There may have been life in the universe billions of years earlier than previously believed, according to a recently released paper by Israeli theoretical physicist Abraham Loeb, who is chair of the Astronomy department at Harvard University.
Terrestrial life as we know it is thought to have evolved on Earth around 3.5 billion years ago, but Loeb’s theory posits that conditions shortly after the Big Bang, more than 13 billion years ago, could have been conducive to the rise of life elsewhere in the universe.
Around 15 million years after the Big Bang, a blink of an eye in cosmic terms, the endemic background cosmic radiation of the universe, which was super-heated after the Big Bang, would have, as the universe expanded, cooled to an approximate Earth-like range, he notes.
This is important because scientists believe that life can arise only under certain conditions, one of which is the right temperature. Much of the current analysis of exo-planets — planets orbiting other stars, of which hundreds have been discovered in recent years — revolves around the search for a “Goldilocks” planet, one where the conditions are “just right” for the support of life.
Loeb said that this period of Earth-like temperature would have lasted around seven million years, giving rise to the possibility that some form of life could have evolved during this time.
Current theory indicates that planetary systems had not formed into their current configurations so soon after the Big Bang, but Loeb’s work could still be applied to free-floating rocky bodies or other masses, which during that brief window could have had Earth-like temperatures, and water, even if they were not in orbit around a sun.
Edwin Turner, an astrophysicist at Princeton University, told Science.com, which published an analysis of Loeb’s paper last week, that the new theory was “very original, stimulating and thought-provoking.”
Loeb is one of the leading theoretical astrophysicists of his generation. Raised in Israel, he received his PhD from the Hebrew University at age 24 and has spent 20 years at Harvard. The author of over 430 papers, Loeb returns to Israel frequently as a visiting professor at both the Weizmann Institute and Tel Aviv University.