Pluto p2
Posted: Wed Jul 30, 2025 10:20 am
6. Pluto has heat convection cells on its giant glacier Sputnik.
Zoom in close to the surface of Sputnik Planitia and you'll see something unlike anywhere else in the solar system: a network of strange polygonal shapes in the ice, each at least 6 miles (10 kilometers) across, churning on the surface of the glacier.
Although they resemble cells under a microscope, they're actually evidence of Pluto's internal heat trying to escape from underneath the glacier, forming bubbles of upwelling and downwelling nitrogen ice, something like a lava lamp.
Warm ice rises up into the center of the cells while cold ice sinks along their margins. There's nothing like it in any of Earth's glaciers, or anywhere else in the solar system that we've explored.
7. Pluto's heart literally beats, controlling its atmosphere and climate.
Cold and far-flung as Pluto may be, its icy "heart" still beats a daily, rhythmic drum that drives Pluto's atmosphere and climate much in the way Greenland and Antarctica help control Earth's climate.
Nitrogen ices in Pluto's heart-shaped Tombaugh Regio go through a cycle every day, subliming from ice to vapor in the daytime sunlight and condensing back on the surface during the frigid night. Each round acts like a heartbeat, driving nitrogen winds that circulate around the planet at up to 20 miles per hour.
"Pluto's heart actually controls its atmosphere circulation," punned Tanguy Bertrand, a planetary scientist at NASA Ames Research Center in Mountain View, California.
Sophisticated weather forecast models Bertrand has created using New Horizons data show that as these ices sublime in the northern reaches of Pluto's icy heart and freeze out in the southern part, they drive brisk winds in a westward direction—curiously opposite Pluto's eastward spin.
Those westward winds, bumping up against the rugged topography at the fringes of Pluto's heart, explain why there are wind streaks on the western edge of Sputnik Planitia, a remarkable finding considering Pluto's atmosphere is only 1/100,000th that of Earth's, Bertrand said. They also explain some other surprising desert-like features.
8. Pluto has dunes.
It's not the Sahara or the Gobi Desert, but hundreds of dunes stretch over at least 45 miles (75 kilometers) of the western edge of Sputnik Planitia, and scientists suspect they formed recently.
Dunes require small particles and sustained, driving winds that can lift and blow the specks of sand or whatever else along. And despite its weak gravity, thin atmosphere, extreme cold, and entire surface composition of ices, Pluto apparently had (or still may have) everything needed to make dunes.
Water-ice mountains on the northwest fringes of the Sputnik glacier may provide the particles, and Pluto's beating nitrogen "heart" provides winds. Instead of quartz, basalt, and gypsum sands blown by sometimes gale-force winds on Earth, scientists suspect the dunes on Pluto are sand-sized grains of methane ice carried by winds that blow at no more than 20 miles per hour, although given the size of the dunes, the winds may have been stronger and atmosphere much thicker in the past.
9. Pluto and Charon have almost no little craters, and that's a big deal.
Finding craters on the surface of planets is kind of the norm in space. But if there's one abnormal thing about the Pluto system, it's that neither Pluto nor Charon has many small craters—they're almost all big.
"That surprised us because there were fewer small craters than we expected, which means there are also fewer small Kuiper Belt objects than we expected," said Kelsi Singer, a New Horizons deputy project scientist and coinvestigator from the Southwest Research Institute in Boulder, Colorado.
Analyses of crater images from New Horizons indicate that few objects less than about a mile in diameter bombarded either world. Because scientists have no reason to believe tectonic activity would have preferentially wiped the surface clean of these small craters, it could mean the Kuiper Belt is mostly devoid of very small objects.
"These results give us clues about how the solar system formed because they tell us about the population of building blocks of larger objects, like Pluto and even perhaps Earth," Singer said, adding: "Every time we go somewhere new in the solar system, we find surprises that challenge current theories. The New Horizons flyby did just that, and in many ways."
10. Charon had a volcanic past, and it could be key to understanding other icy worlds.
New Horizons also captured stunning images of Pluto's moon Charon, and they revealed some surprising geology there, too.
On the side of Charon that New Horizons imaged in high resolution, Charon has two distinct terrain types: an immense, southward-stretching plain officially called Vulcan Planitia that's at least the size of California, and a rugged terrain colloquially called Oz Terra that stretches northward to Charon's north pole. Both seem to have formed from the freezing and expansion of (you guessed it!) an ancient ocean beneath Charon's crust.
Moderate expansion in the north created the rugged, mountainous terrain of Oz Terra seen today, whereas the expansion in the south forced its way through vents, cracks, and other openings as cryolava, spilling across the surface. In fact, Vulcan Planitia is thought to be a giant cryoflow that covered the entire region early in Charon's history.
Zoom in close to the surface of Sputnik Planitia and you'll see something unlike anywhere else in the solar system: a network of strange polygonal shapes in the ice, each at least 6 miles (10 kilometers) across, churning on the surface of the glacier.
Although they resemble cells under a microscope, they're actually evidence of Pluto's internal heat trying to escape from underneath the glacier, forming bubbles of upwelling and downwelling nitrogen ice, something like a lava lamp.
Warm ice rises up into the center of the cells while cold ice sinks along their margins. There's nothing like it in any of Earth's glaciers, or anywhere else in the solar system that we've explored.
7. Pluto's heart literally beats, controlling its atmosphere and climate.
Cold and far-flung as Pluto may be, its icy "heart" still beats a daily, rhythmic drum that drives Pluto's atmosphere and climate much in the way Greenland and Antarctica help control Earth's climate.
Nitrogen ices in Pluto's heart-shaped Tombaugh Regio go through a cycle every day, subliming from ice to vapor in the daytime sunlight and condensing back on the surface during the frigid night. Each round acts like a heartbeat, driving nitrogen winds that circulate around the planet at up to 20 miles per hour.
"Pluto's heart actually controls its atmosphere circulation," punned Tanguy Bertrand, a planetary scientist at NASA Ames Research Center in Mountain View, California.
Sophisticated weather forecast models Bertrand has created using New Horizons data show that as these ices sublime in the northern reaches of Pluto's icy heart and freeze out in the southern part, they drive brisk winds in a westward direction—curiously opposite Pluto's eastward spin.
Those westward winds, bumping up against the rugged topography at the fringes of Pluto's heart, explain why there are wind streaks on the western edge of Sputnik Planitia, a remarkable finding considering Pluto's atmosphere is only 1/100,000th that of Earth's, Bertrand said. They also explain some other surprising desert-like features.
8. Pluto has dunes.
It's not the Sahara or the Gobi Desert, but hundreds of dunes stretch over at least 45 miles (75 kilometers) of the western edge of Sputnik Planitia, and scientists suspect they formed recently.
Dunes require small particles and sustained, driving winds that can lift and blow the specks of sand or whatever else along. And despite its weak gravity, thin atmosphere, extreme cold, and entire surface composition of ices, Pluto apparently had (or still may have) everything needed to make dunes.
Water-ice mountains on the northwest fringes of the Sputnik glacier may provide the particles, and Pluto's beating nitrogen "heart" provides winds. Instead of quartz, basalt, and gypsum sands blown by sometimes gale-force winds on Earth, scientists suspect the dunes on Pluto are sand-sized grains of methane ice carried by winds that blow at no more than 20 miles per hour, although given the size of the dunes, the winds may have been stronger and atmosphere much thicker in the past.
9. Pluto and Charon have almost no little craters, and that's a big deal.
Finding craters on the surface of planets is kind of the norm in space. But if there's one abnormal thing about the Pluto system, it's that neither Pluto nor Charon has many small craters—they're almost all big.
"That surprised us because there were fewer small craters than we expected, which means there are also fewer small Kuiper Belt objects than we expected," said Kelsi Singer, a New Horizons deputy project scientist and coinvestigator from the Southwest Research Institute in Boulder, Colorado.
Analyses of crater images from New Horizons indicate that few objects less than about a mile in diameter bombarded either world. Because scientists have no reason to believe tectonic activity would have preferentially wiped the surface clean of these small craters, it could mean the Kuiper Belt is mostly devoid of very small objects.
"These results give us clues about how the solar system formed because they tell us about the population of building blocks of larger objects, like Pluto and even perhaps Earth," Singer said, adding: "Every time we go somewhere new in the solar system, we find surprises that challenge current theories. The New Horizons flyby did just that, and in many ways."
10. Charon had a volcanic past, and it could be key to understanding other icy worlds.
New Horizons also captured stunning images of Pluto's moon Charon, and they revealed some surprising geology there, too.
On the side of Charon that New Horizons imaged in high resolution, Charon has two distinct terrain types: an immense, southward-stretching plain officially called Vulcan Planitia that's at least the size of California, and a rugged terrain colloquially called Oz Terra that stretches northward to Charon's north pole. Both seem to have formed from the freezing and expansion of (you guessed it!) an ancient ocean beneath Charon's crust.
Moderate expansion in the north created the rugged, mountainous terrain of Oz Terra seen today, whereas the expansion in the south forced its way through vents, cracks, and other openings as cryolava, spilling across the surface. In fact, Vulcan Planitia is thought to be a giant cryoflow that covered the entire region early in Charon's history.