Why Pluto Will Remain a Dwarf Planet

Pluto was the only planet in our solar system discovered by U.S. astronomers.

The five brightest planets Mercury, Venus, Mars, Jupiter and Saturn are visible with the naked eye and were known to people since ancient times. Uranus is, under good conditions, just barely visible to the naked eye, and was officially discovered in 1781 by Sir William Herschel, an Englishman, who initially believed that he had found a new comet.

About 60 years later, English mathematician John Couch Adams and French astronomer Urbain Le Verrier studied small irregularities in Uranus’ orbit and concluded that there must exist another planet beyond Uranus. Following their theoretical predictions, Johann Galle and Heinrich D’Arrest discovered Neptune.

Finally, Pluto was discovered in 1930 by an American amateur astronomer Clyde Tombaugh at Lowell Observatory in Arizona, successfully ending a long search for the so-called “Planet X”. As most of us are probably aware, a well-known Disney character obtained his name after this planet.

At the time of discovery, and for the next 76 years, Pluto was considered the ninth planet of the solar system. The fact is that there is no brighter object than Pluto at a similar distance away from us, so there was no reason to dispute its status.

However, it turned out that Pluto is made mostly of rock and ice, and its reflective, icy surface made it appear very bright, and tricked us to believe it was bigger than it really was. In reality, Pluto is about two-thirds the size of our own moon.

Then, in the 1990s, technological advances made possible much more precise observations, which led to discovery of Eris and other objects of what is today known as the Kuiper belt.

The first estimates indicated that Eris was —> Read More