Cosmic Crises

A World Like Ours

WITHIN THE next few decades we may expect one or other of two events. The more probable of the two is the routine discovery of Earth-sized planets circling nearby stars. And the less likely is the detection of an alien radio signal specifically aimed at us. Either of these highly exciting events will lead to different sorts of crises.

First, what will be our reaction when we find a planet with oxygen and water in its atmosphere?

A planet with an atmosphere has already been found. Earlier this year the Hubble Space Telescope detected such a world orbiting the Sun-like star HD 209458, 150 light-years away in Pegasus. But its atmosphere was of sodium. It distance from its parent sun was a mere four million miles, and its mass was two thirds of Jupiter's. In other words it sounded like a very unpleasant place to live.

But an oxygen-water planet would be a very different proposition, especially if it was in a ``Goldilocks orbit'', neither too hot nor too cold for life, at the right distance from its parent star.

The oxygen in its atmosphere would not be absolute proof that it had life. (The atmosphere of apparently lifeless Mars is 0.15 per cent oxygen), but it would be very strong circumstantial evidence because oxygen suggests the existence of plants, animals or both. Yet a tantalising riddle would arise. Barring the discovery of radio signals emanating from it, we would have no idea what kind  of life we had found. It might be primeval forests or it might be an extraterrestrial equivalent of the Roman Empire.

This would present science with a crisis of frustration. Evidence of life beyond Earth would be combined with ignorance of its nature and, short of sending a fast probe across several light-years (technically unlikely mere decades from now), no means of satisfying our curiosity.

Another crisis, more political in nature, will arise if and when we get a radio message from another civilisation in space that is definitely aimed at us - rather than being one we have picked up by accident. This could happen at any time and could even be detected by somebody's home computer.

The problem will be what to do about it. In 1989 the trustees of the International Academy of Astronautics circulated a ``protocol'' containing a truly fatuous declaration: ``No response to a signal or other evidence of extraterrestrial intelligence should be sent until appropriate international consultations have taken place.''

It was fatuous, not only because the protocol is without legal force, but because news of the message would spread through the world. It would be impossible to keep such a landmark event secret. The more sensational a secret is the harder it is to keep.

And there would be nothing to prevent unauthorised people from sending a reply. What would happen if someone like Saddam Hussein replied to announce that he was king of the Earth? Might not the aliens believe him? Benefits of the first contact with alien intelligence might thus be wrecked by a misunderstanding.

I honestly don't know what the answer to this problem is. Someone should reply at once, but whoever it is will risk being hated for presuming to speak on behalf of humanity.