Twin pulsars.  Credit: Michael Kramer, University of Manchester

Theory of Relativity Passes Another Test

Article Updated: 24 Dec , 2015

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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


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LLDIAZ
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LLDIAZ
July 3, 2008 1:25 PM

I thought nothing moved faster then the speed of light.

GekkoNZ
Member
July 3, 2008 2:33 PM

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 smile

Curtis
Guest
Curtis
July 3, 2008 2:49 PM

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?

mohawker55
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mohawker55
July 3, 2008 10:34 PM

Let’s not argue children.

Librarian
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Librarian
July 3, 2008 4:18 PM

Offtopic:

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.

Astrofiend
Member
Astrofiend
July 3, 2008 4:45 PM
“# Librarian Says: July 3rd, 2008 at 4:18 pm Offtopic: 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… Read more »
Chuck Lam
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Chuck Lam
July 4, 2008 5:08 AM

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?

Ted
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Ted
July 4, 2008 12:02 AM

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.

Marco Fitzgerald
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Marco Fitzgerald
July 4, 2008 5:00 AM

Point for Einstein…

alphonso richardson
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alphonso richardson
July 4, 2008 5:18 AM

“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.

Mek
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Mek
July 4, 2008 6:26 AM

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.

JamesB
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JamesB
July 4, 2008 6:32 AM
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… Read more »
JamesB
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JamesB
July 4, 2008 6:47 AM

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.

Al Hall
Member
Al Hall
July 4, 2008 12:37 PM
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… Read more »
Carnifex
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Carnifex
July 4, 2008 3:59 PM

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.

James
Guest
James
July 4, 2008 7:46 PM

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.

Al Hall
Member
Al Hall
July 4, 2008 7:52 PM

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?

Polaris93
Member
July 5, 2008 3:57 AM

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?

Al Hall
Member
Al Hall
July 4, 2008 9:00 PM

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..

Chuck Lam
Guest
Chuck Lam
July 5, 2008 5:32 AM

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.

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