Well, the universe was warmer then …
Just after the Big Bang, the cosmos was a much hotter place. It was filled with sizzling plasma — superheated gas — that gradually cooled. The first light produced by this plasma is the cosmic microwave background radiation (CMB) that we observe today, which dates from about 389,000 years after the Big Bang.
Now the CMB is freezing cold — around minus 454 degrees Fahrenheit (minus 270 degrees Celsius; 3 degrees Kelvin). It cooled down gradually with the expansion of the universe, and at some point during the cooling process, for a brief period of seven million years or so, the temperature was just right for life to form — between 31 and 211 degrees Fahrenheit (0 and 100 degrees Celsius; 273 and 373 degrees Kelvin).
It is the CMB’s heat that would have allowed water to remain liquid on ancient exoplanets, Loeb said.
Planets? They’re talking about a point 15 mya after the Big Bang when there we no heavier element.
But Loeb says that rare “islands” packed with denser matter may have existed in the early universe, and massive, short-lived stars could have formed in them earlier than expected. Explosions of these stars could have seeded the cosmos with heavy elements, and the very first rocky planets would have been born.
Loeb thinks his theory is testable in that can look for rocky planets forming around stars with “almost no heavy elements.”
Here’s Chapter 1 of Loeb’s new book on the first galaxies.
Whether rocky planets around gassy stars are thought to support his theory or no, another cloud on the horizon is the general unpopularity of the Big Bang itself (discussed here. In fact, that will be the topic of our next post (here).
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