ar X iv : a st ro - p h / 99 04 05 1 v 1 3 A pr 1 99 9 Cosmological Parameters
نویسنده
چکیده
The discussion of cosmological parameters used to be a source of embarrassment to cosmologists. Today, measurements of the cosmological parameters are leading the way into the era of precision cosmology. The CMB temperature is measured to four significant figures, T0 = 2.7277± 0.002K; the Hubble constant is now determined with a reliable error estimate, H0 = (65± 5) km secMpc; the mass density of baryons is precisely determined by big-bang nucleosynthesis ΩB = (0.019± 0.001)h; and the age of the Universe inferred from the ages of the oldest stars is 14± 1.5Gyr, which is consistent the expansion age. Further, we have the first full accounting of matter and energy in the Universe, complete with a self consistency check. Expressed a fraction of the critical density it goes like this: neutrinos, between 0.3% and 15%; stars, between 0.3% and 0.6%; baryons (total), 5%± 0.5%; matter (total), 40%± 10%; smooth, dark energy, 80%± 20%; totaling to the critical density (within the errors).
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تاریخ انتشار 1999