Snowstorms on Earth are common, but did you know it snows on other worlds, too? Here are just a few of the places beyond Earth where you might find snow or ice of various kinds:
1. Mars. The north and south pole of Mars have ice caps that grow and shrink with the seasons. These ice caps are made mainly of water ice—the same kind of ice you’d find on Earth. However, the snow that falls there is made of carbon dioxide—the same ingredient used to make dry ice here on Earth. Carbon dioxide is in the Martian atmosphere and it freezes and falls to the surface of the planet as snow. NASA’s Mars Reconnaissance Orbiter takes photos of the sand dunes around Mars’ north pole. The slopes of these dunes are seasonally covered with carbon dioxide snow and ice.
2. Enceladus. Saturn’s moon, Enceladus, has geysers that shoot water vapor out into space. There it freezes and falls back to the surface as snow. Some of the ice also escapes Enceladus to become part of Saturn’s rings. The water vapor comes from a heated ocean which lies beneath the moon’s icy surface. All of this ice and snow make Enceladus one of the brightest objects in our solar system.
3. Triton. Neptune’s largest moon is Triton. It has the coldest surface known in our solar system. Triton’s atmosphere is made up mainly of nitrogen. This nitrogen freezes onto its surface covering Triton with ice made of frozen nitrogen. Triton also has geysers like Enceladus, though they are smaller and made of nitrogen rather than water.
4. Pluto. Farther out in our solar system lies the dwarf planet Pluto. In 2016, scientists on the New Horizons mission discovered a mountain chain on Pluto where the mountains were capped with methane snow and ice.
5. Io. There are dozens of moons that orbit Jupiter and one of them, called Io, has “snowflakes” made out of sulfur. In 2001, NASA’s Galileo spacecraft detected these sulfur snowflakes just above Io’s south pole. The sulfur shoots into space from a volcano on Io’s surface. In space, the sulfur quickly freezes to form snowflakes that fall back down to the surface.
6. Kepler-13Ab. There might even be snow far outside our solar system! Kepler-13Ab is a hot, giant planet 1,730 light years from Earth. It’s nine times more massive than Jupiter and it orbits very close to its star. The Hubble Space Telescope detected evidence of titanium oxide—the mineral used in sunscreen—in this planet’s upper atmosphere. On the cooler side of Kepler-13Ab that faces away from its host star, the planet’s strong gravity might cause the titanium oxide to fall down as “snow.”
7. Europa. Like Enceladus, Jupiter’s moon Europa is another icy world with a liquid ocean below the frozen surface. NASA is planning to further explore Europa with a mission slated for launch in the 2020s.
8. Mimas. Yes, it’s a moon. Saturn’s small moon Mimas, despite its Death Star look, is actually just a ball of almost pure water ice about 123 miles (198 km) across.
9. Earth’s moon. NASA’s Lunar Reconnaissance Orbiter is one of several spacecraft that have detected water ice in shadowy craters near the north and south poles of the moon.
10. Mercury. No, seriously. Even on the planet closest to the sun, observations by NASA’s MESSENGER spacecraft provided compelling support for the long-held hypothesis that Mercury harbors abundant water ice and other frozen volatile materials in its permanently shadowed polar craters.
Want to learn more about weather and ice on other planets? Check out NASA Space Place.
Bottom line: A list of 10 worlds with snow or ice, beyond our planet Earth.