WEDNESDAY, 25 SEPTEMBER 2013The research, published by Andrew Rushby and his team from the University of East Anglia used stellar evolution models to estimate at which point in the future Earth will stray into the ‘hot zone’ of the Sun, when temperatures will rise so high that the seas will evaporate, rendering all life on our planet extinct.
Humans and other complex life forms however can only tolerate small increases in temperature and will die out relatively quickly, leaving only comparatively hardy microbes to take the heat as the hot zone approaches.
Complex life takes a long time to evolve. Humans have only walked the Earth for the last 200,000 years, but insects have called our skies home for over 400 million years.
Analysing these time scales, or ‘habitability metrics’ on our own planet can help us to estimate the stage that life has reached elsewhere in the galaxy. Rushby and his team compared Earth to eight planets currently in their habitable phase, and found that planets orbiting smaller stars were temperate for longer. Gliese 581d for example has a habitable zone estimated to be ten times the age of our entire Solar System.
Rushby says ‘Of course, much of evolution is down to luck, so this isn’t concrete, but we know that complex, intelligent species like humans could not emerge after only a few million years because it took us 75 percent of the entire habitable lifetime of this planet to evolve. We think it will probably be a similar story elsewhere’.
Written by Joanna-Marie Howes.