Pluto surface ice

Pluto has vast plains of nitrogen ice and water ice mountains, revealed by the New Horizons probe in 2015.

About this subject

Pluto, once considered the ninth planet of the Solar System and now classified as a dwarf planet, has a dynamic and geologically active surface. Observations from NASA's New Horizons spacecraft, which flew by the dwarf planet in July 2015, revealed an astonishing diversity of landforms, including vast plains of nitrogen, methane, and carbon monoxide ice. The most famous region is Sputnik Planitia, an impact basin filled with nitrogen ice that forms a smooth, relatively young plain, less than 10 million years old. This plain exhibits polygonal convection patterns, indicating that the ice is slowly moving, like a pot of boiling water in slow motion.

In addition to nitrogen, Pluto's surface features mountains made of water ice, which is harder and more resistant than other ices. These mountains, such as those found in the Cthulhu Macula region, can reach several kilometers in height. Water ice is believed to form the bedrock of Pluto's crust, while volatile ices form a surface layer. The interaction among these ices, low gravity, and Pluto's tenuous atmosphere creates unique landscapes, such as methane ice dunes and nitrogen glacial flows.

The surface composition of Pluto varies significantly, with dark areas rich in tholins (complex organic compounds formed by ultraviolet radiation) contrasting with bright ice plains. The reddish coloration of some regions is due to these tholins. The average surface temperature is about -230 degrees Celsius, but seasonal variations and an axial tilt of 122 degrees cause dramatic changes in atmospheric pressure and ice distribution. Studies suggest Pluto may have a subsurface ocean of liquid water, kept warm by internal radioactivity, raising questions about potential habitability.

Frequently Asked Questions

What is Pluto's surface ice made of?

Pluto's surface ice is primarily composed of nitrogen, with smaller amounts of methane and carbon monoxide. Water ice forms the mountains and underlying crust.

How did the nitrogen ice plains on Pluto form?

The Sputnik Planitia plain is an impact basin filled with nitrogen ice. The ice slowly convects, forming polygonal patterns visible from orbit.

Is there liquid water on Pluto?

Pluto is believed to have a subsurface ocean of liquid water, kept warm by internal radioactive heat. This is inferred from New Horizons data and geological models.