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تسجيل مستخدم جديدNew dates for the eras of the universe from the Planck data
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تأليف
Kevin Cahill
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Data from the Planck satellite imply new dates for the major eras of the universe. The era of radiation ended 50,150 years after inflation and the era of matter 10.31 billion years after inflation or 3.51 billion years ago.
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Data released by the Planck Collaboration in 2015 imply new dates for the era of radiation, the era of matter, and the era of dark energy. The era of radiation ended, and the era of matter began, when the density of radiation dropped below that of ma
tter. This happened 50,953 pm 2236 years after the time of infinite redshift when the ratio a(t)/a_0 of scale factors was (2.9332 pm 0.0711) x 10^{-4}. The era of matter ended, and the era of dark energy began, when the density of matter dropped below that of dark energy (assumed constant). This happened 10.1928 pm 0.0375 Gyr after the time of infinite redshift when the scale-factor ratio was 0.7646 pm 0.0168. The era of dark energy started 3.606 billion years ago. In this pedagogical paper, five figures trace the evolution of the densities of radiation and matter, the scale factor, and the redshift through the eras of radiation, matter, and dark energy.
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