To understand what happened to Pluto, we must actually go back to the late 1700's, when a number of astronomers thought that there was something odd to the spacing of the planets orbiting the Sun.

Pluto did not meet the third criterion ... It's the only dwarf planet in the inner part of the solar system, orbiting in the asteroid belt between Mars and Jupiter. It was initially thought ...

In October, astronomers announced the discovery of two tiny, new moons orbiting the planet, each one only 30 to 100 miles in diameter. Astronomers have suspected since the early 1990's that Pluto ...

"There's a lot of information to be gained about Pluto's interior, and orbiting Pluto is the best way to do it." The researchers published their work in the journal Nature Astronomy on April 15.

Pluto resembles the icy, comet-like objects orbiting the Sun outside of Neptune's orbit, rather than either the rocky terrestrial planets or the Jovian planets. Factors that distinguish Pluto from ...

NEW HAVEN, Connecticut (CNN) -- Astronomers have discovered a new object orbiting the sun that is smaller ... about one-fourth the size of the planet Pluto. The object is classified as a minor ...

A New Horizons image of Pluto and its moon Charon revealed more surprises about the dwarf planet and its orbiting moon. Click on the hand to see why Pluto and its moon have shaken things up.

Pluto is a dwarf planet ... There are large numbers of asteroids orbiting the Sun in the asteroid belt between Mars and Jupiter. There are also many in a region beyond Neptune called the Kuiper ...