Lava lamp BIG RISA1029

Pluto Churns Like A Lava Lamp

highest-resolution swath of Pluto to the very center of Sputnik Planum, the informally named plain that forms the left side of Pluto’s “heart.” Mission scientists believe the pattern of the cells stems from the slow thermal convection of the nitrogen-dominated ices that fill Sputnik Planum. The darker patch at the center of the image is likely a dirty block of water ice “floating” in denser solid nitrogen, and which has been dragged to the edge of a convection cell. Also visible are thousands of pits in the surface, which scientists believe may form by sublimation. (Image credit: NASA/JHUAPL/SwRI)
Part of a high-resolution swath of Pluto near the center of Sputnik Planum, the informally named plain that forms the left side of Pluto’s “heart.” Mission scientists believe the pattern of the cells stems from the slow thermal convection of the nitrogen ice. The darker patch at is likely a dirty block of water ice “floating” in denser solid nitrogen, and which has been dragged to the edge of a convection cell. Also visible are thousands of pits in the surface, which scientists believe may form when the ice vaporizes in sunlight. Notice the “X” at lower right, explained in the text below. Credit: NASA/JHUAPL/SwRI

A recently released high-resolution swath of Pluto taken by NASA’s New Horizons spacecraft shows all kinds of wonderful things in Sputnik Planum, the informal name given to the icy plains dominating the left side of Pluto’s big “heart”. The strip reveals features less than half a city block in size

View of Pluto during the New Horizons flyby shows the large, heart-shaped feature the spacecraft faced. The left side, dominated by plains of nitrogen ice, is provisionally named Sputnik Planum. Credit: NASA
View of Pluto during the New Horizons flyby shows the large, heart-shaped feature the spacecraft faced. The left side, dominated by plains of nitrogen ice, is provisionally named Sputnik Planum. The surface temperature on the dwarf planet is -400 F (-240 C) Credit: NASA/JHUAPL/SwRI

Sputnik Planum is at a lower elevation than most of the surrounding area by a couple of miles, but not completely flat. Its surface is separated into cells or polygons 10 to 25 miles wide (16-40 km), and when viewed at low sun angles, the cells are seen to have slightly raised centers and ridged margins, with about 100 yards (91.4 meters) of overall height variation.

Pluto's interior may operate like a lava lamp, where denser, warmer material rises to the surface, cools and then sinks back down again. In a lava lamp, wax, mixed with heavier-than-water carbon tetrachloride, is heated, floats to the top, cools and sinks. Credit: RISA1029/Wikipedia
Pluto’s interior may operate like a lava lamp, where denser, warmer material rises to the surface, cools and then sinks back down again. In a lava lamp, wax, mixed with heavier-than-water carbon tetrachloride, is heated, floats to the top, cools and sinks. Credit: RISA1029/Wikipedia

Mission scientists believe the pattern of the cells stems from the slow thermal convection or churning of the nitrogen-dominated ices that fill Sputnik Planum. A reservoir that’s likely several miles or kilometers deep in some places, the solid nitrogen is warmed at depth by Pluto’s modest internal heat, becomes buoyant and rises up in great blobs, and then cools off and sinks again to renew the cycle.

“This part of Pluto is acting like a lava lamp,” said William McKinnon, deputy lead of the New Horizons Geology, Geophysics and Imaging team, from Washington University in St. Louis, “if you can imagine a lava lamp as wide as, and even deeper than, Hudson Bay.”

Computer models by the New Horizons team show that these blobs of overturning solid nitrogen can slowly evolve and merge over millions of years. The ridged margins, which mark where cooled nitrogen ice sinks back down, can be pinched off and abandoned.

 

Latest hi-res swath of Pluto The newest image, returned on Dec. 24, 2015, extends New Horizons' highest-resolution swath of Pluto to the very center of the informally named Sputnik Planum, and nearly completes the set of highest-resolution images taken by New Horizons last July.
This latest hi-res swath of Pluto returned on Dec. 24, 2015 nearly completes the set of highest-resolution images taken by New Horizons last July. Click to enlarge. Credit: NASA/JHUAPL/SwRI

The “X” feature is likely one of these – a former quadruple junction where four convection cells met. Numerous, active triple junctions can be seen elsewhere mosaic image strip.

In other much more local news, I wanted to let regular readers know I’ve been working on a book on a deadline. That’s the reason the blog may occasionally not get updated or otherwise suffer. The topic is naked eye astronomy — all the wonders you can see at night without any other equipment than eyeballs, a star map and flashlight. It’s set to come out in September. Thanks for your patience!