> This applies particularly to power supplies. Sure, CPUs and memory, but the prices aren't nearly as fixed as they are for power supplies. Really, with power supplies, the price range doesn't vary much and the good ones tend to cost (though there are some decent ones for decent prices).
Very true. The problem's one of brand differentiation.
At the low end (vast majority), there's Joe Sixpack, who doesn't know anything about what's inside his box, and who doesn't even think there are modular components in it. "Dude! I got a Dell!"
At the midrange (20%), there's most of us. "It's an ASUS or ABit mobo, an AMD/Intel CPU, and an nVIDIA or ATI card. Umm, and a power supply that came with the box."
At the high end (5%), there's folks who know that no-name power supplies suck (IMHO) and Enermax rox (IMHO). But only because we've read from...
...the really high end (1%), which are the folks who know why one brand/design beats another - say, under-rated capacitors, or a design flaw that results in the switchmode transistor getting shorted in the event of a failure of the +12V or the +5V standby line, and is typically present on the $15 fly-by-night power supplies but not on most of the $50+ brand names.
Unlike ATI-vs-nVIDIA, where the midrange and high-end folks can plunk in an "upgraded" video card and immediately see the difference between "good" brands and "shitty" card manufacturers, brand names in power supplies have trouble gaining traction, because while they're working, they're indistinguishable from each other.
And of course, when they stop working, it's too late. For that reason, always keep a spare supply handy. Even a "free" no-name supply ($5 bucks from a surplus store) will last you a week until your "real" power supply arrives from the web merchant.
Rule of thumb: Put your hand over the PS's exhaust fan. If the air's significantly warmer than the air in the PC's case, get a bigger power supply.
(I learned it the easy way - a d00d at work got a dual Athlon mobo and just tossed it into his old case, and wondered why it was so warm under his desk while his CPU temperatures were normal. Answer: 2-year old 300W supply + dual athlon + two 7200 RPM disks = one massively overloaded P/S. We threw in a 365W "spare" for the weekend and ordered a 450W that got there by Monday. Air flow out the back was much cooler. Frankly, I'm amazed the 300W supply was even able to boot before blowing itself to hell.)
> So, are you saying being around a 4600lb magnet is birth control, or being a big enough geek to have a 4600lb magnet is the birth control??
I don't have a 4600 pound magnet, (you insensitive clod), but that doesn't meant I don't want a 4600 pound magnet!
(Surely that also qualifies as beeing geeky enough for birth control purposes!)
> It's an expensive change, but it's happening already. Hell, there was just an article here on/. which basically said that if you operate mobile phones in your airspace, you can catch stealth planes. Stealth is only a temporary (albeit very effective while it lasts) advantage.
Fair enough. But as you point out, the changeover's expensive. Now... what can third-world countries not afford to do, unless we give them the food so they can afford to divert more money towards doing it? *coughNorthKoreaJimmyCartuhcough*
The mobile phone / cell tower method of defeating stealth is interesting, but it's a huge signal-processing problem. More to the point, it's a huge data communications problem. In 5 years, a PlayStation IV will probably be able to do the math... but how's the adversary's third-world-cellphone-mast-radar net gonna get all that data to the CPU in order to do the computations?
I dunno, but I'd bet something TCP/IPish, over wires. Doing it over the air renders it susceptible to jamming. And doing it over wires makes it like the Internet - one bomb dropped on a NAP and *boom*, router tables oscillate and it's lag, lag, lag.
(My personal prediction is that despite the glam appeal of human-piloted jets, 40 years from now it'll all be UAVs piloted by flight sim geeks in air-conditioned trailers. UAVs are smaller and can take G-loads that would black out, or even kill, human pilots. With respect to fighter jocks, I think they'll change their tune the first time they try to train against a fleet of UAVs:-)
That said, I wouldn't bet the defense budget on the notion that "UAVs will make fighters obsolete". A lot of generals said the same thing 50 years ago - that air-to-air missiles would make guns on fighters obsolete - which turned out to be a very expensive mistake, in both men and materiel.
> Oh, wait a sec, that's right... the US is the only nation who can afford the kinds of missiles that this jet can avoid. So what was the point of this trillion-dollar boondoggle again?
The B-52 has been in service for almost 50 years and anticipated to remain in service for another 30+ years from now. (Yes, there'll be B-52s flying with airframes older than your grandparents!) The F-4 was recently taken out of service, but there are still some A-6s in service. Those planes were in service during Vietnam.
So on what facts do you base your statement about US stealth aircraft will still be true 40 years from now?
And, umm, could you talk to LockMart, Boeing, General Dynamics, Northrop-Grumman, and the US Air Force, because they'd all really like to know what they'll be up against in 2042.
> Also remember, as others have pointed out, the fact that we even know about this plane proves that it's quite out-of-date. God only knows what's in that hangar in Area 51 today.
Angry Security Officer: "WTF? God? Who the hell cleared Him for that?"
And finally, an oh-my-God particle - a proton with the mass of a bacterium, the kinetic energy of a brick dropped on your toe, and which, if it were a spaceship, could make it to the edge of the universe in a week and a half (ship-time, that is!).
The universe offered to us by science isn't just stranger than we do imagine. It's stranger than we can imagine. The universe of the mystics and new-age hucksters is positively boring in comparison.
> how come both and all observers won't see the same effects? if that train zips past me, won't it seem to the passenger like i'm zipping past them in the opposite direction? so both are moving at the speed of light, no?
Correct.
Beside the train (or on the train, looking out the window), things are foreshortened.
Both guys hold a meter stick horizontal to the ground. Each sees their own stick as being 1 meter long. Each sees the other's stick as being, say, 10cm long.
Okay, so if each guy sees the other's stick as "shorter", who's right?
And what if one guy had a tunnel 40m long, and the train was 80m long, the guy in the tunnel sees the train as being 8m long - surely he can simultaneously close a pair of doors and "catch" the 8m train in the 40m tunnel. But the guy in the train sees the barn as 4m long, and obviously an 80m train can't fit in a 4m barn. Who's right?
> > "B-b-b-but the trains are so loud now, they practically forced Johnny to floor it and drive around the gates at the railroad crossing! When they made new trains that could go twice as fast as the old trains, why couldn't they also make them able to stop faster, too? Waaaah!"> > There's a simple solution to that: why not route some of the jet exhaust out of the front of the train. Kind of like a reverse mounted jet engine. Then, when the train needs to stop quickly, the engineer fires up the jet and STOPS.
*evil grin*
I'd love to see that in action. Johnny's pick-me-up truck gets incinerated in a blast of jet wash, windows implode, and then the train, still travelling at 140 MPH, (because even a jet engine producing 50,000 pounds of thrust doesn't do much against a train weighing tens of millions of pounds!) crushes him like a bug anyways.
> You forgot to blame us TiVo users. We upgrade capacity with 2 x 120 Gig drives and they are writing and reading 24x7. The heat in the case can get a little excessive if you are dumb enough to install 7200s instead of the more than fast enough and cooler 5200s. But most of us just want more recording capacity and aren't compensating for anything...:)
In the Middle Ages (ca. 1994) of the 3600 RPM IDE drive, some 5400 RPM drives were called "AV" (audio-visual) drives because they spun fast enough and had funky thermal recalibration and caching features that made them sometimes slower in desktop applications, in order to pretty much guarante a sustained transfer rates suitable for streaming video.
In the brave new world of 7200, 10000, and 15000 RPM drives, the 5400 RPM drives are... well, slower than the average desktop drive, and even better for media use.
The more things change, the more they stay at 5400 RPM?
> > Since when do black holes occupy so much space (I thought they were points)? > >They're big points.
Big heavy points. *G*
(Tried for a/rimshot, but it accelerated to the speed of light as it got slung around, hit the event horizon tangentially, and vanished with a *foop* of radio waves.)
> If such a globular cluster were possible I don't think it would be a matter of a quick change from 'normal' to beyond the event horizon space.
Yeeeeeeeuuuuuuuuuugrh! I hate you;-)
What the other poster said - "For any density, no matter how low, there exists a radius at which a ball of that density will be a black hole. Escape velocity is proportional to sqrt(m/r), and for a ball of uniform density, m is proportional to r^3, meaning the escape velocity is proportional to r. [... and when r is greater than the speed-of-light, anything inside r is in the event horizon, and ain't coming back...] is true.
But...
I just imagined 10-20 neutron stars, all moving towards each other, but not on a collision course. They're aimed by some supernatural billiards player to miss each other by a few miles within a few seconds of each other.
There'll be a point at which, collectively, the grouping of such stars as they whiz about the near-miss point, will have enough mass within a Schwarzchild radius to form a black hole.
But "radius" really isn't the right word anymore. Throw in relativistic frame-dragging effects (brain-meltingly bad enough to imagine for non-rotating neutron stars, and just plain evil if we start with rotating neutron stars!) and the "shape" of the event horizon will be very weird indeed as the neutron stars pass each other and get swallowed up in the resulting mess.
Note to physics profs: Something to torment grad students with! Enjoy! (I think the two-body, non-rotating neutron star setup would make a fun grad-level physics mindbender, but modelling something like the n-body rotating neutron star problem might melt Hawking's brain;-)
Note to folks still hung up on the "size" of a black hole - there are two measures. One, the radius of a spherical (or near-spherical) event horizon, which is pretty well understood as a function of a black hole's mass (except for sick, demented thought experiments such as the "playing billiards with neutron stars" above!), and two, the singularity, which has a size of either zero or is on the order of a Planck length, depending on which brand of theoretical physics your brain maxes out on.
Argh, I fscked up! (Like I said, relativity's weird;)
> From the point of view of you (on the train), looking forward, you'll see the entire universe running about 10000 times normal speed - stars evolving in minutes - and the bullet flying away from you at 2% of the speed of light.
Argh. The sped-up universe is what a guy on the back of the train looking backwards (and the guy on the black hole probe looking up) sees.
The guy on the front of the train (and you, lowering the probe and observing the probe) sees a universe running at 1/10000th speed - a 2.0 GHz Athlon will look like it's running at 0.2 kilohertz and what-not.
> Could you/someone explain to me what would prevent me from building a huge strong ring around the event horizon and lowering a probe from that ring through the event horizon?
The short answer is "relativistic effects".
Near the event horizon, gravity warps space - the conventional notions of "distance" and "time" get fscked up.
What you propose is equivalent to saying "If I'm at the front of a train travelling at 99.999999% the speed of light, and I shoot a bullet forward at 2% of the speed of light, isn't the bullet going to be going faster than light?"
And the answer is, "Well, no. Because space and time are fscked up when you're going very quickly."
From the point of view of a guy standing at the end of the tracks, he'll shine a light down the track, see some X-rays bouncing back from the bullet and the train, before being flattened by both the bullet and the train almost simultaneously.
From the point of view of you (on the train), looking forward, you'll see the entire universe running at about 10000 times normal speed - stars evolving in minutes - and the bullet flying away from you at 2% of the speed of light.
Back to your original question - lowering a probe into the black hole and pulling it out again. Gravity will have a similarly-weird effects.
From the point of view of the guy lowering the probe, the probe will fall towards - but never through - the event horizon. It'll just fall more and more slowly, and if he shines a light at it to observe it, he'll see it get redder and redder, until it vanishes into the infrared.
And since the probe never makes it past the event horizon, he never gets any data back from beyond it.
From the point of view of the probe, and looking up, time speeds up dramatically - in a few minutes, he sees the guy lowering him get change shifts, coming back, growing older, dying, the space station being abandoned, stars evolving, billions of years passing, whole galaxies fading into the infrared, and then when he hits the event horizon, he sees nothing avove him, and if he looks down, then it gets real weird. It's quite literally anybody's guess what he sees. But it's quite certain he can't tell anybody above him a word of it.
Relativity's weird like that. The freaky stuff - time dilation and what-not - has all been demonstrated by experiments involving clocks and airplanes and satellites. (The relativistic corrections made to account for a satellite's motion, for instance, are part of why GPS is so accurate.)
> Theoretcially (we'll likely never have building materials struturally sound enough to test this) light should behave in almost exactly this manner close to a black hole.
Great post. Two basic questions left unanswered in the original article, and a whole host of follow-up questions they've sparked in my imagination...
1) The orbit of this star is described as "eccentric". How eccentric? How close does the star get to the event horizon at its closest point to orbit?
2) Is the star orbiting nearly edge-on to us relative to the black hole (likely, if it's close to the galactic plane), or face-on?
With a period of only 15 years or so, are there points in that orbit at which gravitational lensing effects are significant, and can we get cool data either from lensing or relativistic effects at certain times in its orbit?
Also, how about occlusion events? Can we get data on them? Or is peri"hol"ion (perireallyfsckingbigblackholion!) stuck tantalizingly behind the black hole?
...and finally - and I know this last one's purely a pipe dream - but damn, just imagine what the sky would look like from the radiation-fried surface of a planet that had somehow managed to remain in orbit around this thing, especially during the weeks around periblackholion!
(Oh, the possibilities for a science fiction author. I mean, any species demented enough to try to evolve sentience on such a planet wouldn't need telescopes, would probably call the time their Sun was in the sky "night", and their religious leaders would probably take general relativity for granted until some hereticical freak invented Newtonian mechanics!:-)
> In the railroads' minds, louder is safer. They'll probably take advantage of the jet exhaust by routing it through a huge whistle and horn. It will continuously emit a piercing, deafening alien wail audible dozens of miles away. Railroad crossing accidents will become a thing of the past, because it will be too painful to remain near the tracks as the train approaches.
You're an optimist...
I predict lawsuits from grieving parents of Darwinbait.
"B-b-b-but the trains are so loud now, they practically forced Johnny to floor it and drive around the gates at the railroad crossing! When they made new trains that could go twice as fast as the old trains, why couldn't they also make them able to stop faster, too? Waaaah!"
> Great thought, but if you are going to assign a new word to replace "lose", pick one that is not ALREADY IN USE. Loose is a word, and it already has a meaning.
How about "Luse." (Or "luze", to throw a bone to the 1337 crowd?)
As in, "I hereby loose the hounds of BOFH upon those who can't spell, for they luse badly."
It looks weird at first, but compare it with "fused". It even has similar connotations - burned out, no longer workable, etc.
So a loose fuse can't be fused, and is thus useless. A loose fuse is a lusing fuse until you unloosening it. A fused fuse worse that a loose fuse, it's a very lusing fuse. Luse that fused fuse, (you luser!) before something catches fire!
The proposed conjugation:
I luse, he luses, she luses, we luse.
I lused, he lused, she lused, we lused.
I'm erotic, my friend's kinky, those people are perverted.
I'm a BOFH, my friend's a luser, those people are MCSEs./rimshot.
Now that we've loosed the tight fuses and lused the lusing fuses, can we talk about moose and mice? My sister was once bitten by a moose.
> > > > In Russia they tell jokes about the insane bureaucracy in America. > > >In America we tell jokes about the insane alcoholism in Russia. > >In Russia, they wake up next morning and are sober. >And in England they say "Hey! You stole that line from Churchill!"
In absence of mod points, I've gotta bump that up. *ROFLMAO*
> > Or maybe he's just jealous that the NSA could crack everything and his agency never could. > >
I've heard that historically this has been a bone of contention. The FBI would find some criminal using a home brewed encryption scheme, give it to the NSA. The NSA folks would figure it out on their lunch hour and have a good laugh. Absolutely no comparison between FBI and NSA when it comes to crypto skill level.
I hate to defend Freeh on crypto policy, but it may be more than just jealousy on his part.
Consider that if the bad guy's homebrew crypto scheme was nontrivial, NSA might do more harm than good to disclose that it had been broken. I can think of a time when an FBI prosecutor saying "We used differential cryptanalysis and broke the guy's DES implementation" on the record, in court, would probably have done a great deal of harm.
If that example doesn't ring any bells, imagine the following hypothetical scenario: An overzealous British sex-crimes prosecutor (FBI) in 1940 comes out and says "Alan Turing's encrypted notes [this is hypothetical, remember] are actually homosexual love letters! A guy at Bletchley (NSA) told us about something called 'Enigma' and voila, it's kinda like what Turing's using in his letters! If Turing's using something this complicated just to conceal his love letters, imagine what strong crypto the Germans must have!"
So perhaps it's not jealousy as much as it's sour grapes. Maybe Freeh's pissed that even when a cryptosystem can be cracked, NSA's too smart to tell him about it:-)
> Still only urging, for now. I'm sure at some point one of our fine elected officials will introduce some 'anti-terrorism' bill that mandates government backdoors in crypto, in the interest of 'national security' and 'definding against terrorists', of course.
You're probably right.
But that aside, I'm a lot more comfortable with a now-unemployed Freeh urging businesses to do something stupid, than I was with the Director-of-the-FBI-Freeh trying to force businesses to do something stupid.
As long as Freeh's got the same First Amendment rights as any of us to make an ass of himself, and businesses that listen to him continue to have their Zeroth Amendment right to take his unsound advice and go bankrupt, I see it as win-win.
In a free market, only the clued survive. After seeing the effects of Freeh's domestic security policies on 9/11, and his internal security policies in the form of Robert Hanssen, any company that hires him to advise on crypto policy deserves what it gets.
To be fair, neither 9/11 nor Hanssen were entirely his fault (other folks in other agencies also had to fsck up), but IMHO the culture that he brought to the Agency (a focus on Xtian militia kooks to the point that it prevented anyone from investigating Islamokazi terrorist kooks, and the naive belief that the Cold War was over and that there was no hangover counterintelligence threat from the former USSR) was in part to blame.
(But damn, after writing that, if he ever gets his old job back, I am gonna be so 0wn3d/EM>...;)
> in that year, the chemist Wohler was the first to make synthetic organic substance from inorganic substances. He thus proved that the 'vital force' theory was incorrect.
I was all about to come back with a snappy "Huh? Did Wohler have a fusion reactor to synthesize his own damn carbon?", and then I read this:
After eliminating the guidelines I'd typically used, (and two I hadn't though of!), it appears that the best definition is indeed that "An organic compound is whatever an organic chemist says it is; an inorganic compound is whatever an inorganic chemist says it is."
> The Department of Justice demands their presence in the U.S., but the Department of State denies it. Neither organization is accountable to the other. It's not like the DoJ can say 'well they didn't show up, it's their fault...' > >This is too amusing to NOT be picked up by the media again. I don't think it will result in protests so much as the DoJ and DoS being the butt of jokes for a few weeks, but still.
And then the INS wakes up and says "Hey, he's got a criminal record? C'mon in! Oh, wait, he hasn't been convicted yet. Can't let him in. But since he's here (we didn't find out about his charges until six months after he got here, y'know?), and since he got convicted after arriving, we'll deport him, but we can't do that until after he's served his sentence. After his time's served, we'll just keep him in, uh, "custody" until we can figure out how to deport him. That shouldn't take more than, oh, hell, how am I supposed to know, these forms are hard, maybe, another 4-5 years after his release from custody for us to deport him. If we can't deport him, 'cuz, like, his country won't take him back, well, then we'll just keep him in custody until they change their minds. Can't have folks like that walkin' the street. Oh, wow, is it, like 3:00 already? (*stamps "Approved" on the next two sheets on the pile, some bearded guy named O. B. Larden, and another guy named "Atta" who wants to go to flight school, hey, gotta meet my quota*) Time to go home. Another hard day's work at the INS!"
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Very true. The problem's one of brand differentiation.
At the low end (vast majority), there's Joe Sixpack, who doesn't know anything about what's inside his box, and who doesn't even think there are modular components in it. "Dude! I got a Dell!"
At the midrange (20%), there's most of us. "It's an ASUS or ABit mobo, an AMD/Intel CPU, and an nVIDIA or ATI card. Umm, and a power supply that came with the box."
At the high end (5%), there's folks who know that no-name power supplies suck (IMHO) and Enermax rox (IMHO). But only because we've read from...
Unlike ATI-vs-nVIDIA, where the midrange and high-end folks can plunk in an "upgraded" video card and immediately see the difference between "good" brands and "shitty" card manufacturers, brand names in power supplies have trouble gaining traction, because while they're working, they're indistinguishable from each other.
And of course, when they stop working, it's too late. For that reason, always keep a spare supply handy. Even a "free" no-name supply ($5 bucks from a surplus store) will last you a week until your "real" power supply arrives from the web merchant.
Rule of thumb: Put your hand over the PS's exhaust fan. If the air's significantly warmer than the air in the PC's case, get a bigger power supply.
(I learned it the easy way - a d00d at work got a dual Athlon mobo and just tossed it into his old case, and wondered why it was so warm under his desk while his CPU temperatures were normal. Answer: 2-year old 300W supply + dual athlon + two 7200 RPM disks = one massively overloaded P/S. We threw in a 365W "spare" for the weekend and ordered a 450W that got there by Monday. Air flow out the back was much cooler. Frankly, I'm amazed the 300W supply was even able to boot before blowing itself to hell.)
And besides,
maybe if
Tom put more than
two or three lines
of text
on each page
and 25K of
banner ad HTML
his server
wouldn't get
slashdotted
so easily.
But they don't work without neutrons. It's the goddamn neutral particles' fault. (And besides, like, what have the Swiss done for us lately anyways?)
I don't have a 4600 pound magnet, (you insensitive clod), but that doesn't meant I don't want a 4600 pound magnet! (Surely that also qualifies as beeing geeky enough for birth control purposes!)
Fair enough. But as you point out, the changeover's expensive. Now... what can third-world countries not afford to do, unless we give them the food so they can afford to divert more money towards doing it? *coughNorthKoreaJimmyCartuhcough*
The mobile phone / cell tower method of defeating stealth is interesting, but it's a huge signal-processing problem. More to the point, it's a huge data communications problem. In 5 years, a PlayStation IV will probably be able to do the math... but how's the adversary's third-world-cellphone-mast-radar net gonna get all that data to the CPU in order to do the computations?
I dunno, but I'd bet something TCP/IPish, over wires. Doing it over the air renders it susceptible to jamming. And doing it over wires makes it like the Internet - one bomb dropped on a NAP and *boom*, router tables oscillate and it's lag, lag, lag.
(My personal prediction is that despite the glam appeal of human-piloted jets, 40 years from now it'll all be UAVs piloted by flight sim geeks in air-conditioned trailers. UAVs are smaller and can take G-loads that would black out, or even kill, human pilots. With respect to fighter jocks, I think they'll change their tune the first time they try to train against a fleet of UAVs :-)
That said, I wouldn't bet the defense budget on the notion that "UAVs will make fighters obsolete". A lot of generals said the same thing 50 years ago - that air-to-air missiles would make guns on fighters obsolete - which turned out to be a very expensive mistake, in both men and materiel.
The B-52 has been in service for almost 50 years and anticipated to remain in service for another 30+ years from now. (Yes, there'll be B-52s flying with airframes older than your grandparents!) The F-4 was recently taken out of service, but there are still some A-6s in service. Those planes were in service during Vietnam.
So on what facts do you base your statement about US stealth aircraft will still be true 40 years from now?
And, umm, could you talk to LockMart, Boeing, General Dynamics, Northrop-Grumman, and the US Air Force, because they'd all really like to know what they'll be up against in 2042.
Angry Security Officer: "WTF? God? Who the hell cleared Him for that?"
pr0n! w00t!
>http://lightspeed.sourceforge.net/ but I could be wrong.
More relativistic flight sims and visualizations:
Visual distortions around black holes
Visual effects of special and general relativity.
And finally, an oh-my-God particle - a proton with the mass of a bacterium, the kinetic energy of a brick dropped on your toe, and which, if it were a spaceship, could make it to the edge of the universe in a week and a half (ship-time, that is!).
The universe offered to us by science isn't just stranger than we do imagine. It's stranger than we can imagine. The universe of the mystics and new-age hucksters is positively boring in comparison.
Correct.
Beside the train (or on the train, looking out the window), things are foreshortened.
Both guys hold a meter stick horizontal to the ground. Each sees their own stick as being 1 meter long. Each sees the other's stick as being, say, 10cm long.
Okay, so if each guy sees the other's stick as "shorter", who's right?
And what if one guy had a tunnel 40m long, and the train was 80m long, the guy in the tunnel sees the train as being 8m long - surely he can simultaneously close a pair of doors and "catch" the 8m train in the 40m tunnel. But the guy in the train sees the barn as 4m long, and obviously an 80m train can't fit in a 4m barn. Who's right?
Answer here: A Special Relativity Paradox: The Barn and the Pole.
*evil grin*
I'd love to see that in action. Johnny's pick-me-up truck gets incinerated in a blast of jet wash, windows implode, and then the train, still travelling at 140 MPH, (because even a jet engine producing 50,000 pounds of thrust doesn't do much against a train weighing tens of millions of pounds!) crushes him like a bug anyways.
(Paging Father Darwin, pickup on Track Six!)
In the Middle Ages (ca. 1994) of the 3600 RPM IDE drive, some 5400 RPM drives were called "AV" (audio-visual) drives because they spun fast enough and had funky thermal recalibration and caching features that made them sometimes slower in desktop applications, in order to pretty much guarante a sustained transfer rates suitable for streaming video.
In the brave new world of 7200, 10000, and 15000 RPM drives, the 5400 RPM drives are... well, slower than the average desktop drive, and even better for media use.
The more things change, the more they stay at 5400 RPM?
>
>They're big points.
Big heavy points. *G*
(Tried for a /rimshot, but it accelerated to the speed of light as it got slung around, hit the event horizon tangentially, and vanished with a *foop* of radio waves.)
Yeeeeeeeuuuuuuuuuugrh! I hate you ;-)
What the other poster said - "For any density, no matter how low, there exists a radius at which a ball of that density will be a black hole. Escape velocity is proportional to sqrt(m/r), and for a ball of uniform density, m is proportional to r^3, meaning the escape velocity is proportional to r. [... and when r is greater than the speed-of-light, anything inside r is in the event horizon, and ain't coming back ...] is true.
But...
I just imagined 10-20 neutron stars, all moving towards each other, but not on a collision course. They're aimed by some supernatural billiards player to miss each other by a few miles within a few seconds of each other.
There'll be a point at which, collectively, the grouping of such stars as they whiz about the near-miss point, will have enough mass within a Schwarzchild radius to form a black hole.
But "radius" really isn't the right word anymore. Throw in relativistic frame-dragging effects (brain-meltingly bad enough to imagine for non-rotating neutron stars, and just plain evil if we start with rotating neutron stars!) and the "shape" of the event horizon will be very weird indeed as the neutron stars pass each other and get swallowed up in the resulting mess.
Note to physics profs: Something to torment grad students with! Enjoy! (I think the two-body, non-rotating neutron star setup would make a fun grad-level physics mindbender, but modelling something like the n-body rotating neutron star problem might melt Hawking's brain ;-)
Note to folks still hung up on the "size" of a black hole - there are two measures. One, the radius of a spherical (or near-spherical) event horizon, which is pretty well understood as a function of a black hole's mass (except for sick, demented thought experiments such as the "playing billiards with neutron stars" above!), and two, the singularity, which has a size of either zero or is on the order of a Planck length, depending on which brand of theoretical physics your brain maxes out on.
> From the point of view of you (on the train), looking forward, you'll see the entire universe running about 10000 times normal speed - stars evolving in minutes - and the bullet flying away from you at 2% of the speed of light.
Argh. The sped-up universe is what a guy on the back of the train looking backwards (and the guy on the black hole probe looking up) sees.
The guy on the front of the train (and you, lowering the probe and observing the probe) sees a universe running at 1/10000th speed - a 2.0 GHz Athlon will look like it's running at 0.2 kilohertz and what-not.
The short answer is "relativistic effects".
Near the event horizon, gravity warps space - the conventional notions of "distance" and "time" get fscked up.
What you propose is equivalent to saying "If I'm at the front of a train travelling at 99.999999% the speed of light, and I shoot a bullet forward at 2% of the speed of light, isn't the bullet going to be going faster than light?"
And the answer is, "Well, no. Because space and time are fscked up when you're going very quickly."
From the point of view of a guy standing at the end of the tracks, he'll shine a light down the track, see some X-rays bouncing back from the bullet and the train, before being flattened by both the bullet and the train almost simultaneously.
From the point of view of you (on the train), looking forward, you'll see the entire universe running at about 10000 times normal speed - stars evolving in minutes - and the bullet flying away from you at 2% of the speed of light.
Back to your original question - lowering a probe into the black hole and pulling it out again. Gravity will have a similarly-weird effects.
From the point of view of the guy lowering the probe, the probe will fall towards - but never through - the event horizon. It'll just fall more and more slowly, and if he shines a light at it to observe it, he'll see it get redder and redder, until it vanishes into the infrared. And since the probe never makes it past the event horizon, he never gets any data back from beyond it.
From the point of view of the probe, and looking up, time speeds up dramatically - in a few minutes, he sees the guy lowering him get change shifts, coming back, growing older, dying, the space station being abandoned, stars evolving, billions of years passing, whole galaxies fading into the infrared, and then when he hits the event horizon, he sees nothing avove him, and if he looks down, then it gets real weird. It's quite literally anybody's guess what he sees. But it's quite certain he can't tell anybody above him a word of it.
Relativity's weird like that. The freaky stuff - time dilation and what-not - has all been demonstrated by experiments involving clocks and airplanes and satellites. (The relativistic corrections made to account for a satellite's motion, for instance, are part of why GPS is so accurate.)
Great post. Two basic questions left unanswered in the original article, and a whole host of follow-up questions they've sparked in my imagination...
1) The orbit of this star is described as "eccentric". How eccentric? How close does the star get to the event horizon at its closest point to orbit?
2) Is the star orbiting nearly edge-on to us relative to the black hole (likely, if it's close to the galactic plane), or face-on?
With a period of only 15 years or so, are there points in that orbit at which gravitational lensing effects are significant, and can we get cool data either from lensing or relativistic effects at certain times in its orbit?
Also, how about occlusion events? Can we get data on them? Or is peri"hol"ion (perireallyfsckingbigblackholion!) stuck tantalizingly behind the black hole?
(Oh, the possibilities for a science fiction author. I mean, any species demented enough to try to evolve sentience on such a planet wouldn't need telescopes, would probably call the time their Sun was in the sky "night", and their religious leaders would probably take general relativity for granted until some hereticical freak invented Newtonian mechanics! :-)
You're an optimist... I predict lawsuits from grieving parents of Darwinbait.
"B-b-b-but the trains are so loud now, they practically forced Johnny to floor it and drive around the gates at the railroad crossing! When they made new trains that could go twice as fast as the old trains, why couldn't they also make them able to stop faster, too? Waaaah!"
Yeah, so do I.
Of course, I define "mouse" as "the thing I use to tell X which xterm I wanna type into", so YMMV.
How about "Luse." (Or "luze", to throw a bone to the 1337 crowd?)
As in, "I hereby loose the hounds of BOFH upon those who can't spell, for they luse badly."
It looks weird at first, but compare it with "fused". It even has similar connotations - burned out, no longer workable, etc.
So a loose fuse can't be fused, and is thus useless. A loose fuse is a lusing fuse until you unloosening it. A fused fuse worse that a loose fuse, it's a very lusing fuse. Luse that fused fuse, (you luser!) before something catches fire!
The proposed conjugation:
I luse, he luses, she luses, we luse. /rimshot.
I lused, he lused, she lused, we lused.
I'm erotic, my friend's kinky, those people are perverted.
I'm a BOFH, my friend's a luser, those people are MCSEs.
Now that we've loosed the tight fuses and lused the lusing fuses, can we talk about moose and mice? My sister was once bitten by a moose.
> > >In America we tell jokes about the insane alcoholism in Russia.
> >In Russia, they wake up next morning and are sober.
>And in England they say "Hey! You stole that line from Churchill!"
In absence of mod points, I've gotta bump that up. *ROFLMAO*
>
> I've heard that historically this has been a bone of contention. The FBI would find some criminal using a home brewed encryption scheme, give it to the NSA. The NSA folks would figure it out on their lunch hour and have a good laugh. Absolutely no comparison between FBI and NSA when it comes to crypto skill level.
I hate to defend Freeh on crypto policy, but it may be more than just jealousy on his part.
Consider that if the bad guy's homebrew crypto scheme was nontrivial, NSA might do more harm than good to disclose that it had been broken. I can think of a time when an FBI prosecutor saying "We used differential cryptanalysis and broke the guy's DES implementation" on the record, in court, would probably have done a great deal of harm.
If that example doesn't ring any bells, imagine the following hypothetical scenario: An overzealous British sex-crimes prosecutor (FBI) in 1940 comes out and says "Alan Turing's encrypted notes [this is hypothetical, remember] are actually homosexual love letters! A guy at Bletchley (NSA) told us about something called 'Enigma' and voila, it's kinda like what Turing's using in his letters! If Turing's using something this complicated just to conceal his love letters, imagine what strong crypto the Germans must have!"
So perhaps it's not jealousy as much as it's sour grapes. Maybe Freeh's pissed that even when a cryptosystem can be cracked, NSA's too smart to tell him about it :-)
You're probably right.
But that aside, I'm a lot more comfortable with a now-unemployed Freeh urging businesses to do something stupid, than I was with the Director-of-the-FBI-Freeh trying to force businesses to do something stupid.
As long as Freeh's got the same First Amendment rights as any of us to make an ass of himself, and businesses that listen to him continue to have their Zeroth Amendment right to take his unsound advice and go bankrupt, I see it as win-win. In a free market, only the clued survive. After seeing the effects of Freeh's domestic security policies on 9/11, and his internal security policies in the form of Robert Hanssen, any company that hires him to advise on crypto policy deserves what it gets.
To be fair, neither 9/11 nor Hanssen were entirely his fault (other folks in other agencies also had to fsck up), but IMHO the culture that he brought to the Agency (a focus on Xtian militia kooks to the point that it prevented anyone from investigating Islamokazi terrorist kooks, and the naive belief that the Cold War was over and that there was no hangover counterintelligence threat from the former USSR) was in part to blame.
(But damn, after writing that, if he ever gets his old job back, I am gonna be so 0wn3d/EM>... ;)
I was all about to come back with a snappy "Huh? Did Wohler have a fusion reactor to synthesize his own damn carbon?", and then I read this:
What is the difference detween an inorganic and organic compound?.
After eliminating the guidelines I'd typically used, (and two I hadn't though of!), it appears that the best definition is indeed that "An organic compound is whatever an organic chemist says it is; an inorganic compound is whatever an inorganic chemist says it is."
Thus endeth the lesson. I hope.
>
>This is too amusing to NOT be picked up by the media again. I don't think it will result in protests so much as the DoJ and DoS being the butt of jokes for a few weeks, but still.
And then the INS wakes up and says "Hey, he's got a criminal record? C'mon in! Oh, wait, he hasn't been convicted yet. Can't let him in. But since he's here (we didn't find out about his charges until six months after he got here, y'know?), and since he got convicted after arriving, we'll deport him, but we can't do that until after he's served his sentence. After his time's served, we'll just keep him in, uh, "custody" until we can figure out how to deport him. That shouldn't take more than, oh, hell, how am I supposed to know, these forms are hard, maybe, another 4-5 years after his release from custody for us to deport him. If we can't deport him, 'cuz, like, his country won't take him back, well, then we'll just keep him in custody until they change their minds. Can't have folks like that walkin' the street. Oh, wow, is it, like 3:00 already? (*stamps "Approved" on the next two sheets on the pile, some bearded guy named O. B. Larden, and another guy named "Atta" who wants to go to flight school, hey, gotta meet my quota*) Time to go home. Another hard day's work at the INS!"