Pluto: No Longer a Dwarf, But Still Not a Planet

Pluto and its satellite, Charon, in happier times. Image credit: Dr. R. Albrecht, ESA/ESO Space Telescope European Coordinating Facility; NASA.

It looks like it is time to revise those astronomy textbooks once again. For the second time in as many years, the world’s astronomers have reclassified Pluto. The International Astronomical Union has issued a statement saying that small bodies such as Pluto would be known by a new name: plutoid.

Two years ago, the IAU sparked a major controversy by reclassifying the distance world as a dwarf planet. The decision seemed especially upsetting to many schoolchildren, who identify with the tiny world that hovered forever on the periphery of a Solar System populated by much larger, grown up planets.

Whether this latest decision will mollify or mystify children is yet to be seen. However, it doesn’t really remove the confusion over why the IAU just didn’t leave well enough alone two years ago. Pluto orbits the sun, has an atmosphere, and possesses three satellite (including one, Charon, that’s half its size). In other words, it seems to fit most people’s definition of a planet. Why the change?

What was really confusing, however, was why astronomers would tempt fate by demoting a planet named after the Roman god of the underworld. One assumes they’re not very superstitious. Otherwise, they might be a tad worried that Pluto will exact his revenge on them, if not in this life then definitely in the next.

ESA Evaluating Candidates for 105- and 520-Day Mars Mission Simulations

Mars500 Habitat
Mars500 Habitat (Credit: ESA TV)


Last week, 32 talented candidates gathered at the European Astronaut Centre in Cologne, Germany, with the hope of becoming part of a unique study that will act as a platform for human exploration of the Solar System. The study, called Mars500, is a ground-based simulation of a mission to Mars and back.

Two of the candidates, together with four Russian volunteers, will be sealed in an isolation chamber for a total of 105 days starting in October. This is followed by the full isolation period with another two European candidates, which lasts for 520 days starting early in 2009. Part of the chamber simulates the spacecraft that would transport them on their journey to and from Mars and another part will simulate the landing module that would transfer them to and from the Martian surface.