Frank Drake: Half a century listening for ET

Alien invasions, four-armed ETs and the cosmic lottery – New Scientist talks to the founder of Project Ozma and the inspiration for the modern search for extraterrestrial life.

What gave you the inspiration to set up Project Ozma?

In 1957 I was studying the Pleiades star cluster at Harvard University's radio observatory. On one occasion we saw an added feature in the data. It turned out to be an amateur radio enthusiast near the observatory, but at the time I thought we had detected clear evidence of another civilisation. You feel a very strong emotion that you never feel otherwise. It's a combination of elation and excitement and the sense that everything we know is going to change.

How optimistic were you when it all began?

In 1960, when Ozma started, every star in the sky could have been radiating signals, for all we knew. There was a chance we'd succeed almost immediately. But we knew so little of the universe that one could not seriously speculate.

You kept Project Ozma secret: was that because your peers would be sceptical?

Back in 1960 it was taboo to think about extraterrestrial life; it was something done by bad scientists. However, we were fearless. We did not feel we should be embarrassed in any way.

Fifty years on, do you think we should have heard something?

Over the years, I've gotten more realistic. The equation I devised [the Drake equation] says that we're going to have to look at 10 million stars before we find one that might host life. Even then there's no guarantee they're transmitting, or on the frequency we're looking at. We've done a lot of searching to date but it doesn't add up to 10 million stars. In a way what we've been doing until now is buying a ticket in the lottery. There's no reason to think we should have succeeded yet.

Should we start broadcasting in a coordinated way?

Frankly, no. A civilisation not much more advanced than ours could build a telescope that could detect the signals we already transmit, such as television. For us to spend our resources adding one more signal to that cacophony would be frosting on the cake.

There is also an argument that broadcasting could elicit an invasion.

Yes, and if that happens it might be my fault! Back in 1974 I broadcast a signal from the Arecibo Observatory in Puerto Rico, which is still the strongest signal ever sent. That stimulated a major outburst from the Astronomer Royal at the time. He was very concerned.

What do you think an alien would look like?

Our physiology and morphology are certainly not unique. Humans are basically a good design: it's good to stand upright, because it frees our hands to manipulate tools, for instance. It's best to have the head on top, so you can see prey. Our two arms are arguably not optimum, however, as anyone who has tried to carry groceries from their car to their house will find! So my hypothetical ET looks a lot like us but has four arms. Then again, who knows what evolution will lead to elsewhere?

via Frank Drake: Half a century listening for ET - opinion - 13 January 2010 - New Scientist.