Telltale Wobbles

Is the solar system unique in the universe? This question has long driven astronomers to search for planets beyond our sun's. Last week three Canadian astronomers presented the first hard evidence that at least one planet, probably larger than Jupiter, may orbit around Epsilon Eridani, a nearby star favored by planet hunters.

Such planets, if they exist, are too small and dark to be detected directly. For six years the Canadians have monitored 16 stars from an observatory on Mauna Kea, Hawaii, looking for the distinctive wobbling motion caused by the gravitational pull of nearby orbiting bodies. Epsilon Eridani, among several others, shows the telltale wobbles.

Most astronomers want further confirmation before they believe other planets exist, but few deny the special appeal of the search. Says Gordon Walker, a member of the Canadian team: "You often wonder when you're looking at these things if someone up there isn't looking back."