IN THE NOT-TOO-DISTANT FUTURE, maps of the solar system may be redrawn to add another planet - or perhaps take one away. Last month, when scientists announced the discovery of a possible 10th planet, some nine billion miles from the Sun, they reignited a long-running debate about what a true planet is. They are grappling with whether the newly found celestial body, known for now as 2003 UB313, should be granted planetary status, and if it is not, whether Pluto, a like-size ice ball in a far orbit of the Sun, should be stripped of the title.

Astronomers are afire over the shake-up, and their musings have been lighting up the news media. But they aren't the only ones excited about the discovery. Their mystical cousins, astrologers, have also been jolted; they are speculating about what it might mean for their cosmic readings and prophecies. After all, they, too, are students of the solar system.

Astrologers often employ the maxim "as above, so below." Now suddenly that which is "above" may be radically changed.

"It's exciting," said Richard Brown, an astrologer from Toronto. "I'm immediately on the Internet, and I'm just jumping up and down."

Michael E. Brown (no relation to Richard), an astronomer and a member of the team that discovered 2003 UB313, said he has been peppered with inquiries from astrologers seeking to know the exact moment he made his observation. Dr. Brown, a professor of planetary astronomy at the California Institute of Technology, subsequently posted the time of discovery on his Web page for their benefit, he said, because he has always appreciated astrologers' enthusiasm for the heavens. "The astronomical world frequently sits around and bickers," he said. "It's nice to see a group sit around and take pleasure in new discoveries."

If 2003 UB313 is a 10th planet, astrologers say it may have a profound influence over people's lives, and thus on the forecasts astrologers make. But its potency cannot be discerned until perhaps several years after the astronomical debate is settled, when astronomers have had time to chart its orbit. So astrologers are not inclined to do anything hasty. There will be no tearing up of charts, no hurriedly penciling in a new planet and certainly no crossing out of Pluto, a body that many astrologers hold near and dear.

On the contrary, astrologers seem to have reached an unspoken consensus to take a wait-and-see approach. Wait and see if there is a 10th planet. Then wait and observe its influence on human life. Astrologers have been searching the sky for centuries for clues to how the positions of stars and planets could affect life on Earth. Their celestial observations intrigued Chaucer, Shakespeare and even Galileo. The profession still thrives, supported in no small part it seems by people who say they do not really believe in it, as evidenced by the enormous popularity of horoscopes in magazines, newspapers and on the Web. Last year America Online's most popular search term was "horoscope."

A Gallup Poll telephone survey conducted in June found that 25 percent of Americans believe that the position of the stars and planets can affect people's lives.

"We like to think of ourselves as the second-oldest profession," said Mr. Brown, the astrologer.

Dr. Brown said, "I think of it as entertainment," adding that his wife reads her horoscope in the newspaper each morning, though not because she believes the predictions will come true.

But to some critics, the discovery of a potential 10th planet is just more evidence that astrology is humbug. If astrologers were able to detect the influences of planets on people's lives accurately, should they not have noticed the influence of a 10th planet long before astronomers detected it?

"You would think astrologers would have noticed after 2,000 years of making predictions that every 20 years or so things would get messed up," said Phil Plait, an astronomer at Sonoma State University, in Rohnert Park, Calif. "And then someone would say, 'Maybe there's another planet out there.' "

Astrologists argue that they have never asserted that the known planets and stars account for every last detail of human life. "We assume there are going to be other planets," said Deb McBride, an astrologer in Brooklyn.

Leigh Oswald, an astrologer in London, said unknown forces may determine when scientists discover new planets. "A planet is discovered when it's appropriate for humanity to understand it," she said. "In other words, when we are ready for it."

Throughout history, when faced with the addition of a new planet, many astrologers have duly figured out how to use it in their calculations. Pluto, the most recently discovered planet, is so tightly woven into astrological charts, to lose it would be unthinkable, Ms. Oswald said. "It's been observed to have a huge influence on people's lives."

Because Pluto is an outer planet, it operates on a level that affects humanity as a whole as well as individuals, astrologers say. (The farther out a planet is, theoretically, the more global its effects.) Named for the Greek god of the underworld, Pluto brings about unexpected changes. "It's usually dark," Ms. McBride said. "It's usually a huge upheaval in someone's life." That upheaval - in a person's health, family or career - is generally followed by a rebuilding, a resurrection, she said.

Pluto is in Sagittarius right now, which to astrologers means it is exerting an influence on larger social forces like religions, ideologies and cultural traditions. "When you put Pluto in a sign like Sagittarius, you start getting religious wars, differences in cultures," Ms. McBride said.

Astrologers are especially eager to learn 2003 UB313's permanent name, because in their business, a celestial object's name is essential to its interpretation. "Naming is important, particularly when a name has a mythological charge to it," said Barry Perlman, a San Francisco astrologer. "You're connecting it to a lineage of cultural traditions."

Even though a planet's name is chosen by mere mortals, astrologers do not consider the choice a matter of chance. Rather, they see it arising from an alignment of unseen forces that affect the collective human unconscious. They find it no accident that Pluto, for example, was discovered in 1930, in the era of the rise of Nazism and the development of the atomic bomb.

Dr. Brown has been informally calling the possible new planet Xena, after the title character from the cult television series "Xena: Warrior Princess." (He has given equally playful nicknames to other planetary bodies he has discovered, including Santa, Easter Bunny and Flying Dutchman.)

The official name of 2003 UB313 has yet to be determined however. First the International Astronomical Union, which has the last word in naming celestial objects, has to decide if it is a planet, something that is unlikely to happen before 2006, Dr. Brown said. He would not reveal the name his team has nominated, but allowed that it is neither Xena nor the name of any Greek or Roman god.

With or without a new planet, some astrologers say they already have plenty to study, because they believe that celestial bodies, from the Moon to the billions of stars, can be incorporated into readings. "There's a whole treasure trove that we haven't used," said John Cook, an astrologer from New York City.

Like many astrologers, Mr. Cook is fascinated by the work of astronomers, but he knows the feeling is rarely mutual. "Every time people meet an astronomer, they ask them what their sun sign is, and they hate that," Mr. Cook said with a chuckle.

But Dr. Brown, a Gemini, doesn't mind. "I'm happy that they're thinking about the solar system," he said, "even if I don't agree."

It is not enough to be compassionate; you must act.
-- The Dalai Lama

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