The search for extraterrestrial intelligence has made huge strides in recent years.
Using new techniques, scientists have identified many apparently habitable planets, thereby suggesting that the first ingredient of extraterrestrial intelligence — a planet where a sophisticated alien race might develop — is much more common than people once thought. Studies have shown that life has developed and thrived in the most inhospitable climates on Earth, from superhot underseas vents to the coldest ice caves at our poles. And now, astronomers are targeting specific stars with radio frequency searches designed to hear any radio wave activity.
The astronomers examined Gliese 581, a red dwarf 20 light years away that is orbited by six planets, including two jumbo-sized Earth-like planets. If Gliese 581 were aiming a similar array at Earth, it would hear countless radio broadcasts from 20 years ago — lots of the music of Nirvana, and reports on the upcoming Bush-Clinton presidential election, no doubt. But from Gliese 581, the astronomers heard . . . nothing. If there is life on the planets in the Gliese 581 system, it either hasn’t progressed to the point of using radio technology or uses some other form of communication we haven’t discovered.
The fact that we haven’t heard an answer yet doesn’t mean life isn’t out there somewhere. The technique used on Gliese 581 was targeted at a small dot in a universe that has countless such dots. The astronomers could experience years of radio silence from their targets, but the world would change immediately if the radio astronomers heard alien communications from just one target — as was the case in Maria Doria Russell’s excellent novel The Sparrow.
We don’t know if we’re unique, and whether Earth is the only planet in the vast universe where intelligent creatures capable of extraterrestrial communications have developed. Being something of a skeptic, I’m not willing to accept that proposition. Time, and some more efforts to listen in on alien radio, will tell.