It is believed that the age of the universe is 13.8 billion years, and our planet was formed only 4.5 billion years ago. Some scientists believe this time gap indicates that life on other planets could be billions of years older than on Earth.
However, new theoretical research, accepted for publication in the journal Cosmology and Astroparticle Physics, indicates that modern life may in fact be cosmically premature.
'If you ask me – When is life most likely to arise? “You’ll get a very naive answer: now,” said lead author Avi Loeb of the Harvard-Smithsonian Center for Astrophysics. “We also see that the potential for life in the distant future is much higher than it is now.”
Today, scientists are confident that life as we know it became possible about 30 million years after the Big Bang, at the moment when the first stars inhabited space and fed it with essential elements such as carbon and oxygen. According to this concept, life should end 10 trillion years after the last stars have disappeared. Loeb and his colleagues were able to calculate the relative probability of life between these two boundaries.
The dominant factor was the lifetime of the stars. The higher the stellar mass, the shorter the life of the stellar 'battery'. According to the new model, stars that are more than three times the size of Earth will disappear before life has a chance to evolve. The smallest stars, weighing less than ten percent of the mass of the Sun, on the contrary, will emit light for 10 trillion years, while giving life enough time for it to appear on any planets around them. Thus, the likelihood of life around such stars increases over time, and the chances of life in the distant future are 1,000 times higher than they are now.
“After that, you can ask me why we don’t live in the future next to a low-mass star?” Asked Loeb. “One of the explanations is that we are premature. Another possibility is that the environment around the low-mass star is simply life-threatening. '
Despite the fact that low-mass, red dwarfs live for a long time, they pose unique threats. In their early periods, they emit powerful flares and ultraviolet radiation that could destroy the atmosphere of any rocky world in the habitable zone.
In order to determine which of the proposed versions is correct: our premature existence or the danger of low-mass stars, Loeb recommends studying red dwarf stars and their planets for habitability. In this, scientists should be helped by space missions of the future such as the Survey Satellite and the James Webb Space Telescope.
