What is Pluto – a Star or a Comet?

Which is the planet farthest from the sun? Pluto, of course. But, some recent findings suggest that Pluto is not a planet at all. It seems Pluto could actually be a comet, reports the National Geographic website.

Basically, it is Pluto’s small size that has got it into trouble. It has a diameter of approximately 1,420 miles or 2,280 kilometers. This makes it six times smaller than Earth. This fact irked scientists who always suspected that something so small could never belong to the hallowed club of planets.

Pluto also has an unusual orbit. In fact, it is the only planet which travels in an elliptical orbit and it also crosses the orbit of its closest neighbour, Neptune. This makes Pluto spend 20 years of its 248 year orbit as the second most farthest planet from the sun.

The Kuiper belt

In 1992, David Jewitt and J. Luu of the University of Hawaii discovered a small icy body which they named 1992 QB1. This object was found around Pluto’s domain. Since then, over 100 such objects have been discovered and are thought to be similar to Pluto in composition, consisting primarily of ice and rock.

This swarm of Pluto-like objects beyond Neptune is known as the Kuiper Belt, named after Gerard Kuiper, who first proposed that such a belt existed.

The Kuiper belt is estimated to have at least 35,000 Pluto-like objects. Scientists are therefore thinking of demoting Pluto from the status of a planet to that of a Kuiper belt object or a KBO.

However, there is a great amount of debate in the scientific community regarding this new finding. Several astronomers believe that Pluto is a planet because it is larger than any of the KBOs and it is spherical in shape.