(09. Oktober 2002) Pluto and Neptune‘s largest moon, Triton, are presently about the same distance from the sun, and each has a predominantly nitrogen atmosphere (with a surface pressure 100,000 times less than that on Earth), so one might expect similar processes to be occurring on these two bodies.

A 1997 occultation of a star by Triton revealed that its surface had warmed since the Voyager spacecraft first explored it in 1989. On Triton, „Voyager saw dark material rising up as much as 12 km above the surface, indicating some kind of eruptive activity,“ Elliot said. „There could be more massive activity on Pluto, since the changes observed in Pluto‘s atmosphere are much more severe. The change observed on Triton was subtle. Pluto‘s changes are not subtle.“