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From an article in Fermilab Today:
Our universe is as mysterious as it is vast. According to Albert Einstein's theory of general relativity, anything that accelerates creates gravitational waves, which are disturbances in the fabric of space and time that travel at the speed of light and continue infinitely into space. Scientists are trying to measure these possible sources all the way to the beginning of the universe.
The Holometer experiment, based at the Department of Energy's Fermilab, is sensitive to gravitational waves at frequencies in the range of a million cycles per second. Thus it addresses a spectrum not covered by experiments such as the Laser Interferometer Gravitational-Wave Observatory, which searches for lower-frequency waves to detect massive cosmic events such as colliding black holes and merging neutron stars.
The absence of a signal provides valuable information about our universe. Although this result does not prove whether the exotic objects exist, it has eliminated the region of the universe where they could be present.
(Score: 5, Interesting) by maxwell demon on Saturday April 11 2015, @10:48AM
While I'm not in the field, I think I understand enough of it that I can answer at least some of your questions:
I don't think anyone can give a definitive answer to that question yet, since we still don't know what is the right way to quantize spacetime (or if it should be quantized to begin with). But if it is quantized, the expansion should be quantized, too, and the quantum would be the quantum of volume (most probably something of the order of the Planck volume).
It expands everywhere (at least in non-quantized spacetime, no idea how quantized spacetime would enter), but that doesn't mean that the atoms grow because the size of the atom is determined by Coulomb attraction and quantum mechanics; imagine having an object on a treadmill, but held by a rope; despite the treadmill, the object won't move because the rope holds it back.
Now if you look closer, you'll find that the rope, while not expanding over time, will actually be slightly longer than if there were no treadmill since it the force needed to keep the object from moving slightly extends the rope due to the rope's elasticity. As far as I understand, the same happens in principle in atoms, however the difference is too small to measure. However if the expansion gets large enough, it should be sufficient to even rip atoms apart. Given that we observe an accelerated expansion, it has been hypothesized that this might indeed happen some time in the future; that scenario is known as Big Rip.
Now here things get interesting. I've never heard considerations about that; but from QCD we know that confinement cannot be broken, but as soon as you apply to add enough force trying to separate the quarks, new quark-antiquark pairs are generated, so you actually get two colour-neutral particles again. However if expansion is high enough to do that, it should immediately try to rip those apart again, causing the generation of even more quark-antiquark pairs. So it seems that the universe would ultimately get filled with quark-gluon-plasma. But then I wonder if all that new matter would not affect the further expansion of the universe; also, would the dark energy be used up for generating that matter? I guess to say more here we would need a real expert in that stuff.
The Tao of math: The numbers you can count are not the real numbers.
(Score: 2) by HiThere on Saturday April 11 2015, @06:48PM
Sounds like you've explained the source of the big bang. Which is rather interesting, and implies that the universe didn't start with the big bang, only the observable universe.
I don't know whether that would work out, but it may imply that the original creation of the universe is an indefinite number of big bangs ago, and thus it could be an EXTREMELY unlikely event. Sort of the kind of thing that's less probable than a Boltzman brain.
It's not clear to me, though, that this would imply we shouldn't expect to detect gravity waves.
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