Pluto is now known to have at least five moons (Charon, Nix, Hydra, P4, and the newly discovered P5), and its burgeoning population might pose a risk to New Horizons during its flyby, three years from now.
It's been a very full day at the DPS-EPSC 2011 joint meeting. My day was less full than it might have been, because I overslept and missed most of the morning's session. I really needed the rest though so I think it was probably for the best!
I'm preparing a talk for the Pacific Astronomy and Telescope Show here in Pasadena on Sunday afternoon at 1:45. I have spent the morning putting together a slide that I have long wanted to have for presentations.
Jeff Moore's presentation was cool because of the discussion it stimulated. He considered what exogenic processes might be operating on Pluto's surface. What's an exogenic process? It's something that modifies the shape of the surface from the outside, and doesn't require the body to be geologically active inside.
Today and tomorrow I'm attending the New Horizons Workshop on Icy Surface Processes. The first day was all about the composition of the surface and atmosphere of Pluto, Charon, Triton, and other distant places.
Pluto's atmosphere has been a subject of fascination for planetary astronomers since -- well, since astronomers first discovered that it had an atmosphere in the early '90s. The interest is partly because it's fascinating that such a distant and cold world is capable of supporting an atmosphere, and partly because the presence of the atmosphere confounds all attempts to measure Pluto's size precisely.
A Planetary Society trifecta -- that's what Neil Tyson calls this episode of his StarTalk radio show broadcast this week. His guests include the Society's Vice President, Heidi Hammel, and its Executive Director, Bill Nye, (along with the Society's friend, Steve Squyres, Principal Investigator for the Mars Exploration Rovers).
Several astronomers pointed their telescope at Eris to watch it pass in front of a background star. Occultations permit precise measurement of the diameters of distant, faint objects, and it turned out that Eris was much smaller than previously thought, so much so that its diameter may turn out to be the same as, or even smaller than, Pluto's.
An awful lot of the talks in the Pluto session on Tuesday morning, October 5, at the Division of Planetary Sciences meeting spent more time focusing on how bad weather conditions were during the astronomers' attempts to view Pluto as it occulted background stars than they did on any measurements or science that came out from the data.
This is just a brief note to advertise this evening's edition of NOVA on public television here in the U.S. The show is "The Pluto Files" and is hosted by former Planetary Society president Neil DeGrasse Tyson.
I just posted my writeup of today's press briefing on a new map of Pluto produced from Hubble images. The main conclusion was that Pluto has shown an astonishing amount of changes across its surface between 1994 and 2002 -- more, in fact, than any other solid surface in the solar system.