WMAP Refines "Precision Cosmology"
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From: Sam Wormley on 19 Feb 2010 17:30 WMAP Refines "Precision Cosmology" http://www.skyandtelescope.com/community/skyblog/newsblog/84347742.html Space, as far away as we can see, is flat to a new degree of precision. The total density of normal matter, dark matter, and dark energy adds up to 1.0023 � 0.0055 of the critical flatness density. This is consistent with a value of exactly 1 (flat space) to a precision of just half a percent! The breakdown of the basic components of the universe is now: Ordinary matter, 4.56 � 0.16 percent Nonbaryonic dark matter, 22.7 � 1.4 percent Dark energy, 72.8 � 0.5 percent. The dark energy's "equation of state," a parameter known as w, is �0.980 � 0.053, consistent with a value of exactly �1 to a precision of about 5%. This is the value that w would have if the dark energy is an inherent, constant property of any given volume of space, regardless of how much the space may have expanded in the past. This property matches Albert Einstein's idea of a "cosmological constant," which he inserted into his equations in 1917, and pretty much rules out the idea that the dark energy is some kind of "quintessence" existing in space that thins out as space expands. For the first time, WMAP has extracted evidence from the microwave background that directly reveals primordial helium emerging from the Big Bang � not just hydrogen. This was totally expected, but it's nice to see it confirmed. This is the first direct evidence of helium existing before the first stars.
From: kado on 26 Feb 2010 01:26
On Feb 19, 2:30 pm, Sam Wormley <sworml...(a)gmail.com> wrote: > WMAP Refines "Precision Cosmology" > snip > > The breakdown of the basic components of the universe is now: > snip > > Nonbaryonic dark matter, 22.7 ± 1.4 percent > snip > Do you realize that this fundamentally contradicts your next post? On Feb 19, 10:47 pm, Sam Wormley <sworml...(a)gmail.com> wrote: > Pardon the Intrusion, But Your Data Show No Signs of Dark Matter > > http://news.sciencemag.org/sciencenow/2010/02/pardon-the-intrusion-bu... > > "Physicists may not know what dark matter is, but they're getting a > better idea of what it's not. Data from NASA's orbiting Fermi Gamma-ray > Space Telescope puts a crimp in particle theorists' favored explanation > of the mysterious stuff whose gravity holds the galaxies together, > ruling out a hefty range of masses for the hypothesized particles, a > team announced this week. Curiously, the result comes not from the Fermi > team itself, but from other particle astrophysicists who analyzed the > Fermi data". In other words; one, the other, or both are just plain wrong. D.Y. Kadoshima |