We know that the Search for Extraterrestrial Intelligence (SETI) is often strapped for cash. But what if the aliens out there trying to reach us, rather than being far superior technologically and beaming signals in all directions, are actually starving scientists, too?
In a pair of papers in Astrobiology, three members of the Benford family—Gregory, an astrophysicist and sci-fi author; James, president of Microwave Sciences; and James’ son Dominic, of NASA—ponder the possibility of E.T. trying to reach us on a budget, and say that we might have to revise the way we hitherto have watched.
Aliens wishing to communicate would probably broadcast at frequencies between 1 and 10 gigahertz, where there is less astronomical background noise than in other wavebands. Most SETI projects tune in to the “cosmic water hole” waveband between 1.42 and 1.72 gigahertz. The reasoning goes that alien astronomers might expect earthly scientists to be looking there anyway as this is the frequency of radiation emitted by interstellar hydrogen and hydroxyl clouds [New Scientist].
In a half-century of hunting, the Search for Extra-Terrestrial Intelligence (SETI) has turned up nary a whisper from E.T. But for renowned physicist Stephen Hawking, the non-success of SETI and others who hope to contact alien life might be for the best: Aliens, he says, might not like us.
Hawking caused waves with this suggestion in his new Discovery Channel special, which debuted last night. He has long believed that extraterrestrial life exists, simply because of the sheer vastness of the universe. While much of what’s out there might be simple microbial life, there may indeed be new civilizations far more advanced than our own. But that doesn’t mean they’ll be friendly.
Said Hawking: “We only have to look at ourselves to see how intelligent life might develop into something we wouldn’t want to meet. I imagine they might exist in massive ships, having used up all the resources from their home planet. Such advanced aliens would perhaps become nomads, looking to conquer and colonise whatever planets they can reach” [The Times].
If you’ve been expecting to hear from a far-off alien civilization, don’t hold your breath, suggests Frank Drake, the founder of Search for Extraterrestrial Intelligence (SETI)–the odds of ET phoning Earth may be diminishing. And your digital TV might well be to blame.
Speaking at a meeting of the Royal Society in London, Drake said that digital transmissions are effectively “gagging” the planet. In the fast-fading analog age, TV and radio signals transmitted around the world escaped into space. At present, the Earth is surrounded by a 50 light year-wide ”shell” of radiation from analogue TV, radio and radar transmissions, he said [The Telegraph]. Those signals reach distant stars, which means that if someone is home at any of those stars, they could heard us.