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<a href="http://www.cnn.com/2002/TECH/space/09/20/cosmic.radiation.reut/index.html" target="_blank">Antarctic Telescope Sees Big Bang Echo</a>

I just saw this on CNN.com.
How do they know it is what they think it is?

Please believe me, I would love to be able to point to this article and say, "See? More proof that the universe is more than 6,400 years old, and that we are on the verge of discovering exactly how it began". But I am hesitant.

Since this forum is not my usual hang-out, I apologize if this is old news to you S&S regulars. I was just wondering what you thought of this news, and how it can be applied?

lpetrich

What they had measured was how polarization varies with direction in the Big Bang's Cosmic Microwave Background.

This polarization is a side effect of scattering of light off of the material of the Big Bang, and it does not cancel itself out because the Big Bang had a tiny bit of lumpiness. This lumpiness has been measured in other observations; these polarization measurements will provide additional details on this lumpiness.

This lumpiness is important because the more dense parts eventually collapse on themselves to form galaxies; one can attempt to predict what initial lumpiness is necessary to produce the distribution of galaxies that one sees.

The CMB is the result of "recombination", which happen 400,000 years after the Big Bang's start, when the Universe cooled enough so that hydrogen and helium nuclei could successfully capture electrons. This greatly reduced the opacity of the Big Bang material, allowing the Big Bang's light to travel freely -- and become redshifted into the microwave part of the spectrum.

The pattern of lumpiness at that time was a side effect of conditions very early in the Big Bang -- whatever had made the Universe essentially flat at large scales had not made it completely flat. The most plausible hypothesis that anyone has come up with is that the Universe had gone through a period of exponential expansion ("inflation"), about 10^-36 seconds after the start of the Big Bang. This flattened out the Universe -- and quantum fluctuations in it produced a tiny bit of lumpiness. Which has persisted after that inflation had ended.

So that measurement could provide some clue as to what had happened very early in the Universe's history.

[ September 20, 2002: Message edited by: lpetrich ]</p>