It looks like you're using an Ad Blocker.
Please white-list or disable AboveTopSecret.com in your ad-blocking tool.
Some features of ATS will be disabled while you continue to use an ad-blocker.
A large array of radio telescopes has begun its first sustained search for extraterrestrial intelligence (SETI) and at rates faster than ever before. Even so, the project has scrambled to find money to stay open and reach its planned size. "We've had a chequered time here," says Don Backer, director of the Allen Telescope Array (ATA) in Hat Creek, California. "We're skating on thin ice."
The ATA has 42 six-metre dishes swivelling in the high desert, far fewer than the 350 dishes planned. In May, the array began combing the centre of our Milky Way Galaxy for alien signals across a broad slice of the radio spectrum.
Backer hopes that once completed, the ATA, covering vast swaths of sky rapidly, will usher in an era of transient radio astronomy — the study of things, such as supernovae, that go bump in the night rather than shine constantly like stars. Science targets could include the star-fuelling hydrogen that surrounds galaxies, and the radio afterglow of the γ-ray bursts that follow supernovae.
Because the distant solar systems that may be inhabited by SETI-candidate civilizations are really, really far away, the path loss between them and us is really, really big. We are, in effect, trying to see headlights on a car that is millions of miles distant. So for a SETI receiver to successfully detect these signals, the receivers have to be really, really sensitive (and there are limits imposed by the laws of physics on how sensitive a receiver can be made to be), the bandwidth being searched has to be really, really small, or the antennas have to be really, really big - or better yet, all three of these techniques applied at once. We have to assume that it is extremely unlikely that an extraterrestrial civilization will be aiming its signal at us with the specific intent that we hear it, and that we will be aiming our very narrow-beam antennas in just the right direction, and tuning our receivers to just the right frequency all at just the right time in order for us to detect the signal. Therefore, for us to hear an alien civilization, we are going to have to get extremely lucky. Recognition of this reality is why so much effort is being expended by the SETI projects to increase the number of antennas and receivers being used for the search.