Even at the speed of light ( which is impossible to achieve) would take 100s of 1000s of years or millions of years. If we sent "them" a message today to call round, it would take similar time till they got it, & then they would have billions of of suns galaxies & solar systems to go to with billions of billions of planets to chose from if they came in our direction.
After arriving in several billion years they would look at our stockmarket,... OXR would be $1000/share & Goblin will be very rich. LOL
Would seem highly probable that life in some form does exist in the vastness of space simply because of the incomprehesible number of planets which could possibly support life. Equally the impossibility of spanning the times & distances means they wont be calling on us.
A good book which explains some of this & lots of other good stuff is Bill Brysons "A Short History of Nearly Everything"
