Are aliens real? We don’t know for sure, but we want to believe. Outer space is a vast expanse that we have so much more to learn about, which is why it’s hard to flat-out deny the possibility that other intelligent lifeforms exist.
If life can exist—and persist—in seclusion and in some of the harshest conditions on Earth (just look at tardigrades), it’s likely that other interplanetary lifeforms have evolved and acclimated to conditions in space, too. The renowned science writer Arthur C. Clarke once said, “Two possibilities exist: Either we are alone in the universe or we are not. Both are equally terrifying.”
Several discoveries and theories from some of the greatest minds in science point to the likelihood that there’s something beyond us in the universe, so there’s a pretty decent chance we have neighbors somewhere in the ether. Consider the evidence.
No one knows which aspects of living systems are necessary, in the sense that living systems everywhere must have them, and which are contingent, in the sense that they are the result of evolutionary accidents such that elsewhere a different sequence of events might have led to different properties of life. In this respect the discovery of even a single example of extraterrestrial life, no matter how elementary in form or substance, would represent a fundamental revolution in science. Do a vast array of biological themes and counterpoints exist in the universe, or are there places with living fugues, compared with which Earth’s one tune is a bit thin and reedy? Or is Earth’s the only tune around?
Within academia, prospects for an alien invasion of Earth are dismissed as Earth does not have any special resources that aren’t already abundant elsewhere, among other reasons.