Scientists searching for extraterrestrial life focus on “Goldilocks Planets“; these are planets which fall into a star’s habitable zone. Planet Earth seems to have exactly the right conditions for life to exist – its distance from the Sun means the temperature is right, water can exist as a liquid solid and a gas, and there are the right combination of chemical compounds available to build complex life forms. Other planets thought to have similar features are known as Goldilocks planets.
In the Milky Way alone there are estimated to be 500 million potential Goldilocks planets, so if life can exist in places other than Earth there is a huge number of potential planets on which it might thrive. If these numbers are applied to all the galaxies in the universe there could be a staggering variety of planets capable of supporting life. Of course, we have no evidence life exists elsewhere, but if it does there are plenty of places for it to set up home.