I’ve just met one of my scientific heroes, Frank Drake.
He started the search for extraterrestrial intelligence – SETI – 50 years ago when he pointed a large radio-telescope in West Virginia at the nearby star Tau Ceti and listened for any radio signals that might be coming our way from an alien civilisation based on a planet orbiting the star.
Of course SETI has not heard a clear peep from ET over the past half-century, despite listening to thousands of stars with technology far more sophisticated than anything available to the young Drake in 1960.
But enthusiasts are not discouraged – far from it. The discovery of hundreds of “extrasolar” planets over the past few years has reinvigorated the search.
This week Drake, aged 79 and still working on SETI, was in London for a discussion about extraterrestrial life at the Royal Society.
At a meeting with science journalists, it was clear that the sliver-haired astronomer is as convinced as ever that detectable civilisations are out there – about 10,000 in our Milky Way galaxy, he estimates, making reasonable assumptions about the various unknowns in his famous Drake equation for estimating the chances for hearing from ET.
There are at least 100bn stars in the Milky Way, so just one in 10m has a detectable civilisation, according to Drake. Although that means a lot more searching, the technology continues to improve rapidly. And, as Drake says, SETI can now work hand in hand with the new planet-hunting telescopes such as Nasa’s Kepler, so that astronomers will be able to listen for signals from Earth-like planets as soon as they are discovered.
So far SETI has relied mainly on radio-telescopes but an alternative, just coming into operation, would look for short but incredibly powerful bursts of light from alien lasers, producing coded flashes that would outshine their parent star for an instant.
“In the universe elsewhere there is intelligent life. I’m confident about that but how easy it is to find we don’t know,” Drake says. How wonderful it would be if we made contact in his lifetime.