I screwed up and originally posted this on the religion board.What's your take are we the only life in the universe?Or is there others?and have they visited earth?
If you have ever taken an astronomy class in college then you know there is life on other planets. There are simply too many galaxies with stars and attendant solar systems for earth to be the only planet with life. So, yes, there is certainly life out there—lots of it. Undoubtedly, some of it is far more advanced than life on earth while others are not as advanced.
I am certain there are star faring races that routinely move between planets and solar systems. There may even be communities among planets like the Federation in Star Trek or the Galactic Senate in Star Wars.
Are aliens aware of us? Maybe. Have they come to earth? I have no reason to think so. We are too primitive to warrant serious attention from advanced civilizations.
In both technology and social development we are not yet worthy of contact with alien visitors. Aliens that have the technology to come here also have the technology to observe us without detection. They could easily study us from a distance, learn our languages and customs, monitor our radio/tv broadcasts and our global internet. Having done so, they would quickly learn we are deeply divided over superficial things like international borders, gender, race, sexuality, religion, and on and on. Having observed that we can not even get along with one another why would aliens (who would certainly not look like us) decide that we could handle contact with beings that would certainly look like freaks (to us).
I am certain there are plenty of advanced civilizations out there but I do not think earth is on their radar screen for now. We are not technologically and socially ready to handle contact with aliens.
Even in Star Trek (TNG) they limit First Contact to new planets that have developed warp drive (light speed) technology. One episode in particular deals with this subject
http://www.startrek.com/startrek/view/series/TNG/episode/68484.html