New Horizons Spacecraft Approaches PlutoLeave a Comment
The New Horizons spacecraft, launched in January 2006, is now in the Pluto system and returning photos. It will fly by Pluto and its 5 known moons on July 14. This region of the Solar System contains a number of Pluto-like objects; what makes Pluto particularly interesting is that it appears to have an atmosphere – very thin, admittedly. Pete will talk about some of Pluto’s weird characteristics at the July star party.
Why is Pluto weird? With apologies to Elizabeth Barrett Browning, let me count the ways… For starters, Pluto’s largest moon, Charon, is about a quarter the diameter of Pluto, making it by far the largest moon in relation to its host planet in the solar system. Strictly speaking, Charon does not revolve around Pluto; instead, both objects orbit a point between them. This point, called the barycenter, is the center of mass of Pluto+Charon. You can see this effect in this video.
Next, Pluto is much brighter than Charon, though they should be made of the same material. Hmm.
There’s lots more about Pluto and New Horizons in NASA’s Pluto toolkit.