if they happened to be fairly full at the time, but even this is rarely severe enough to be fatal, or even have any permanent effects.
NB: the only known accident with explosive decompression from pressures much higher than 1 atmosphere (8 atmospheres in a diving decompression chamber) was very nasty indeed for all involved, including those who had to clean up the aftermath.
I'm not going to change your sheets again, Mr. Hastings.
I would fancy that, evaporisation of water at the body surface in the vacuum of space would also substantially contribute to net heat loss, at least until the skin is completely dried up. (OTOH, those Himalaya climbers wear no pressure suits, either ...)
You would have to lose only about 1kg of Water per hour to match the 640W of radiation loss you come up with.
"I can't speak to the no vapor, but craft that make urine dumps in space produce, well, urine crystals"
This can happen in space on the sunward side of orbiting structures where the temperatures aren't particularly low because surface evapouration happens very quickly in vacuums, which cools the liquid globules.
I'm not going to change your sheets again, Mr. Hastings.
So... vaccum-insulated thermoses are less effective than styrofoam-insulated thermoses?
I could swear that was not actually the case, and that conduction (especially with materials that conduct heat well) is more effective than radiation. As a result, you freeze to death much more slowly in a vacuum far from the sun (or in the shadow of the earth, an environment regularly explored by Astronauts) than you would if you were dipped into a vat of Nitrogen that was the same temperature of 2.73K.
"No problem. I have the capacity to do infinite work so long as you don't mind that my quality approaches zero."-Dilbert
Ahhh -- vacuum-insulated thermoses are effective because the vacuum is held within a metal vessel. The metal is chosen such that it has a very high reflectivity and, necessarily then (since T+R+A=1 and E=A at each wavelength), a low emissivity. Hence the purpose of such a thermos is to inhibit radiation since "blackbody" radiation assumes an absorptivity of 1 (A=1, hence E=1) and for lower emissivities it is less effective.
However, I certainly concede that under some circumstances, such as the LN2 that you describe, conduction can be more effective than radiation. Much of the energy in that case turns into latent heat as your body heat boils the N2, turning it to gas.
Cherenkov radiation is similar to them talking about phosphorus, light is only emitted when the high-energy particles are traveling through a medium like water at faster than the speed of light in that medium. The light is produced by radiation traveling through the medium, not by the radioactive object directly. Simply handling a radioactive object or being near a radiation source will not make you radioactive, at least not at nearly the levels of the original radioative elements. Most of the 'fallout' from a radioactive incident is in the elements that are radioactive being released and absorbed into the environment. For instance, the human body absorbs Strontium as if it were calcium, but compound containing radioactive Strontium would have to be absorbed by the body somehow, just standing next to it will not make you radioactive.
The actual radiation could cause atoms in your body to become radioactive themselves, but exposure to radiation creates much less radioactivity than the radiation itself, which is a lot less radiation than is contained in the radioactive materials. For instance the half-life of Strontium 90 is about 28 years. If you encased a pellet of Strontium 90 in something and planted it in your body, 1/2 of it would decay over 28 years, producing radiation. If ALL of that radiation went into turning elements in your body into radioactive isotopes, then your whole body, minus the strontium pellet, could contain about 1/2 the radiation from the original pellet in the form of those isotopes. However, those would have been decaying over the years as well, so you will never come close to being as radioactive as the original isotopes. If the radio active isotopes in your body decayed faster than strontium, most would already be gone at the 28 year point. If they decayed slower, they would put out less radiation. In either case, you wouldn't glow. Also, most of the radiation will simply pass through your body, punching wholes in your cell walls and interfering with cell division, killing your cells and causing radiation sickness if the exposure is high enough.
Expecially in the superman movie where he lifts the statue of liberty, and proceeds to move the moon to cause a solar eclipse. If he exerted enough force, he would simply fly through the moon.
If you do the math for black body radiation using the sun and earth, and appropriate view factors and the known albedo (which I cannot remember at the moment), you'll find that the equilibrium temperature is very close (within a couple K, iirc) to the average earth surface temperature.
Radiation is cool stuff.
Is it just my observation, or are there way too many stupid people in the world?
The oldest method for making dry ice:
...
1) make liquid CO2 via pressurization.
2) pour liquid CO2 into container of desired shape (in a closed system, as in tank to hose to box).
3) disconnect tank and hose from container.
4) flip open valve to container.
The heat in the liquid CO2 is expended in the state change to gas as "a good bit" of the CO2 boils away and the remaining liquid is frozen. The liquid doesn't stop cooling when it reaches a "CO2 as a liquid" temperature, it just keeps getting colder because the vapor pressure difference between the surrounding air and the "pool" of liquid doesn't reach equilibrium. The block of resulting "dry ice" remains cold for a very long time because after that, the block can only sublimate, which involves paying the price of both state changes.
Now if we follow your references:
"The standard enthalpy change of vaporization, vHo, also (less correctly) known as the heat of vaporization is the energy required to transform a given quantity of a substance into a gas. It is measured at the boiling point of the substance, although tabulated values are usually corrected to 298 K: the correction is small, and is often smaller than the uncertainty in the measured value. Values are usually quoted in kJ/mol, although kJ/kg, kcal/mol, cal/g and Btu/lb (obsolete) are also possible, among others.
As neither entropy nor enthalpy vary greatly with temperature, it is normal to use the tabulated standard values without any correction for the difference in temperature from 298 K. A correction must be made if the pressure is different from 100 kPa, as the entropy of a gas is proportional to its pressure (or, more precisely, to its fugacity): the entropies of liquids vary little with pressure, as the compressibility of a liquid is small.
These two definitions are equivalent: the boiling point is the temperature at which the increased entropy of the gas phase overcomes the intermolecular forces. As a given quantity of matter always has a higher entropy in the gas phase than in a condensed phase (vS is always positive), and from"
We see that the measurements are made "at the boiling point of the substance", but we also learn that the entropy of the _GAS_ is "proportional to its pressure" but the entropies of _liquids_ "vary little with pressure as the compressibility of a liquid is small". We note that the energy cost is expressed as "kJ/mol" and we note the lack of any equivocation about pressure or density in that unit of measure. (That is, it is measured at the boiling point of the material, not the boiling point of the material at a given pressure, etc)
Since I sweat _liquid_ and not _gas_ things are still on track.
Now, as you have observed, the ambient pressure in a vacuum is approximately zero. This means that there will be virtually no noticeable "evaporation" as there will be a _HIUGE_ amount of boiling. Oh, wait, you are a pendant and will need a reference:
"Boiling, a type of phase transition, is the rapid vaporization of a liquid, which typically occurs when a liquid is heated to its boiling point, the temperature at which the vapor pressure of the liquid is equal to the pressure exerted on the liquid by the surrounding atmospheric pressure. Thus, a liquid may also boil when the pressure of the surrounding atmosphere is sufficiently reduced, such as the use of a vacuum pump or at high altitudes. Boiling occurs in three characteristic stages, which are nucleate, transition and film boiling. These stages generally take place from low to high surface temperatures, respectively."
Note the explicit mention of the low pressure states (q.v. "vacuum pump") leading to boiling.
So if you can generalize your knowledge at all, you now know that sweat will "boil" off your skin in a vacuum, and the "heat of vaporization" (which is a function of that boiling independent of pressure because the initial state is a liquid at least until you freeze solid and begin to sublimate) will be paid by some
Innocent people shouldn't be forced to pay for inferior software development.
--"Code Complete" Microsoft Press
When you are dealing with "near time period" Sci-Fi (such as Armegeddon and Final Impact), where both had supposedly NASA spacecraft that were but marginally more advanced than the Space Shuttle, it is surprising that they invented "artificial gravity" as a plot device in there as well.
In the case of the astronauts running around the surface of an asteroid, I don't know how you would even be able to visually notice the difference between genuine weightlessness and a very low gravity field, except that stuff would eventually fall down over time. Like over several minutes or even hours. An astronaut using just his own foot power would be able to achieve genuine escape velocity. Indeed I think that would be the #1 hazard that would be mentioned during any training exercise, to avoid pushing too hard on the ground.
US space craft generally run at 5 PSI and high percentage of O2, that's why they look flimsy compared to soviet/Russian spacecraft that run at 14.7 PSI and 20% O2 and look like dive bells. I have a hard time considering 5 psi as explosive
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Calories are a measure of heat, degrees are a measure of temperature, it's easy for most people to confuse the two; they are related through the specific heat of a mass. At sea level it takes 1 calorie to raise a gram of water 1 degree C until you get to 100 degrees, then it takes 510 calories to boil that gram of water to steam at 100 degrees. That's why a steamer cooks faster than placing your food in boiling water, steam has more calories to give up to the food. It takes the same number of calories to boil a gram of water at any temperature. Ice doesn't boil technically, but it does turn into water vapor, a process called sublimation the heat required to sublimated a gram of water ice is the same as it would take to boil it as water. Put some ice cubes off to the side in the freezer for a few months, they will have shrunk noticeably due to sublimation.
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Maybe gp i referring to fact that revolvers are too "loose" to be effectively silenced: "Revolvers, due to their 'loose' structure, cannot be made quiet, with few exceptions: The Nagant M1895 revolver used an unusual gas-sealed cylinder that made it suitable for use with a suppressor."
source: http://www.search.com/reference/Suppressor
"Calories are a measure of heat"
They are indeed.
"At sea level it takes 1 calorie to raise a gram of water 1 degree C until you get to 100 degrees (etc.)"
All true.
"That's why a steamer cooks faster than placing your food in boiling water, steam has more calories to give up to the food."
Again true, except that I didn't mention steamers, but pressure cookers, which don't actually cook with steam, but use it to raise the internal pressure, which also raises the boiling point of the water (or other primarily water-based liquid) so the food inside can be cooked at above 100C (or whatever its ambient boiling point is where one happens to live). They're actually required cooking items for people who live at high altitudes because water doesn't boil at a high enough temperature to kill certain types of harmful bacteria and fungi.
"It takes the same number of calories to boil a gram of water at any temperature"
Where did I say otherwise? My contention is that the _boiling point_ of water (which I correctly expressed in terms of temperature) changes with pressure. The number of calories required to boil water thus depends on _the temperature_ it was at before one began to boil it, and _the temperature_ at which it boils, because you need a lot more calories to raise a gram of water from freezing point to its boiling point of 400C in the deep oceans than to raise it from freezing point to 0C in deep space.
"Ice doesn't boil technically, but it does turn into water vapor, a process called sublimation"
This is true.
"The heat required to sublimated a gram of water ice is the same as it would take to boil it as water"
But this isn't. Sublimation is surface effect like evapouration in liquid water, and therefore happens at all temperatures above absolute zero (when by definition all particulate motion ceases). Freeze-drying for example is based upon sublimation even though the temperature is being lowered rather than raised.
"Put some ice cubes off to the side in the freezer for a few months, they will have shrunk noticeably due to sublimation."
And they'll shrink a lot faster in a "no frost" freezer at an identical temperature for the same reason clothes on a clothesline dry faster on a cold windy day than a hot still one. Just because boiling water also evapourates doesn't mean that evapouration or sublimation effects that occur below boiling point are the same phenomenon, or are equivalent in energy terms.
I'm not going to change your sheets again, Mr. Hastings.
You don't know some of the teachers I know. Don't get me wrong - I know some good ones too. In fact I'm about to marry a teacher.
Your other statement is puzzling. The uni makes you do it but you're not a teacher? Huh? If it's part of your paid duties, or part of earning your qualifications, you're a teacher.
These posts express my own personal views, not those of my employer
Read the thread.
We weren't talking about US or Soviet spacecraft. We were discussing an episode of Battlestar Galactica, an armored spacecraft in which a set of blast doors were explosively jetisoned with unprotected people in the compartment behind them. The link to NASA was to bring in an authoritative explanation of what happens to humans upon exposure to vacuum.
"Democracy is two wolves and a lamb voting on what to have for lunch. Liberty is a well-armed lamb contesting the vote."
Technically, sure, I'm a teacher I guess. But I spend the vast majority of my time in a lab in the cold, dark basement. I spend 5 hours a week teaching and grading undergrads. And it doesn't feel like part of my paid duties because if I somehow get overlooked for a teaching assignment and end up not doing any teaching for the semester, I get paid the same. Also, I didn't know I'd have to do it before I got here. Post-docs don't have to teach at most universities.
Which is something to keep in mind when sending your kids to university: large "prestigious" schools often have grad-students (or post-docs, grumble, grumble) who don't care about teaching doing the teaching, whereas smaller schools often have their professors doing it.