NASA's New Horizons spacecraft is nearing the end of its long journey that will see it fly by Pluto. The probe has snapped images showing light and dark regions that may be ice caps on the dwarf planet's surface.
The images, taken earlier this month with a telescopic camera, show broad areas featuring surface markings of various brightness, including a very bright one at one of the planet's poles that might be a polar cap of some frozen substance — possibly nitrogen or methane.
"As we approach the Pluto system we are starting to see intriguing features such as a bright region near Pluto's visible pole, starting the great scientific adventure to understand this enigmatic celestial object," said John Grunsfeld at NASA's Science Mission Directorate in Washington.
New Horizons will fly by Pluto on July 14 – the first-ever spacecraft visit to the dwarf world – gathering compositional data by spectrometers that should confirm whether or not the polar bright spot is indeed an ice cap.
"It's a mystery — whether these bright and dark regions are caused by geology or topography or composition," said Alan Stern, the New Horizons principal investigator at the Southwest Research Institute in Boulder, Colo. "But New Horizons has the capability, as we get closer, to solve just those kinds of mysteries, and we're looking forward to that."
New Horizons has spent the last 9 years traveling through space since its launch in 2006 — the same year that Pluto, once considered the ninth planet in the solar system, was demoted to dwarf planet status.
Since its discovery in 1930, astronomers have been struggling to discern Pluto's surface details, with little success. At best, Hubble images have suggested possible variations in brightness across it surface.
At about 3 billion miles from Earth, Pluto is little more than a pinpoint of light in most observations.
That's why astronomers are so excitedly looking forward to the Pluto views they'll get when New Horizons passes within just 7,800 miles of the dwarf planet.
"After traveling more than 9 years through space, it's stunning to see Pluto, literally a dot of light as seen from Earth, becoming a real place right before our eyes," said Stern. "These incredible images are the first in which we can begin to see detail on Pluto, and they are already showing us that Pluto has a complex surface."
