E.T. doesn’t even know we’re here yet — if he exists at all — and we’ve been texting him the wrong way.
Those are among the conclusions in Paul Davies’ fascinating book about SETI, The Eerie Silence: Renewing Our Search for Alien Intelligence. Davies’ account is such a sci-i page-turner that it’s tempting simply to summarize the questions he asks.
Is life rare or fairly common throughout the universe? What if astrobiologists are looking in the wrong places? What about all those volcanic vents on ocean floors — what if they harbor non-carbon-based life forms (or evidence of a genesis or two prior to the one we’re familiar with)? If life has started over a couple of times right here on Earth, that at least increases the odds of finding bacterial E.T.’s.
Life is one thing; intelligent life, quite another. Yet for 50 years, SETI has been sending out radio signals — which is outmoded even by Earth standards. (We’ve basically switched over to cable.) So why aren’t we looking instead for laser beams or neutrino streams? And if we have any longstanding galactic neighbors, by now they could have flooded our quadrant with self-replicating nanotechnology beacons. So, as in Enrico Fermi’s famous paradox, where is everybody? Why hasn’t E.T. phoned in yet?
Partly because even nearby aliens — say, a thousand light years away — would only be able to observe an Earth that’s medieval, not modern. And there’s no reason to assume that E.T. is chronologically aligned with our own civilization. Given the vastness of time, it’s more likely that E.T. dates from millions of years ago.
The most horrific possibility, as Davies notes in his final pages, isn’t that intelligent alien civilizations never existed (and that we’re all alone) — it’s that they’ve all been killed off (by nukes or cosmic rays).
While peppering his account with pop-culture references — he jokes about A for Andromeda and The X-Files — Davies also speaks from a position of authority. Not only has he published 22 books, but he chairs SETI’s Post-Detection Taskgroup. If E.T. calls next Tuesday, Davies will be among the first 12 people on Earth to know.