Could We Really Find E.T?

Allen Telescope Array

By Seth Shostak, Director of the Center for SETI Research, and Nathalie Cabrol, Director of the Carl Sagan Center

Some recent articles in the press convey the impression that our current efforts to find intelligent life beyond Earth are unlikely to succeed simply because our technology is not advanced enough to sense alien signals.

Of course, that’s not true. Consider the Allen Telescope Array, currently being used every day by the SETI Institute in its hunt for signals from other star systems. This instrument is exquisitely sensitive – it could find some of the powerful radars that we have here on Earth at a distance of dozens of light-years. Any society that is even slightly more technically advanced than our own could easily manage a deliberate radio transmission that the Array could pick up. For SETI researchers, it’s a matter of aiming our antennas in the right direction, and tuning to the correct spot on the dial.

But could it be that our incomplete understanding of physics is keeping us from finding the extraterrestrials? Perhaps they don’t use radio, but have moved on to some hypothetical new communication mode. Of course that’s possible, but it’s at least as probable that radio and light are – and always will be – the most efficient method of sending bits of information from one star system to another. 

In any case, the possibility of “new physics” invalidating today’s SETI experiments is an indefensible reason to abandon the search. One might have pointed out to Columbus that wooden ships were a poor way to traverse an ocean, and he should just wait for aviation. But the wooden ships were good enough.

Our SETI technology will, of course, improve with time. Nonetheless, the discovery of a signal betraying extraterrestrial intelligence could still happen today, tomorrow, or next week. But only if we search.