Finding new worlds (is Mr. Spock next?)

For astronomers, detecting new planets is now almost as commonplace as, say, stumbling upon a new Starbucks outlet.

American and Swiss teams have just announced the discovery of nine new planets orbiting stars outside our own solar system.

In the past five years, 41 such "exoplanets" have been found, out of a total 50 known planets. And while so far there is evidence of only two solar systems, other than our own, that have more than a single planet, scientists say that's partly due to the limitations of today's search methods. The findings are furthering speculation that planets are not uncommon in the universe, and raising hopes of finding planets that will be able to sustain human life. British science writer David Whitehouse says, "Astronomers are confident that Earth-like planets will be found."

The latest discoveries were announced Aug. 7 to the general assembly of the International Astronomical Union in Manchester, northern England.

Most intriguing to the stargazers is the discovery of a planet roughly the size of Jupiter orbiting the star Epsilon Eridani, a mere (galactically speaking)10.5 light years from Earth. A light year is the distance light will travel in one year in a vacuum - about six trillion miles.

EPSILON ERIDANI, which is near enough to be seen with the naked eye, is about the same size as our sun. In addition, for fans of the "Star Trek" series, it's one of two choices identified as home star for the planet Vulcan, where the emotionless, point-eared Mr. Spock hails from. (The late "Star Trek" creator, Gene Roddenberry, however, said he personally favored 40 Eridani.)

William Cochran, of the University of Texas McDonald Observatory, says the findings suggest intriguing possibilities for human colonists.

"Detecting a planet orbiting Epsilon Eridani is like finding a planet in our own backyard," Dr. Cochran says. "The planet itself is uninhabitable, but it is far enough away from its parent star for there to be Earth-like planets closer to it."

Also revving up the pulses of the researchers is the discovery of the second known example of a star being orbited by more than a single planet.

Astronomers from research teams in the US and Europe briefed the Manchester conference about the discoveries.

Astronomers from Switzerland's Geneva Observatory spoke of detecting six new planets. A team from the University of California at Berkeley announced that it had found three.

Geoff Marcy of San Francisco State University told the conference: "We are now at a stage where we are finding planets faster than we can investigate them and write up the results. Planet hunting has morphed from the marvellous to the mundane."

Dr. Whitehouse is excited also by the Swiss team's detection of a star that is being circled by two planets.

A year ago, a Berkeley research team placed three planets around Upsilon Andromidae - 44 light years away in the constellation Andromeda. In May, Geneva Observatory astronomers announced the discovery of one planet orbiting a star known as HD 83443, in the constellation Vela. The Swiss team presented evidence of a second planet this week. Both are roughly the size of Saturn, which in turn is about 95 times as massive as the Earth.

The Geneva Observatory's Michel Mayor says the new planetary system is "unusual in more ways than one.

"It has two very low-mass gaseous giant planets, and both orbit very close to the star." One takes less than three days to circle the sun, the other 30. Mercury, the innermost planet in our solar system, takes 88 days to complete its orbit.

The detection of new planets is being greatly assisted by breakthroughs in space observation techniques.

Most of them are too far away to be pinpointed by even the most high-powered optical telescopes. Instead, astronomers observe how the gravitational pull of a planet can cause what they call a "wobble" in a neighboring star's movement.

They measure the size and frequency of the wobble, and from that calculate the mass and orbit of the planet. So far only relatively large planets can be detected using this method. Earth-size planets are beyond the range of the technique.

Whitehouse, however, forecasts that the planet now known to be orbiting the star Epsilon Eridani may be within range of the Hubble Space Telescope.

"Were the Hubble to be able to observe it, it would be an astronomical landmark," he says."It would be the first planet actually seen circling another star."

(c) Copyright 2000. The Christian Science Publishing Society