Pluto was discovered by astronomer Clyde Tombaugh in 1930. A 9th planet had been looked for for some time. It was believed that such a planet had to exist in order to explain some odd …

At 2400 kilometers in diameter, Eris is slightly larger than Pluto. Its discovery was one of the reasons the International Astronomical Union felt it was necessary to definitely define what …

However, as astronomers learned more about the planets and also about a new group of objects known as the Kuiper Belt Objects, it became clear that Pluto was more like the objects in that …

We now know this was incorrect. He thought the unusual motion of Uranus was due to another planet that had not yet been discovered. Le Verrier used math to calculate where to find the …

Sir William Herschel labeled these objects as asteroids, so in 1802 Ceres became known as an asteroid, not a planet. Ceres was the largest known asteroid in the asteroid belt until 2006. In …

Galle acted on Le Verrier's work and became the first person to observe Neptune. After the discovery of Neptune, the director of the Cambridge Observatory pointed out that John Couch …

Its actual discovery is a controversial topic in the world of astronomy. A team of astronomers from Caltech first published the discovery online on July 20, 2005 using data they collected on May …

Dwarf planet is a new class of astronomical objects. It was created in 2006 by the International Astronomical Union as part of their struggle to define the word 'planet'. The discovery of …

While a student there he used math to predict the presence of a new planet beyond Uranus. A few months after Adams made his prediction, a French astronomer also made the same …

Eris is the largest known dwarf planet in our solar system. It is a little larger than Pluto. Eris is about 2400 kilometers wide. Eris was first found by a team of astronomers at Palomar …