roughly the size of Arizona from north to south. Pluto was discovered in 1930 by Clyde Tombaugh while he worked at Lowell Observatory in Flagship, Arizona. Sputnik Planitia is a white basin ...

Of the five dwarf planets in the Solar System – including Eris, Ceres, Makemake, and Haumea – Pluto is easily the best-known ...

It must have cleared all other celestial bodies, except its own moons, from its orbit.

Scientists have noticed something strange about Pluto and its big moon, Charon, and it's making them rethink a lot! Unlike most moons, Charon is almost half the size of Pluto, so they actually orbit ...

Neither one is “big.” Earth’s moon is 2,160 miles in diameter. Some scientists believe Pluto should be upheld, but others suggest that Pluto, UB313 and other icy denizens of the Kuiper Belt ...

And so on May 1, Lowell Observatory announced that Planet X would be named Pluto. But with its peculiar, tilted orbit and confoundingly small size, the world remained an enigma. Over the years the ...

About the same size and shape as a grand piano, New Horizons travels 300,000 miles per year, faster than any other man-made object. Having launched from Earth in 2006 and photographed dwarf Pluto ...