Scientists are arguing that denying Pluto planetary status is invalid and erroneous. A team led by Philip Metzger, a planetary scientist at the University of Central Florida (UCF) in Orlando, is indicating that the basis on which Pluto was rejected as a planet does not have any support in the research literature.
When Pluto was discovered in 1930, it was the ninth planet in the solar system based on an overestimation of its size. However, Pluto seemed to look out of place among the other larger planets after the discovery of swarms of ice dwarfs – icy rocks in the Kuiper Belt, at the very edge of the solar system billions of miles from the sun. Due to this, some astronomers suggested that Pluto could be just another Kuiper Belt Object (KBO) and not a planet.
In 2006, the International Astronomical Union (IAU) laid out some guidelines for a celestial body to be called a planet. The IAU said that there were three conditions that must be fulfilled for a celestial body to be termed as a planet: 1) it must be round; 2) it must orbit the sun, and 3) it must have “cleared the neighborhood” of its orbit.
According to the IAU’s definition, Pluto does not meet the criteria, as Neptune’s gravity influences it, and Pluto shares its orbit with frozen gases and objects in the Kuiper belt.
Pluto downgraded to “dwarf planet”:
After several years of intense debate, astronomers finally reached a consensus in August 2006. They decided to demote Pluto in an extreme redefinition of planethood that seemed to favor scientific reasoning over historic and cultural influences. The decision meant that Pluto will not be a planet anymore.
Pluto stood apart from the other discovered planets. Not only because of its small size, but because its elongated orbit was tilted with respect to other planets, and it goes insider Neptune’s orbit as part of its 248-year journey around the sun.
Pluto has five known moons, the largest of which is Charon. Charon is about half the size of Pluto itself, making it the largest satellite relative to the planet it orbits in our solar system.
Pluto orbits the Sun about 3.6 billion miles (5.8 billion km) away on average.
A year on Pluto is 248 Earth years. A day on Pluto lasts 153 hours or about 6 Earth days.
Pluto has a thin atmosphere of nitrogen, methane and carbon monoxide. The atmosphere has a blue tint and distinct layers of haze.