Monday, March 17th, 2014

What Time Is "Primordial Gravitational Waves"?

Later today, science-type people are going to make an announcement that they promise is super-exciting and also possibly intelligible to the non-science community. The Harvard-Smithsonian Center for Astrophysics, the rumors have it, will be talking about evidence for "primordial gravitational waves." Now is the time to bone up on your weird science, so that you can have an opinion about it, or what else is the point of living?

Here's an explanation from a few years back:

So-called gravitational waves are a prediction of Albert Einstein's theory of general relativity—moving objects perturb spacetime, generating waves like a boat moving across a lake….Such primordial waves might offer the best means for testing cosmological models such as inflation, which holds that the newborn universe ballooned from a tiny pocket to something roughly 1026 times larger in just a sliver of a second.


6 Comments / Post A Comment

Logan5 (#233,031)

Plus, last night was the "worm moon!"

Annie K. (#3,563)

Sorry, I can't help with this one. Ok, I get that the Big Bang left behind the microwave background, and that the microwave background is basically light, and that light can be polarized, whatever "polarized" is, but what does the polarized light have to do with gravity waves? Sometime those astronomers just gallop out ahead and leave me in a cloud of dust.

Werner Hedgehog (#11,170)

@Annie K. Gravitational waves are difficult to detect – no one has really done it directly – since they are so weak. There was, however, a time when they were plentiful and intense: right after the Big Bang. The gravity waves induced a kind of anisotropy in the way that electrons scatter/polarize photons, and this anisotropy persists to the present day.

@Annie K.: My super crude, probably wrong, take is that gravity waves contains gravitational radiation in a fashion analogous to how light waves have light radiation. They also both have characteristic particles (gravitons and photons) and can interact with surrounding particles as they pass. The gravitational radiation of a passing gravitational wave causes photons to move in a biased manner, in other words become polarized. Gravitational radiation is super weak so finding any direct evidence for it has been almost impossible. Gravitational radiation is caused by moving massive things very fast, so they can detect this wave because it's produced by the huge mass of the early universe moving very, very fast.

Annie K. (#3,563)

Thank you, Werner and brilliant. So the gravity waves would have been intense enough to change the way that photons scatter off electrons? And I'll assume that latter phrase is the definition of "polarization?" Can gravity, no matter how intense, affect photons? electrons? why don't I know this?

Freddie DeBoer (#4,188)

Is that gif from the Lucasfilm game Loom?

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