NASA released new pictures of Neptune's freezing moon Triton, made from data taken by the Voyager 2 spacecraft on its way out of the solar system in 1989.
The close-up shots reveal Triton's pockmarked surface, covered with crater scars from years of space rock impacts, as well as smooth volcanic plains, mounds and round pits formed by icy lava flows.
The photographs were released to commemorate the 20-year anniversary of the Voyager flyby of the moon, the last solid object visited by the spacecraft. The images were made using topographic maps derived from Voyager 2 photographs.
Among its discoveries at the moon, Voyager 2 revealed that Triton has active geysers. And with surface temperatures at minus 391 degrees Fahrenheit (minus 235 degrees Celsius), Neptune's largest moon is one of the coolest objects in the solar system.
The unmanned Voyager 2 probe launched in 1977 on a grand tour of the solar system, visiting Jupiter, Saturn, Uranus, and Neptune, as well as many of their moons, before moving on to interstellar space.
The probe is currently about 8.4 billion miles (13.5 billion km) from the sun, or almost 90 times the distance between the sun and Earth.
Voyager 2 and its sister, Voyager 1 (also launched in 1977, and currently the farthest away man-made object, at about 10 billion miles, or 16 billion km from the sun) are still operational and still transmitting data.
Both probes carry with them golden phonograph records with sounds chosen to communicate a sampling of humanity to any extraterrestrial life they may encounter. The contents, which include greetings in 55 languages, as well as music such as Bach's Brandenburg Concerto, gamelan music from Indonesia, Louis Armstrong's "Melancholy Blues," and many others, were chosen by a NASA committee headed by Carl Sagan.
By Clara Moskowitz/SPACE.com