Triton, in orbit around the gas giant Neptune, has been imaged like never before in a new color map, created from NASA observations from 1989.
Paul Schenk, from the Lunar and Planetary Institute, pieced together images of Triton taken by the Voyager 2 probe, as it flew past the giant moon. That close encounter took place in 25 August 1989. This new map has a resolution of 1,970 feet per pixel.
Schenk also produced a minute-long video, showing the only visit to Neptune and its attendant moons by a human-built spacecraft.
Triton, like Pluto, is slightly smaller than our own moon, and each possesses a thin atmosphere of nitrogen. The surface of both worlds is covered in frozen carbon dioxide and monoxide, nitrogen and methane.
The icy moon was captured by Neptune long ago, subjecting the frozen satellite to heating. This creates geysers and volcanoes of nitrogen erupting from the surface.
"In the intervening quarter century and its many discoveries, I think we have tended to forget how strange and exotic Triton really is! Its effective surface age may be a little as 10 million years, clearly implying that active geology is going on today," Schenk said.
The new map of Triton was compiled from photographs taken in green, blue and orange light. Colors in the composite image are enhanced in order to provide greater contrast, while remaining similar to the way humans would view the sight.
Triton is the largest moon of Neptune, and is the only satellite in the solar system known to orbit in a direction opposite to the rotation of its companion planet. The alien moon was discovered on 10 October 1846, by William Lassell, an astronomer in England.
This frozen moon, warmed by its proximity to the Neptune, provides a unique terrain unseen elsewhere in our family of planets.
"The cantaloupe terrain, which I interpreted back in 1993 as due to crustal overturn (diapirism), hasn't been seen anywhere else. The volcanic region, with its smooth plains and volcanic pits large and small, is the size of Texas. And the southern terrains still defy interpretation," Schenk wrote on his blog.
Jet Propulsion Laboratory released the video, showing the approach, encounter and departure of Voyager 2 and Triton, on their YouTube page.
Voyager 2 passed quickly past Triton, at a time when most of the northern hemisphere was in shadow. Less than half the moon is visible in the video, due to the long rotational period of Triton, compared to the length of the encounter.