We have written many articles about Pluto and Neptune on Universe Today. We have recorded an entire episode of Astronomy Cast just about Neptune. You can listen to it here, Episode Neptune. Skip to content. Like this: Like Loading Pluto may have or may have had a subsurface ocean, although the evidence is still out on that finding. If the subsurface ocean existed, it could have greatly affected Pluto's history.
For example, scientists found that the zone of Sputnik Planitia redirected Pluto's orientation due to the amount of ice in the area, which was so heavy it affected Pluto overall; New Horizons estimated the ice is roughly 6 miles 10 km thick.
A subsurface ocean is the best explanation for the evidence, the researchers added, although looking at less likely scenarios, a thicker ice layer or movements in the rock may be responsible for the movement.
If Pluto did have a liquid ocean, and enough energy, some scientists think Pluto could harbor life. Atmospheric composition : Methane, nitrogen. Observations by New Horizons show that Pluto's atmosphere extends as far as 1, miles 1, km above the surface of the dwarf planet. Magnetic field : It remains unknown whether Pluto has a magnetic field, but the dwarf planet's small size and slow rotation suggest it has little to no such field.
Chemical composition : Pluto probably consists of a mixture of 70 percent rock and 30 percent water ice. Internal structure : The dwarf planet probably has a rocky core surrounded by a mantle of water ice, with more exotic ices such as methane, carbon monoxide and nitrogen ice coating the surface. Pluto's highly elliptical orbit can take it more than 49 times as far out from the sun as Earth.
Since the dwarf planet's orbit is so eccentric, or far from circular, Pluto's distance from the sun can vary considerably. The dwarf planet actually gets closer to the sun than Neptune is for 20 years out of Pluto's Earth-years-long orbit, providing astronomers a rare chance to study this small, cold, distant world. As a result of that orbit, after 20 years as the eighth planet in order going out from the sun , in , Pluto crossed Neptune's orbit to become the farthest planet from the sun until it was demoted to the status of dwarf planet.
When Pluto is closer to the sun, its surface ices thaw and temporarily form a thin atmosphere, consisting mostly of nitrogen, with some methane. Pluto's low gravity, which is a little more than one-twentieth that of Earth's, causes this atmosphere to extend much higher in altitude than Earth's. When traveling farther away from the sun, most of Pluto's atmosphere is thought to freeze and all but disappear.
Still, in the time that it does have an atmosphere, Pluto can apparently experience strong winds. The atmosphere also has brightness variations that could be explained by gravity waves, or air flowing over mountains. While Pluto's atmosphere is too thin to allow liquids to flow today, they may have streamed along the surface in the ancient past.
New Horizons imaged a frozen lake in Tombaugh Regio that appeared to have ancient channels nearby. At some point in the ancient past, the planet could have had an atmosphere roughly 40 times thicker than on Mars. In , scientists announced that they might have spotted clouds in Pluto's atmosphere using New Horizons data.
Investigators saw seven bright features that are near the terminator the boundary between daylight and darkness , which is commonly where clouds form. The features are all low in altitude and roughly about the same size, indicating that these are separate features.
The composition of these clouds, if they are indeed clouds, would likely be acetylene, ethane and hydrogen cyanide.
Pluto's rotation is retrograde compared to the solar systems' other worlds; it spins backward, from east to west. Average distance from the sun : 3,,, miles 5,,, km — Perihelion closest approach to the sun : 2,,, miles 4,,, km — Aphelion farthest distance from the sun : 4,,, miles 7,,, km — In , astronomers discovered that Pluto had a very large moon nearly half the dwarf planet's own size. As it moves away from the Sun, the gases cool and refreeze.
The atmosphere may vanish as Pluto moves farther from the Sun. Many Hubble Space Telescope images were combined to create these views of Pluto's surface. Distinct geologic features can't be seen, but the colors may indicate different surface compositions.
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