Despite being so far from the sun, tiny Pluto, which is smaller than Earth’s moon, has had an active geologic life from the start, one that continues to present day, research published on Thursday shows.
The evidence is all over Pluto’s face, which was observed close-up for the first time by NASA’s New Horizons spacecraft on July 14, 2015.
With most of the high-resolution images from the flyby now back on Earth, scientists say Pluto’s mountains, glacial flows, rotated ice blocks, volcano-like mounds and other features rival the geology found on much larger, warmer planets like Mars.
The physical and chemical conditions on Pluto, located about 40 times farther away from the sun than Earth, have played out in unusual and largely unforeseen ways. Highly volatile cryogenic ices, such as nitrogen, carbon monoxide, methane, vaporize into Pluto’s hazy and surprisingly compact atmosphere. Internal heating, fueled by the natural decay of radioactive elements in Pluto’s rocks and other sources, likely keeps an ocean of ammonia-rich water liquid beneath the dwarf planet’s frozen surface.
“We now have half a dozen worlds, like (Saturn’s moon) Enceladus, (Jupiter’s moons) Europa and Ganymede, and now Pluto, that seem to have oceans in their interiors,” New Horizons’ lead scientist Alan Stern, with the Southwest Research Institute told Discovery News.