Pictures of Pluto

INCREDIBLE NEW PHOTOS OF PLUTO: NASA is still downloading images from the Pluto flyby two months ago. Some of the new arrivals, like this one received on Sept. 13th, are causing researchers to question what they thought they knew about the distant dwarf planet:

New Horizons snapped the picture looking back at Pluto about 15 minutes after its closest approach on July 14th. Backlit by the sun, Pluto’s rugged, icy mountains tower over a vast frozen plain extending to the horizon. The backlighting highlights more than a dozen layers of haze in Pluto’s tenuous but distended atmosphere.

The new pictures provide evidence for a remarkably Earth-like “hydrological” cycle on Pluto – but involving soft and exotic ices, including nitrogen, rather than water ice. There are signs of hazes, evaporation, precipitation, and flowing glaciers similar to the frozen streams on the margins of ice caps on Greenland and Antarctica.

“We did not expect to find hints of a nitrogen-based glacial cycle on Pluto operating in the frigid conditions of the outer solar system,” says Alan Howard, a member of the mission’s science team from the University of Virginia. “Driven by dim sunlight, this would be directly comparable to the hydrological cycle that feeds ice caps on Earth, where water is evaporated from the oceans, falls as snow, and returns to the seas through glacial flow.”

“Pluto is surprisingly Earth-like in this regard,” adds Alan Stern, principal investigator of the New Horizons mission, “and no one predicted it.”