Originally Posted by Dr_Watso
Not on earth, or anywhere near us, but yes. I don't think our circumstances are all that unique, in such a huge universe nor do I limit the thought patterns to only being "life" forms like us. It could quite literally get weirder than we could ever imagine.
The universe is huge, but time is much more vast. It could be that life forms pass each other in the night, separated by millions of years and millions of light years.
The universe is about 14 billion years old and the Earth, 4.5 billion years. Life on Earth: 3.6 billion years. Sentient live on Earth: Maybe 200,000. So, for the entire life of the universe, life has existed for less 25 one-hundredths of the time and sentient life for 14 millionths of the time. And I'm not even speculating whether interplanetary travel is possible, practical, useful or affordable. Entire species could evolve, do their thing and their solar systems crumble and the species, at the interplanetary traveling stage, might never get closer together than a million years.
The best we might do is discover that there is life on other planets, but it's millions or billions of years away from having sentient life, if ever. The closest thing life ever gets to interplanetary travel is on comets, carrying amino acid fragments and the seeds of life from one planet to the next.
We are really alone.