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Slashback: Iridium, Synthesis, Drives
In this household, we obey the laws of physics! Tuesday before last, we mentioned that two scientists had announced what they claim is the first accurate measure of the speed of gravity.
Now, Emperor_Alikar writes "In an article on Space.com, many physicists have criticized the current work on the speed of gravity, calling it 'nonsense' and 'simply incorrect.' Many of them still doubt the claims made by Fomalont and Kopeikin even before the results were even announced. Many of the physicists still hold on to the idea that gravity works instantaneously no matter what the distance, an idea that originated by Newton, but that was argued against by Einstein."
Back from the back from the back from the dead. Checkers writes "Spacedaily.com posted the following two stories about Iridium today. The first story is about the DoD committing the first of three renewal options that will use Iridium through 2005. The second story related story is about an agreement inked between Iridium and Harris Corp. that allows Iridium the right to use Harris' OS/COMET satellite command and control system for the life of the Iridium satellite network."
E.T. was also into this scene. In re: matt simpson writes "Another fantastic Speak & Spell modder is Dave Wright of the band "not breathing". You can check his work out, among other modifications to toys, at www.carrionsound.com Dave has made speak & spell/math/read for Nine Inch Nails, Meat Beat Manifesto, and many other bands. Figured you might be interested in other neat synth hackers :)"
Further evidence, never a good time to buy. SpinnerBait writes "It's seems like Serial ATA Controllers have been on the market forever but where have all the Serial ATA Hard Drives been? The wait seems to finally be over, as HotHardware shows with this review and showcase on a pair of new Seagate Barracuda V Serial ATA drives. This article covers benchmarks with the product in single drive configurations, as well as RAID 0. In addition, they show performance on two different SATA controllers, from Promise and Silicon Image. And oh, those nice thin neat little SATA cables! Gotta love 'em."
We've had a few articles about Serial ATA; I hope it lives up to its reputation.
Just to add to the confusion ... probejockey writes "A current article in the Globe and Mail claims SCO will start collecting licensing fees from some Linux users, not all Linux vendors as previously reported here."
Birds of a feather, separate rooms. Finally, Declan McCullagh sent in a few interesting links yesterday regarding the RIAA and its announced opposition to mandated DRM technologies:
"First, here are the photos from today's press conference.
Second, the supposed news of today's announcement was that the RIAA would no longer pursue mandatory-DRM technologies like the Hollings bill. But it was the MPAA that was behind Hollings from the beginning (September 2001). And when Hollings finally introduced his bill in March 2002, it was the MPAA that endorsed it, while the RIAA pointedly did not."
Thanks to Declan for the links.
Wasn't smart enough to get in, either ... Finally, thanks to the several readers who alerted me by email and in comments that the school variously rendered Cal Tech, CalTech and other things even worse is in fact properly spelled "Caltech."
"In this house, we obey the laws of thermodynamics!" Homer mutters this when Lisa, bored at being out of school, creates a perpetual motion machine.
--
Disclaimer: The above statement probably includes half-truths, because real truth is too complicated.
Since this is slashback: What's up with the new karma system?
- Put satellites in orbit
- ???
- Profit!!
It seems they've filled in the '???' part - sell 'em to the DoD.I couldn't help but think about the GPS system though. As the military shifts from laser guidance systems for bombs and cruise missiles to GPS-based ones, the GPS network becomes more and more critical and overloaded. Is the Iridium network being used only for simple voice/data communications or is there a dual-use capability (targeting, whatever) in the network as well?
If the Sun suddenly disappears (hypothetically), would the Earth continue to hold its orbit for 8 or so minutes, or would it go whizzing off into space instantly? Does this new "Speed of Gravity" research change that answer from what it was, say, a year ago?
Now I'll have actual drives to work with the onboard RAID controller. Rejoice.
Dude's name sounds like a boxing match...
Help save the critically endangered Blue Iguana
All general relativists (and for that matter, all physicists) I know think that gravity propagates at the speed of light. In the linked articles, the criticism is that they've measured the speed of light by virtue of the radio photons, not the speed of gravity, which they're claiming.
There's nothing about 'infinitely' fast gravity in the article that I can see, and of the two physicists claiming to disagree with the results, the one who says it is 'nonsense' then refuses to comment any further.
Dr Fish
GPS is a passive system. It can't be overloaded.
You like splinters in your crotch? -Jon Caldara
I think the real problem with determining the speed of gravity if indeed it does have a speed is the fact that we can not turn gravity on and off. Some of the first very very very rough measurements of the speed of light were made by a light source standing away from an oberserver and being turned off and on in a way that an algorithm they designed would use the information to tell them the approximate time it took for the light to get to the observer from the source. The problem with gravity is that we can not turn it off and on. Perhaps even like we can with a magnetic field. Just get a wire, run some current through it and use a switch to open/close the circuit. We could then measure the speed of a magnetic field (if it has one). The inability to turn gravity off and on is the key inhibitor to any substantial calculations on its part. And, I'm sure that when we can turn gravity off and on we really won't care that much anymore about trying to determine how fast it travels
It looks like the Carrion Sound is now officially dead. Gotta love a site whose title describes its hosting status.
Many of the physicists still hold on to the idea that gravity works instantaneously no matter what the distance, an idea that originated by
Newton, but that was argued against by Einstein.
So, if I put gravitons in a microwave will they go back in time?
Man, this topic is so heavy...
Eve Fairbanks says I drive a hybrid!LOL
according to this Inquirer article.
pot, kettle, black?
My Karma is fsck'd up as well. I not posting at the +2 level either. Now I had a few post that got modded flamebait(hey It was, I was in a bad mood) but the karma still shows excellent yet I not getting the bonus.
Any clue what is up?
Slashdot, home of supporters of free software, free music, and free speech.Except for Moderators that disagree with you.
If you haven't already seen one, Iridium Flares are really quite impressive.
It was great. I really could make a call from a remote jungle location, hundreds of miles from the nearest phone, and it worked. There was some latency on the communication, but the call worked. It gave me a sense of safety that I could call for help if I needed it. I still have my handset. I hope they reactivate the consumer service.
They're toast, though, no matter what half-assed "intellectual property" scheme they come up with. I mean, really - who're you going to stay friends with? A girlfriend who gave you your toothbrush back and said, "Bye, and thanks for all the fish," or one who boiled your fucking cat alive? SCO is kicking its customers in the nuts while they walk out the door; they might squeeze a little cash out of them on the way, but they're only hastening the exit. Did I mention that SCO is toast? That quote alone should get them on FC Translation: "We're desperate and rudderless, checking under sofa cushions for spare change. Got any?"
This isn't as much "normalization" as it is "don't take so many drugs when you're designing tables."
Finally, thanks to the several readers who alerted me by email and in comments that the school variously rendered Cal Tech, CalTech and other things even worse is in fact properly spelled "Caltech."
And of course, "Caltech" is pronounced: sall-TEESH
Glad I could clear that up!
The thing is, you wouldn't know the Sun disappeared till 8 minutes after the fact anyways. Wouldn't it be so cool that here we are whizzing off into space for 8 minutes while the sun is still shining brightly.
"What's this strange force pulling us off into space?"
"It's actually the lack of the sun's gravity. The sun must've disappeared!"
"Let's enjoy the last 8 minutes of sunlight while we can! Woohooo!"
<tim><
My understanding is that this has been done, and continues to be done all the time. The Gravitational pull of the Sun preceeds the source of light by 8 minutes.
I would be interested in hearing from someone who has done this experiment for themselves.
Okay, we can't make the sun disappear and watch what happens to the earth's orbit (and really, why would you want to?)
/.'ers, but are there any arguments against this being possible?
/. post - no replies necessary!!! (But the replies will still come. So sayeth the spider)
BUT - what if scientists create an amount of matter and anti-matter, and using very sensitive equipment measure the gravity effect it has on say a hanging weight (ala the two really heavy bags suspended next to each other). Then, all of a sudden combine the matter and anti-matter and measure how quickly the gravity "disappears". (BTW, the antimatter can be "held" in a magnetic field, as opposed to wearing really thick gloves)
Okay, there's a lot of work to be done before this could even be considered, let alone be done in the garage of
I'm not sure if the energy released by the matter/anti-matter combination would interfere in any way (it probably would, for all I know). Also, it's probably not practical to generate a significant amount of anti-matter, and I believe it may have a very short half-life. Also, do we have equipment sensitive enough?
There we go - I've suggested a better experiment, shot it to bits, admitted my ignorance and also taken the piss out of my suggestion a bit! This is the ultimate
Last year, Caldera renamed itself SCO Group, reflecting the fact that the vast majority of its revenue came from the Unix products.
Yeeeeeah... I see.
Well, I'm going to change my company's name to ZQL Enterprises, to reflect that fact that most of our revenue comes from selling farm equipment.
So basically, SCO just wants to get paid for its libraries so when its customers move to Linux and want to continue to run SCO binaries. They also seem willing to help with the transition. Sounds fine to me.
The earlier story about attempting to collect an IP tax on Linux turns out to have been mistaken. I would, however, be surprised if it hadn't at least been discussed.
Ah,
Now I understand. Ok I can now set it to +1 and get the system working the way it was before.
Thanks.
Slashdot, home of supporters of free software, free music, and free speech.Except for Moderators that disagree with you.
"Since the end of the dot-com era, there's a lot more application of intellectual property" in licensing and lawsuits to boost revenue.
Jeez, and here I am working for a living.
Hypothesis: The speed of gravity == infinite
:-)
If the above hypothesis where true then one could (theoretically) build the following device: At place A we have a measurement tool that measures the gravitational pull of an object at place B. At place B we move the object back and forth based on a coded pattern (sending information). At spot A the difference in gravitational pull allows us to decode the pattern (reading information). The time it takes to send this information is based on the time it takes for the gravity 'waves' to reach from point B to point A. Our hypothesis says that this time is 0 so it means that we can now build a device that can send information FASTER then the speed of light. Einstein allready proofed that there is nothing faster then the speed of light.
Conclusion: The hypothesis is FALSE.
(disclaimer: bah, I'm no physicist, so don't flame me for not writing the above proof in a perfect physicist lingo...I tried
Many of the physicists still hold on to the idea that gravity works instantaneously no matter what the distance, an idea that originated by Newton, but that was argued against by Einstein."
I ain't no physicist, but I think i'm gonna go with Einstein on this one. It's like trying to block Jordan when he was in his prime.
Sig:
Barbeque is a noun. Not a verb.
People, we need to boycott this insidious attempt by Micro$haft and the evil **AA along with Senator Disney and the BSA to control our PCs! Join the EFF, delete your Windows partition, and FIGHT BACK against this menace! Power to the people!
oh, Iridium? oops, never mind.
sulli
RTFJ.
hehe, you can assign negative values to people using the karma bonus. That's pretty nice, you can now mod down the big-swinging-cock-because-i've-got-karma people. :-) yaaa
All editorial writers ever do is come down from the hill after the battle is over and shoot the wounded.
The 'original' threat to the BSD effort was the lawsuit over its UNIX roots. The settlement was that BSD did not have UNIX code and did not infringe.
So now the 'threat' to GNU/Linux is the same as the old threat to BSD. At least BSD delt with the 'threat' years ago.
So what if SCO tries to collect money. You can always move to BSD and be Free of SCO. (SCO emulation might have to go in BSD....:-( )
It's a site hosted in the US, run by people who live in the uS. You can always find another blog, or turn off the YRO section or ignore it, or just not read slashdot. All there is to it.
Why not fork?
But the speed of gravy is 0.0023 miles per second (faster on the Lard Lovers buffet table).
Found it...try looking in 'Prefs/Comments'....
"Karma Bonus (modifier assigned to posts where the user has good karma"
Here is a case for why the speed of gravity could (and possibly is) instantaneous:
:-)
To measure the speed of gravity you have
1) point in space WHERE you measure
2) an object in space THAT you measure
the fastest that the object could ever travel is the speed of light, so the fastest change you could ever measure is the speed of the object, thus if we measure that the gravity changes with the speed of light, it might well be that the object changes position with the speed of light while gravity changes instantaneous.
I know that the way the two physisist measured the speed of gravity was indirect, yet that still means that the fastest any object was moving in their experiment was with the speed of light.
Does this make any sense? (just thought of it...not a lot of physics to back me up yet
There are still scientists that argue EVOLUTION. This is nothing new, scientists looking to ride the coat-tails of rising stars in the field by doubting them. Obviously with the results not out before the entire idea was refuted, but this doesn't surprise me. PhD's who are "experts" in their field tend to be arrogant asses when it comes to something they didn't "discover".
Don't believe me, walk on to your local university and sit in on a graduate level class. Some people love to get paid to hear themselves speak.
Ignore the "p2p is theft" trolls, they're just uninformed
No, no, no! The contraversy over the results of the gravity measurement surrounds the MEASUREMENT TECHNIQUE, not the conclusion. You would have to look *really*, *really* hard to find a working physicist who thought that the influence of gravity was instantaneous. You'd have an easier time finding a "Pacifists for Bombing Iraq" organization to join.
Actually, if gravity is instantaneous, then you would percieve the sun as moving away from the earth instantaneously after it vanished due to the earth moving quickly out of orbit. The earth would fling off in a straight line from the sun as soon as it vanished at incredible speed, and the light from where the sun WAS would take longer to reach the earth as the earth moves away.
While you are correct in pointing out that we'd see the light for slightly longer than 8 minutes (with a slight accompanying redshift), the time (and distance) difference is very small.
The time between gravity shutoff and light shutoff is 8 minutes. The Earth's orbital period is about 526,000 minutes. That gives an angle of about 9.6e-5 radians. Over that small an angle, the Earth's orbit is close enough to being straight already that divergence from the path would be negligeable.
For one thing, if gravity was instananeous it could conceivably be used to send information anywhere in the universe with zero ping time. Imagine a gravity-wave wireless link that would enable us to communicate with civilizations in other galaxies. Imagine playing Q3 with an alien on a planet in M3 and still having a 20ms ping.
Now imagine sending energy via gravity waves. With the right technology you (in energy form) could be beamed, Star Trek style, to another galaxy. You could go visit your alien buddy for a lan party and be back in time for dinner.
Unfortunately, the notion of energy (and indirectly, matter) moving at infinite velocity seems to violate the entire theory of relativity. Moving you from here to another galaxy instantly certainly seems to violate the theory of relativity.
Out of every benchmark I've seen of the new Seagate Barracuda V S-ATA drives, _none_ of them benchmark against it's parallel ATA brother, but instead benchmark it against either an older generation drive, or a drive of another manufacturer completely.
Look, if you want to know how SATA performs, benching one of these 'cuda V drives against a western digital p-ata drive isn't going to tell you anything. Those drives from Seagate aren't all that fast compared to drives from Maxtor or WD (or IBM/Fujitsu).
Expecting SATA to speed anything up is pretty ridiculous - the drive mechanism is what determines performance in current hard drives - we're nowhere near ATA drives that can match even ATA100 speeds (even burst rates are only reaching ATA66 speeds, if that!).
SATA won't increase your speed, PERIOD. New generation drives with higher data density, etc., are what speed up drives. The interface doesn't matter in speed.
FYI.
If the speed of gravity isn't infinite, then I think you get a paradox when two bodies are orbiting each other.
:-)
Let's say we have two bodies, body 1 and body 2, both orbiting a central point.
Both of them are getting pulled in towards the central point by the other one. Right?
But if the speed of gravity isn't infinite, each body will be pulled not exactly towards the center, but towards the point at which the other body used to be, a certain time ago.
Try this experiment: You will need:
1 friend
2 tennis balls
1 roundabout (the circular playground variety)
Stand on a point on the circumference of the roundabout, and get your friend to stand opposite you. Spin the roundabout so you are both orbiting the central point.
Now throw your tennis ball at your friend. Chances are you will miss, because your friend will have moved by the time the ball gets there. So now change your aim so that the ball actually hits your friend. Get your friend to do the same.
When you've got things sorted, you should get the tennis balls hitting you from slightly 'front-on' compared to the center of the roundabout.
So what this means is that if gravity has a speed, then each orbiting body will be pulled by the phantom ghost of the other one, which will appear to be slightly behind the center of rotation. Therefore, the two bodies will keep on accelerating, pulling themselves up by their shoelaces, until the orbits around the central point become so huge that the effect isn't very big at all.
In other words, orbits won't be stable if gravity has a speed.
If we assume that 2-body orbits are stable, then gravity must be instantaneous, but this introduces a communication paradox (as pointed out by many other posters).
So we have a paradox! If you were God, would you make gravity have a speed, or not? Or do you make it so friggin' hard to measure that people give up and argue over which physicist has the bigger reputation?
I am artificially intelligent.
"For one thing, if gravity was instananeous it could conceivably be used to send information anywhere in the universe with zero ping time."
According to special relativity, if gravity (or any other form of information transmittal) were instantaneous, you could talk to yourself in the past.
If FTL anything is possible and special relativity still holds true, FTL = time travel. It also throws the concept of causality out the window (and the concepts of "consciousness" and "free will" along with it).
looks startled, then guilty. He starts to say something and stops. He starts to
say something else and stops. Suddenly he seems to see the bulldozer for the
first time, stops starting to say things and starts."
A simple "yes" would have sufficed.
Do you know what "*" does in a glob?
Why couldn't you get a mass large enough that we can measure its gravity, and move it, in a prescribed pattern back and forth in front of the measuring device?
/. doesn't seem to care about the pre tag.
I'll try to ASCII-diagram, where [X] is the thing with mass and D is the measuring Device. The numbers at the side are the time. The dashes are because
t0: D ---- [X]
t1: D ---------- [X]
t2: D --------------------- [X]
t3: D ---------- [X]
t4: D ---- [X]
So, if you begin at rest, you should be able to measure the time between the moving of the mass, and the recording of the change in gravity, right?
The only problem with this approach that I can see is a lack of ability to measure time this closely. Are there others?
-Zipwow
I don't know which is more depressing, that 2/3 didn't care enough to vote, or that 1/2 of those that did are crazy.
The new defaults effectively disable karma; since the bonus is nothing, there is no benefit to having good karma anymore. Basically, its now opt-in and how many people are going to bother to opt-in?
Worse, there is now an incentive to always uncheck the karma bonus, so your good comments more likely to get voted up by moderators who have the karma value set to no-zero. After all, who mods up a comment that is already at the max?
Which brings us to something that must be a bug: the point cap on comments is still 5, though the bonus can go to 6. Thus, I can set the karma bonus to +6, but comments never have values above 5. I don't see how this would ever be the desired behavior.
I've seen a bunch of people point out that GPS is a transmit-only system (think of a foghorn blowing in a pattern of blasts) and doesn't take in any communications itself. I haven't seen anyone smack the original poster around for the "Profit" part.
The DoD never bought GPS, and GPS was NOT created to make a profit. Its signal was even originally encoded in such a way that non-US military receivers could not use it in an effective manner to maintain its original purpose: giving the US military a vast edge in determining exactly where its units were in 3D space. Land and sea units suddenly knew exactly where they were on the map at any time, speeding up navigation or even making effective navigation possible in places like the Iraqi deserts.
It wasn't until civilian GPS receivers had been using a neat hack-ish bit of logic (have a fixed receiver in a known place take in the encoded signals from GPS to figure out how to correct for their signal skewing, then transmit this) for a while that the DoD opened the GPS system to official civilian use and stopped screwing with the signal timings on the satelites.
For GPS I have updated the list:
By the way, how the fuck would someone make a profit from the GPS sats? The only thing you can make money on is a one-time sale price of a receiver unit. You certainly can't charge per-use fees...
I wonder what he thought it would get us...
Great sig!
Truth isn't Truth - Guliani
That was just...beautiful. You're my new hero. Cunt-shunner...I don't even know what it means, but I'm in love with the phrase. I shall use it mercilessly on my enemies from now on. If I didn't just use my last mod-point modding some half-assed Iradium or whatnot humor up, it would have gone to you. Consider yourself granted an honorary +1, Funny.
First you say no one is testing PATA vs SATA,
then you say it won't make a difference anyway.
What exactly was your point? Everyone is ignoring the interface standard, and just testing like any other HDD, but with a nice cable.
BTW the reason no-one is testing the PATA vs the SATA versions of the same drives, is that the PATA version has a 2Mb buffer and the SATA has a 8Mb buffer (with a slightly lower access time). The drives are not comparable.
In the Januaray edition of Electronic Musician:
If you read the article, they imply--numerous times--that the issue with SCO is solely if you are using their libc on Linux in order to run legacy SCO applications. That should not be able to impact Linux in any real way, unless I am grossly misunderstanding something.
A big problem is that gravity bends light. So if gravity traveled instanteously, a star light years away could move causing the light to suddenly change course, but uh-oh that means it is now travelling a smaller distance than before *in the same amount of time*. Suddenly the speed of light is no longer constant.
There would be no clue that anything happened to the sun until 8 minutes after it happened.
Unless we suddenly shift orbits 8 minutes before we see the sun go "blink."
For one thing, if gravity was instananeous it could conceivably be used to send information anywhere in the universe with zero ping time.
No. If Gravity is instantaenous, it's not a force, it's a property. (besides which, if we _could_ alter gravity, it'd be a bitch to find a sensor to pick up the minute graivty vibrations.)
Unfortunately, the notion of energy (and indirectly, matter) moving at infinite velocity seems to violate the entire theory of relativity. Moving you from here to another galaxy instantly certainly seems to violate the theory of relativity.
No, it'd just be in a differenet paradigm. If you achieve instant transmission you're not moving at instant velocity--you're taking a shortcut.
The military loves Iridium and will not let it die until we start hearing about the system they are producing to exceed its capabilities.
The blurb about OS/Comet doesn't really say anything, because Iridium doesn't have the capital to replace something that is a huge part of their infrastructural investment (it'd be like replacing the linux kernel and tcp/ip on your computer without changing any other files and doing it while the machine is running and, oh yeah, you have to write it yourself and nobody else has ever done anything remotely resembling it, including all the ancient, legacied bugs).
The big story would have been if Iridium had told Harris to take a hike, because then we'd get to wonder where Iridium got the "fuck you" money.
Now getting back to what someone asked earlier, what would happen if the sun were to be removed, would the earth spin off or stay in place for 8 minutes. To answer you question i use will use einstien's theory of gravity. He equated space to a 2-d surface, like a trampoline, gravity would warp that surface and create indentions. Ok say i put a bowling ball (sun) on the trampoline, and put a baseball (earth) in orbit of it. Now lets say i pick up the bowling ball quickly (almost instaneously), the baseball does just go off in a straight line, right?. What if i did it slowly?
Now saying that, you all know that you just simply can't move a mass such as the sun faster than the speed of light, heck you can't even make an bowling ball go faster than the speed of light, but the problem is relativity doesn't quite work for very large or very small objects. My theory is that gravity can move faster than the speed of light but the mass that generates it can't so you could never use it to create any paradox that was suggested.
A Fatal OE Exception has occurred, Sig will now reboot.
Many of them still doubt the claims made by Fomalont and Kopeikin even before the results were even announced.
Paging GrammarNazi, come in!
We have a major bogey...
a case of vastly different tenses.
There are two different versions of each 'cuda V drive - 2meg buffer versions (model numbers end in 23A and 23S) and an 8meg versions (model #'s end in 24A and 24S).
The point in saying that it won't make any difference anyway was just to clarify that for people who wouldn't know that, in general, the interface doesn't matter, assuming the interface is implemented correctly, which we won't know until a p-ata version is tested against an s-ata version.
It's... In my sig! 20th Century Vole
What if, on some wild chance, another star of similar size came whizzing in from above the solar system at near light speed and collided with the sun, splattering it downward and away from the solar system. In that case, the sun would be moving at some speed that is close enough to the speed of light for this to be noticeable.
SATA wasn't invented by the industry because of speed limitations.
SATA was invented to lower assembly costs in various sweatshops and to make case design more flexible.
If the simpiler SATA plug saves Dell 5 seconds of assembly time per machine, that adds up to millions of dollars a year.
*ahem*
WAKE UP! There is no difference between "Theory" and "law" in the scientific field. laws MAY have more proof behind them, but that never EVER makes them "fact"
The THEORY of relativity had held up to every test up on it so far.
The second LAW of theromodynamics may have been broken with special substances. i believe this was even on slashdot awhile ago.
In fact, you'll find that the term "law" is legacy. no recent discovery is called law anymore and the older ones are only called law because nobody feels like changing them. (Newton's theories of motion? it has no ring to it!)
Actually, that's only the approximation for points *outside* the earth's surface. Once you cross the boundary that approximation is meaningless.
What's REALLY interesting is that for a point *inside* the earth, the gravitational effect can again be represented as that from a point mass. The difference this time is that you don't give it the mass of the whole Earth, just the bit between the center and the point you're measuring. This is because the net gravitational pull of the other bit (the shell between your position and the Earth's surface) works out to ZERO. So as you approach the center, your "mini-Earth" gets smaller and smaller, and the gravitational effect drops off until it's zero at the exact center.
FTL = time travel
Why? Not being a troll or flaimbait, I'm interested. If I'm on earth at 04:00UTC, Wednesday, then step through a portal to a ship 1 light day away from earth, taking 1 minute for my matter to get to the ship (while still being perfectly conscious), I emerge, according to my wristwatch, at 04:01UTC, Wednesday. I look out the window, with my powerful telescope and see yesterdays newspaper back on earth. I sync a clock on the ship to my wristwatch and step back through the portal to earth, at 04:02UTC, My wrist watch. I emerge at 04:03UTC, My wrist watch, and compare to a control watch on earth, they are the same.
I then wait for 23 hours 55 minutes, and look at the ship with my telescope. At 04:01UTC, Thursday, I see myself emerge on the ship, look through a telescope, then go back through the portal. The clock I see says 04:01UTC, Wednesday.
If the ship then travels to earth at a slow speed (say 0.001c - about 1,000,000km/h), 1000 days later, the ship enters earth orbit, I fly up on the shuttle, and look at the clock. Relativistic forces havent changed the time of the clock by more then a few seconds, if that.
Wheres the time travel? I look back in time, but astronauts on the moon looked back in time to earth when they were 1.5 light seconds away.
In fact one of the big problems with Linux is the extreme fear of changing the defaults on the chance that it will be incompatable. This is why tcsh still does not do the full editing and tab completion by default, why "find" is a pain to use for simple searches, and why programs like make are such horrors to program.
Probably the criticism you wanted was that Open Source often puts *no* checkmark in the control panel. You are supposed to figure out that you can change things by setting an environment variable and you can only figure that out by reading the source.
F*** you you d*** s*** do you f***ing not know what a f***ing * does to a f***ing word thats sprinkled with the little s***s? Or just because some f***ing piece of s*** digital systems use a c***ish * to represent multiple unknown little b****y letters that means that we all have to f***ing start to write the way some c*** wants us all to? Sorry I forgot, you just a typical f***ing /. c*** who likes to f*** with peoples heads by t****ing!
Never underestimate the dark side of the Source
but we can alter gravity! well sort of...
if i remember my physics correctly, the closer you are to an object the stronger the gravity.
now, all you have to do to make "gravitational vibrations" is to move the object towards and away from the object you want to send information to. and also it isn't really a "bitch to find a sensor" we do have instruments designed to measure gravity. maybe they aren't fast enough to measure the gravity waves in this example, but the point is that it exists. and just because you don't know how to do it doesn't mean it is impossible...remember how slow computers were 20 years ago?
so given the assumption that Gravity is instananeous then faster than light communication is possible!
How can it live up to its reputation if it isn't even available yet you dumb tool. It lives up to expectations.
Here's another (and IMO better) review of the SATA Barracuda V. And they don't use that joke of a drive benchmark Sandra.
0 110ST3120023AS_1.html
http://www.storagereview.com/articles/200301/2003
Maybe so, but benchmarks aren't testing assembly time. :)
"Why?"
Because c isn't just the speed of light, it's the speed of change through the universe. Every change in the universe, every interaction between two objects can only move at the speed of light. And if that change in the universe "hasn't reached you" yet, then for every conceivable purpose it simply hasn't happened yet. Period.
"I look out the window, with my powerful telescope and see yesterdays newspaper back on earth."
Here's the tricky part: It's not just that you're seeing an image that left your home yesterday, it's that you are actually looking at yesterday. Yesterday's reality is washing over you like a wave at the beach.
If you see yourself in that telescope, that's not just an image of you, that is you. Changes you made in the universe, everything you did "yesterday" is happening now, as you watch it. As far as space, time, and the universe (from where you sit) are concerned, you are now in two places at the same time. If you were able to step back into your teleportation device, you would end up back on the earth "yesterday."
There's a more drawn-out explaination of the circumstances and the consequences using the classic example of a duel with tachyon pistols here
I just recently stumbled across Metaresearch.org's speed of gravity page.
The article "The Speed of Gravity - Repeal of the Speed Limit" says "[a binary pulsar experiment] places the strongest lower limit to the speed of gravity: 2 x 10^10 x c." It tackles the Special Relativity objection mentioned in another reply.
The article "Possible New Properties of Gravity" goes even further with it. It talks about the orbital effect you mentioned as a specific example right away. It might be a little bit easier to understand than the article above. It dives head-first into what some of the observable consequences are--and that discussion is what makes it much more believable to me. It's what moves him from the "just another crackpot" bucket to the "if he's a crackpot, he's one with a convincing case" bucket.
FTL = time travel
Why? Not being a troll or flaimbait, I'm interested.
It's not easy to explain, but I'll take a shot at it.
If gravity (or anything) is "instantaneous" (or merely FTL) that means it affects a distant point at the same instant. That is a crucial point - it implies that "now" here is the same as "now" at some distant point.
According to relativity there is no independant universal "clock". All time is relative. Different observers see time differently. Without some independant clock it is impossible to say "now" here is the same as "now" over there. Different observers will dissagree on the timing of events. The key point here is that two different observers can dissagree on the order of two events. If you have two supposedly "simultaneous" events then an observer moving to the left at 0.9C would see event B happen BEFORE event A, and an observer moving to the right at 0.9C would see event B happen AFTER event A.
What this means is that if you can send a signal faster than the speed of light then someone moving fast enough in the right direction sees the signal recieved before he sees it sent and he can carry that information back to the place the signal came from before the signal is sent. He can tell you exactly what message you are going to send which means you can use that fast moving observer to carry messages into your past for you. And if the message is the equivalent of a "startrek transporter matter stream" then you could "beam" your self into the past.
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They don't *need* patents. They just need for the SCO C library licence to say that programs developed using it may only be run on genuine SCO Unix. In that case, anyone running such a program would be in trouble -- they wouldn't have to redistribute it.
I suspect the background for this story is that a few long-standing SCO customers with an eye to the future have had a bright young nerd look at how hard it would be to get their vertical application to run on Linux instead of SCO. (Perhaps it's a dental surgery management suite running on Ingres or something similar.) Probably in many cases the customer has a binary app without source access, but that can be fixed with Linux-ABI. It's probably not so hard in most cases.
It's a good deal for the customer: they cut out their SCO licence costs, they get a platform with a bright future, and they have much less trouble finding people who can support and enhance it.
This is a bit bad for SCO, though. Once word gets back to HQ that this is happening, they start to think about methods that can be used to keep their customers locked in. One technique is to exploit the licence that the customer's application vendor originally signed to get the SCO libraries. If SCO were smart enough to put in a "this can only be used on SCO" clause, then they're set!
Anybody who has the source for their applications should be easily able to move to Linux, and probably most of the commercial applications like Oracle already have native ports. Linux-ABI and this licensing strategy really just apply to people with legacy SCO apps who can't, or don't want, to port to Linux.
Microsoft could use such a clause in the Office (or DirectX or MSVC Runtime) licences to put an end to all this Wine, Crossover and Transgaming nonsense, if they wanted to. I think there are enough precedents for that kind of restriction in software licences that it would be possible. For example, lots of driver software comes with a licence saying it may only be used with the vendor's original software. I think this technique is a terrible abuse of customers, like most proprietary software licences. But it would probably work to shake down some more money.
No. If Gravity is instantaenous, it's not a force, it's a property.
Acording to relativity it doesn't matter if you call it a force or a property. If it has an effect that is faster than C then it allows you to send a message into the past.
it'd be a bitch to find a sensor to pick up the minute graivty vibrations
True, detecting it is really really hard, but not impossible. We believe we are on the verge of detecting a pair of black holes and or neutron stars spiraling in on each other. Now a thought experiment - imagine we send a space ship out to a neutron pair and find an asteroid in the system. We could use normal rocket engines to nudge that asteroid between the neutron stars. The asteroid can cause a detectable change in the detectable gravity signal. By carefully choosing the path of the asteroid we can embed a short message into the collapse signal.
And as I said, according to relativity any FTL signal means you are sending information into the past. At this point you might be tempted to simply say relativity is wrong on that point. While physisists admit that relativity is incomplete, they have really good reason to believe you can't throw out that part.
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If the sun disappears (hypothetically) we would only see it disappear 8 minutes later. Think we would go flying off while we still see the sun in place? (Hey, like, what's happening dude, how can we be flying away from the sun?)
Well at least i forgot more about physics, than 99% of americans will ever even think about in an entire lifetime.
A Fatal OE Exception has occurred, Sig will now reboot.
If gravity "waves" would propagate faster than light (or instantly), it would be possible to communicate faster than light (or instantly). Sure, earth is small compared to the speed of light, but even here on earth you notice half-a-second of delay for example in an overseas telefone call due to the speed of light (and 36kkm geostationary orbit of satelites). It would certainly be a win to overcome the speed of light in communication systems, for example when remote-controlling a mars explorer robot (where interactivity is completely absent). Not even to mention realtime communication with alien races.. So unfortunately, gravity is not faster than light. Sorry.
What that really means is that this experiment doesn't tell you much of anything--the outcome is as expected, and it doesn't discriminate among plausible alternative theories.
Search for "kopeikin" on arxiv.org; he has several papers there explaining what the idea is behind the experiment.
It does, but that doesn't mean that gravity propagates instantaneously. Many theories of gravity get that effect with finite propagation velocities. There are analogous effects in electrodynamics.
Yes, it does. But the justification for the theory of relativity is based on not having observed anything that violates it. If we see superluminal communications, then we have. Logically, there is no intrinsic problem with sending information faster than light.
read my previuos comment here.
is what i said. if you use only gnu/linux apps running in plain gnu/linux you don't have to pay.
now, if you use some sort of compatibility layer to run UNIX binaries on gnu/linux they'll charge you a fee.
it's a sane model. after all, it IS their code.
What ? Me, worry ?
However....the jamming can be done with cheap $40 devices, and knowing people like Saddam, there'll be one in every home. Hey, we've declared our limitations - avoid civilian casualties. So, he'll hide the jamming devices in civilian homes. No, GPS is usefull for targetting, but the signal is too easy to overwhelm - it's not a strong signal. They'll use more reliable technology such as terrain mapping and the like...
I always thought it wasn't. Black holes, for instance, slow the speed of light to below zero. Or the velocity of it, anyway. My head hurts.
"News for nerds. Stuff that matters."
Support Israeli punk bands. Man Alive.
If the speed of gravity is equal to the speed of light, and all forms of energy exert a gravitational force on eachother (including light), then it should be possible to test this:
Assume an intense coherent pulse of light of known intensity is traveling through space towards an object. Since the beam is traveling at the speed of light it is not currently exerting a force on the object. The instant the light hits the object, the total gravitational force between the light and the object would occur instantaneously. This gravitational force will oppose the pressure exerted on the object by the light. If the speed of gravity is the same as the speed of light, the gravitational force will be the integral of the gravitational force between the light and the object over the entire length of time the light was traveling. If the measured pressure of the light pulse differs from the theoretical pressure of the light pulse, then gravity must have played some role. If the difference between the theoretical pressure of light and the measured pressure of light is the same as the integral gravitational force, then gravity must move at the speed of light.
Black holes, for instance, slow the speed of light to below zero. Or the velocity of it, anyway.
I won't claim to fully understand Lorentzian transformations, but I'm guessing that this is incorrect. I imagine that an observer standing next to a photon of light would observe it flying past him at the speed of light. An observer outside of the black hole wouldn't see it at all (since you can't see anything until the photon actually reaches you - which it won't). If it arrives it will arrive travelling at the speed of light, but it might take a really really long time (relative to the observer a distance from the black hole) to get there, as time itself passes very slowly at the surface of a black hole.
A real physicist might be of more assitance here, but light going away from the singularity in the black hole does travel at the speed of light away from it - it is just that space is curved such that the singularity is in front of it as much as it is behind it. I guess you could look at it like this:
1. I leave New York, travelling as fast as I can in any direction along the surface of the Earth (which we will assume is a perfect sphere). No matter how fast I run away from New York, I eventually end up there anyway. Why? Because if you travel in a straight line (a great circle) you always end up where you started. Your velocity is not zero at any time - it could even be at the speed of light, but the curvature of the space you are travelling on takes you back to where you started.
Flamebait? A complaint about the non-stop offensive anime topics is flamebait? I'm sorry, that's a very valid complaint.
But the speed of light is relative, right? Since relativity centers around time not being absolute, and speed = time/distance...
I'll admit that i'm in way over my head here, but I'd still like to know.
Just curious, I don't get it. Is there really a past to send messages to in the first place?
Does current modern physics say there is a past?
So far the FAQs etc don't seem to touch much on this.
Fig 1
Dude
Fig 2
Ball
Fig 3
Dude
Fig 1 tosses Fig 2 to Fig 3, and vice versa, on cue, producing a binary transmitter of gravity waves.
If you see yourself in that telescope, that's not just an image of you, that is you. Changes you made in the universe, everything you did "yesterday" is happening now, as you watch it. As far as space, time, and the universe (from where you sit) are concerned, you are now in two places at the same time. If you were able to step back into your teleportation device, you would end up back on the earth "yesterday."
So what you are saying is that because you cant perceive what is going on "now", it's not going on? Isn't that more of a philosophical question (tree falls in forrest does it make a noise)? Because you havent heard an explosion 4 miles away when it goes off, it doesnt mean its gone off.
If its something to do with schrodingders cat and uncertaintly, FTL communications would break the uncertaintly about it, as sure as a CCTV or XRay will break the view of cat in the box.
As for the tacyon pistols, thats a very self centered view of the universe. Because I fire at someone doesnt mean it's there. If I track a plane via sound waves, then fire my laser, I'll miss. It wouldnt look like I had hit the person, as the tachyon "bullet" would travel away from me, and hit the person instantly. However as light is slow, the light from the bullet would take 16 seconds to reach me from where the person was when I fired. It would "look" like the bullet travelled at the speed of light (if it did travel at the speed of light it would look like it travelled at half the speed of light).
To the bloke being shot, He would fire his gun, then get hit at the same time. He'd then (if he didnt die) see the bullet he was hit by move backwards out of him at 1.0c An optical illusion, nothing more.
If you have two supposedly "simultaneous" events then an observer moving to the left at 0.9C would see event B happen BEFORE event A, and an observer moving to the right at 0.9C would see event B happen AFTER event A.
If theres two simultaneous explosions, one (A) at 3 miles north of X, one (B) at X, an observer at 3 miles south of X would hear Explosion B before A, and could then radio in to the observer to the north that explosion B has occured. B doesnt know the explosion has occured because he hasnt heard it yet. He ehars A, then B, and Believes A is nearer then B, which the Southern observer denies.
If I sit here at my computer, I dont know if you are typing a reply until I load up the page. Does this mean I can stop you typing it if I havent read it?
I think this boils down to the "universal clock". Just pick a clock that is the same distance from both people at any given point.
For more then 2 people, pick a clock (Z) that is equidistant between person A and B, and a clock (Y) between C and D, and X between E and F, and W between G and H.
A will see the same time as B (the time clock Z appears to be).
C will see the same time as D (the time clock Y appears to be).
E will see the same time as F (the time clock X appears to be).
G will see the same time as H (the time clock W appears to be).
Then set the clock Z and clock Y to the time that it perceives clock V, equidistant from Z and Y. then Z will see the same time as Y.
Therefore A will see the same time as B, C and D.
Then set the clock X and clock W to the time that it perceives clock U, equidistant from X and W. then X will see the same time as W.
Therefore E will see the same time as F, G and H.
Then set the clock V and clock U to the time that it perceives clock T, equidistant from V and U. then V will have the same time as U.
Therefore A will see the same time as B, C and D, E, F, G and H.
That syncronises watches for people A throguh H.
You are missing the relativity aspect. I'll do my best to explain it, but relativistic effects are bizzare from our point of view.
I bet you've never traveled more than about 400MPH (on an airplane perhaps). 400MPH is less than 0.0000006 of the speed of light. The size of the relaivity effect at 400MPH is 0.0000000000002. You have been essentially motionless your entire life therefore you've never seen what happens when you move. That effect is real and it messes up your example.
It is not merely a matter of a delay in hearing the explosion. For a moving observer one explosion REALLY DOES happen before the other. You want to pick one clock in the middle to look at, but there is nothing special about that clock. All points of view are equally valid. Someone else's clock is just as valid as the one you picked.
That syncronises watches for people A throguh H.
Realativity says time is not fixed. For a moving observer the seperated clocks really truely are not sychronized. I assume you've heard of the twin paradox? That's the one where you age more slowly if you take a trip near the speed of light. It's the same thing, time itself gets distorted and changes. If the two explosions are seperated by a distance of one light-hour then for some observers explosion A really does happens up to one hour ahead of B, and for other observers explosion A really does happen up to one hour after B. And they both are equally correct. The only thing everyone can agree on is that your clock sitting halfway between them has a reading half way between the explosions.
The reason this matters is that we can create messengers traveling close to the speed of light. We can use subatomic particles to carry messages. And for those particles the order of events really is different. If the order of events gets too far out-of-whack then someone will see an effect happen before a cause. That is sending a signal back in time.
If two points have a distance of one light hour between them then the timing of events has a "fudge factor" of up to +/- one hour depending on who you ask. But that one hour fudge factor doesn't cause a problem because it takes at least an hour to get a signal from one to the other. One hour +/- a fudge factor of up to one hour is always greater than zero. Different observers will dissagree how long it too the signal to arrive, but everyone gets an answer greater than zero. If you could get a signal from one point to the other in less than an hour then for some observers the fudge factor of minus one hour means the message took a NEGATIVE amount of time to get from one point to the other - it arrived before it left - the signal went backwards in time.
The point is that if we arrange it right then WE can be the ones to see the signal go back in time. The observer can be a stationary human and points A and B can be two subatomic particles moving left or right at close to the speed of light. If an effect or signal can get from A to B at faster than the speed of light then WE will see that signal go backwards in time.
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Funny that it's not in some Physics FAQ somewhere. I've been looking for quite a while (avoided bad pun ;) ).
;).
I'll try to understand the FTL + Relativity = time machine thing.
The FTL effects of two separated entangled particles thing is funny tho. Coz I'm thinking: Isn't the Universe already entangled too?
There should be a "So..." somewhere, I just haven't figured it out yet
Link.
My point/hypothesis was if you take the universe as a whole (and entangled), the "is"/"already" effect could become more understandable.
When you do something to a particle, you and the particle (and friends) could be like coherent light from the same source, just split a long while ago. Sure that's a bit recursive, but I doubt one should assume the observer/experimenter/experiment as being in a fully independent universe from the tested particles.
It may turn out that we have independent sources but can we assume that?
There may not be multiverses (but due to limits we may still have to resort to calculations using that concept).
The speed of light in a vacuum is constant in all frames of reference. Any observer will always measure the speed of light to be c. That means that if you turn on a flashlight just as I'm wizzing by at a speed you measure as being 99% of c, we both see the same photons moving at c relative to ourselves.
In relativity neither time nor distance is absolute in all frames of reference. A fast moving observer would measure a given distance as being different as an observer at rest (of course, even the term "at rest" is silly since to the "fast-moving" observer the "at-rest" observer is just moving fast in the opposite direction).
Right now there is no way to assign an absolute speed to an object. You could argue that the Earth is stationary in the universe, or you could argue that everything in the universe is moving in a particular direction at any arbitrary speed whatsoever. If the speed of light were relative this would not be the case. You could set up a speed-of-light measuring device and move it in various speeds and directions until you found a configuration that gave you a maximum figure. Then you would know that this frame of reference is truly at rest, as it is moving the slowest relative to light. In reality, this is not possible, as the experiment would come up with the same answer in every configuration. This is similar to the experiment that demonstrated that light does not propagate in the "Ether" - as the speed of light did not change with respect to the motion of the earth.
They don't know how the world is shaped. And so they give it a shape, and
try to make everything fit it. They separate the right from the left, the
man from the woman, the plant from the animal, the sun from the moon. They
only want to count to two.
-- Emma Bull, "Bone Dance"
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