We all know that our solar system is consist of nine planets but this changed recently. When in year 2006 International Astronomical Union (IAU) observed some irregularities and downgraded Pluto to a dwarf planet. So now we have eight planets in total instead of nine. Question is that why this happened?
Let’s first understand characteristics of any space object to become a planet.
Three Characteristics to become a planet:
So there are three basic characteristics defined by International Astronomical Union to declare some space object as a planet, which are:
– It must orbit any star.
– It must have sufficient mass to assume a hydro static equilibrium (almost a round shape)
– Object must not have any neighborhood around its orbit.
Pluto is a Dwarf Planet:
Pluto meets just first two characteristics and doesn’t meet the third requirement to become a planet. To become a planet it is essential that you clean up your orbit from all other space objects of similar size. It is okay to have your own satellites under your gravitational pull. In all these years it didn’t cleared its path from all other objects. So that’s why it is demoted to a “Dwarf Planet”. It lies in the Kuiper belt of solar system. Other than Pluto there are bit of rocks and ice, comets and dwarf planets in Kuiper belt. Few main objects of Kuiper belts are Eris, Makemake and Haumea. They are dwarf planets just like Pluto.
It is orbited by 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. Both are often referred to as a “double planet.”
Pluto is named after the Roman god of the underworld.
Read more about Pluto at NASA Website
Now you know some cool facts about dwarf planet and you can tell your friends that why Pluto is no longer a planet anymore. Thank you for reading.
Read here if you’re curious about Comet Neowise
Happy Star Gazing!