9 ms·

Einstein Was Right: NASA Announces Results of Epic Space-Time Experiment

294 points by tableslice 15y ago

wallfly 15y ago
It would be interesting to find out if using Hans Montanus's non-canonical formulation of GR (which involves a Euclidean metric and perfectly flat space-time) would yield the same numerical predictions, just with different "book keeping". That would put a different spin on the notion of Einstein "being right" as I think a lot of folks subconsciously equate GR with the "strangeness" of the Minkowski metric and non-Euclidean space-time manifold.
ColinWright 15y ago
Same story, many comments: http://news.ycombinator.com/item?id=2516510 http://news.ycombinator.com/item?id=2516510
tzs 15y ago
It's not all that epic. These effects had already been measured by other experiments and were found to agree with general relativity to much more accuracy than the GP-B measurements. What GP-B brought to the table was a direct measurement, as opposed to indirect measurements used by the other experiments. However, because the way they measured it pushed the limits of engineering, if GP-B had NOT agreed with GR there is good chance the results would have been dismissed as most likely due to equipment flaws. While it is in general a good idea to confirm measurements, especially using different techniques, in a case like this where the confirmation will be much less precise than the other experiments and will likely be rejected if it fails to confirm, you have to wonder why this was funded over other projects. The answer to that turns out to be simple: politics. When space scientists ranked all the proposed missions under consideration, GP-B came in dead last. However, its proponents went to Congress, and got Congress to override the normal process for prioritizing missions, forcing NASA to move it to the front, ahead of more scientifically worthy missions. There are a lot of very worthwhile scientific missions that we can't fly due to budget limitations. It's a shame to see $750 million of the limited budget go to a mission so far down on the importance list.
- phlux 15y ago
  It is epic because he predicted this before any of the technical wizardry was even in existence. So, sure - the proof may not be epic -- but the prediction certainly is, especially even moreso that he is correct (again)
  - Florin_Andrei 15y ago
    The precision they manufactured those things was pretty epic, too.
  - jonnathanson 15y ago
    Einstein was so brilliant that his very name became a popular cliche. And yet, the more modern science digs into his theories, the more we see that, if anything, his brilliance is still underrated.
  - dedward 15y ago
    It's important to realize these predictions were not all separate things - where he just said "Oh hey, what about X?" He developed mathematical models for currently available observations. Those models in turn also suggested other phenomenon that could not be measured at the time. As time went on, some of these have been measured and found to hold true, others observations about the universe have been had that suggest they don't hold true in all cases (eg: "dark" stuff)
- Zaak 15y ago
  I'm interested in the indirect measurements that have been done. Where could I find more information about them?
  - tzs 15y ago
    They are mentioned in this article: http://www.skyandtelescope.com/news/121390204.html http://www.skyandtelescope.com/news/121390204.html
- caf 15y ago
  An "epic" was originally a very long story in the form of a poem. As an experiment lasting 47 years, this certainly qualifies.
scottdw2 15y ago
Did the experiment use a control? That is, did they put other gyros in places where space time should not have been twisted and observe no deviation? If not, how do they know that the deviation was in fact caused by twisting space time?
- scottdw2 15y ago
  WTF? I just got 2 down votes for this? It was a serious question. I want to know, did they take a negative measurement too, and if they didn't, how does this prove relativity?
  - humbledrone 15y ago
    This experiment did not set out to "prove" anything. I think you'll find that the original article does not use the word "prove" even once. The experiment set out to experimentally test the accuracy of Einstein's predictions. The results of the experiment showed that under these specific circumstances, the predictions line up extremely well with observations. There's no "control group" for this kind of test. Of course, they could potentially run multiple experiments to verify Einstein's predictions under different circumstances. That might provide useful information, but the lack of such information in no way discredits the results of this particular experiment. If you want to read more about the experimental protocol, check out the final results paper: http://arxiv.org/pdf/1105.3456v1 http://arxiv.org/pdf/1105.3456v1
  - throwaway32 15y ago
    please do not complain about downvoting, it does nothing to contribute to discourse, and litters up the site.
    - throughaway 15y ago
      please do not complain about complaints about downvoting, it does nothing to contribute to discourse, and litters up the site.
- ignifero 15y ago
Vivtek 15y ago
I initially read this "Einstein was right, announces results of epic space-time experiment", which would have been epic and a much more interesting story.
known 15y ago
My understanding is we should benchmark everything with http://en.wikipedia.org/wiki/Speed_of_light http://en.wikipedia.org/wiki/Speed_of_light
catechu 15y ago
From article: "The mass of Earth dimples this fabric, much like a heavy person sitting in the middle of a trampoline." I will never imagine general relativity the same way again.

294 points by tableslice 15y ago

It would be interesting to find out if using Hans Montanus's non-canonical formulation of GR (which involves a Euclidean metric and perfectly flat space-time) would yield the same numerical predictions, just with different "book keeping". That would put a different spin on the notion of Einstein "being right" as I think a lot of folks subconsciously equate GR with the "strangeness" of the Minkowski metric and non-Euclidean space-time manifold.

ColinWright 15y ago

Same story, many comments: http://news.ycombinator.com/item?id=2516510 http://news.ycombinator.com/item?id=2516510

tzs 15y ago

It's not all that epic. These effects had already been measured by other experiments and were found to agree with general relativity to much more accuracy than the GP-B measurements. What GP-B brought to the table was a direct measurement, as opposed to indirect measurements used by the other experiments. However, because the way they measured it pushed the limits of engineering, if GP-B had NOT agreed with GR there is good chance the results would have been dismissed as most likely due to equipment flaws. While it is in general a good idea to confirm measurements, especially using different techniques, in a case like this where the confirmation will be much less precise than the other experiments and will likely be rejected if it fails to confirm, you have to wonder why this was funded over other projects. The answer to that turns out to be simple: politics. When space scientists ranked all the proposed missions under consideration, GP-B came in dead last. However, its proponents went to Congress, and got Congress to override the normal process for prioritizing missions, forcing NASA to move it to the front, ahead of more scientifically worthy missions. There are a lot of very worthwhile scientific missions that we can't fly due to budget limitations. It's a shame to see $750 million of the limited budget go to a mission so far down on the importance list.

phlux 15y ago
It is epic because he predicted this before any of the technical wizardry was even in existence. So, sure - the proof may not be epic -- but the prediction certainly is, especially even moreso that he is correct (again)
- Florin_Andrei 15y ago
  The precision they manufactured those things was pretty epic, too.
- jonnathanson 15y ago
  Einstein was so brilliant that his very name became a popular cliche. And yet, the more modern science digs into his theories, the more we see that, if anything, his brilliance is still underrated.
- dedward 15y ago
  It's important to realize these predictions were not all separate things - where he just said "Oh hey, what about X?" He developed mathematical models for currently available observations. Those models in turn also suggested other phenomenon that could not be measured at the time. As time went on, some of these have been measured and found to hold true, others observations about the universe have been had that suggest they don't hold true in all cases (eg: "dark" stuff)
Zaak 15y ago
I'm interested in the indirect measurements that have been done. Where could I find more information about them?
- tzs 15y ago
  They are mentioned in this article: http://www.skyandtelescope.com/news/121390204.html http://www.skyandtelescope.com/news/121390204.html
caf 15y ago
An "epic" was originally a very long story in the form of a poem. As an experiment lasting 47 years, this certainly qualifies.

scottdw2 15y ago

Did the experiment use a control? That is, did they put other gyros in places where space time should not have been twisted and observe no deviation? If not, how do they know that the deviation was in fact caused by twisting space time?

scottdw2 15y ago
WTF? I just got 2 down votes for this? It was a serious question. I want to know, did they take a negative measurement too, and if they didn't, how does this prove relativity?
- humbledrone 15y ago
  This experiment did not set out to "prove" anything. I think you'll find that the original article does not use the word "prove" even once. The experiment set out to experimentally test the accuracy of Einstein's predictions. The results of the experiment showed that under these specific circumstances, the predictions line up extremely well with observations. There's no "control group" for this kind of test. Of course, they could potentially run multiple experiments to verify Einstein's predictions under different circumstances. That might provide useful information, but the lack of such information in no way discredits the results of this particular experiment. If you want to read more about the experimental protocol, check out the final results paper: http://arxiv.org/pdf/1105.3456v1 http://arxiv.org/pdf/1105.3456v1
- throwaway32 15y ago
  please do not complain about downvoting, it does nothing to contribute to discourse, and litters up the site.
  - throughaway 15y ago
    please do not complain about complaints about downvoting, it does nothing to contribute to discourse, and litters up the site.
ignifero 15y ago

Vivtek 15y ago

I initially read this "Einstein was right, announces results of epic space-time experiment", which would have been epic and a much more interesting story.

known 15y ago

My understanding is we should benchmark everything with http://en.wikipedia.org/wiki/Speed_of_light http://en.wikipedia.org/wiki/Speed_of_light

catechu 15y ago

From article: "The mass of Earth dimples this fabric, much like a heavy person sitting in the middle of a trampoline." I will never imagine general relativity the same way again.