None of the new discoveries appear habitable. Planets as large as Jupiter are generally gaseous like Jupiter. But each may have moons, and who knows? Earthlings may have neighbors after all. But scientists have more arcane matters to chew on first, such as how such a large planet formed so close to its sun. The science of planetary formation seems due for a shakeup. And a brand-new science -- that of comparative planetary systems -- has just been born.
The sun, it seems, has a long lost brother. Astronomers announced Thursday that they had for the first time found another set of multiple planets orbiting a single star -- indicating that our solar system, indeed our Earth, isn't as unique as we thought. The star of the show is Upsilon Andromedae, a solar-type star 44 light-years away with three large planets around it. One, a planet three-fourths the size of Jupiter, circles close, with an orbit of only 4.6 Earth days. Another, twice Jupiter's size, orbits at about the same distance of Venus; the third planet is twice as large as that and perhaps three times as farther away. Astronomers, meanwhile, are tickled. "The single planets we found around other stars was a glorious discovery, but the architecture of other planetary systems had been missing," Dr. Geoffrey Marcy, a leader of the discovery team, told the New York Times. "Here for the first time, we can see a kinship between these planets and our own solar system."