Date: 25 Aug 1989
A global color mosaic of Triton taken in 1989 by Voyager 2 during its flyby of the Neptune system. Color was synthesized by combining high-resolution images taken through orange, violet and ultraviolet filters; these images were displayed as red, green and blue images and combined to create this color version.
With a radius about 22 percent smaller than Earth's moon, Triton is by far the largest satellite of Neptune. It is one of the few objects in the solar system known to have a nitrogen-dominated atmosphere (the others are Earth and Saturn's giant moon, Titan).
Triton is so cold that most of Triton's nitrogen is condensed as frost, making it the only satellite in the solar system known to have a surface made mainly of nitrogen ice. The pinkish deposits constitute a vast south polar cap believed to contain methane ice, which would have reacted under sunlight to form pink or red compounds. The dark streaks overlying these pink ices are believed to be an icy and perhaps carbonaceous dust deposited from huge geyser-like plumes, some of which were found to be active during the Voyager 2 flyby.
The bluish-green band visible in this image extends all the way around Triton near the equator; it may consist of relatively fresh nitrogen frost deposits. The greenish area includes what is called the "Cantaloupe Terrain," whose origin is unknown, and a set of "cryovolcanic" landscapes apparently produced by icy-cold liquids (now frozen) erupted from Triton's interior.
What Scientists/Engineers Say About This Image:
"When we got to Neptune the big surprise was Triton's terrain, which was covered in these strange surface features: the cantaloupe terrain, the evaporative features and the plumes -- 'What were these big smoke-stack plumes?!'
It was very bizarre -- it still is bizarre, I don't think we really understand it."
--Fran Bagenal: Professor of Astrophysical and Planetary Sciences, University of Colorado, Boulder and Co-Investigator for the New Horizons Mission
(Read More of what Fran Bagenal has to say about this and other significant events by clicking here.)
"I was at some of the other Voyager encounters, and the final encounter with Voyager 2 at Neptune was exciting and poignant in a lot of ways. For one thing the last solar system object that Voyager visited up close was Neptune's moon Triton, which of course is one of the coolest objects. Voyager had already been on this epic multi-year journey and then it saved one of the juiciest nuggets for last, which was the strangeness and beauty of Triton."
--David Grinspoon: Curator of Astrobiology, Denver Museum of Nature and Science
(Read More of what David Grinspoon has to say about this and other significant events by clicking here.)
Last Update: 6 Mar 2012 (AMB)