Answer to Question #69708 in Astronomy | Astrophysics for SANJAY
If the temperature of the background radiation today is 3 K, at what time after the birth of the universe was the temperature 10^15 K. Take the age of the universe as 15 × 10^9 years.
Please see at (https://en.wikipedia.org/wiki/Chronology_of_the_universe) the table with the universe chronology. The given temperature was somewhere between inflationary epoch, electroweak epoch and quark epoch or between 10^-32 and 10^-12 second after the Big Bang.
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