Pluto's "heart" contains shifting glaciers of frozen nitrogen, methane and carbon monoxide, and its atmosphere is both deeper and disappearing more rapidly than scientists predicted, New Horizons mission leaders said Friday.
Close-up images of Tombaugh Regio, the large heart-shaped formation near Pluto's equator, show the smooth, brightly colored area flowing around mountains and filling craters. The geology appears just like glaciers on Earth, the scientists said.
Observations of Pluto's atmosphere meanwhile show a haze extending 100 miles above the surface, farther than they expected. And air pressure on the surface, a tiny fraction of air pressure on Earth, is dropping dramatically as the dwarf planet moves into the cold, farther from the sun in its elliptical orbit.
The revelations are some of the first to come from New Horizons' historic encounter with Pluto on July 14, a mission managed by the Johns Hopkins Applied Physics Laboratory in Laurel. Most of the data gathered during the fly-by is still on the spacecraft, but with about 5 percent of it on the ground, it is already proving illuminating, the scientists said.
"It's really turning out to be just a scientific wonderland," said Alan Stern, the mission's principal investigator and a researcher at the Southwest Research Institute in Boulder, Colo.
The scientists believe that heat from within Pluto may be driving some of the motion of the ice that covers the western half of Tombaugh Regio, causing it to rise and fall beneath the surface. Even at Pluto's surface temperatures of about 380 degrees below zero, the elements prevalent in the ice are relatively soft and malleable, said Bill McKinnon, deputy leader of the mission's geology team.
The dwarf planet is so cold, scientists suspect that much of its atmosphere is frozen to its surface. New Horizons data show its atmosphere's mass has dropped significantly relative to estimates from two years ago, likely because Pluto is moving away from the sun in its 248-year orbit.
Air pressure on its surface is 1/100-thousandth that of the pressure on the surface of Earth, they said.