A Movie of Triton Made From Voyager 2's Fly-by 25 Years Ago 34
schwit1 writes: Using restored images taken by Voyager 2 when it flew past Neptune's moon Triton 25 years ago, scientists have produced a new map and flyby movie of the moon. "The new Triton map has a resolution of 1,970 feet (600 meters) per pixel. The colors have been enhanced to bring out contrast but are a close approximation to Triton's natural colors. Voyager's "eyes" saw in colors slightly different from human eyes, and this map was produced using orange, green and blue filter images. ... Although Triton is a moon of a planet and Pluto is a dwarf planet, Triton serves as a preview of sorts for the upcoming Pluto encounter. Although both bodies originated in the outer solar system, Triton was captured by Neptune and has undergone a radically different thermal history than Pluto. Tidal heating has likely melted the interior of Triton, producing the volcanoes, fractures and other geological features that Voyager saw on that bitterly cold, icy surface. Pluto is unlikely to be a copy of Triton, but some of the same types of features may be present." Dr. Paul Schenk provides provides further information on his blog, and the movie can be viewed here.
Triton is different from other moons (Score:5, Informative)
The summary mentions that Triton used to be a dwarf planet, in its own orbit, but was captured by Neptune. The reason we believe this, is because Triton orbits in the wrong direction. No other large moon in the solar system has a retrograde orbit. If it formed from the same dust cloud as the planet it orbits, or formed from other orbiting debris (as Luna did after Earth's collision with Theia [wikipedia.org]), then it would orbit in the same direction. It is also one of the few moons with a detectable atmosphere (mostly nitrogen), and also one of only a few with geologic activity, including liquid nitrogen geysers. About a third of its mass is water, although all is believed to be frozen.