Now then: Are we alone in the universe? I think probably not; turns out a guy named Paul Gilster agrees with me.
We live in a world that is increasingly at ease with the concept of intelligent extraterrestrial life. The evidence for this is all around us, but I’ll cite what Louis Friedman says in his new book Alone But Not Lonely: Exploring for Extraterrestrial Life (University of Arizona Press, 2023). When it polled in the United States on the question in 2020, CBS News found that fully two-thirds of the citizenry believe not only that life exists on other planets, but that it is intelligent. That this number is surging is shown by the fact that in polling 10 years ago, the result was below 50 percent.
Friedman travels enough that I’ll take him at his word that this sentiment is shared globally, although the poll was US-only. I’ll also agree that there is a certain optimism that influences this belief. In my experience, people want a universe filled with civilizations. They do not want to contemplate the loneliness of a cosmos where there is no one else to talk to, much less one where valuable lessons about how a society survives cannot be learned because there are no other beings to teach us. Popular culture takes many angles into ETI ranging from alien invasion to benevolent galactic clubs, but on the whole people seem unafraid of learning who aliens actually are.
But, as a biologist, and after considering the history of life on Earth, I suspect that life is common – in fact, I suspect (with absolutely no evidence but my personal opinion) that life arises pretty much anywhere conditions allow it, and you need only look at the wide variety of environments right here on Earth in which life finds a way.
Intelligent life, on the other hand, is probably vanishingly rare. In Earth’s 4.55 billion year lifespan, it has harbored life for almost 4 billion years, but intelligent life – as in, technological life that someone out there could detect, which is what the SETI folks are looking for – has only been around for a little over a hundred years.
When humanity finally does make first contact, it probably won’t be sexy green space chicks with flying cars. It’s far more likely to be microbes. Not as sexy – but a lot more realistic to expect.