Theory of Relativity Passes Another Test

Article written: 3 Jul , 2008
Updated: 24 Dec , 2015

Einstein’s theory of General Relativity has been around for 93 years, and it just keeps hanging in there. With advances in technology has come the ability to put the theory under some scrutiny. Recently, taking advantage of a unique cosmic coincidence, as well as a pretty darn good telescope, astronomers looked at the strong gravity from a pair of superdense neutron stars and measured an effect predicted by General Relativity. The theory came through with flying colors.

Einstein’s 1915 theory predicted that in a close system of two very massive objects, such as neutron stars, one object’s gravitational tug, along with an effect of its spinning around its axis, should cause the spin axis of the other to wobble, or precess. Studies of other pulsars in binary systems had indicated that such wobbling occurred, but could not produce precise measurements of the amount of wobbling.

“Measuring the amount of wobbling is what tests the details of Einstein’s theory and gives a benchmark that any alternative gravitational theories must meet,” said Scott Ransom of the National Radio Astronomy Observatory.

The astronomers used the National Science Foundation’s Robert C. Byrd Green Bank Telescope (GBT) to make a four-year study of a double-star system unlike any other known in the Universe. The system is a pair of neutron stars, both of which are seen as pulsars that emit lighthouse-like beams of radio waves.

“Of about 1700 known pulsars, this is the only case where two pulsars are in orbit around each other,” said Rene Breton, a graduate student at McGill University in Montreal, Canada. In addition, the stars’ orbital plane is aligned nearly perfectly with their line of sight to the Earth, so that one passes behind a doughnut-shaped region of ionized gas surrounding the other, eclipsing the signal from the pulsar in back.

Animation of double pulsar system

The eclipses allowed the astronomers to pin down the geometry of the double-pulsar system and track changes in the orientation of the spin axis of one of them. As one pulsar’s spin axis slowly moved, the pattern of signal blockages as the other passed behind it also changed. The signal from the pulsar in back is absorbed by the ionized gas in the other’s magnetosphere.

The pair of pulsars studied with the GBT is about 1700 light-years from Earth. The average distance between the two is only about twice the distance from the Earth to the Moon. The two orbit each other in just under two and a half hours.

“A system like this, with two very massive objects very close to each other, is precisely the kind of extreme ‘cosmic laboratory’ needed to test Einstein’s prediction,” said Victoria Kaspi, leader of McGill University’s Pulsar Group.

Theories of gravity don’t differ significantly in “ordinary” regions of space such as our own Solar System. In regions of extremely strong gravity fields, such as near a pair of close, massive objects, however, differences are expected to show up. In the binary-pulsar study, General Relativity “passed the test” provided by such an extreme environment, the scientists said.

“It’s not quite right to say that we have now ‘proven’ General Relativity,” Breton said. “However, so far, Einstein’s theory has passed all the tests that have been conducted, including ours.”

Original News Source: Jodrell Bank Observatory

34 Responses

  1. LLDIAZ says

    I thought nothing moved faster then the speed of light.

  2. GekkoNZ says

    You are correct, nothing moves faster than the speed of light.

    But remember, some people say relativity is “just a theory”, so maybe you *could* move faster than light speed if you believe in magic hard enough 🙂

  3. Curtis says

    The theory specifies that nothing in Space time as we currently understand it can travel faster than light. However Einstein’s theory’s do say FTL is possible. There are predictions for worm holes, and possibly white holes as well, however the white hole theories are hard to consider since you have to travel “through” a black hole to get to a white one. Add to that, some white hole theories state that each blackhole has an adjoining white hole in an entirely different universe.

    Excellent experiment. One would wonder what Einstein would think if he were here, eh?

  4. mohawker55 says

    Let’s not argue children.

  5. Librarian says


    Einstein came up with the theory of Relativity. However, he wasn’t the first one. There was actually a Croatian man that came up with it first in the 1700’s i think (not sure, maybe 1800’s) and since Einstein married a croatian woman she maybe talked a little about relativity as it probably was a part of general knowledge for croatians.

  6. Astrofiend says

    “# Librarian Says:
    July 3rd, 2008 at 4:18 pm


    Einstein came up with the theory of Relativity. However, he wasn’t the first one. There was actually a Croatian man that came up with it first in the 1700’s i think (not sure, maybe 1800’s) and since Einstein married a croatian woman she maybe talked a little about relativity as it probably was a part of general knowledge for croatians.”

    >>>Sorry, but sounds like BS to me. Firstly, the article deals with general relativity, and that was exclusively Einstein’s brain child (with a little mathematical help from friends). You seem to be referring to special relativity. It may be true that some of the elements of this theory or some of it’s more philosophical underpinnings were dreamt up at one time or another by other people – indeed, the Lorentz transformations existed before Einstein came up with SR. But almost everyone acknowledges Einstein (including Lorentz himself) as the man who brought it all together, realised the physical significance of the theory and interpreted its results. I’ve heard the ‘it was really his wife’ line before – and it has basically been thoroughly discredited.

  7. Chuck Lam says

    I’m having trouble wrapping my mind around what is happening between two objects only about a half million miles apart at 1700 light years distance. The resolution of this pulsar pair can’t be more than a few pixels. What am I missing?

  8. Ted says

    I assume the “along with an effect of its spinning around its axis” refers to so-called “frame-dragging”? If so, why not include that in the post? That’s what it has been called the last few hundred times I’ve seen the concept referenced in articles like this.

  9. Marco Fitzgerald says

    Point for Einstein…

  10. alphonso richardson says

    “It’s not quite right to say that we have now ‘proven’ General Relativity,” ;

    That’s what I call good science, despite this observation, these guys are careful not to be so certain/arrogant that they have CONCLUSIVELY proven Einstein’s theories.

    Before anyone starts’, i’m NOT saying they’re wrong, or there’s some ‘mystical energy field controlling everyone’, but they have acknowledged that Einstein came up with a very good model of describing certain aspects of the universe (remember, even he came across problems & holes in his theories), and have been able to test it using sound, evidence-based observations.

  11. Mek says

    Funnily enough, Einstein’s work is a great example for why nothing is proven in science (good science, anyway.)

    In any case, it’s a pity we will never have dead-resurrection technology because I would dearly love to have all those that lambasted his work, back in the day, as “Jewish Physics” eat it. No, really, I want them to eat every work of science that built off Einstein’s; it’s the only way they can realize how horribly, horribly wrong they were.

  12. JamesB says

    Nothing can travel faster than the speed of light (the velocity of light is denoted by the symbol ‘c’), within it’s OWN frame of reference.

    However when observed from other frames of reference light can SEEM to be traveling faster than ‘c’.

    A key concept of Relativity is that no frame of reference is special and things like ‘c’ are only valid within it’s particular frame of reference.

    So while we may see light exceeding ‘c’ from our frame of reference, within it’s own frame of reference it isn’t going any faster than ‘c’.

    It’s this key component of Relativity that makes things such as time travel impossible since this assumes a preferred frame of reference.

    The fact that there is a limit to the speed of light exposes that dimensionality is the lowest building block of our universe. As the 19th century was the Golden Age of kinetic physics, and the 20th century was the Golden Age of electromagnetic physics, the 21st century can be the golden age of dimensional physics.

    We just need to move past the 20th century!

  13. JamesB says

    BTW- they have slowed light down to 38mph in a laboratory. The conditions used to do it CAN exist in nature and may be quite common in deep space.

    Much of what we assume about the expansion of the universe is based on the idea that light travels at a constant speed most of the time, very close to the upper limit of ‘c’.

    If this ISN’T true then the light we are seeing is NOT a true representation of expansion and would in fact tend to support a steady state universe. Now I want to point out that this is NOT ‘tired light’ I’m talking about, but a change in it’s speed not it’s energy.

  14. Al Hall says

    Theory, theory, theory… After we hear they same theories long enough, we start thinking they are facts. I’m still not convinced the equations are correct. There may be a missing variable.
    But who am I? I still think some day we will be able to build a machine that can propel us faster than 300M m/s (and I’m not talking about warping space or going through wormholes) and also without traveling in time, per se.
    I don’t believe that a mathematical equation can give us an ‘absolute’ of something we can or can’t do.
    The theories could be true, maybe there is a speed limit for mass.. Maybe. 10,000 years from now, if we are still around and gotten a lot smarter (I hope) we may have to make ourselves ‘mass-less’ in order to travel that fast, or the almost silly “warp”, “wormhole” things might not be so silly then. Or maybe we will have discovered new math to help with building a machine that can propel us faster than 300M m/s.
    Just my two cents worth.. 🙂

  15. Carnifex says

    I just wanted to point out that JamesB got some things wrong. Objects have no velocity in their own frames of reference (well, d’uh). Einstein’s theory predicts that no object may exceed the speed of light in ANY inertial frame of reference.

  16. James says

    Al Hall:
    One of the fun things about science is you never know what’s coming. Just a hundred years ago, a long-term home for humans orbiting the Earth would have been called bologna. But now look at us and our ISS.
    Who really knows what another 100 years will bring, right?
    The only definite thing about it is we probably don’t even imagine it as possible right now.

    In regards to Einstein: I love him! I hope we have another Einstein in the making to draw us an even better picture of this crazy universe we live in.

  17. Al Hall says

    James –
    Exactly! It would be offensive to countless future generations of ‘thinkers’ to say that there won’t be anymore “Einsteins”. Does anybody really think they won’t be more intelligent than we are today?

  18. Yael Dragwyla says

    Great article, and fascinating experiment. But I couldn’t get Quicktime to play the video that goes with this article — I never can. Could you please do those videos in Flash versions, or provide Flash versions on some other site just for that? I can get Flash to work. I can get Windows media player to work. But Quicktime, for some reason, is a dead loss. Anybody else have that problem?

  19. Al Hall says

    A personal note for those who care,
    I kind of wish that our next generation of thinkers had never heard of Einstein or Newton. I think that when hearing another’s theory dilutes the thought process.. It would be great to compare..

  20. Chuck Lam says

    To: Al Hall, I agree; future generations would probably do better in the idea department outside the influence of the world’s science greats. I hate the term “outside the box,” but it appears to birth fresh abstract thought experiments.

  21. JamesB says

    Carnifex – I’m not wrong.

    What you say is only true in Special Relativity, which handles the special case of frames of reference that are NOT in motion (hence it’s called ‘Special Relativity’ as it handles only this special case which does NOT exist in the real world and is a “thought experiment” only).

    General relativity took a lot longer to figure out since it handles the case of frames in motion and multiple frames in motion relative to each other. And it covers multiple viewpoints within a single frame of reference IE- everything in a space ship is in the same frame of reference as the space ship itself, but can move around within that space ship.

    In the case of the spaceship traveling at 90% ‘c’ you can turn on a flashlight and shine it in the direction of travel and the light emitted is still only traveling at ‘c’.

    You’d think that the speed of the ship would add to the speed of the light from the flashlight. It doesn’t as the speed of the ship is it’s own frame of reference and is the only place that a measurement of the speed of light from the flashlight is relevant.

    To other frames of reference it may look as if the light is going faster than ‘c’, whereas in even other frames it may look as if it’s slowing down. The ONLY frame that matters is the frame of reference the light is in. The illusion of faster than ‘c’ is only that, an illusion. That light is still limited by ‘c’ and the only place that matters is in the space ship itself.

    Another example is a train passes you as it’s blowing it’s whistle and the pitch gets higher as it gets closer the as it passes you and recedes in the distance the pitch of the whistle gets lower. But the engineer blowing the whistle hears only a single pitch, the true pitch of the whistle. The sound seems to speed up as you get closer then slows down as you pass and move farther away. The actual speed of the sound never really changed, though in your frame of reference standing next to the tracks it seemed too.

    In General Relativity the speed limit is still ‘c’, however this is only true within it’s own frame of reference. In any other frame it’s irrelevant, it has no meaning.

    The idea of the only frame of reference being relevant is the one you are in is what allows physics to work as well on a train going 80MPH as it does at your house going 0MPH. Something like a microwave oven will operate identically in either case. If it weren’t true then different microwave ovens would need to be made that worked on trains.

    There is plenty of empirical proof that ‘c’ is truly the speed limit in the universe (remember energy and mass are the same, so if it’s true for light it’s true for solid objects too). This tells us that there is an underlying structure to the universe that forces this limitation.

    There are some nice theories that attempt to uncover this underlying structure, only time will tell which one will provide us with the answers we seek.

    In the meantime it’s best to remember that current cosmology is based on hypothetical assumptions (though some of these hypotheses are based on theories like General Relativity they are still HYPOTHESES) and that until some of these hypotheses are actually tested and verified it’s a waste of time, effort and funding to continue down these paths.

    Let’s quit playing so much ‘what if’ and do some actual science!

  22. Marveloseus says

    “I think that when hearing another’s theory dilutes the thought process..”
    “I agree” too and it is proven, yours has done it to me.

  23. David says

    To Al Hall:
    You say: “Theory, theory, theory… After we hear they same theories long enough, we start thinking they are facts. I’m still not convinced the equations are correct. There may be a missing variable.”.

    It depends on how do you define “correct”. If you look at the “right places”, you’ll not see relativistic effects and could equally say that there must be something missing. In effect, SR and GR brought a huge bit of “hidden” physics.
    Phenomenae requiring SR and GR for proper understanding and interpretation was always there, but they remained somewhat hidden until the right questions were asked and new experiments showed them to us.

    In a sense, GR is indeed “wrong” as it depends on some assumptions and clearly doesn’t contain quantum mechanics. Further models and theories will eventually show that GR was only an approximation of XYZ theory at some specific conditions.

    But be careful, some things as “faster-than-light travels” through wormholes could as easily be wishful thinking as new physics waiting for us.

  24. David says

    Just to clarify my last comment, I’m not saying that GR is wrong.
    It is a very good description of some of the physics of our universe, but IMHO, surely new theories will do even better, as it should be.

  25. Talendear says

    While the theories of Einstein have not been proven, you still have to be impressed by the track record with them. Many of the things that his theories predicted have been confirmed. Even some things that he predicted and thought would never be able to be proven have been shown to be correct, like finding a gravitational lens warping light. To completely dump a theory that has the resilience to last for 93 years through constantly evolving technology because it “dilutes the thought process” is not logical.

    The very fact that the predictions of General Relativity keep being proven correct over and over means that its either correct or we need to learn where it isn’t correct. That is why all of these experiments are done in the first place. And if someone comes along that is more intelligent or has a better theory than Einstein’s, I doubt that hearing the theory of General Relativity will keep that individual from making it known. After all, they wouldn’t be much of a genius if they were held back because of something someone said 90+ years ago. As for another Einstein or Newton, I don’t think anyone will see another one. After all, the work done by them has already been done. Besides, the genius that it takes to pull off coming up with these world changing theories seems to come in multi-generational gaps so it could very well be another 50 to 100 years or more before someone comes up with a truly revolutionary theoretical addition to physics like those provided by Newton and Einstein.

  26. Greg says


    “The sound seems to speed up as you get closer then slows down as you pass and move farther away.”

    This is just plain wrong – although it illustrates your misconception about looking “as if the light is going faster than ‘c’. ”

    The pitch of the sound changes, not the speed – this is analogous to the frequency of light – not its speed. Independent observers may disagree about the frequency of a light source – but they will never disagree about its velocity. And the velocity of light in free space never appears to be anything other than ‘c’.

  27. Al Hall says

    I anticipated a response or two, so here we go in chronological order.. 🙂

    Marveloseus – Thankfully I didn’t offer any of my own theories (if I had any), so it’s probable that my comments had no real influence on your beliefs. We march on in our search for the truth. And I am sure that is what we both want.

    David – I won’t argue with you there.. The math is all there… always has been… We just need to know what we are looking at so we can know how to do the math.

    Talendear – Einstein’s theories also seem logical to me. I made a conscious point to say “I KIND OF wish..” that they never heard of them. Of course many great ideas were built on previous thinkers. I know that. My point was that when one hears a theory that has such a large following, it may detour or discourage that person from pursuing an idea they may have.. just for the simple fact that they fear being ridiculed. So an idea lost.. I’m not talking about “dumping” theories.
    It may not take another Einstein or Newton to come up with an epiphany that could change mankind as we know it. Just takes an idea. I have noticed just in this forum over the past months of many posters offering their thoughts and ideas only to be called idiots.. Then notice they never seem to post again.. It’s a pity.

    Greg –
    Are you sure? All of our experiments and observations have been done ‘locally’.. When we observe a star 100,000 light years away, we aren’t looking at the light ‘there’, we are looking at it here. After the light traveled 100,00 years (we assume).. As it hits our retinas. Therefore it is a “local” observation. Maybe there is an intergalactic ‘autobahn’ for light and it slows down (or speeds up when it hits our galaxy (or solar system).. Somebody here commented that light can be slowed in a laboratory. I haven’t looked that one up but if that is true then why wouldn’t nature be able to do it? Okay, okay.. That may be stretching it… Anyway, you get my point, I’m sure. 🙂

  28. Chris says


    Greg is spot on with his analysis. Are you just making stuff up? Please, if you don’t know enough about a topic to make an intelligent statement about it, save other people the confusion. This new evidence is supposed to be a tribute to Einstein, not a mockery of his theories by an erroneous explanation.

  29. sunil says

    we thought that the einstein is right in the assumption of the speed of any object can not cross the speed of the light! but when the speed of any object reaches the speed of the light then the mass of that object become infinity, this from the einstein mass equation, but there any object that has infinity mass in this universe, no! then the assumption of the einstein is wrong! he take the speed of the light as the reference but he forget that if the object cross the speed of the light then what will be its mass. einstien call the rest mass of an object is that the object is moving with the speed equal to 0, but all the universe is moving away there is no reat in the universe, then what is the rest mass? which is to be taken as the reference? for this ambiguty, if we take the speed of the light as the refence then we solve this problem. i have lot of things to discuss about it, what we need is to find the correct solution for the einstein formula, but actually i found the solution for the speed of an object which cross the speed of the light, but we need to find the solution for the speed equal to c.

  30. Frank Glover says

    “…I would dearly love to have all those that lambasted his work, back in the day, as “Jewish Physics” eat it.”

    Agreed. I find it ironic that they killed or drove away to the Allies many of the very people who might’ve given them the atomic bomb, first…

  31. LLDIAZ says

    Could’nt it be said that the speed of darkness is just as fast as the speed of light. I read somewhere that the reason the background of space is black and no other color is because of the absence of light. So does’nt that mean that where light suddenly turns off darkness fills the void at the same speed or am I wrong?

  32. Chuck Lam says

    Here are a few “outside the box” thoughts. What if the visible universe, that is all we can see in any direction out to about 13.7 billion light years, is a finite speckMaybe . . . in a boundless void. Maybe mankinds current perception of the universe being all there is is simply wrong. Maybe the expansion is nothing more than galaxies moving through space. Maybe the “big bang” is still in progress and we simply can’t see the trees for the forest. So may possibilities!

  33. Larry says

    Carnifex, Greg and Chris:

    Great, insightful posts, guys. Thank you!


  34. Brandon Santora says

    Great site. Nice info. You really know your science. Lots of pics. I like. Thanks for keeping us informed.

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