A life form is an entity that is living. Humans share the planet with as many as 8.7 million different life forms at present and it is estimated that 99% of all the species that ever existed on earth which amounts to over 5 billion species are extinct. It is estimated that the Milky Way galaxy alone has at least 100 billion stars with 100 billion planets, possibly many more and the universe contains hundreds of billions of galaxies or more. Where else other than planet earth may we find life forms?