What If It’s Just Us?
“Our scientific discoveries have led us to a remarkable point in the quest for knowledge about our Universe. We know how big the Universe is, how many stars and galaxies are in it, and what fraction of stars are Sun-like, possess Earth-sized planets, and have planets in orbits which are potentially habitable. We know the ingredients for life are everywhere, and we know how life evolved, thrived, and gave rise to us here on Earth.
But how did life arise to begin with, and how likely is a planet to develop life from non-life? If life does arise, how likely is it to become complex, differentiated, and intelligent? And if life achieves all of those milestones, how likely is it that it becomes spacefaring or otherwise technologically advanced, and how long does such life survive if it arises? The answers may be out there, but we must remember the most conservative possibility of all. In all the Universe, until we have evidence to the contrary, the only example of life might be us.”
When it comes to the big questions, there’s perhaps none more profound than asking about life in the Universe beyond planet Earth. Are there other intelligent alien species out there, flying through the galaxy, modifying their planets, generating enormous signals, colonizing other worlds, and so on? Or, perhaps, in all the Universe, is life like us, and perhaps life at all, a great cosmic rarity? While most of the stories you’re likely to read on the topic are extraordinarily optimistic about the existence of intelligent aliens, we must let the science, rather than our hopes or emotions, guide us.