Pluto, the Ninth Planet

Cold and dark, but still a great vacation spot.

Ever since the early 1980's, I've been fascinated by Pluto and have been working to learn more about this little world. Every line of study is fair game and I've worked long and hard from many directions to add to our collective knowledge. The items listed below will take you to areas that I've worked on or perhaps point you to interesting information that others have come up with. If you don't see something here that you want to see explained, send me e-mail and I'll add it to the list of questions answered on these web pages.

We're going to Pluto! New Horizons was successfully launched on January 19, 2006 at 2:00pm EST. I was there to see it and it was a glorious sight. We pass Jupiter in February 2007 and get to Pluto on July 14, 2015.

Here's a copy (3.5Mb) of my public lecture at the Kennedy Space Center on January 17, 2006.

  • Pluto reached perihelion (closest point to the Sun) on 1989 September 5 at 12:00 UT. At that time it was at 29.66 AU, or 4.4 billion kilometers, or 2.7 billion miles from the Sun. Pluto became the "eighth" planet on 1979 February 7 at 10:44 UT when it came to a distance from the Sun less than Neptune. It will continue in this status until 1999 February 11 at 11:22 UT when it will once again be further from the Sun than any other planet. Its status as the ninth planet will remain undisputed for the next 220 years when it will once again be approaching perihelion. Of course, in that time we might discover another planet further out but only time will tell.

  • So what is Pluto, really? A planet, asteroid, comet, dog?

  • Indirect maps of the surface of Pluto and Charon. What do they look like and how do we know?

  • Check out this latest release on new direct maps of Pluto that I've been working on with Dr. Alan Stern at the Southwest Research Insitute. I also participated in a InterNet-based talk show, Live with Derek McGinty on Discovery Channel Online, discussing these and other Pluto results.

  • Just how cold is Pluto and what effect does that have on the surface and atmosphere?

  • Ever wonder what the phases of the moon (Charon) would look like if you lived on Pluto?

  • Information about and for the "Live from HST" program.

  • Here's some interesting information in an area dedicated to the memory of Clyde Tombaugh.


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    Marc W. Buie, Lowell Observatory