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'Einstein Probe' Delayed
isorox writes "The BBC is reporting that a NASA satellite designed to test frame dragging, predicted by the theory of relativity, has been delayed for 24 hours because mission control couldn't verify the correct software had been loaded. The probe was proposed 35 years ago, but has never had the funding until now. The question remains is what happens if Frame Dragging isn't observed - will the experiment be wrong (in other words there's no point to it), or will we get faster-than-light ships for Christmas?"
-- johntracy.com, because everybody else is wrong.
I'm voting for warp drive on this one!
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You expect negative results from good experiment in science sometimes...
There are four possibilities:
1) Bad result, but result appears to confirm the prediction - this is not a successful experiment
2) Bad result, but result appears to invalidate the prediction - this is not a successful experiment. Possibility of an insufficiently sensitive instrument, or just a badly designed experiment.
1) Good result, but result appears to confirm the prediction - this is a successful experiment - a negative result is as valid as a positive one.
1) Good result, and result appears to confirm the prediction - this is a successful experiment
because mission control couldn't verify the correct software had been loaded.
Man, I must have missed a career as NASA flight controller, because I feel exactly the same way each time XP goes to windowsupdate.microsoft.com...
"A door is what a dog is perpetually on the wrong side of" - Ogden Nash
The question remains is what happens if Frame Dragging isn't observed - will the experiment be wrong (in other words there's no point to it),
Then you have a Type II error, methinks. It's not that you are wrong outright (like a Type I error. You've just missed the chance to reject the null hypothesis correctly was munged. Refine. Try again.
Comparing it to Windows will be a moot point, since El Dorado is going to have a 40% larger code base than XP.
by British scientists!
--- You shall know the truth, and the truth shall make you mad- Neal (not Cowboy) Boortz
Its 2004, I was supposed to have my flying car and a moon base by now. These "scientists" dont have their priorities straight.
*beep* wrong answer Obviousguy
Try the russians don't care for safety for $600.
Whenever I try to run games at too high resolution on this computer, the frames just start dragging along...
you dumbass .. that's like saying Newton was wasting his time coming up with his theories .. I mean who knew there'd be any practical applications of figuring out the laws of physics?
They had built the pyramids and horse & buggy just fine without Newton.
Frankly, I hope they find that einstein was wrong and that there is a way to easily "bend" what we observe in the curvature of space time.
Imagine a warp bubble rendering the contents essentially massless, thus the input energy for kinetic motion is miniscule enabling fantastic speeds.
However if they are right, that might mean that general relativity rules and we are forced to live by it's law (It's still a theory, will this make it a law?). How unfortunate.
Never let your sense of morals prevent you from doing what's right. --Isaac Asimov
Will we get faster-than-light ships for Christmas?
only if your name is Joao Magueijo
Hmm..... perhaps this 24 hour delay is nothing more than good ol' special relativity kicking in: the satellite only appears to be 24 hours behind because it's going so fast!
The question remains is what happens if Frame Dragging isn't observed - will the experiment be wrong (in other words there's no point to it), or will we get faster-than-light ships for Christmas?
:)
Let me put it this way:
Greetings from next Tuesday!
As a classically trained scientist, I'd be loathe not to point out a misconception here.
Experiments themselves are never 'wrong' experiments are merely poorly designed or interpreted. If they are niether of these then the experiment simply gives you data which you must explain. If it doesnt give you the expected results, it may not be the design that is in error, but instead our understanding of the world.
Data never lies, except when viewed through a human bias.
What, it doesn't have a CLI with telnet access?
Gravity_Probe_B # show version
Gravity Probe B software version 0.9.1
I'm sure it's got a Cisco interface
faster-than-light ships for Christmas
:P
Antimatter not included
Candle burns its brightest in the dark
That image is piss-funny :-)
I am artificially intelligent.
Excuse me, but are you nuts ??
The American space program is one of the safest in the world, thats why they're being so cautious with the shuttle fleet.
The Russian space program on the other hand has been known to take huge saftey/performance/cost trade offs in order to get things off the ground ( no pun intended ). Just because the Russians are launching day and night does NOT imply a higher operational saftey. You are mistaking the effect for the cause, sir.
That means it will have to take off yesterday instead of the day before.
Except that the general theory of relativity was created because newtonian gravity violated the speed of light. If this test showed that frame dragging did not exist, we would be have to figure out a new way of making those two consistant, and (on the surface at least) one (unlikely) possibility would be that some things can travel faster than light.
The aliens invented the horse and buggy?
"You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
install hfnetchk, it'll check the installed versions of dlls vs the updates.
microsoft repackages this as the baseline security analyzer
I've read that frame dragging had already been reported in astronomical observations, and that this is expected to be an important but unsurprising laboratory confirmation of the phenomenon.
I guess one could accuse certain modern physicists of coming up with "theories that fit reality". But we should remember that Einstein came up with his theories when most of them could not have been possibly proven correct or wrong, so there are at least some theories there, that are not after the fact descriptors of reality but true predictors of the behaviour of the universe.
As far as the usefulness of this, it is also usefull to know how the world around you works. Take nuclear physics -- i am sure people would have characterized the early experiments with radium as pointless, but now the long term future of humanity depends on nuclear energy. The ultimate destruction of humanity also depends on nuclear energy. So whether you are pro or anti humans, nuclear energy is your best bet!!!
In this case its called "foot dragging", not "frame dragging".
Table-ized A.I.
The American space program is one of the safest in the world
Funny, I sort of remember that Soyuz capsules have a better safety record than space shuttles. Hell, they're even used as emergency reentry vehicles on the ISS...
"A door is what a dog is perpetually on the wrong side of" - Ogden Nash
The question remains is what happens if Frame Dragging isn't observed
You can listen to John Turneaure, co principle investigator for Gravity Probe B. He was interviewed by Ira Flatow on NPR's Science Friday.
When Ira Flatow asked him what would happen if the probe did not find anything and that Einstein might be wrong, he "hemmed and hawwed" a lot and said that wouldn't be the case - that Einstein was right. He also mentioned that the data would go to a physicist and then be released to the public.
It's not that I'm wearing a tin-foil hat (well maybe), but science is based on conducting experiments in the open and openly sharing data with an unbiased view and procedure, even if it means that Einstein might be wrong.
If they really wanted to do this neat, they would stream the data live to a website, rather than can up the data until they are ready to release it.
There are critics of Einstein that are academically serious and not off their rocker like some zero point/tesla fanatics. There have been critics of Einstein ever since he released his theories. You don't hear much about them as they are all heaped into one group and astrocized.
I am not saying that Einstein was wrong (not in the sense that Newton was wrong either), but that true science is keeping an open mind, rather than cower to the politically favorable theory of the moment.
As an aside, frame dragging is like when you take a single electric mixer and use it in a bowl of pudding. Or when you use an electric stirrer in a can of paint. That is frame dragging.
This happens because gravity is a field (according to Einstein). Newton treated gravity like a force.
Physicists reading may improve upon this anology.
Take the cheese to sickbay, the doctor should see it as soon as possible - B'Elanna Torres, "Learning Curve"
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Isn't 'special relativity' just a special case of 'general relativity', as the name implies? That is, general relativity includes constancy of light speed, inertial frames (as a special case) and all the results of special relativity.
Of course its delayed, if you know anything about relativity, you would know that as things move closer to the speed of light, it has an more significant effect on relative time.
Its moving very fast, and actually ahead of schedule acording to atomic clocks on board; however, according to the time that we perceive it is delayed by 24 hours.
"...test frame dragging, predicted by the theory of relativity... will we get faster-than-light ships for Christmas?"
What does frame dragging have to do with faster-than-light?? The wikipedia link mentions nothing about how frame dragging has to do with faster-then-light, so I searched google and found this article on msn:
"Spinning black holes may pull in gaseous matter from their sister stars as a rapidly rotating "accretion disk," analogous to water circling down a bathtub drain.
The American scientists built on their previous research into the mass and spin of black holes to look for signs of space-time distortion, or frame-dragging.
In Einsteinian physics, the space-time continuum is often compared to a sheet of rubber. Mass creates a gravitational "dimple" in that space-time sheet. But a rotating object -- like a spinning black hole -- adds an extra twist to the dimple. Matter caught in that twist would appear to wobble in orbit around the object, like a toy top wobbling on its axis.
Cui explained that travelers passing close to a black hole would feel as if "nothing happened." But a distant observer would see the travelers being dragged around the black hole."
my karma will be here long after I'm gone
A question for physicists?
:: electricity:magnetism
You know how there is an electric force caused by electric charges and a magnetic force caused by the movement of electric charges. Then when you study maxwell they tell you that the electric and magnetic forces are really two aspects of one force.
Is frame dragging the result of a force that is equivalent to magnetism for gravity. In SAT analogy terms, is:
gravity:frame dragging force
To observe time warping, they will launch a probe into space with balls in vacuum flasks frozen to near absolute zero 400 miles above the earth. They are making it hard. There is really nothing to time warping.
It's just a jump to the left
And then a step to the right
Put your hands on your hips
And bring your knees in tight
And it's the pelvic thrust that really makes you insane
Let's do the time warp again!
Let's do the time warp again!
How ya like dat?
Which means that the satellite could end up sucking me up into space?
Diego
diegoT
Don't worry,
time is relative...
The question remains is what happens if Frame Dragging isn't observed.
Then they'd better figure out if their experiment was badly designed, because frame dragging has already been observed by other research platforms.
NASA's Rossi X-Ray Timing Explorer observed frame dragging in a distant system consisting of a binary pair of black holes. This was back in 1997.
Analysis of the motion of two earth-orbiting satellites, LAGEOS I and LAGEOS II, also reveals frame dragging going on. This was also over 4 years ago, and it's the result that this Einstein probe is supposed to refine.
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I think you're confusing soyuz, which is a capsule, with launch vehicles.
the shuttle is both (kinda).
'There is a Light that never goes out.'
yeah give me 10 feet of steel and lets set if it survives reentry!
hell we've moved past simple caskets of steel to something more of a truck in outer space.
Building a ship to go faster than the *speed* of light is (relatively, ha ha) easy. Building a ship to *pass* light is difficult. No matter how fast you chase after that light (even if you cross the universe in seconds!), it will always remain 300,000 km/sec faster than you are! And if you do manage to reach light speed (good luck) you'll be just as frozen in time as photons are. In other words, you'll get to travel the universe, but you'll never know that you did it.
Of couse, the only way we know we're travelling "faster than the speed of light" is that we can measure the time between our point of origin and our point of destination. Time dilation makes sure that we're never able to pass light. If there was nothing else in the universe but your ship and light, you'd have no way of knowing that you were moving! How annoying is that?
Javascript + Nintendo DSi = DSiCade
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you dumbass .. that's like saying Newton was wasting his time coming up with his theories .. I mean who knew there'd be any practical applications of figuring out the laws of physics
They had built the pyramids and horse & buggy just fine without Newton.?
While I completely agree with your sentiment towards the original poster, I think it has to be conceded that no scientist can see any practical application coming out of this for a long time.
That being said, I think just increasing our knowledge of the universe is a valuable endeavor in itself. We are very impressed when we realize that such and such ancient culture could predict astronomical phenomena (even if the exercise was not very useful to them). I think it is amazing to live in a time when many of life's deepest mysteries are being solved.
Tor
If this test showed that frame dragging did not exist, we would be have to figure out a new way of making those two consistant, and (on the surface at least) one (unlikely) possibility would be that some things can travel faster than light.
Why do you humans always misquote Einstein. General relativity states that nothing can *accelerate* to the speed of light. It says nothing about things already going the speed of light. Experiments in Photon / Quantium Tunneling have indicated that photons can apear to tunnel through barriers faster then light.
mean who knew there'd be any practical applications of figuring out the laws of physics?
You can not change the laws of physics
laws of physics
laws of physics
You can not change the laws of physics
Laws of physics Jim!
There once was a lady named bright
Who travelled much faster than light
She set out one day
In a relative way
And returned on the previous night
The Anal probe is on full speed ahead!!
Doesn't the emission of entangled-quanta already violate thee speed of light? I believe this was tested in the Aspect Experiment.
Also, I just took a course in the philosophy of physics but the one thing I never understood was how anything going was than the seepd of light would ruin Einstein's theory? If another THING was found that was faster as light and had the same speed in all inertial frames wouldn't that be sufficient? You could have THING-cones (where volume(THING-cone) > volume(Light-cone)at any time T --by volume I mean the fourth-dimensional equivalent), and things that are currently space-like seperated could be reclassifed as THING-like(for things faster than light but slower than THING) or space-like seperated (faster than THING), and this could account for the Aspect results. It also wouldn't need to violate the rule of not travelling faster than the speed of light since it could be mass-less and then as it approach and crossed C it mass would still be zero as opposed to approaching infinity.
IANAPhyisicist but IAALPhilosopher
Your CPU is not doing anything else, at least do something.
Unfortunately, black holes are sparse in this neck of the woods
_UN_fortunately?
According to the Wiki, frame-dragging has already been observed within 20% of predicted value. If this probe doesn't detect it, it's definitely worth taking a long, hard look at the experiment, given that past efforts have already seen it - just not with anything resembling precision.
NB: YMMV. IANAL. Take the above with a grain of salt.
Neither does the expense that goes into things. This is not intended to prove a point on its own, but the ratio of safe to unsafe launches is one point to consider; the number of unsafe launches, on its own, is another. In this case, "unsafe" is determined by Mother Nature proving it so.
If they've cut corners wisely, the fact that they've cut corners is less significant than some might want us to believe.
NB: YMMV. IANAL. Take the above with a grain of salt.
HTH.
I emailed the GPB team a long time ago to ask where I could submit predictions about the probe.
Anyone could have seen problems coming.
They sure didn't want to hear any predictions though, saying it would lessen the results they where seeking by introducing prediction into the experiment.
That confused me, wasn't it a prediction they were testing anyway?
Regardless, it's a seriously complicated experiment where the onboard electronics can introduce and infect the instrumentation with the very information they are trying to measure.
Have *not* heard if they ever fixed that problem.
Suspicious if you ask me.
If you wanted to save face, you'd launch anyway and come up with an excuse later cause any PR is better than failure at this late stage in the game.
It's a beer bet gone bad I fear, but in this black box experiment, gratefully anything can happen.
Ah, but the question becomes are the powered by Cold Fusion?
Your CPU is not doing anything else, at least do something.
search for superluminal object or motion.
Things DO travel faster than the speed of light, they just can't slow down and cross that barrier, no more than we can speed up past it.
BS in Physics taught me that....
Ground controllers could not verify the rocket had all its correct flight software loaded, and halted the launch.
I bet they're wishing now they'd kept the About box in the spec.
In Soviet Russia, Soyuz launches you.
I'm really sory if my question sounds stupid, but...
I thought that the fact that, time was distorted by variation in relative speed was already proven and actually had to be taking in account with GPS sattelites.
Or did I misunderstand and it is another property of General Relativity, that they are trying to prove.
Murphy(c)
frmdrgtst --version
Yes, one could accuse modern scientists of that. It's when they come up with theories that don't fit reality that we accuse them of being WRONG.
why not?
What kind of software / hardware / techs does NASA pay for? It seems like the cheap stuff to me. Rovers with bad flash hardware. Shuttles that blow up. Techs that can't use version control. I have to hope that we don't have to endure another disaster.
Why the name Gravity B? Was there a probe called Gravity A?
That website looks extremely fluffy to me, masked by a veneer of professionalism. How can I verify your claim that these guys have serious criticisms of Einstein? Where on that site is the list of NPA-authored critiques of Einstein, published in respectable peer-reviewed journals?
While we're at it, try the list of NPA members on that site. Halton Arp is an astrophysicist who did good work once, but then descended into crankdom. Arp is pretty much the only guy who doesn't agree that his statistical analysis was flawed; check the Harvard astronomy abstract site for the rebuttals. And then they cite Kieren's flawed Compton shift explanation of redshift. This does not engender confidence in the NPA. While these people may be "academically serious", they are also wrong, and refuse to admit they are wrong.
Yeah, so? There have been critics of every theory ever produced. The question is, how good is the criticism?
Nonsense. Go read Cliff Will's book Was Einstein Right?, or his living review, particularly this section and its references.
You don't hear much about alternatives to GR nowadays because most of the alternatives have already been falsified, except for the ones that are so similar to GR that experiment can't distingish between them. Go back 80 years and you heard a lot more criticism. GR became the mainstream theory of gravity for a reason: it worked, and the alternatives didn't.
P.S. In my experience, whining about how alternative theorists are ostracized is a dead giveaway of a crackpot. Real scientists know that all theories are honestly criticized, and they can point to the literature in which alternatives have been proposed.
...John Titor, by chance?
> > Unfortunately, black holes are sparse in this neck of the woods
:)
> _UN_fortunately?
Well, in most necks of the woods they're actually rather dense.
HOO-ha!
---- I'll take you in a Hunt deathmatch any day.
Hm, you're wrong there. As your speed approaches infinity, your mass also approaches infinity. Thus, the energy required to accelerate you ALSO approaches infinity. Therefore, it would take an infinite amount of energy -- more energy than you could get, even if you converted the entire universe to pure energy.
:)
So, you'd have to already be traveling at, or greater than, the speed of light. It is impossible to accelerate past it. However, you're right that, even then, you would measure the speed of light as being exactly c faster than you.
I've read a lot years ago that said there was some basic proof they did indeed exist or could be artificially created or something. but it's been ages since I've seen a single word on this subject.
so if tachyons are real, then they do travel faster than light. remember, there's nothing in einsteins ideas saying you CANT travel faster than light, from what I remember its just basically saying you can't accelerate to faster than light.
but if you "jump" (warp, etc) or whatever, then you kind of side-step the issue, not really breaking the physical laws. I mean all sorts of weird things happen inside black holes that violate our natural laws (hence a whole new section of physics just for black holes). like time moving backwards, etc...
but really I'd be curious if anyone had any updated info about tachyons or the like? are they debunked now or what?
No matter, energy, or information is propagated faster than light in quantum entanglement.
Einstein's theory itself doesn't forbid something from going faster than light. (However, there are problems with FTL objects and causality, such as observers for which effects take place before causes, and tachyons also destablize the vacuum in quantum field theory.) It does forbid objects from crossing the c barrier (which would require infinite energy).
In a theory with Lorentz symmetry (i.e., relativity), there is only one invariant speed: the speed of light. There can't be another speed (faster or slower than c) that is invariant in all inertial frames.
In relativity, massless objects can travel at only one speed (c), neither faster nor slower.
If I get a vote...I want the 'faster-than-light' ship for Christmas!
Jason Lockhart
Virginia Tech
weebaldman
Why do you humans always misquote Einstein.
:-)
Because schools nail silly ideas into people heads, and Einsteins book "Relativity: An Explaination That Anyone Can Understand" wasn't so easy to understand?
General relativity states that nothing can *accelerate* to the speed of light.
Err... I thought that was Special Relativity. General Relativity deals with the way that gravity works. i.e. Gravity is acceleration. Therefore, matter and energy must curve space-time to make a "downward" slope.
That being said, you have the "halfway" problem of accelerating to light speed. As you accelerate, time dilation increases. As time dilation increases, your engines are less effective to an external observer. Therefore it becomes a lot like drawing a line halfway to the destination, then drawing another line halfway of the remainder, ad infinitum. You'll never reach the end. And because your mass increases, you could only use a rocket (converts your near infinite mass -> energy) to make the transition. An external force like a particle accelerator doesn't have enough energy (infinite) to push you to light speed.
It says nothing about things already going the speed of light.
Correct. When a collegue of Einstein's suggested that it was impossible for an object with mass to reach light speed, Einstein felt compelled to point out that a photon has mass and it travels at light speed.
Experiments in Photon / Quantium Tunneling have indicated that photons can apear to tunnel through barriers faster then light.
That really has more to do with Quantum Mechanics than relativity. Overall, the photon is incapable of exceeding light speed. However, it can temporarily "steal" a bit of energy from nearby particles to tunnel out of existance and into existance elsewhere. The amount stolen is then payed back, resulting in a zero sum gain in velocity.
There are many things in this universe that appear to defy light speed. Unfortunately, not one of them is capable of transmitting useful information faster than light. Considering that this holds true at all levels of physics, one would almost conclude that the universe is out to "get" us.
Javascript + Nintendo DSi = DSiCade
Give me my orbiting brain lasers. Linux powered of course
You misunderstand. To the observer on a rocket, they can travel ten, one hundred, or even one million times the speed of light. He never actually *passes* light however. It would seem to him that light speeds up just to frustrate him.
What's really going on is that time is dilating. And since our rocketman measures speed as "distance traveled per time", he calculates his speed differently than an observer watching him on Earth would. To an Earth-bound observer, his rocket ship never exceeds light speed. All that appears to happen is that his engines appear to slow down their rate of burn. To the observer on the craft, he's still accelerating at the same rate he always was. So the rocketman can jet home in ten minutes (hey, you actually CAN get anywhere in 10 minutes!), but everyone at home will have aged by however many lightyears he traveled.
Does that make sense?
Javascript + Nintendo DSi = DSiCade
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Here's a link for you on this oddity of relativity:
http://www.fourmilab.ch/cship/cship.html
Remember, everything is relative. All frames of reference are equally valid, and there is no "universal speeed limit". There is however, a universal time dilation limit. Once you reach light speed (impossible with a rocket or particle accelerator), you'll be forever frozen in time (just like a photon).
Javascript + Nintendo DSi = DSiCade
When Kepler figured out the planetary orbits, he envisioned invisible brooms sweeping the planets towards the sun. When I read "gravity is just curved spacetime" I think of Kepler's brooms as they both seem to say about as much.
Saying "mass warps spacetime" doesn't explain how it pulls that stunt anymore than answering who was pushing Kepler's brooms.
Just how does mass warp space? How does space know the mass is around? What particle is gravity's carrier? If there is a gravity particle, how come planets don't speed up as they plow into them orbiting the sun? And how come it gets to escape black holes but no other particles can come out and play?
I find it really weird that here we are 400 years after Kepler and Newton figured out planetary motion and we still don't know what the heck makes it work. We can describe gravity's effects but we can't say how it does the trick.
...because mission control couldn't verify the correct software had been loaded.
"Excellent, Johnson; so we're all loaded and set for -- hold on, did you just say 'running on WINDOWS ME'?! Crikey, Johnson, stop that rocket! Abort! Abort!!"
There are only 10 types of people: those who understand decimal, those who don't, and, uh, 8 other types I forget.
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Allow me to clarify. Our rocketman takes a trip from Earth to Alpha Centauri. His rocket is so powerful, that he makes it there in 6 months his time. Rounding the distance to an even 4 lightyears, means that he's traveled 8 times the speed of light! And yet on his journey, he is never actually able to pass a photon. The blasted little buggers keep running ~300,000km/sec faster than he is! He then gets back to Earth in another 6 months and finds that everyone has aged ~10 years more than he has.
He soon learns that to everyone on Earth, time has passed much more quickly. So much more quickly, that they were able to observe the fact that he never exceeded light speed. "Poppycock!", he says. "I got there and back inside a year!" Which from his frame of reference is correct. But because everything is relative and all frames of reference are equally valid, the observations that he never traveled faster than the speed of light are also correct.
Javascript + Nintendo DSi = DSiCade
Disclaimer - I worked on the Gravity Probe B (GPB) team back in 1994-1995 while I was an undergraduate at Stanford. Due to personal interest, I watched the launch attempt on NASA TV.
While technically correct, the post's claim that the lauch was delayed "because mission control couldn't verify the correct software had been loaded" doesn't convey the whole picture of what happened.
Well prior to T minus 4 minutes, three weather balloons had reported excessive (out of limits) high altitude wind shear. This wind shear would have caused the launch to be delayed for 24 hours.
However, shortly after T minus 4 minutes, a fourth weather balloon reported that windshear had dropped to within acceptable limits. At this time, the flight profile of the delta II rocket needed to be updated to successfully guide the rocket through the high altitude wind shear and in to GPB's desired orbit.
The launch window for GPB is very narrow - about one second. This is because GPB needs to be in a polar orbit in the plane of a particular guide star.
A launch director from Boeing (Boeing made the delta II rocket) could not confirm that the flight profile had been successfully updated. So, with the clock counting down, he made the decision to "hold" the launch. Upon review, all the launch directors agreed that this was the correct decision.
So, you have a situation where, under time pressure, about 300 seconds before launch, due to changing launch conditions and unverifyable equipment status, a conservative and correct decision was made to delay the lanch 24 hours - until the next one second long launch window.
The other thing to consider is that the closer you get to launch, the more costly and complicated it is to abort the launch. So even though confirmation of a successful profile upload may have come later, if it hadn't, the costs of scrubbing the launch would be higher.
While it may be fun to bash NASA, just remember that it really is rocket science, at least in this case.
I think it was appropriate:
He still cannot accelerate to or past the speed of light. If he were enclosed in a box traveling at a constant velocity => lightspeed, then yes everything would appear normal to him, and it's only the stationary observer who would notice anything odd. However, assume that same box is ACCELERATING to lightspeed, and suddenly the man in the box is exposed to all of the effects that entails. Namely, mass going to infinity, and energy required to continue acceleration going to infinity.
.... But the more massive an object is, the harder it is to increase its speed. .... Since a the mass of a muon increases without limit as its speed approaches that of light, it would require a push with an infinite amount of energy to reach or to cross the light barrier. This, of course, is impossible and hence absolutely nothing can travel faster than the speed of light."
Let me dig up a reference...
The Elegant Universe, by Brian Greene, PhD (from Oxford)
Page 52
"You may have wondered, for instance, why6 we can't take some object, a muon say, that an accelerator has boosted up to 667 million miles per hour -- 99.5 percent of light speed -- and "push it a bit harder," getting it to 99.9 percent of light speed, and then "really push it harder" impelling it to cross the light speed barrier. Einstein's formula explains why such efforts will never succeed. The faster something moves the more energy it has and from Einstein's formula we see that the more energy something has the more massive it becomes. Muons traveling at 99.9 percent of light speed, for example, weigh a lot more than their stationary cousins. In fact, they are about 22 times as heavy -- literally.
but now the long term future of humanity depends on nuclear energy.
...
;-) ...
Say what?
I thought the long term future of humanity depended on how we are going to solve some trivial little problems like over-consumption of resources to over-produce energy and consequentially pollution; overpopulation; inequality of our social, political and economical environments regardless of population size;
I don't see how nuclear energy solves any of those problems, especially if you're suggesting that we should release even MORE energy than today.
I can see how those problems could be at least approached by scaling _down_ on practically any- and everything the so-called modern man is taking for granted. Scale down on energy production to scale down on wasteful consumption. Scale down on junk production 'cause we really aren't so fucked up in our minds yet that we couldn't live without our disposable cellphones. Scale down on pre-produced entertainment so our minds won't GET that fucked up. Scale down on selfishness because honestly, do we really think we've deserved all THAT?
Oh, don't mind me. Just keep the ball rolling and we'll all have a Really Cool Time really soon now.
After all, everyone's loving it. No?
Offtopic, I know, but isn't that just the way with this shit every time, every where? Yet notice how my rant allows frame dragging research to continue -- people certainly aren't taking that for granted
The man's been dead for decades and now someone wants to "probe" him? What kind of sick world are we... errr... ohh... (hahaha)... oh, you mean a SPACE probe. [shuffles offscreen] ;p
Un-news
Quoth the poster:
The probe was proposed 35 years ago, but has never had the funding until now.
This is so, so, so wrong. This thing is the thing that wouldn't die. It's been expunged by congress zillions of times, and every time ressurrected. . . it's a hard project, and some things had to be done several times (witness the super-duper round quartz gyros), and a whole host of other technological feats of wonder had to occur, first. But to blame the lengthy wait on a lack of funding is an incorrect conclusion on the part of the poster.
Special Relativity is the special case of General Relativity when there is no matter to bend spacetime.
General Relativity has "constancy of light speed" and "inertial frames" just the same as Special Relativity. Light travels a null-geodesic in both SR and GR. If you had faster than light travel in one theory, then it would be easy to bridge that to the other theory, they go hand in hand. The difference between the two is usually just a matter of changing metrics and covariant derivatives.
+5 Sheesh.
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Actually, at the speed of light, traveling towards the arth from Alpha Centauri, light from Sol would be traveling at 600,000km/sec in relationship to him. Light originating from his ship would be travling at normal speed to him, but faster or slower in perspective to anyone (or anything) he was passing.
That's something I don't quite grasp.
The milky galaxy is spinning at x km/s. The galaxy itself is moving away from the center of the (our?) universe at x km/s. A photon on the outward rotation of our planet, on the outward rotation of our solar system, on the outward rotation of our galaxy, moving away from the center of the universe (myself, as my girlfriend says I believe) would be traveling far faster than say a photon moving in the opposite direction from say the opposite side of the same planet.
To each other, their relative speeds would be 600,000km/s, even though to the casual observer standing on the planet, each one would be moving at 300,000km/s.
A photon moving towards the center of our universe could/would encounter one of our example photons moving outward from the center of the universe at a *MUCH* higher speed.
We'll name the photon coming from our planet at max speed Pa , and the incoming photon Pb.
Pa = speed of light (it's speed at creation) + rotation of the planet + rotation of the galaxy + rotation of the universe
Pb = speed of light (assuming it came from an absolute stand still in relation to the universe)
So, the speed of incidence would be Pa + Pb, which to either photon would be rather high.
A little NASA trivia
So, if you were to walk across your yard (at the equator) at 4mile/hour in the same direction as the rotation of the earth, you're really moving at roughly 1004 miles/hour.
Serious? Seriousness is well above my pay grade.
He still cannot accelerate to or past the speed of light.
:-)
You're missing the frame of reference. Yes, you can't actually *catch* light. Light speed will always be light speed. But from a frame of reference on a rocket ship experiencing time dilation, you can most certainly accelerate to a speed that would *appear* faster than light.
So thanks to time dilation, I can make it to Alpha Centauri in 6 months. But to everyone back home, it took me 4 years. Which one is correct? The answer is that both are. To the observer on board the ship, he's traveled 8 times the speed of light without ever passing a photon. To the observers on Earth, he's never gone faster than light speed. You see, it's all relative.
An interesting aspect of our universe is that every particle is already traveling light speed. (It's in Elegent Universe. Go ahead, look it up. I'll wait.) The trick is that our trajectory is in 4 dimensions. By traveling faster in three dimensions, we travel slower through the forth. i.e. Everyone on our slow planet is aging very quickly. We just don't know it because we have no other frame of reference. But if you speed up to 99.99% of c, you will age much more slowly than people on Earth. The reason is that you are now traveling slower in the forth dimension.
If this isn't making sense to you, then you need to reread Elegent Universe.
Bonus link on the Speed of Light.
Interesting tidbit: Einstein called his theory (in original German) "The Theory of Invarients", since the speed of light was constant in all frames of reference. It was an english speaking collegue of his that dubbed it "Theory of Relativity".
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Date: Mon, 19 Apr 2004 17:57:17 -0700
From: Bob Kahn
To: gpb-update@lists.Stanford.EDU
Subject: Gravity Probe B Launch Postponed 24 hours to April 20,
GRAVITY PROBE B LAUNCH POSTPONED FOR 24 HOURS
Today, a launch hold was called three minutes before the scheduled
liftoff of the Gravity Probe B spacecraft. Marginal upper level wind
conditions had been observed throughout the countdown, and there was
insufficient time to confirm that the Delta II rocket had the correct
wind profile loaded for the data from the final weather balloon. The
launch of Gravity Probe B has been re-scheduled for tomorrow (Tuesday),
April 20, 2004 at 9:57 AM Pacific Daylight Time, from Vandenberg Air
Force Base in South-central California.
If all launch conditions are not "Go" at the scheduled launch time
tomorrow, the launch countdown will be stopped again. If this happens, it
will be necessary to stand down on Wednesday, while the Dewar's guard
tank is refilled, and then another launch attempt will occur on Thursday,
April 22 at approximately 9:49 AM. And, if conditions are not "Go" on
Thursday, another attempt will occur on Friday, April 23 at 9:45 AM.
Should further launch attempts be necessary, we will post updated launch
information on our Web site and in this email update.
Yes, i cant wait for CNN to start reporting bush's thoughts on the probe, and how it is proof that we are moving allong, dispite the terrorists threats and we should all be in bush's debt. Thank you CNN. All hail bush.
This all begs the question "How does frame dragging actually work?"
"Begging the question" refers a very specific logical fallacy. It is not the same as saying "this all raises the question" or "this all prompts us to ask the question," etc.
You're forgetting a key fact: length contraction. A moving frame appears shorter than a stationary frame by a factor of gamma. This counteracts the time dilation, which is also by a factor of gamma. Thus, when a spaceship travels from here to Alpha Centauri, the distance the ship travels is smaller than the distance we measure here on earth. You take the distance value measured by the spaceship and divide it by the time value measured by the spaceship and you will always get a value less than the speed of light. In fact, the value you get will be the same as the speed of the spaceship as measured from earth. Taking into account time dilation without time contraction is an incorrect calculation.
There's a flaw in your scenario. As your rocketman goes faster, space contracts more in the direction he is travelling. That means that Alpha Centauri gets closer to Earth, according to his frame of reference. He's able to get there in 6 months only because the dialation has contracted the distance from Earth to it to less than 6 light months.
What a fool believes, he sees, no wise man has the power to reason away.
Where to Publish Your Paper
- If you understand it and can prove it, then send it to a journal of mathematics.
- If you understand it, but can't prove it, then send it to a physics journal.
- If you can't understand it, but can prove it, then send it to an economics journal.
- If you can neither understand it nor prove it, then send it to a psychology journal.
- If it attempts to make something important out of something trivial, then send it to a journal of education.
- If it attempts to make something trivial out of some-thing important, send it to a journal of metaphysics.
I'm sure folks can add a few items suitable to this conversation and Slashdot."It is a greater offense to steal men's labor, than their clothes"
Actually, at the speed of light, traveling towards the arth from Alpha Centauri, light from Sol would be traveling at 600,000km/sec in relationship to him.
You're off by a factor of 2. Light travels ~300,000 km/sec to all observers.
Light originating from his ship would be travling at normal speed to him, but faster or slower in perspective to anyone (or anything) he was passing.
Nope. Light originating from his ship would travel ~300,000 km/sec to him and anyone else who might be watching.
So, the speed of incidence would be Pa + Pb, which to either photon would be rather high.
That's Newtonian physics, which Einstein disproved. The speed of the photon will always be Pb. Have you read "Elegent Universe" yet? It's the best explanation I've ever seen. In short, we're all traveling at light speed through four dimensions. By traveling faster through space, we travel slower through time. This scales so perfectly, that we will always measure light as going ~300,000 km per one of our current seconds. We may actually be reaching 99.9999% of the speed of light, but it will seem to us that light is still traveling at ~300,000 km/sec. If we manage to obtain light speed, our time dilation will become infinite and we will forever be frozen in time. Thus photons never age, because they expend their entire velocity in only 3 dimensions.
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Not really. The main motivation for the general theory was simply that Newtonian gravity (or more specifically, the Newtonian gravitational potential) failed to make predictions which agreed with observation. The most well-known example of this is the precession of perihelion of Mercury. If you're referring to the fact that Newtonian gravity imposes no upper bound on velocities, then you're correct, but this was more an illustration of the fact that Newtonian gravity was largely irreconcilable with special relativity.
Nope. I am afraid that the parent was correct and that you may have misunderstood him.
Einstein's motivation for GR (General Relativity) was that SR (Special Relativity) is inconsistant with NG (Newtonian Gravity). NG does indeed predict faster than light effects. If you wiggle a particle on one side of the galaxy, then a particle on the other side would feel that immediately.
This is a theoretical motivation, and not a physical motivation. Once you have SR, you immediately have to fiddle with gravity. He would have had to do this even if we had no conflicting evidence against NG.
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Don't know if I'll get a personal response but what the hell. You mentioned those pictures of "a ball placed on a rubber sheet" to illustrate the curvature of spacetime. Here's my question: Since most of these massive bodies are relatively spherical, wouldn't the "curve" around the entire sphere cancel itself out since the same curve on the other side of the sphere would be the same but 180 degrees opposite? And if that's the case, wouldn't the total curve be zero and massive bodies don't actually curve spacetime? I'm not a physics guru and would really like to know. Thanks.
Taking into account time dilation without time contraction is an incorrect calculation.
;-)
'Tis true. But our rocketman can *think* that he's traveled faster than light because he takes the measurements before his trip. If he then uses those measurements in his speed calculation, he'll find that he's traveled faster than light. Given that it's very difficult for our rocketman to make a measurement without again involving time, he could be forgiven the mistake. His only way of measuring the distance is by measuring via light. Since time is passing slower for him, a light year appears to have contracted into a much shorter distance.
An external observer might also note that our rocketman is quickly becoming flatter than a pancake thanks to Lorentz Contraction.
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Response is here.
;-)
When it comes down to it, it's all about the fourth dimension. Space only appears to contract because travel through the fourth dimension has slowed. Of course, since everything is relative both space contraction and time contraction are equally valid viewpoints of the same observation.
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I'm not sure I understand why they feel the need to probe Einstein. Despite being dead, I'm sure he would mind so-called scientists sticking cold, metal devices in his corpse's rectal cavity.
True story.
No, I think you mean:
1) Bad result, but your graduate advisor yells at you. This is not a successful experiment.
2) Good result, but your graduate advisor takes the credit for it. Your advisor might consider this a successful experiment, but then he also calls you his "lab bitch" at faculty luncheons. Call it a draw.
3) Good result, but you will be unable to reproduce it ever again. Like the fabled WOW! event in radio astronomy, this tantalizing glimpse of success will haunt you through your waking hours, spent alternately drinking and working as an assistant manager at Radio Shack.
4) Bad result, but your graduate advisor is "accidentally" vaporized in the process. Although not strictly a successful experiment, you hear no complaints from your fellow grad students, the surviving faculty members, or the long-suffering department secretary as you are lead to the police car, leaving your former lab (and former career in academia) in glorious, if somewhat radioactive, flames.
Hope this helps!
to probe Einstein, even if you're a necro, and that's just gross.
WWJD? JWRTFA!
and after we figure that out, please dear god let us focus all this brain-power on solving the chronic switching of a's and e's in slashdot posts...
pr0n - keeping monitor glass spotless since 1981.
I was actually just talking to my advisor about this (astronomy chair) and the basic idea is this: the scientific communtiy has been killing this project constantly (he several times graphically depicted shooting something on the ground) just to have someone in congress decide to bring it back. It's the most illconceived experiment - they are trying to measure not only what has been completely PROVEN but also in the most inane manner. Just about everything else that affects the gyroscopes are larger effects, what they are trying to detect is so small. When this was first thought up, it was probably kind of novel, but we're beyond that (can you say strings) now and its just one messey experiment (would you want to do the math for that?).
So why not work on something useful like alternate propulsion systems or batteries that keep my mp3's coming for more than 10 hours....
The last comment in the cited Wikipedia entry has some timing issues:
"Recently, the project was delayed 24 hours."
There are many things in this universe that appear to defy light speed. Unfortunately, not one of them is capable of transmitting useful information faster than light. Considering that this holds true at all levels of physics, one would almost conclude that the universe is out to "get" us. :-)
Maybe it's the other way around -- a hard speed-of-light barrier essentially makes interstellar war on any scale impractical. This could be why we're still here and not a Borg colony. It won't stop us from colonizing this system, and in the long run won't prevent colonizing with generation ships, but unless aliens have a much longer life- (and attention-) span than us humans, they're not going to bother attacking us.
Mal-2
How is the Riemann zeta function like Trump rallies? Both have an endless number of trivial zeros.
Yes, everything you say is true. Except this:
"But from a frame of reference on a rocket ship experiencing time dilation, you can most certainly accelerate to a speed that would *appear* faster than light."
Nothing you've argued backs that up. I've read a lot about this recently, and everything I've read contradicts that statement. I see you're familiar with the book, and I understand everything you're saying -- but what you're saying doesn't lead to your conclusion.
I will point helplessly back to my quote. Dr. Greene wouldn't have made that absolute statement in the last sentence if he didn't mean it (his writing style is very careful not to use superlatives carelessly). I don't claim to be an expert on these subjects, but I've read some well-informed opinions. Maybe my understanding is lacking somehow, but I don't believe it is.
Sorry we can't seem to resolve this. You've been a great sport though, and I appreciate the dialogue. I'll keep an open mind. I'm continuing my attempts to learn this stuff, so I'll keep my eyes open for this kind of thing, for sure.
The speed does not change, but the color does.
Maybe it's the other way around -- a hard speed-of-light barrier essentially makes interstellar war on any scale impractical.
Poppycock! If you had colonies/armies that always traveled at high percentages of c, then they'd all be within similar enough frames of reference that they'd be able to easily carry out wars. To everyone on a "slow" planet, a war would take anywhere from hundreds to millions of years, but to the factions fighting it's all happening within real-time.
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Photons have mass? I thought they were classic examples of massless particles?
Photons do not have mass.
Ken Thomposn built Gravity B as a constrained version of Gravity BCPL. Once K&R got their hands on the technology and added a type system, they were ready to launch Gravity C. Gravity C++ soon followed in an attempt to incorporate Quantum Mechanics.
/. articles, there is much talk about Gravity D; hopefully it will have some nice black-hole garbage collection.
A perfect SuperString implementation has yet to be added to the language, although many incompatable approximations exist.
As we know from recent
But in your example, the particle doesn't appear to us, no matter how much we accelerate it, to go faster than light. But what if we were in the frame of reference of the particle? It doesn't mean anything in that frame of reference. Sure the particle would still not be able to pass any photons but it would see the rest of the universe approach being frozen in time, much like the approach to a black hole.
Err.. obviously I meant it would observe everyone else moving faster and faster through time.
Correct. When a collegue of Einstein's suggested that it was impossible for an object with mass to reach light speed, Einstein felt compelled to point out that a photon has mass and it travels at light speed.
Photon's have zero rest mass. The only mass they have is a relativistic consequence of their velocity.
M.
Forgive me if this has already been stated somewhere else by someone better qualified, but I was too lazy to keep scrolling down. Oh well...
Sure, it'd be possible to send armies of men (or whatever) and machines at near-lightspeed, and take advantage of relativistic time-distortion, but no matter the outcome, it'd be a one-way trip. Even if they ever won and returned home, it would be to find a world to which they no longer belonged. I can't think of many people patriotic enough to want to cut themselves off from everything and everyone, no matter the threat.
On the other hand, if you really, really wanted to fight a war across interstellar distances, why bother with living beings at all? Just send some sort of handy self-replicating machine-thingy their way and wait. You really only need to send one automated factory, with maybe one as a backup. It arrives at the destination years later, starts cranking out whatever machines and vehicles it needs using stuff from asteroids or comets or whatever, and eventually wipes out the enemy. If you have the capability to build a self-replicating factory and then send it across interstellar distances in the first place, designing one smart enough to fight a war on its own wouldn't be very hard.
The way the headline's worded, I'm thinking that Einstein is pretty nervous about his probe and wishing the doctors would just stick it in there and get it over with instead of these damn delays.
newtonian gravity violated the speed of light.
You mean the theory that a magical force pulling two masses together violated other theories.
Assume there is constant stream of particles moving from every direction to every other direction but are so small that that they have a one in 10^$BIGNUM chance of hitting anything. They just happen to travel at c and their mass is small enough that they won't rip apart a molecule when it gets hit. Assume that they work just like standard Newtonian physics. Anything accelerating close to C would need an ever increasing energy to do so and the gravity==acceleration works out fine and at an atomic scale, things would end up being compressed. If you do this with a lump of cesium and treat it as a very tiny mechanical clock, this theory matches exactly what the GPS sat clocks do as they go around the earth. The deacceleration forces would also be in the same realm as the unexplained forces on the last Pioneers.
Newton invented the calculus because he wanted to do calculations with this theory (with bigger, slower particles) but it was beyond his ability.
At this point in time, I figure any crackpot gravity theory is just as wrong as whatever is being tought in Physics classes just as Alchemistry was wrong even though it was the basis for the dye industry and taught in the best schools in the world. All the current theorys are good enough for most work but then again I can get around using a map pretending the world is flat too but it doesn't mean its correct.
Hmmmm..
So, if we're in the expanding universe, which is moving at near the speed of light, time is really dilated to almost infinitely slow to the outside observer?
Serious? Seriousness is well above my pay grade.
Us humans? What are you, a vulcan?
The BBC article has it slightly wrong. The launch was delayed because of changing high level winds, and they could not confirm that the launch vehicle had the proper information loaded. Details here.
Since most of these massive bodies are relatively spherical, wouldn't the "curve" around the entire sphere cancel itself out since the same curve on the other side of the sphere would be the same but 180 degrees opposite?
No, because the curves are in different places. A bowling ball on a trampoline doesn't *not* distort the trampoline just because it's spherical, and space-time is the same way.
Of course, the trampoline analogy is a little flawed, because space-time is represented as a 2D plane instead of a 3D volume. It's kind of hard to visualize the distortion in 3D, though.
"...always new atoms but always doing the same dance, remembering what the dance was yesterday." -Richard Feynman
Hmm, I can't see where the problem is...
So, no problem at all...
plim-plam-plompudding
...but also whethere or not mass bends space/time. The probe was designed to test for both, and includes a set of gyroscopes for this purpose. These contain the most spherical spheres ever constructed. The mass bending thing was to be tested by measuring the length of the orbit. If an inch is 'missing', mass bends space/time. Imagine if massy objects were placed on a sheet that was anchored along the edges. They sag into the sheet. An object orbiting one of these objects now has a shorter distance to travel than if the objects did not cause the sheet to sag.
I have all the answers. You just ask the wrong questions.
This aired last Friday on public radio:
Talk Of The Nation Science Friday
Seek to 27:30 for the start of the audio program on Frame Dragging.
To blog is sublime
The problem with GPB is that it measures a pretty uninteresting effect and takes a lot of money to do so.
Why is the effect uninteresting? According to the parameterized post-Newtonian (PPN) formalism, which describes most reasonable extensions of Newtonian gravity, frame dragging is a combination of only two effects: the amount of curvature of space caused by matter and lack of spatial isotropy, each given by a parameter. In GR, those parameters are 1 and 0, respectively.
Now, we know the amount of spatial curvature caused by a mass. With that, frame dragging of the amount predicted by GR is pretty much a given unless there is significant lack of isotropy.
So, GPB becomes a very expensive test to see whether space is isotropic. But even at that, GPB isn't a very good test: if its results disagree with General Relativity, we learn something, but that result is very unlikely and there would be better ways of looking for anisotropy. If GPB's results agree with GR, however, we have learned nothing, because there are many ways in which this particular experiment could fail to observe anisotropy even if it exists.
GPB's results should agree with GR. If they don't, then the most likely explanation is an engineering mistake. If they do, GPB will be hailed as a great "confirmation" of GR, although in reality, we will have learned nothing.
I'm not sure what you're trying to describe. I'd tell you to ASCII a diagram, but that probably wouldn't help. Your problem is with the actual geometry anyway, which I probably wouldn't be able to help you with, so I'm just going to do this quick explaination of what the rubber-sheet crap is supposed to help you visualize and hope it gets somebody somewhere.
We have a ball, it's moving. Let's just say that it's moving through the time dimension of spacetime, for the sake of clarity. We also have a second ball, moving alongside to the first. As far as they're concerned, though, they're stationary. They can't see anything that isn't moving, so they assume both of them are motionless. They're wrong, though. They're moving, and they're also curving spacetime by their mass. Newton's laws still work here, so our balls are trying to move in a straight line. However, since the surface they're moving on has become curved, the shortest distance between points is now also curved. This forces their paths to converge, and since they aren't aware of their motion in the first place, all they see is the motion towards eachother, and the centripedal force pushing them together is gravity.
Einstein hasn't always been right. In the later years of his life, he made some very stupid statements like 'If the quantum theory is correct, then the world is crazy.' However, the quantum theory has been proved in several cases.
I believe Dr. Green statement is from the view of the observer, not from the view of the Muon.
of course, from inside the muon, photons would pass you at the speed of light.
in the previous posters example, the man never achieve the seed of light when compatered to a photon, or when observerd. However, if calculated his speed based on how much distance he travelled during a specific time(the time would have to have been from a timer inside the ship) it would seem as if he travelled faster then light.
This effect is caused by the fact that the man's time has slowed down.
Now, if you took time dilation(relatve to where he blasted from) into effect when calculating his speed, then No, he never would have travelled faster then the speed of light.
This is why when giving an example using light speed, it's usually something like:
"Two spaceships approaching each other at 90% the speed of light relative to some third observer..."
The Kruger Dunning explains most post on
Simply put, a massive object like a spaceship cannot travel faster than light since it would require infinite energy.
..and thanks to people who so much believe in ancient fairy tales that they want to outlaw anything that would threaten their own way of living I might be forced about 50 years from now to stop pursuing what I think is the meaning of life: wisdom and knowledge.
However, this only applies to POSITIVE energy density (=mass) of the spaceship.
An advanced civilization could collect enough negative energy from for example a large array of very powerful lasers using spinning mirrors to make one of their spaceships to have NEGATIVE MASS.
With a negative total mass when accelerating it's mass would increase ever getting closer to 0 and when moving at c the mass would be exactly 0. After that, it could gain more speed (and positive mass from velocity - rest mass would of course still be negative) just like photons can temporary move faster than light (for example tunneling).
One notable feat of this level of technology is that it would allow them to freely enter and exit event horizons and view the singularity. Also, time travel would naturally be trivial as well as practically limitless lifespans but I assume that this level of species had already made itself immortal a long time ago - one of the major reasons that history seems to repeat itself here on Earth is the very short lifespan of the current dominant species of this planet.
Capitalization is the difference between "Helping your uncle jack off a horse" and "Helping your uncle Jack off a horse"
Well, that depends on why you want to fight a war. If you just want another planet's resources that you can use to replicate more of your own kind, then it doesn't matter if you ever return to your home world.
___
It's the end of my comment as I know it and I feel fine.
If a photon had mass, it would appear to have infinite mass when travelling at the speed of light.
Infinity. Not good.
# cat
Damn, my RAM is full of llamas.
Or a big black slab?
btw any one read Joe Haldemans Forever War?
"goatse? What's that? Anyone have a link?" - AC
So what happens when all that space trash we've been hearing about starts to crash into this thing?
Free Image Hosting
Correct. When a collegue of Einstein's suggested that it was impossible for an object with mass to reach light speed, Einstein felt compelled to point out that a photon has mass and it travels at light speed.
But a photon has no rest mass, unlike the objects that cannot reach light-speed.
Posters recognized by their sig,
My mother is a religious nut and she drags quite a few other religious nuts into the house. However, they're just plain vanilla Catholic nuts so they're not too wacky - ie accept that evolution happens even if they think there is a purpose behind it etc... But I end up getting into quite a few atheistic world view vs. religious debates which I enjoy thoroughly.
But the "well, it's just a theory" thing drives me insane. I didn't study science in university, and I didn't go to any special high school or anything, but I do know the difference between a scientific theory and what a detective on TV means when he says, "I have a theory about those murders...". It's partially the fault of these "creation science" nutters and partially the fault of the churches in general shrieking ""God! Evidence of God!" whenever scientists run into something they can't instantly explain, but sometimes it seems like it's a wilful confusion. I sometimes get the sense that people who know better deliberately confuse others... Anyway, it's personal pet peeve and frankly, unless you're trolling, if you're posting to
No No No....
We need to transfer our conciousness to machines....
Then 300 million years would be a *short* period of time.
I want to live to see things change on a geological scale, don't you?
WhiteWolf666 an exBush supporter. All you new-school,compassionate,save the children Republicans can rot in hell
Einstein breathes a sigh of relief as the box of rubber gloves is placed back into the drawer.
See "The Forever War" by Joe Haldeman, explores the human part of your post.
Perhaps you can accept the following two axioms that help you cope with the situation: 1. There are theories that are not completely understandable, nor can we formulate them in an easy way. 2. General relativity will never be fully understood, even if you crunch your brain to pieces. Don't expect anything to be faster than light. It was not observed as of now and will not, as a result of testing the special theory very deeply. All effects are well confirmed as of now. However, quantum physics is a different matter. If you wiggle one particle here, the particle at the other end does feel this because of quantum effects that just are plainly absent in relativity. Then, those particles have to know about each other, which means that you cannot do this to any random particle swirling about. They have to be what is called entangled to each other. Einstein was aware of this, yet thought of it as a paradox (Einstein-Podolsky-Rosen-paradoxon), but nowadays, string theorists and super-symmetry guys are on their way to incorporate relativity into quantum theory. Then, any speed becomes effectively a pathological quantity by the Heisenberg uncertainty principle. So does of course the speed of light. It will become a distribution having a peak at the most likely value, but it is probable to go beyond, perhaps. This is what can be sait about the faster thing. Now. As long as GR holds (and it does so for much longer most physisists thought), there is an absolute speed, called the speed of light. It is important to see, that one of the fundamental ingredients of general relativity are so-called local inertial coordinate systems (LICS), where, being inertial, special relativity applies. From there we build space-time using Riemannian differential geometry, which basically makes predictions on local (NOT global) properties on space time. Think about livin on earth. How can we tell its a ball without looking from outside? We can only make measurements of lengths and angles: If the sum of angles in a triangle is bigger than 180 degrees, we live on a ball, if not, its another geometry. The same thing applies to space-time. We cannot see beyond, we have to measure, so all we can do is make local statements, and statements about the ways they are connected by using an arbitrary large set of LICSs . So this is not a totally useless concept. But in each LICS, the speed of light is a frontier not to be touched. And as for the general theory. It was invented because there is just no simple way to include gravity (as thought of by Newton) into the special theory. Whilst electrodynamics, governed by Maxwell's equations is consisten with the Lorentz transformation (as opposed to Galilean transformations in classical mechanics), there are no real problems. In fact Einstein did incorporate relativistic mechanics with electrodynamics in his 1905 paper introducing special relativity. Now, Newton's equation is not consistent with Lorentz-transformations, and therefore has to be modified. General relativity was the answer that took Einstein about 10 years to figure out. I think of him as one of the most brilliant minds ever to takle the question of how it all fits together. On a par with Newton perhaps. So, while classical electrodynamics was the field-theory of electricity and magnetism, general relativity is the field-theory of gravity. Now in Einstein's days, these where the only fundamental interactions known. Today we are up to four of them: electromagnetism, weak and strong interaction and gravity. The former three of them have already been incorporated in one giant theory, yet gravity waits to be formulated consistently in quantum mechanics. This could be a flaw in general relativity, but in toppling older theories, one always has to bear in mind that they stood so long because they are magnificent and, most importantly, tested and found to accord with what we call reality. So even if one gets disappointed about that one, I don't think that there will be something usable that's faster than light for the next few decades, sorry folks.
Black holes were created when god tried to divide by zero
When a collegue of Einstein's suggested that it was impossible for an object with mass to reach light speed, Einstein felt compelled to point out that a photon has mass and it travels at light speed.
A photon has mass? When did this happen? Is this the mass implied by E=mc**2 equation applied to its energy?
I still don't understand frame dragging, but I'm hoping my friend Google will after I post this.
The term "dragging" implies some sort of friction or direct force pulling something along with a rotating body. You give the analogy of the electric motor, but at least there you have dipoles in both electricity and magnetism (do opposite potentials for each of two forces). But gravity is a single force, and it is a monopole.
And if the theoretical rotating body is a perfect sphere, there aren't even any bumps or anomolies to rely upon. The mere orientation of the body would have no discernable difference on a system since it is entirely symmetric, so it must be from the motion -- but how?
To the stupid mods who dragged the parent down. Get a sense of humor. It's for measuring frame dragging or lag, and a joke about it being delayed is -1 Troll??
I'm out of my mind right now, but feel free to leave a message.....
Taking a distance from one frame of reference and a time interval from another is cheating. To the observer in the rocket ship, the distance to Alpha Centauri appears contracted as well, so that observer will measure its speed relative to the rest of the universe as being less than the speed of light.
And if you're really interested in learning Special Relativity, you might consider supplementing pop science books with an actual physics text, to avoid misunderstandings like these.
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If you can accelerate a significant mass (such as an army or colony) to a high percentage of c, then why would you bother sending armies ? Just send a large rock, aimed at their planet. KABOOM !!!
Forget magic. Any technology distinguishable from divine power is insufficiently advanced.
Wow, you just explained the majority of the plot to gunbusters - an old anime series about fighting in space at near c, and the problems that arise on returning to 'earth' (won't say any more incase some of you actually watch it sometime)
so my spaceship is slowely approaching light-speed.
... no problem; the faster i go, the heavier my
i'm nearly out of fuel, but i suddenly notice that
the fuel is sooo much heavier now and my electrons
are suddenly really really heavy! super!
my flight computer is running on muons and my
computer is telling me that another five seconds and
it will be running on taus.
so
fuel gets. (m1*v1)=-(m2*v2)
I sometimes get the sense that people who know better deliberately confuse others...
Themselves, more likely. When the facts contradict a cherished belief and you refuse to modify that belief to fit the facts, cognitive dissonance results. Something has to be done to reduce that dissonance. A common method for doing so is to claim that the facts presented are 'just a theory' and therefore not sufficient evidence to require a re-evaluation of the cherished belief. It's a form of wilful self-deception, a pathology of the mind; in fact, a deliberately imposed form of mental sickness.
People will go to great lengths to ignore reality in favor of what they wish were true. The refusal of creationists to modify their world-view in the face of paleontological evidence is a prime example of this, but it can apply to just about any human belief you care to name (e.g., that your spouse is faithful despite the discovery of love letters and lipstick on the collar).
Max
My god carries a hammer. Your god died nailed to a tree. Any questions?
Someone ate your paragraphs.
will the experiment be wrong (in other words there's no point to it), or will we get faster-than-light ships for Christmas?
It just irritates me that someone that doesn't understand got to submit this first.
double-meh.
When I was working at JPL in the early 80s I spoke to a researcher who had published a number of papers on experimental General Relativity and was well regarded in the field. He told me privately that the expected results of Gravity Probe B were the same for Einstein's theory and virtually every other proposed theory of gravity, and that if the results conflicted with these theories most researchers would conclude that the measurement was incorrect.
I guess my point is that there is a reason this mission has been postponed so many times: most investigators believe it is pointless.
There must have been some confusion about the mission statement, this is supposed to demonstrate gravitic "frame dragging", not NASA "foot dragging". They should keep re-issuing the memo with different wording until people get it.
> Einstein would be rolling over in his grave if that were to happen.
Put one of the probes in space, then put on the ground near his grave.
If either detects frame dragging, you've solved one of lifes mysteries.
Lets be accurate here.... It's impossible for an object with INTRINSIC mass to reach the speed of light. A baseball has intrinsic mass when it's sitting still. When it's moving it has its intrinsic mass plus its mass due to velocity. A photon has no intrinsic mass and therefore it can never travel at any speed but the speed of light (little more convoluted here, but I won't bother to explain). Light can travel slower than the speed of light through media only because it is being canceled and regenerated by the electrons in the medium.
As for the faster than light stuff, well I never really studied that, so I won't comment, but the parent is at least mostly correct about that. In particular, the real problems only come about when information travels faster than the speed of light, because that violates causality.
Now, I'd like to also point out that there is no real reason why we can't violate causality, causality is in fact highly overrated. People always tell the metaphorical story about someone going back in time to kill his father, but they never really think about it. Quantum uncertainty indicates that each time you go back the result will be a little bit different, so there is no such thing as an infinite loop (it must break 'eventually' because quantum uncertainty will cause you to burst into flame or get hit by a bus or whatever). So, go back, kill your father, don't exist, don't go back (because you don't exist), nobody kills your father, so you exist, so you go back......get hit by a bus, and there we have it, the time line is correct again.
IAAP (I am a physicist)
In other words, you'll get to travel the universe, but you'll never know that you did it.
How is this bad? This is one of the cool things about relativistic travel. One of the bigger challenges we're facing right now is keeping people alive long enough to reach their destination. The good news is, if we travel at (or approach) c, this becomes less of a problem.
Besides, I always hated the travel part of vacations anyway...
Sure I'm paranoid, but am I paranoid enough?
Mu.
Define "outside observer" to the universe... and therein lies your problem. It's a meaningless question, since it is impossible to observe from the outside. Additionally, since time is a dimension along with space and those 3+1 dimensions exist within the universe, there is no time outside of the universe. Or at least, not what we'd call time. Or space, for that matter.
Think of a person living on a sheet of paper, with length, height, and time. They have no depth. Additionally, remember that length, height and time all end at the surface of the paper. Just "above" the paper, there is no length, height or time. There is something else (since you've moved in a 3rd spacial dimension) and there might be some other time dimension up there, but not the same ones.
Oh, and anything you'd use to observe the inhabitants of the sheet of paper universe (i.e. light) are also constrained to stay on the surface of the paper. This is why your question cannot be answered - any observer outside the universe has no ability to view anything in the universe, since no information-carrier can leave the universe.
-T
This is incorrect. NASA and Stanford have been working on the project for 35 years. Project delays and budget mangling have delayed the probe. I know this for a fact, since my brother's been working on this project for 10 years. (And finally got his PhD this last month. Go Rob)
The scary thing is after all that money, there is still like a 5% chance that the launch vehicle will explode on the pad. (fingers crossed)
That's alright, time is relative.
Now, I'd like to also point out that there is no real reason why we can't violate causality, causality is in fact highly overrated. People always tell the metaphorical story about someone going back in time to kill his father, but they never really think about it. Quantum uncertainty indicates that each time you go back the result will be a little bit different, so there is no such thing as an infinite loop (it must break 'eventually' because quantum uncertainty will cause you to burst into flame or get hit by a bus or whatever). So, go back, kill your father, don't exist, don't go back (because you don't exist), nobody kills your father, so you exist, so you go back......get hit by a bus, and there we have it, the time line is correct again.
At the risk of getting extremely theoretical here, I'd like to point out that an extra dimension of time would solve this issue. Einstein showed that we could perceive the fourth dimension by observing the rest of the Universe while traveling at a very different 3D speed in relation to it. To a space traveler, this would become a very intuitive thing.
But how would we see two dimensions of time? Well, Quantum mechanics states that instead of true cause and effect, we have all possible events at the same time. If there were any way to perceive that extra dimension, it would be as decisions/random events splitting the timeline. Each event in the universe would give the timeline a velocity into the fifth dimension. Thus timelines would exist were you did kill your grandfather and where you didn't. Causality is intact because you simply obtained a different fifth dimensional velocity by killing your grandfather.
The difficulty is in attempting to define vectors for such a dimension. If it did exist, how might one achieve a perpendicular trajectory in relation to the fourth dimension? If one did achieve a perpendicular trajectory, what would be the results? Is there any measurable thing in the universe that already "slides" perpendicular to the fourth dimension?
These are questions that it may take another Einstein to answer. I wonder if anyone's attempted any equations for this?
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Stanford hysics prof Everitt has been working on this project for 40 years, out-living his two co-investigators. The physical resemblence of Prof Everitt to Einstein is striking. Everitt always had a mustache and scragly-long 1960s hippee hair. Now it has turned white, he looks like Einstein.
Why move a ship when all you really have to move is space itself? Der. Just shrink space in front of the ship and expand it behind. Nobody breaks any speed limits because the ship never actually moves.
I'm in the hole of the broadband donut.
from all these hadrons escaping from it!
Xenu loves you!
How is this bad? This is one of the cool things about relativistic travel. One of the bigger challenges we're facing right now is keeping people alive long enough to reach their destination. The good news is, if we travel at (or approach) c, this becomes less of a problem.
It's not cool to be forever stuck in time. Actually, it could kind of suck. Relativistic effects, OTOH, tend to suck for those who are planet-bound. They could send a spaceship out to explore the Universe, but it wouldn't be back until long after civilization has fallen and our Sun has gone cold. Under Newtonian physics, our intrepid space travelers would have been able to reach other planets super-fast to both them and people on Earth. Einstein kind of pokes a hole in that idea and said that relativistic travel over extreme distances means that you'll never again see your friends, family, and possibly even the human race.
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*aims a flashlight at the ground, turns it on*
Earth's still there. Photons don't have infinite mass at light speed, and hence have no rest mass. ;)
Basically, photons have 'pretend mass'. They have finite 'mass' when going at the speed of light, and no mass when stopped. (Of course, you can't stop them.) As opposed to normal matter, which has infinite mass when going at the speed of light, and finite mass when stopped.
To understand photon mass, you have to use pretend math: A photon's mass is so small it doesn't exist until you multiple it by infinity, at which point you get a finite number. ;)
If corporations are people, aren't stockholders guilty of slavery?
The neat thing is, if we every find something that goes faster than light, we don't need to use it to travel faster than light...because it has 'negative mass', it will hold wormholes open for us, and we can just use those to travel. ;)
If corporations are people, aren't stockholders guilty of slavery?
It all depends on how you look at it.
The REAL jabber has the user id: 13196
What you do today will cost you a day of your life
You are aware that was basically the theory 100 years ago, and there were some serious problems with it, right? Newtonic physics does, indeed work 99.9999% of the time...but it only takes one counter-example to disprove a theory. And there are a good half a dozen of them, including some pretty specific proofs there is no 'background' to the universe, there is no absolute frame of reference.
If you want a theory on those ground, you're going to need to address the fact that light travels at 300,000 kps no matter how fast you move.
If corporations are people, aren't stockholders guilty of slavery?
"The question remains is what happens if Frame Dragging isn't observed - will the experiment be wrong (in other words there's no point to it), or will we get faster-than-light ships for Christmas?"
The question that interests me more is: doesn't *anyone* know how science works anymore? The only failed experiment is one with *no* results.
If frame dragging is not observed, then lots of scientists will be trying to work out why. Did the experiment measure what we thought it would? If yes, what do we have to do to contemporary physics (which is a pretty darned good fit to observed reality) to account for the result? If no, what did we miss?
(I'm now thinking of the hoary old joke about the cub reporter who came back from a society wedding to tell the editor that there was no story because the groom never showed up.)
So, has anyone actually measured the speed of propagation of the other three interactions? Of course information communicated by means of the electromagnetic interaction can't arrive faster than the photons carrying it. I think that the simplification, "nothing can travel faster than light," depends on assertions which are reasonable but not actually known.
(Quick, Robin! To the gravitic interferometer!)
Um, doesn't your army have to slow down in order to occupy the planet?
People like you completely ruin the academic experience, and my ability to enjoy learning. If people don't want to jump through the hoops of formalism right along side you and share in your misery and lack of purpose, then you go out of your way to dis-credit our achievements. I'm sure this is simply to justify your own pathetic grant-writing existence. Have a nice life.
My only regret... is that I have... bonitis..
"We need to transfer our conciousness to machines.... Then 300 million years would be a *short* period of time."
Be careful what you wish for. Go read Asimov's "Eyes Do More than See" again. (Okay, he does away with the machines *too*, but it still applies.)
Don't forget the general framework of the scientific method. A. Generate a hypothesis B. Observe nature C. Use the observations to determine the evidence AGAINST the hypothesis. If there IS EVIDENCE AGAINST the hypothesis, you reject it and develop a new or refined hypothesis. Otherwise, we state there is no evidence to reject the hypothesis. The formal scientific method (initially developed by Sir Francis Bacon (1561-1626) and Rene Descartes (1596-1650)) can only DISPROVE a scientific theory. For instance: A. Newtonian Mechanics describes the motion of planets B. Observe the motion of the planets C. Compare the observed motion to the theoretical predictions: In this case, they didn't match up, which required a new theory --> Special Relativity. Note that it is probably true that the theory of relativity is FALSE...but useful. Just as Newtonian mechanics is false, but useful in most situations. "All models (theories) are wrong...but some are useful" (somebody famous said this)
The probe was proposed 35 years ago, but has never had the funding until now.
I don't know whether to laugh or cry.
"Funding" was never a problem for this pig. It's been sitting in the middle of NASA's Office of Space Science budget for well over a decade, burning money at a rate totally out of proportion to its supposed science return, and compromising funding for other much more interesting astrophysics and space science missions in the process.
NASA OSS and the astrophysical community have repeatedly tried to get GPB cancelled, but the California Congressional delegation has kept it alive as a pork offering to Stanford, and to California's moribund aerospace industry.
The reason GPB is finally being launched is not that it is ready -- many people at NASA headquarters fully expect its systems to fail in orbit, as they repeatedly did in lab testing. It's just that it's cheaper to launch the fucking thing than to let it sit around for another decade, burning even more of the dwindling supply of cash that NASA expects to spend on actual science (as opposed to Buzz Lightyear adventures on Mars).
I only hope the perpetrators of this travesty of peer review don't attempt to inflict a "Gravity Probe C" upon us.
GNU Info is documentation optimized for machine readability
They're called Berserkers. You've been reading Fred Saberhagen again.
Doesn't sound like you at all, does it.
My only regret... is that I have... bonitis..
Why does everyone keep talking about planets?! I didn't mention planets. I'm talking about space-faring races. These space travelers with similar frames of reference could easily continue conflicts for millions of our years.
As for supply replenishment, it doesn't matter as long as you decelerate for only a short period of time. e.g. Two ships are traveling side by side at 99.99% c. As they pass near a solar system one suddenly disappears for a second or two, then reappears from behind with new weapons, ore, food, and men. In reality, the ship that disappeared has been gone for a year, but thanks to relativity it's able to rejoin the battle with no significant loss in time.
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Terry Goodkind actually noted this - in fantasy, of all things. It's the namesake aphorism in "Wizard's First Rule", namely, "People are stupid. They'll believe anything if they want it to be true, or if they're afraid it might be."
It's fiction, yes, and the two latter parts sometimes come into conflict, but it's reasonably astute for all that.
NB: YMMV. IANAL. Take the above with a grain of salt.
This post is ill-informed. The effect of acceleration is the only observable effect on the spacecraft, and it is constant. At a constant acceleration, there is no point when "suddenly" the observations in the craft will seem odd. That requires something to measure relative inertial frame against. When you say "approaches light speed", you forget that without something to observe your speed against, this means nothing.
Remember that when you talk about the required energy for acceleration going to infinity, you forget about length and time dilation. If you take a trip to the center of the galaxy that Netonian Gravity predicts will take you fifty years, round trip, if you could accelerate beyond C, you could make that trip! Thanks to time dilation. But you'd notice galactic time speeds up around you, so that when you finished your round trip, you really had still not gone faster than C. On earth, tens of thousands of years have passed, but to you, you have made the trip in the predicted fifty years. On the ship, these effects are not observable. Without an earth to worry about returning to, or a home frame to worry about accelerating into the future from out of (and finite but indeterminitely large propulsive energy), you could travel anywhere you wanted to in subjectively as short a time as your spaceship could withstand acceleration for. But if you return to where you start, you can measure the fact that your trip hasn't actually been so swift after all, and you've spent most of it in dilated time, oblivious.
They must have changed the explanation of Cerenkov radiation, then, since my high-school physics classes.
>I guess one could accuse certain modern physicists of
>coming up with "theories that fit reality"
Well, I suppose that's better than coming up with theories that don't fit reality.
un-ALTERED reproduction and dissimination of this IMPORTANT information is ENCOURAGED
Must be a religious war, then, since they're not after each other's resources or territory or population.
To paraphrase Futurama, "You win again, gravity." Great models that don't work are kind of pointless, whether it be FTL, time travel, or high speeds in Newtonian physics. We also know that Newtonian physics aren't going to get better in this aspect. That means our only real options are relativistic travel, with all the drawbacks, or FTL, whose possibility seems unlikely.
Sure I'm paranoid, but am I paranoid enough?
What do you mean by "a large array of very powerful lasers using spinning mirrors to make one of their spaceships to have NEGATIVE MASS"? Do you have references to current research showing this possibility (I dunno, maybe research showing lower mass by firing a laser at a spinning mirror or something)?
Reason is the Path to God - Anon
By traveling faster through space, we travel slower through time. This scales so perfectly, ....
Perhaps somebody could answer this for me. I've heard of this theory before, and to me it makes a lot of sense. However, when measuring this, have scientists found that it does indeed scale correctly? I've heard of an experiment involving a plane containing an atomic clock that flew around for awhile, and proved this effect (afterwards the clock was slower than it should have been).
Have they been able to extrapolate from this, to prove that the velocities in each dimensions do scale on an 1:1 basis, inverted? It would be interesting if the equation was not 1:1, but something like:
Overall Velocity Constant = (Velocity in Space)^2 + (Velocity in Time)
Instead of the 1:1 equation of:
Overall Velocity Constant = (Velocity in Space) + (Velocity in Time)
Meaning if you speed up to 0.5 c you are not going 50% slower in time, but more like only 25% slower. I guess the implications would be that the space and time dimensions are not orthogonal but stetched in one way or the other?
...is that the experiement will falsify the theory. When we realize that Einstein was wrong we start seeing the world as it actually is and the illusion will fall apart. Most people will die instantly by the sudden change of perception. I, however, will survive and become the most powerful man alive, since I already figured out the truth and bought the right stocks in advance.
No. There are several competing theories that are similar to the General Relativity, all of them predict that the speed of light is the ultimate speed (let's ignore "space warp" things for a moment, shall we?), but not all of them predict effects such as Frame Dragging. Einstein's own view predicts Frame Dragging as a measurable effect, but that's just one theory among other.
So, the alleged absence of Frame Dragging will not imply that you can break the speed of light limit; it will merely imply that we're living in a Universe slightly different from the one described by the "vanilla" General Relativity.
The Einstein Probe merely tries to figure out which theories are definitely false and which ones can still be suspected to be true, at least for the time being.
This all begs the question "How does frame dragging actually work?" Well, everyone is used to the idea that an electric current can give rise to a magnetic field. We're also familiar with the way in which we can use this phenomenon to build motors that harness the rotation produced. It's the same idea in general relativity except that instead of an electric current, we need to have a mass current to produce the effect. There's really little conceptual difference between one type of current or another, so don't be fooled by the strange-sounding term "mass current"; it just means that mass (and hence energy) is flowing through spacetime.
Please finish your analogy. First you said that electric current can produce magnetic field. Then you mentioned mass current. But what exactly does this mass current produce? Another type of field?
The purpose of life is to find the purpose of life.
I don't suppose I am the first with the news, but BBC is reporting successful launch. (19.00BST)
If you have the capability to build a self-replicating factory and then send it across interstellar distances in the first place, designing one smart enough to fight a war on its own wouldn't be very hard.
Maybe not.
But you might also have the problem that these smart machines would decide to wage war on their creators instead...and we all know that only Neo can save humanity then!
p
In Korea, long hair is for old people!
According to everybody I know, the world is crazy.
Yes, J. Richard Gott, a professor of astrophysical sciences at Princetown university has written many articles about this subject.
The idea is that since every laser pulse contains a very short time when the pulse has negative energy density, a mirror spinning very fast (but well below c) could be used to seperate the bulk of the pulse containing positive energy and the brief moment of negative energy. However, this requires tens of millions of the most powerful lasers on Earth to collect enough energy in less than a century, however a supercivilization could build these lasers for superluminal travel.
Hell, it could be done with a single laser if they could just wait (=live) for 10,000,000 times longer.
Capitalization is the difference between "Helping your uncle jack off a horse" and "Helping your uncle Jack off a horse"
Er...I'm a student, not a "grant writer", and have no love for formalism. But the incredible number of errors that I see in the comments to this and many other articles are proof that reading pop science alone won't let you understand science. I'm sorry if it sounds like I'm "discrediting your achievements", but spouting ignorance is not a good thing.
Slashdotters in general seem to have an odd blindness when it comes to areas outside their specialty. Often, they fall into the old fallacy of thinking that logical reasoning is enough to let you talk intelligently about any subject. Listen to how less-knowlegeable people talk about computers, and realize that you're doing the exact same thing with physics.
Now I certainly don't want to discourage people from trying to learn new things. But you have to understand the limits of your knowledge before you try to pass yourself off as an authority on something you don't really understand.
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Good luck in school. I enjoyed it, may go back someday.
My only regret... is that I have... bonitis..
If you want a theory on those ground, you're going to need to address the fact that light travels at 300,000 kps no matter how fast you move
Can you prove that? To do that you need a good clock to measure speed but every known clock is subject to differences when moved. That counter argument doesn't disprove the theory but simply proves you don't have a good clock. Most of the other major issues with the theory involve things not slowing down (which they do, see Pioneer 10/11).
So far none of the current theories explain the funny clocks exactly nor the oddness with pendulums nor why GPB's balls are going to slow down when it comes out of the shadows in the direction of the spin but a modified ether theory does. The modified ether model also clears up some oddness involving pulsars and what has been observed near black holes. Since no real physicist would consider it but from what I can see its just as wrong as all the current theories.
You don't need a moving clock to show the speed of light is constant, because the planet itself is moving. You just take a beam of light, and split it in half with a mirror, send it along two perpendicular paths, bounce it back, and see if it arrives in sync. As the earth is moving around the sun, it's trivially easy to make one direction that's 'forward' along the motion of the sun, and one direction that's 'sideways'.
Ah, but there's nothing proving the mirrors are the same distance, or possibly the combined motion of the earth and the sun and everything cancelled out...but this is the clever bit: You wait 12 hours, when the entire arrangment has been rotated so it faces the opposite direction with regard to the movement of the sun, thanks to the rotation of the planet, and run it again. In fact, run it at six hour intervals, just for the hell of it.
Oh, and here's the other gag: You don't need any clocks. You don't need to measure the time, the two beams of light coming together will create a noticable interference pattern. If the beams at any point took even slightly longer, the pattern would change.
And, just so you don't actually have to run that experiment, I'll tell you the results...no matter in what direction you aim the arrangement in, in relation to the movement of the planet, light always takes the same amount of time to run the same distance. Yes, this experiment has been run plenty of times, with more than enough accuracy to measure the movement of the planet.
So you have two options: Either the planet isn't moving, with the rest of the universe spinning wildly around it, or the speed of light is constant no matter how fast you're moving.
Do you honestly think the scientific community accepted such a crazy theory as relativity without having inconvenient facts that required such a theory?
If corporations are people, aren't stockholders guilty of slavery?
You are describing an effect as a cause which may or may not be true. Which is the cause and which is the effect. There are reasons why your going to measure c the same with both theorys if you understand them both. Thats the point I'm tring to make its just the in the problem space I deal with, the old junky theory gives better answers so just like using a flat map on a round world, it works so I'll use it till something better comes along.
If you plagia--uh, borrow--ideas, use only the best, I always say.
It IS kinda like Saberhagen. Only without the whole 'machines turning on their creators and going on a galaxy-wide destructive rampage for a hundred thousand year' thing. Extinction is kind of a drag.
That's what war droids are for ^^)
/IS/ a weapon. It doesn't even have to slow down, so given that it's already moving at a significant fraction of c, all it has to do is coast in and hit like a sniper round. Boom. Because it's small, dark and moving fast, by the time anyone sees it, it's too late. Or it drops a load of heavy iron balls a few light hours out on course for targets before slowing down to refuel and re-arm. You could canvass a whole bunch of solar systems that way, using one automated ship. Lots of return on a small investment. Either way, you can't tell the difference between an incoming friendly and an incoming bullet until it's too late to do anything about it.
Only if you're interested in conquest. But we're not likely to have anything that an alien race couldn't get somewhere else a heckuvalot easier and closer. So there's probably no reason to come here to take anything.
On the other hand, going to some other star system at relativistic velocities has its own share of risks--ESPECIALLY for the guys you're going to visit. The ship doesn't have to carry any weapons--the ship itself
A really paranoid species might not wait until the folks next door come calling, they might simply make sure that there's nobody near them capable of coming to visit. Do unto others before they do unto you, and do it first. Try reading THE KILLING STAR by Charles Pellegrino and George Zebrowski. Great book.
Ender will save us all!
And according to the update on Wikipedia page for GP-B was sucessfully placed in orbit:
The satellite was placed in orbit at 11:12:33 AM (18:12:33 UTC) after a cruise period over the south pole and a short second burn.
Couldnt verify that with the GP-P Offical Site or NASA GP-P Site but I may have not been looking hard enough.
:P
Not the slightest trace of this movement has ever been detected. There are only the two options that I said...either we, for some unknown reason, are not moving through space, which makes the entire universe spin around us in random patterns, or our movement through space somehow has no effect on how fast light moves past us, that unlike every other speed in existence, the speed of light is not additive with other velocities, aka, it's 'constant'.
There simply are no other possibilities to explain this oddity. As velocity is just space divided by time, you obviously need to postulate some some sort of time and/or space change to explain this velocity inconsistancy. Einstein postulated both, that they are in fact the same thing and converted back and forth, which keeps us from having to explain where space came from or where the extra time went after it was used.
And just in case you're wondering, there are other experiments that rule out the first possiblity, although I can't think of them off the top of my head. You'd probably object to them because, obviously, if we're checking the speed of light with anything except vs the earth's speed, at some point the 'clock' is going to moving. Interesting how all those moving clocks fail in exactly the correct way to make us think relativity exists, but whatever.
Now, if you want to use another set of math to explain the universe, feel free...99.999% of the time, people use Newtonic physics anyway. We don't need to worry about time dilation when everyone is going within a close fraction of the same speed in the same direction.
If corporations are people, aren't stockholders guilty of slavery?
The lady was Bright but not bright
Took part in the next day's flight
So soon two made the date
And then four and then eight
And her spouse got one hell of a fright!
Be faithful to your obsessions. Identify them and be faithful to them, let them guide you like a sleepwalker. JG Ballard