In the massive place called the universe, you seem to believe that Terra is the only place that has life. And, to quote Carl Sagan, the "billions and billions" of worlds, stars, solar systems, etc. you seem to let on that you think that the Earth has some privileged position in the universe. May I inquire why you believe that?
The fact that there are billions of other stars, solar systems, and other planets may not be all that irrelevant. It may be that the conditions for life emerging are very complex and demanding, and they only emerged on Earth because of a very fortuitous sequence of events. if so, the probability of life emerging elsewhere might be so low that it's irrational to believe that extraterrestrial life exists.
Here's an anology. Suppose someone offered you the following bet. He will toss a six-sided die ten times; he offers you odds of 2-1 that either a 1, 2, or 3, will appear in one of those ten die rolls. Sounds like a fair bet, right? But what if, unbeknownst to you, the die is loaded, so that 4, 5, and 6 are overwhelmingly likely to turn up? In that case it's clearly not a fair bet.
The anology is that we shouldn't be so quick to assume that the conditions for life emerging are distributed symmetrically throughout spacetime (like the symmetry of a six-sided die). Instead, the emergence of life may have been "loaded" on Earth (like the unfair die). If we found out that a sequence of fortuitous astronomical, geological, and chemical events were necessary for life to emerge, this might make extraterrestrial life extremely unlikely---no matter that there are billions of planets in the universe.