Because it does exist, here.
So there’s at least one.
Is there more?
I honestly don’t know.
Or looking at it another way, are we alone?
I honestly don’t know that either.
I sometimes wonder if there really has been enough TIME since the Big Bang (BB) for life to florish.
The Sun and Earth are about 4 billion YO, and the BB was 13 billion Years ago.
However, the Solar System has a lot of heavier than Hydrogen/Helium elements. The heavier elements are actually made in gigantic supernova’s—exploding massive stars.
How many cycles of this manufacturing did it take to make enough heavier elements to make a planet the size of Earth, full of Silicon, Iron, Carbon, Nitrogen, Aluminum, Manganese, Sodium, Sulfur, Oxygen,, and all the other elements necessary for life? We’re carbon-based... So we had wait for that element. We also need lots of oxygen, at least to make water.
Maybe it takes 8-9 billion years of exploding stars just to get enough heavier elements into the universe to start making life?
Maybe we’re just the first?
I honestly don't either. I'm open to the possibility, and all the sci-fi fi stories of exotic civilizations millions of miles away are great fun, but I cannot understand why anyone would be certain.
Could be.