NASA’s New Horizons spacecraft continues to deliver on images and information about Pluto and its moons with this image of the dwarf planet and moon Charon.
As NASA writes:
They’re a fascinating pair: Two icy worlds, spinning around their common center of gravity like a pair of figure skaters clasping hands. Scientists believe they were shaped by a cosmic collision billions of years ago, and yet, in many ways, they seem more like strangers than siblings.
The image shows the high-contrast array of bright and dark features of Pluto’s surface and, apart from the polar region, a generally more uniform light grey terrain on Charon.
There are other differences. Pluto has a significant atmosphere whileCharon does not and Pluto contains frozen nitrogen, methane, and carbon monoxide but Charon’s surface is made of frozen water and ammonia compounds. The interior of Pluto is mostly rock, while Charon contains equal measures of rock and water ice.
“These two objects have been together for billions of years, in the same orbit, but they are totally different,” said Principal Investigator Alan Stern of the Southwest Research Institute (SwRI), Boulder, Colorado.
Charon is about 1,200 kilometres across, about half the diameter of Pluto.
NASA’s unmanned New Horizons spacecraft is closing in on the Pluto system after a more than nine-year, three-billion-mile journey and will be at its closest on 14 July.
As it prepares for that approach, NASA has many of its assets and instruments focused on Pluto and its moons.
“NASA is aiming some of our most powerful space observatories at Pluto,” said Paul Hertz, Astrophysics Division Director at NASA Headquarters, Washington. “With their unique capabilities combined, we will have a multi-faceted view of the Pluto system complementary to New Horizons data.”
Right around New Horizons’ closest approach to Pluto, Cassini will take an image of the dwarf planet from its station in orbit around Saturn. Although Cassini is the closest spacecraft to New Horizons’ distant location, the image of Pluto will be but a faint dot on a field of stars. Even so, the image will provide a scientific measurement of Pluto from a different vantage point that will complement data collected by New Horizons.
“The Cassini team has been pleased to provide occasional imaging support for New Horizons for several years to aid with the Pluto-bound spacecraft’s navigation. It’s great to provide one last look at it soars through the Pluto system,” said Earl Maize, Cassini project manager at NASA’s Jet Propulsion Laboratory in Pasadena, California.
On 23 July, Spitzer Space Telescope will begin a seven-day series of observations, gathering infrared data at 18 different longitudes. The data will reveal possible changes in ice on Pluto’s surface.
“Spitzer is around 4.87 billion kilometres from Pluto,” said Noemi Pinella-Alonso from the University of Tennessee in Knoxville, and lead investigator of the Spitzer observations.
“The spacecraft provides an effective tool to study the ice on the surface and search for other materials that have not yet been identified.”
Beginning in October, the Kepler spacecraft in its new mission, K2, will observe Pluto for nearly three months. It will record the change in the reflected light off Pluto and Charon.
Scientists will learn more about the effects on the atmosphere and surface of Pluto imparted by the dwarf planet’s eccentric and expanding orbit about the sun. The data may also reveal seasonal changes on this chilly world.
“K2 observations will expand the time coverage of the speedy New Horizons’ flyby of Pluto, making observations of the dwarf planet-moon system every 30-minutes,” said Steve Howell, project scientist for Kepler/K2 at NASA’s Ames Research Center in Moffett Field, California. “We are excited to turn the planet-hunting Kepler spacecraft’s attention to this distant solar system object to provide additional scientific insight into this far off, mysterious world, itself a miniature solar system of five moons in orbit about Pluto.”
More of the latest news and images here and more Cosmos coverage of Pluto and the New Horizons mission here.
Bill Condie is a science journalist based in Adelaide, Australia.
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