Pluto’s Moons

It’s been 32 years since the discovery of Charon, one of Pluto’s moons. Today, we know that Pluto is a dwarf planet—an object orbiting the sun, large enough to resemble a planet but too small to pick up objects along its orbit. But, that doesn’t mean Pluto is sans-lunar. Pluto has not just one but three moons: Charon, Nix and Hydra.Closer to Earth, IKAROS, a solar spaceship, is en route to Venus on the other side of the sun. Using a 66-foot wide aluminum sail, IKAROS is being pushed through space by solar wind—electromagnetic discharge from the sun—and is guided by a solar-powered navigation system. Plus, how to determine a star’s temperature based on its color. Here’s a hint: “red-hot” might be a misnomer out in space.[audio: st20100621.mp3]