BellaOnline Forums Education Astronomy Pluto - it's a whole new story now

Scientists are thinking that there's volcanic activity on Pluto - it would explain smooth areas where the land has been resurfaced. Interestingly, they've found two good candidates for volcanoes. Using the latest data to arrive from New Horizons, they've created topographical maps of Pluto. Blue is for lower elevations and brown for higher elevations. (The colors don't relate to what Pluto looks like.)

Two of the mountains look similar to shield volcanoes Examples of earthly shield volcanoes are the Hawaiian islands. But if these mountains on Pluto are volcanoes, they don't throw out melted rock. They'd be cryovolcanoes, erupting an icy liquid.

Planetary scientist Oliver White says that if the mountains aren't volcanoes, no one is sure what to call them. “Whatever they are, they’re definitely weird.”

With 80% of the New Horizons data still to come, the surprises still keep rolling in.

How it is that Pluto still has an atmosphere when it's so cold? It should freeze and drop to the surface. The atmosphere is very sparse, but there's enough to scatter light and make the sky blue, as we saw in pictures of the blue ring around the dwarf planet.

New Horizons data shows that the atmosphere is much colder and more compact than they had expected. It's certainly being lost at a rate that's thousands of times less than they had predicted. Leslie Young (Southwest Research Institute) says,"We expected escape rate rapid enough to lose the equivalent of a half-mile-thick layer of surface ice over 4½ billion years, but now it's more like half a foot."

What's going on?

Researchers have been working to explain New Horizons data that shows geologic activity on Pluto's surface. It is, after all, quite small and extremely cold there.

Earth has a geologically active surface because the mantle is moving – that's the layer between the crust (where we live!) and the core. It's a very slow convection where hot material rises and cooler material sinks. It can bring new material to the surface and wipe out old features, though on Earth it's mainly weathering that changes the surface. So what's up on Pluto?

Many people thought that below Pluto's surface was a mantle of pure water ice. It would be around 300 degrees below zero. But one research group suggests that there is also ammonia present, which acts like a bit of antifreeze to lower the temperature needed to get convection in the mantle. They've tested this idea through mathematical modelling.

Pluto's day is just under six and a half Earth days long. But from New Horizons data, here is a montage of images of Pluto that cover an entire day on Pluto.

The rotation of Pluto's big moon Charon is locked around Pluto as the Moon is to Earth. It turns once on its axis for each revolution. So Charon takes just under six and a half Earth days to orbit Pluto and turn on its axis. Here is another montage, this one of a full rotaion of Charon.

It's Pluto's al-Idrisi mountains in high high resolution from New Horizons in a view about 50 miles wide.



Credit: NASA/JHUAPL/SwRI

An enhanced color mosaic made up from high resolution shots from New Horizons' close approach.



Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

A Christmas present from New Horizons is this very high resolution picture showing the center of Sputnik Planum. Sputnik Planum is the plain forming the left side of Pluto's “heart”. The pattern of polygonal cells was created by slow thermal convection of the ice (mostly nitrogen). It shows there is internal heating and that it has changed over time. "X" marks the spot where this is happening. The dark object is a dirty block of water ice – it's less dense than the solid nitrogen under it. (Credits: NASA/JHUAPL/SwRI)

Thank you, Mona. I have looked at this photo several times and even showed my husband.
Chel

Today is the 16th anniversary of the launch of New Horizons. Pluto was still a planet on January 19, 2000 when the spacecraft set off with an unusual addition to what you'd usually expect on board - some of the ashes of Pluto's discoverer Clyde Tombaugh.

Whether planet or dwarf planet, Pluto has turned out to be one of the most interesting objects in the Solar System. And the data is still on its way home!

The latest photographs from the New Horizons mission have revealed hills of water ice that ‘float’ in a sea of frozen nitrogen and move slowly over time, like icebergs.

Since these hills are composed of water ice, which is less dense than nitrogen ice, scientists believe they are essentially adrift in a sea of frozen nitrogen. And since these ice floes behave much like glaciers here on Earth, it is believed that the hills are fragments from the rugged western portion of Tombaugh Regio. These would have then broken off, and are now being carried slowly along by the nitrogen glaciers into Sputnik Planum.

Credits: NASA/JHUAPL/SwRI