2 v 1 7 J un 1 99 3 Look Back Time , the Age of the Universe , and the Case for a Positive Cosmological Constant ∗
نویسنده
چکیده
We present explicit expressions for the calculation of cosmological look back time, for zero cosmological constant and arbitrary density parameter Ω, which, in the limit as redshift becomes infinite, give the age of the universe. The case for non-zero cosmological constant is most easily solved via numerical integration. The most distant objects presently known (approaching redshift z = 5) have implied ages of ≈ 1-2 Gyr after the the Big Bang. The range of such age is narrow, in spite of a variety of cosmological models one might choose. ∗To be published in the Journal of the Royal Astronomical Society of Canada, August, 1993 issue.
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تاریخ انتشار 1993