What is Sedna made of?
We don’t know. Because it’s surface is relatively bright, from the thermal observations (see above), we might expect it to have water ice or methane ice like Charon and Pluto have. But observations from the Gemini Telescope and (in collaboration with Chris Koresko at JPL) the Keck telescope suggest that this is not true. From observations at the 1.3-m SMARTS telescope in Chile, we do know that Sedna is one of the most red objects in the solar system — almost as red as Mars. Why? We’re currently baffled. Do we see a moon around Sedna? When we first announced the discovery of Sedna, we noted that circumstantial evidence suggested that there is a moon around Sedna. Soon after, we acquired the images below with the Hubble Space Telescope . Much to our suprise no moon is visible! Why did we think we would see a moon? The evidence for the existence of a moon is circumstantial, but nonetheless compelling. The story is a little complicated, though, and it goes like this: We have found that Se
