

Rumours swirl over credibility of big bang ripple find - hachiya
http://www.newscientist.com/article/dn25558-rumours-swirl-over-credibility-of-big-bang-ripple-find.html

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Udo
At first I was skeptical about the article (this being NewScientist), but it
seems that BICEP's findings might indeed be in doubt. This would be exciting,
since it moves our search for gravity waves back to square zero.

People have tried for quite some time to measure them and so far no experiment
has succeeded. On the other hand that's not surprising for such an elusive
phenomenon, so the jury is still out.

~~~
mrfusion
What would it mean if gravity waves are never found, even by equiptment we are
sure should be finding them?

Are there any theories of gravity that don't include gravity waves?

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Udo
_> What would it mean if gravity waves are never found, even by equiptment we
are sure should be finding them?_

We are currently far, far away from that point. We're just at the beginning of
a long, statistics-driven process.

If gravitational waves remain elusive, that would mean there is something
profoundly wrong with the way we understand relativity. To be fair, there is
arguably a lot about gravity which we don't yet understand - but gravitational
waves are pretty much a required feature in many respects.

For example, without them our understanding of the orbital mechanics of
massive objects would have to be revised. It would mean that massive bodies
orbiting each other do not lose energy due to gravitational radiation.

 _> Are there any theories of gravity that don't include gravity waves?_

Not any credible ones that I know of, maybe someone else can present one?

~~~
mrfusion
Would it also mean that changes from gravitational sources would affect other
bodies instantaneously? Or have we already proven experimentally that's not
the case?

I guess I'm saying, if gravity waves conclusively didn't exist, how would
information about gravity travel?

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has2k1
Well, I feel for the scientists involved.

Before that revelation my expectations where that gravitational waves would be
detected after the next supernova in the milky-way galaxy. That would require
a lot less ingenuity.

I would take discovery by any method during my lifetime, in fact the less
expected the better.

~~~
ISL
Look to the Hulse-Taylor binary pulsar; perhaps you needn't wait any longer:
[http://en.wikipedia.org/wiki/PSR_B1913+16](http://en.wikipedia.org/wiki/PSR_B1913+16)

The energy loss rate from it and similar systems is in agreement with the
gravitational wave predictions of General Relativity at the ~0.3% level or so.

The detection method by which BICEP has made its claim is somewhat indirect,
too, as they see _very_ weak distortions of CMB polarization made by the
aftereffects of said waves.

Direct detection on earth is likely to come from a neutron-star binary merger.
If we're lucky enough to get a local supernova in our lifetimes, it will be a
huge deal for gravitational waves and _many_ other branches of physics and
cosmology. Our observational powers have increased by orders of magnitude
since 1987A.

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galvanist
See also the National Geographic coverage:
[http://news.nationalgeographic.com/news/2014/05/140514-bicep...](http://news.nationalgeographic.com/news/2014/05/140514-bicep2-physics-
rumors-science-big-bang/)

