Recent results from the Kepler Space Telescope indicate that 17% of stars in our galaxy have a planet up to 1.25 times the size of Earth in a close orbit. Our galaxy is a twin of Andromeda (pictured) with about one hundred billion stars and thus has at least 17 billion (17 000 000 000) earth like planets.
Look at the myriad of stars in the photograph and imagine how many beings are (or rather were as it is 2.5 billion light years away from us) looking back at our ancestors who were of the same vintage as Lucy (approx 3.5 million years old) and still breaking rocks in Africa.
The Seti Institute recently announced 461 new candidate planets, a substantial proportion of which are about the size of Earth. Four of these orbit in the habitable zone with temperatures compatible with the existence of life as we know it.
Remember there are 170 billion 170 000 000 000 galaxies in the visible universe.
Number of planets like Earth? You do the maths!
Life as we know it based on carbon chemistry may not be the only way…….