Mark Sykes says enough already — the solar system ought to have 13 planets, and all this bickering over whether Pluto qualifies as one has been a bad thing. You’ll recall the debate, dating back to 2006, over the definition of a planet, and how many there ought to be. The International Astronomical Union, which represents astronomers, decided on a fairly elaborate definition — that planets had to be spherical, orbit a star, and have enough gravity to clear out their "neighborhoods" of debris. By that standard, only eight planets qualified; Pluto and like places were first demoted to "dwarf planets" and then "Plutoids." Sykes is director of the Planetary Science Institute in Arizona, and he says it’s time to settle this nonsense. If a body is round and orbits a star, good enough. He’ll make that argument at a conference at Johns Hopkins starting Thursday. His list of planets: Mercury, Venus, Earth, Mars, Ceres (previously an asteroid), Jupiter, Saturn, Uranus, Neptune, Pluto, Charon (previously a moon of Pluto), Eris, and the recently discovered Makemake (pronounced MAH-keh-MAH-keh; it and Eris are small rocky bodies that orbit beyond Pluto). And he takes this shot at his colleagues: "The IAU damaged the public perception of science by the high-profile spectacle of imposing, by vote, a controversial definition of a commonly used term," Sykes said. "Too often, science is presented as lists of facts to be learned from authority, instead of the dynamic open-ended process that it really is. The IAU reinforced this misconception of science."