Solar System Chatter

What’s Pluto Emitting Now?

Two reports came out today that describe the interesting things coming from Pluto’s direction. The first one explains why its moon Charon has that strange reddish tint at its north pole region (see photo). It turns out that Pluto is a bit of a “graffiti artist,” says Will Grundy from NASA’s New Horizons’ team. Methane gas escapes the dwarf planet’s atmosphere, gets trapped by Charon’s gravity and freezes. Ultraviolet light from the sun turns the methane into hydrocarbons, and finally into reddish-colored organic material called tholins.

Meanwhile, another team of scientists are perplexed by X-rays coming from Pluto. NASA’s Chandra X-ray Observatory observed Pluto four times while New Horizons was en route and measured a somewhat surprisingly high amount of radiation coming from the planet. All solar system objects with atmosphere emit some level of X-rays, because of the way the gasses interact with solar wind. While New Horizons did discover Pluto had more atmosphere than predicted—scientists thought it would have a thin atmosphere similar to a comet—it still does not account for the level of radiation given how weak the solar wind is that far away from the sun.

Heather Goss is the Departments Editor at Air & Space.

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