The New Horizons spacecraft approaching Pluto has just returned the first color image ever taken of the dwarf planet. Also included in this historic image is the largest moon of the planetary system, Charon.
New Horizons will make a close encounter with the distant bodies in July 2015. Traveling 3 billion miles in 9 years, New Horizons is the fastest spacecraft yet launched by mankind.
Venus and Mars were first explored by spacecraft in the 1960s, followed by study of Jupiter and Saturn a decade later. Uranus and Neptune were visited by the Voyager spacecraft in the 1980s. Now, New Horizons is poised to carry out the first exploration ever of the Kuiper Belt - the region just beyond the realm of the planets.
Pluto, once deemed the ninth planet of the solar system, is now classified as just another member of the Kuiper Belt, although it is, by far, the best known to the general public. This dwarf planet is currently known to have at least five moons, a significant nitrogen atmosphere, and it possibly holds an ocean of water beneath its icy surface.
Charon, discovered in 1978 by astronomers at the United States Naval Observatory, is the largest moon orbiting Pluto, and is roughly the size of the state of Texas. As satellites orbit other worlds, the two bodies each revolve around a center of gravity, known as a barycenter. In most systems, this balancing point is well within the larger body, usually near its core. Our moon is so large in relation to our home planet that the barycenter of the Earth/moon system is located roughly 1,000 feet beneath the surface of the ground, three-quarters of the way from the center of our world. For Pluto and Charon, the barycenter is well away from the dwarf planet, in space between the two bodies.
"The image was made from a distance of about 71 million miles (115 million kilometers) - roughly the distance from the sun to Venus. At this distance, neither Pluto nor Charon is well resolved by the color imager, but their distinctly different appearances can be seen," the Johns Hopkins Applied Physics Laboratory reported on its Web site.
At closest approach on July 14, images of Pluto and Charon will be provide enough detail to resolve images as small as a few miles from side-to-side.
"This is pure exploration; we're going to turn points of light into a planet and a system of moons before your eyes! New Horizons is flying to Pluto - the biggest, brightest and most complex of the dwarf planets in the Kuiper Belt. This 21st-century encounter is going to be an exploration bonanza unparalleled in anticipation since the storied missions of Voyager in the 1980s," said Alan Stern, principal investigator for the New Horizons program at the Southwest Research Institute.
After its encounter with Pluto and its moons, New Horizon will race off into interstellar space, never to return home. Scientists, however, except to continue to get data from New Horizons flyby of Pluto that is stored in onboard memory for a full 16 months after it passes the dwarf planet.
