A Trans-Neptunian Object and Its Moon

Department: 
Pluto and the Kuiper Belt
Teaser: 

"Orcus, if you haven't heard of it before, is probably the seventh largest known trans-Neptunian object, and Vanth is its satellite."

Link: 
Source: 

Planetary Society Weblog Download time: Jan 12 2011 8:40 AM ET

As part of a big, ongoing project to make a comparison chart of the dimensions and physical properties of solar system objects I've spent the morning tackling the difficult problem of summarizing the physical characteristics of the biggest things that are out there beyond Neptune. These things are very faint and very difficult to study. Consequently, while the sizes and shapes of their orbits and their absolute magnitudes have been nailed down ....