We might be the only ones, it\'s hard to tell.
The unviserse has been around for such a long time. We have no idea how often life exists anywhere, we just know about our own planet\'s life. There are so many planets. But life on ours has only been around for a relativly short time, So I mean, perhaps life exists elsewhere and perhaps not. Maybe life never exists at the same time as other life....
On the other hand, it is probley true that there is atleast bacteria somewhere else. The only really debateable thing is how did life begin on earth, and how would it begin somewhere else. However life started on earth, it certainly has shown to be able to adapt to any situation. Because of this, if the reasons life began on earth occoured somewhere else, then it probley happens a lot more often then we think.
Then again, perhaps life can begin in MANY situations, in which case, a large number of planets or commets or moons etc could have life.