Solar System

Astronomers have found what may be the largest object in the far reaches of the solar system, a ball of rock dubbed 2001 KX76 that is an estimated 788 miles in diameter. Pluto's moon Charon, in comparison, has a diameter of 744 miles. 2001 KX76 resides in the Kuiper Belt, which extends almost 2 billion miles beyond the orbit of Neptune. Astronomers think that at least 70,000 objects with diameters larger than 100 kilometers (62 miles) exist in the belt.

QUESTION: I like warm swimming water and I want several extra months of use. How effective are the new pool solar heating systems that help to cool a house too? Are there any budget-priced do-it-yourself solar units? ANSWER: Installing a budget-priced solar system can easily extend your swimming season by several months and warm the water. If your pool overheats in mid- summer, run the solar system at night instead of day.

The Hubble Space Telescope has detected a previously unseen population of at least 200 million mountain-size comets orbiting in a flattened ring, perhaps 90 billion miles in diameter, that encircles the sun, Earth and the eight other planets. The astronomers who announced the discovery Wednesday said it confirms decades-old theories about the origins of comets--dazzling objects with fuzzy heads and long tails that sweep periodically through Earth's field of vision.

Question: What is a planet? Answer: Something round that orbits a star, according to the new definition proposed last week by the International Astronomical Union. In the case of our solar system, that star is the sun. Q: Didn't we already know that? A: Actually, no. Although many people thought they knew what a planet was, there had been no clear definition that all astronomers could agree on. Q: So why do we need one now? A: Recent discoveries of bodies in the Kuiper Belt, a huge region of icy objects beyond the orbit of Neptune, raised the question of whether they should be considered planets.

Plans to make the moon into an orbiting laboratory for space exploration suddenly seemed much closer to reality with this week's announcement that frozen water may have been found deep inside a crater on the moon's frigid south pole. At a Department of Defense-sponsored news conference in Washington on Tuesday, Rice University's Paul Spudis called the crater "possibly the most valuable piece of real estate in the solar system. It's certainly a place we can go . . .

The Sunborn A Novel Gregory Benford Warner Books: 330 pp., $24.95 * Gregory Benford's new novel, "The Sunborn," is a sequel to "The Martian Race," in which a private consortium led by biochemical magnate John Axelrod won a $30-billion prize by outstripping sluggish, bureaucratic NASA in a contest to colonize the Red Planet. Two decades have passed. Axelrod's astronauts, Julia and Viktor Barth, have become the First Couple in a thriving settlement on Mars.

An astronomer has found "irrefutable evidence" of at least two planets orbiting a nearby star--the first confirmed observation of planets outside the solar system humanity calls home. What has scientists most excited, however, is that the finding suggests that planets can form around almost any star and that the galaxy may well be crowded with planets.

Scientists have discovered a distant planet where virtually no one would have expected it to be, orbiting a pulsar star that was born during one of the most violent events the universe has to offer, according to research published today. If confirmed, this would be the first planet discovered beyond our solar system.

Scientists say they may have solved a far-out mystery: how Uranus and Neptune came to exist at the very edges of the solar system. A new study in today's Nature says the two icy planets may have been born much closer to the sun than previously thought, and ended up in their current orbits after gravitational forces from Jupiter violently hurled them away.