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Sci­en­tists learn why Mor­dor mars Pluto moon

- Traci Wat­son Space · Spacecraft · Solar System · Science · Planets · Space Flights · Milky Way Galaxy · J. R. R. Tolkien · The Lord of the Rings · The Lord of the Rings trilogy · Texas · Arizona · Space Technology · University of Texas · Lowell Observatory

On the out­skirts of the so­lar sys­tem lies an icy lit­tle moon called Charon with a mys­te­ri­ous blem­ish: a great dark blotch the color of a dried blood­stain.

The blotch, nick­named Mor­dor af­ter J.R.R. Tolkien’s for­bid­ding “dark land” in The Lord of the

Rings, is the sub­ject of much spec­u­la­tion. Now sci­en­tists think they know why it’s there. Re­searchers say in this week’s

Na­ture that Mor­dor was born of ma­te­rial pur­loined from the nearby dwarf planet Pluto. As Pluto’s at­mos­phere drifts into space, some of the es­cap­ing mol­e­cules are cap­tured by Charon and even­tu­ally trans­formed into dark-red chem­i­cals — a phe­nom­e­non seen nowhere else in the so­lar sys­tem, says Lau­rence Trafton, an as­tronomer at the Univer­sity of Texas-Austin who was not in­volved with the study.

The mys­tery of Mor­dor be­gan last year, when the New Hori­zons space­craft be­came hu­man­ity’s first am­bas­sador to Pluto.

As the space­craft ap­proached its tar­get, sci­en­tists saw “this per­sis­tent dark spot at the top of Charon … (that) never went away,” says Will Grundy, study co-author and a sci­en­tist at Ari­zona’s Low­ell Ob­ser­va­tory. “We were all scratch­ing our heads.”

Per­haps the dark blotch stemmed from the same ge­o­log­i­cal events that carved out Charon’s ridges and canyons. Or per­haps Mor­dor formed from chem­i­cals from Pluto that got trapped on Charon’s icy sur­face.

Grundy and his col­leagues cal­cu­lated the tem­per­a­ture on Charon dur­ing its win­ter. They found Charon’s north pole stays “ridicu­lously cold” for decades, Grundy says — about -415 de­grees Fahren­heit or be­low from the mid-1800s to the late 1980s.

That’s cold enough, and long enough, for mol­e­cules that drift away from Pluto’s at­mos­phere to freeze onto Charon’s north pole.

 ?? NASA ?? The New Hori­zons space­craft ob­serves mys­te­ri­ous color on Charon, a moon near Pluto.
NASA The New Hori­zons space­craft ob­serves mys­te­ri­ous color on Charon, a moon near Pluto.

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