After its discovery in 1930, Pluto was long regarded as our solar system's ninth planet. But residing in the icy realm of the outer solar system, where the sun’s brightness is less than 1/1000 of the brightness here on Earth, Pluto is nothing like the other planets of our solar system. It differs tremendously from the gas giants Jupiter, Saturn, Uranus, and Neptune, but does not resemble the rocky terrestrial worlds Mercury, Venus, Earth, and Mars.
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Despite being unlike any other planets in our solar system, Pluto is not unique. In the past several years, scientists have discovered many more objects like Pluto. These objects, nicknamed “icy dwarves,” are relatively small and made mostly of ice, with orbits that are often highly elongated and steeply inclined to the plane of the solar system.
Identifying these objects is not the same as understanding them, however: even our best images of Pluto are hazy and unresolved. In order to study Pluto and the other icy dwarves of this mysterious realm we need to get closer. And we will.
On January 19, 2006, the New Horizons Mission set out on a decade-long voyage to Pluto.
Traveling at unprecedented speeds, New Horizons reached our Moon’s orbit in just nine hours—a distance that Apollo astronauts took three days to traverse. And in just 13 months, the spacecraft will encounter Jupiter, study the gas giant, and use its huge gravity to gain speed. But even traveling faster than any spacecraft ever launched, it will take another eight years to get to Pluto and its moons before proceeding into unexplored regions of the solar system, beaming back the first images from the realm of icy dwarves.
This interactive also uses data from the Digital Universe Project, a collaboration of NASA and the American Museum of Natural History, to create an accurate three-dimensional map of the visible Universe. The Digital Universe includes dozens of constantly updated datasets, and is free to download.