NASA Announces That Pluto Has Icebergs Floating On Glaciers of Nitrogen Ice (blastingnews.com)

MarkWhittington writes: The most recent finding from New Horizons show that icebergs have broken off from the hills surrounding the Sputnik Planum, a glacier of nitrogen ice, and are floating slowly across its surface, eventually to cluster together in places like the Challenger Colles, informally named after the crew of the space shuttle Challenger, which was lost just over 30 years ago. The feature is an especially high concentration of icebergs, measuring 37 by 22 miles. The icebergs float on the nitrogen ice plain because water ice is less dense than nitrogen ice.

Comments

Original NASA article

[Anonymous Coward]

Why can't we link to the original NASA article?

http://www.nasa.gov/feature/pluto-s-mysterious-floating-hills

Re:Icebergs float on glaciers

[Rei]

Nitrogen ices at these temperatures, while crystalline, have rather low viscosity. If you put weight on them, they slowly diffuse around it until the object either sinks or is buoyantly balanced out. The latter happens in the case of water ice.

Also, it's worth noting that it's not pure nitrogen ices, it's a nitrogen-carbon monoxide-methane eutectic. Nitrogen is the most common component, however. Also, there are multiple crystal phases that can be taken, depending on the conditions. Nitrogen ices are most famous for having some rather "explosive" phase transitions between different states.

Re:Plutonic Warming

[spork invasion]

Pluto is getting colder. It has a highly eccentric orbit and right now that's taking Pluto farther from the Sun. As a result, temperatures will decrease on Pluto.

Re:Icebergs float on glaciers

[Rei]

No, it does not form "one huge crystal". Nitrogen ices at these temperatures have little structural integrity. It was well known before we got to Pluto that if we saw any sort of relevant topography, we'd know immediately that it was from water ice, as nitrogen ices are so weak that they'd just flow slack over time.