Slashdot Mirror
'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?"
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
This seems to call for a bit of clarification. A Type II error in this case would be that the scientists proclaim that Frame Dragging is true when a specific alternative is actually true. A Type one error is that they declare Frame Dragging to be false when it is in fact true. In this case, however, they wouldn't really be committing either. The author just states that they plan on ignoring any results that don't match their hypothesis. That would just be bad scientific practice and not a calculation error.
_____
Thank you.
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"
"Einstein would be rolling over in his grave if that were to happen."
I think He was cremated
"I want to be cremated, so people don't come to worship at my bones," he once said.
An interesting story if you don't already know it
"Einstein would be rolling over in his grave if that were to happen."
Einstein's brain would be spinning in its jar (the rest of his body was cremated).
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
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
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.
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.
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?
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
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.
I don't know shit, but I expect they're probably talking about something like the Alcubierre warp drive.
In the black hole example, those wobbling bits of matter aren't wobbling in their own "frame", it's the space they're sitting on that's wobbling. It's like a moving sidewalk. You can only run at the speed of light, but if you get on the sidewalk that's already going X, then you can run at your top speed but move in relation to the rest of the universe at the speed of light + X.
The Alcubierre drive is a theoretical trick with negative energy and shit where you stretch out space behind you and scrunch it up in front. You sit in something with a hell of a lot of radiation shielding in the middle and as far as you're concerned you're stationary, but outside your little bubble you're zooming along. I think other people have improved it a little, I think there's one that doesn't require negative energy and some that have brought the required energy down to something theoretically possible (like, the energy of a galaxy and not the energy of 10 billion universes).
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".
Javascript + Nintendo DSi = DSiCade
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.
A Usenet Troll Triumphs on Slashdot
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.
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.
Javascript + Nintendo DSi = DSiCade
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 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.
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"
like that guy who thought he had come up with an amzing invention when he riged up a smoke alarm to a toaster. The idea being that the toast pops up when it is done and never burns. In all fairness to him it did work, but the guy clearly didn't understand how smoke alarms work.
basically he claimed that his invention tasted the air to see when the toast was done... actually it is just a smoke alarm above a toaster not a magic air tasting device. The smoke alarm is actually triggerd by the water vapour/smoke that is produced when the bread turns to toast, blocking the path of the alpha particles in the smoke alarm (that is how smoke alarms work btw!). It is just a matter of getting the smoke alarm the right distance away from the toaster.
I have somehow managed to make this seem like quite a decent invention (that was not what i was going for) but before you rush out and buy one, consider what will happen as soon as you get a few crumbs in the bottom of the toaster...
"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.)
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