Cosmic Puzzle

For years astronomers have scanned the heavens beyond the solar system in search of other planets. If they exist -- and evidence is rapidly accumulating that they do -- the possibility greatly increases that some of the planets may be similar to the earth. U.S. and Canadian astronomers last week reported tantalizing discoveries that strengthened that likelihood.

The U.S. team, led by David Latham of the Smithsonian Astrophysical Observatory in Cambridge, Mass., found evidence of what might be a gigantic planet 20 times as large as Jupiter orbiting a star 550 trillion miles away. The Canadians reported nine stars with possible planets within 588 trillion miles of earth; they calculated that one of them was about the size of Jupiter.

Because the suspected planets are lost in the glare of the stars they orbit, they could not actually be seen. Instead, the astronomers analyzed the shifts of light in the spectrum associated with a star as it moves. A shift toward red means the source is moving away from the observer, toward blue that it is moving toward him. By carefully measuring these color shifts, astronomers detected a characteristic wobble in the motion of the stars that could be caused by the gravitational pull of a nearby orbiting body.

The purported sightings of new planets have generated a good deal of excitement. Latham's, especially, seemed stronger than the others because it was confirmed independently, in this case by a European team in Geneva that had been observing the same star. But the "alleged planet," says Latham, is "hotter than an oven" and has a noxious, gaseous atmosphere. Says he: "This is not a place you would look for life."