Microbes on Venus May Herald Human Extinction (Though Not in the Way You Think)
This week’s report that astronomers have discovered possible evidence of life on Venus is good news for science journalists. But it may be bad news for the future of humanity. One theory on why we haven’t encountered advanced civilizations from other star systems is that the conditions that lead to life are extremely rare. But if those conditions aren’t rare—as illustrated by, say, the appearance of two life-bearing planets in the same solar system—then another reason is more likely: We haven’t seen aliens because advanced civilizations tend to self-destruct before they have time to colonize the stars. Much of this discussion is rooted in the so-called Fermi paradox—whose Italian-American originator, Enrico Fermi (1901–1954), famously wondered why humanity seems alone in the vastness of the universe. Our galaxy alone contains an estimated 20 billion Earth-like planets. Many of these worlds are likely over a billion years older than Earth. So you would think there’s been plenty of time for an alien civilization to reach us, even if it expanded at only a tiny fraction of light …