Charon is the largest satellite of the dwarf planet Pluto. Charon was discovered by astronomer James Christy on June 22, 1978, when he was examining highly magnified images of Pluto on photographic plates taken a couple of months earlier.
Nix and Hydra, the far-flung satellites of Pluto and its large moon Charon, could hold the trump card in understanding just how this beguiling four-body system actually formed. Data from the Hubble Space Telescope presented last week during a workshop on Nix and Hydra at the Space Telescope Science Institute in Baltimore, Maryland, indicate that the two satellites vary in brightness, suggesting that they are very elongated - more like asteroids than spherical moons. Read more
Lonely Pluto floats in the darkness at the edge of our solar system. It's so far away even the Hubble Space Telescope has trouble making out the details. Nevertheless, Pluto is so interesting, even fuzzy images of the dwarf planet are compelling. A team of researchers led by Marc Buie of the Southwest Research Institute recently released the best Hubble images to date. The data reveal an icy molasses-coloured world with a surprising amount of activity. Buie compared Hubble images taken in 1994 vs. 2003 and discovered that Pluto's northern hemisphere has brightened while the southern hemisphere has dimmed. Ground-based observations suggest that Pluto's atmosphere doubled in mass during approximately the same time period. And no one is certain what's causing the molasses-coloured splotches on Pluto's surface. Read more
"Inhospitable" doesn't do it justice: the temperature on Pluto, even during its summer (which comes around only every 248 years) is -230°C. Sheathed in layers of frozen nitrogen and methane, its average distance from the sun is 3.6 billion miles. A contrarian among the spheres, it rotates in the opposite direction to the earth. Yet it's hard not to feel some affection for this unluckiest of heavenly bodies, identified 80 years ago this week at the Lowell Observatory in Arizona. Read more
Nasa scientists say that dwarf planet Pluto, on the edge of our solar system, is becoming increasingly red. Images taken by the Hubble space telescope show that the planet is some 20% redder than it used to be. Read more