Pluto surface ice

Pluto's surface is covered by vast plains of nitrogen, methane, and carbon monoxide ices, revealing an active and diverse geology.

About this subject

Pluto, reclassified as a dwarf planet in 2006, has a surface dominated by volatile ices. NASA's New Horizons spacecraft, during its 2015 flyby, revealed a complex world with vast plains of nitrogen ice, such as the region known as Sputnik Planitia, part of Pluto's heart-shaped Tombaugh Regio. Nitrogen ice is so soft that it flows slowly, forming cellular patterns similar to terrestrial glaciers. In addition to nitrogen, there are methane and carbon monoxide ices, which contribute to the reddish coloration of some areas due to the formation of tholins, complex organic compounds created by solar and cosmic radiation. Mountains of water ice, harder than nitrogen ice, rise up to 5 km in height, suggesting a crust of water ice. Surface temperatures are extremely low, around -230 degrees Celsius, but the atmospheric pressure is so thin that ice sublimates directly into vapor, creating a tenuous nitrogen atmosphere. Seasonal variations, due to Pluto's elliptical orbit, cause changes in the distribution of ices over time. Active geology, with possible cryovolcanoes and fractures, indicates that Pluto is still a geologically alive body, challenging the view that dwarf planets are inert. Pluto's ice is not just a static component; it shapes the landscape and reveals processes that may also occur on other icy bodies in the Kuiper Belt.

Frequently Asked Questions

Why does Pluto have ice on its surface?

Pluto is located in the Kuiper Belt, a region very far from the Sun. Its low temperature allows substances like nitrogen, methane, and carbon monoxide to remain solid, forming an ice cover.

What is the composition of Pluto's ice?

Pluto's ice is composed mainly of nitrogen, with smaller amounts of methane and carbon monoxide. There is also water ice, which forms mountains, and tholins, organic compounds that give a reddish coloration.

Does Pluto's ice change with seasons?

Yes, due to Pluto's elliptical orbit and axial tilt, seasons are extreme. During summer in one hemisphere, nitrogen ice sublimates and may deposit on the other hemisphere, causing landscape changes over decades.