ET `would not be a pretty sight'

Life on the only known planets outside our solar system would not be a pretty sight. ET would have antennae and the physique of a brick public convenience, writes Steve Connor.

Alexander Wolszczan, the scientist who three years ago discovered Earth- sized planets orbiting a dead sun in another part of the galaxy, yesterday speculated on what life forms would have to cope with in order to survive.

"You'd probably have to be heavily armed against high-energy radiation," Mr Wolszczan, of Pennsylvania State University, told the American Association for the Advancement of Science.

The dead star is known as a pulsar, an extremely dense object just 20 kilometres in diameter that spins thousands of times faster than typical stars. "Living on a pulsar planet would be very much like standing in front of a gigantic X-ray machine," Professor Wolszczan said.

Sunbathing on the pulsar planet would be even more risky than sitting on a Mediterranean beach at midday. "You'd probably have to have a lead- covered umbrella if you wanted to go out in the heat just to protect yourself against the rays of the pulsar."

The dead star sends out pulses of radio waves at a frequency of 160 times a second. This may have led to pulsar life evolving its own radio receivers - antennae - to tune in, Professor Wolszczan suggested.

Gravity on the planet would be around three times that on Earth. "You'd feel a little bit heavier" so life would have to be chunky to cope with the extra weight, but it would be able to make use of the planet's rich metallic compounds. "I guess it would probably not be a very attractive picture of life the way we know it."