Cosmic 'treasure trove' revealed (BBC) {more from WMAP}

[eppur_se_muova]

By Helen Briggs
Science reporter, BBC News

A Nasa space probe measuring the oldest light in the Universe has found that cosmic neutrinos made up 10% of matter shortly after the Big Bang.

Five years of study data also shows that the first stars took over half a billion years to light up the Universe.

WMAP launched in 2001 on a mission to measure remnants of light left over from the Big Bang.

Scientists say it is collecting a "treasure trove" of information about the Universe's age, make-up and fate.

The Wilkinson Microwave Anisotropy probe (WMAP) is mapping the Cosmic Microwave Background (CMB) radiation in the sky. This is the oldest light in the Universe, shifted to microwave wavelengths as the Universe expanded over 13.7 billion years.
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more: http://news.bbc.co.uk/2/hi/science/nature/7288463.stm

http://map.gsfc.nasa.gov/news/index.html

[villager]

1. Surely, according to the White House, this "light" can't be more than 6,000 years old?

n/t

[Peace Patriot]

2. Any physicists here? How much of the universe is currently made up of neutrinos?

And if it's quite a lot more than 10% (and I think it is), and, also, depending on whether or not neutrinos have mass (which I think some recent studies show that they do), and, thus, possibly determining the issue of the universe expanding forever, vs. the reverse, the universe collapsing upon itself (eventually; or even right now, sporadically), how did the quantity of neutrinos INCREASE to prevent levels?

Do you sometimes feel that--as cosmologists--we are like Medieval doctors trying to stem a plague without realizing that germs cause disease, and pass among humans by sneezing, coughing and touch? Like we are missing some VITAL CLUE to what's really going on? And, like, it's so simple, if only we would take off the blinders that we only barely realize we are wearing (some of us barely realize--most others consider the blindered view to be reality), it would be OBVIOUS...a) how the universe is constructed, b) how to move around in it, c) that the length of our lives--and our decline and fall into old age and death--is determined by our ties to the earth and the solar system, and if we break those bonds, and move around in TIME, we will conquer disease and death, and d) find out what life is for.

Me and Kurt Vonnegut, I guess, think thoughts like this. But, hey, we have a whole lot of history clearly demonstrating a whole lot of blinder-wearing by a whole lot of people on a whole lot of subjects, until....somebody pulled the blinders off.

[eppur_se_muova]

3. "...less than 1 percent neutrinos."

According to the 2nd link in the OP.

[Peace Patriot]

4. Thanks--I missed that. But it doesn't make sense...

If the early universe had 10% neutrinos, and neutrinos have mass (and I don't know if it has firmly established that they do), how could the universe ever have expanded? The 1% amount for now would be consistent with continued expansion only if neutrinos do NOT have mass--as I understand it. 1% with mass is a big drag, in order words. And 10% with mass would likely have stopped the initial expansion. So, does this mean that neutrinos DON'T have have mass?

[caraher]

5. Neutrinos almost certainly have mass

Under the current understanding of neutrino oscillation the three known flavors of neutrinos only mix because they have nonzero masses. At the same time, attempts to measure neutrino mass have only yielded upper limits; as far as I know there's nonzero lower limit on mass established by experiment.

I think you're overestimating the effect of neutrinos. 10% of matter is not the same as 10% of the total energy... I'm not sure how soon after the Big Bang this 10% figure refers to, but in the very early universe far, far more energy was in the form of radiation than matter. So that 10% is a larger piece of a much smaller pie. And we do understand neutrinos well enough to calculate with pretty good confidence their effects on the expansion of the universe, and apparently neutrinos don't really make much of a dent in the "missing mass" problem.

But I think you're probably right as far as the big picture... recent observations showing the expansion of the universe accelerating suggest that there's a LOT we don't really understand. When I was in grad school not that long ago one day a high energy theorist would assure us that the Standard Model is the final word on everything and is basically complete, and the only important parameter to measure is the mass of the Higgs boson. Then the next day the astrophysicist confess we don't know what most of the matter in the universe really is... And of course, there's the ongoing problem of developing a theory of gravity that works at the Planck scale, and a slowly but steadily growing awareness of the Pioneer anomaly.