- The Washington Times - Sunday, August 13, 2000

''You can go outside at night, even in Austin, and point at it and say that star there has a planet around it," said William Cochran of the University of Texas astronomy department.

Epsilon Eridani, the star in question, is not especially bright, but it is very close: That is why it is visible to the naked eye. Nobody has found a star with planets that close to us before but, then, until 1995 nobody had found any stars with planets orbiting them at all.

Then astronomers developed techniques for detecting planets (though only very big ones) around other stars, and the floodgates opened. In the past five years, 40 new planets have been discovered, all gas giants on the same scale as Jupiter, our own system's biggest planet. Last week, at the International Astronomical Union's 24th general assembly in Manchester, England (Aug. 7-10), another 10 were revealed, including the planet found around Epsilon Eridani by Mr. Cochran's team.

"It's a very exciting discovery," explained Geoff Marcy of the rival planet-hunting team at the University of California Berkeley, "[because] it's only 10 light years away. In the next hundred or 200 years, it will be one of the first stars humans visit." And it is on planets, not stars, that we may find life more or less like ourselves.

Fifty new planets in only five years, all detected by cumbersome techniques that can only spot massive planets in relatively close, fast-moving orbits whose plane is more or less edge on to us and each one took years of patient work to find. But the Berkeley team did announce in Manchester that they had gone back and checked stars already known to have one planet and in 5 out of 12 cases, they found a second.

It begins to look like a universe where it is normal for a star to have a family of planets. While existing techniques still cannot discern smaller, rocky planets like our own around other stars, the Solar System's familiar pattern of several gas giants in outer orbits and some smaller, more habitable planets closer in to the warmth of the sun also seems more and more likely.

So if suitable planets are as common as dirt, and life is not rare but commonplace on them then where is everybody?

The puzzle has been growing ever since the SETI (Search for Extra-Terrestrial Intelligence) project was set up in the 1970s. Every plausible frequency of the electromagnetic spectrum has been monitored more or less continuously for signs of intelligent life forms on other planets. The result? Silence. Either there is nobody intelligent out there, or for some reason they are not talking.

This raises three possibilities, each of which would have large implications for our view of our own place in the universe.

One is that an intelligent species capable of producing high technology is not a normal evolutionary outcome, but a freakish event. In that case, there is a whole universe of friendly habitats with no intelligent natives out there waiting for us, and the human race's far future could well resemble the kind of "galactic empire" so beloved of early science fiction.

The second, darker possibility is that while intelligent life crops up relatively often, it doesn't last long: Species that develop technology wipe themselves out quite fast. That could explain the silence, for if the average survival time of a high-tech civilization is only a few hundred years, then even if there are tens of billions of suitable planets in our galaxy, there would on average be only one civilization (or none) in existence at any given time.

The third, darkest possibility is that there are indeed lots of intelligent species in the galaxy, but the smarter ones are keeping their heads down. If you have no idea what is out there or if you know what's out there, and it scares you half to death then the last thing you want to do is attract attention by broadcasting your position across the cosmos.

A fanciful speculation, but then all three of these options seem quite unlikely yet one of them must be true. Our ignorance about the universe is still very great, and unless the human race wipes itself out later generations will probably lump us together with the Ottomans and the Tang Chinese and the Roman Empire as "dawn civilizations." But it is an interesting time to be alive.



Gwynne Dyer is a London-based independent journalist.

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