Because just think about one time we have sun and sun = star. Near a sun always have like a earth planet means all stars have like a earth planet and there can alien who wanna contact to us .. and i just listen ..our Milky way and Andromeda galaxy and more than 50+ Galaxies create a group .. called Local group and thousands of Local groups create a more group called Laniakea Supercluster and thousands of Laniakea Superclusters create a more group and that's called observable universe ..Even scientist is dunno ..what comes after observable universe.. We are the part of observable universe is 0.000000001%
