Why Did Astronomers Kick Pluto Out Of The Planet Club?
(Photo : Nasa.gov Video/YouTube)
Since we were kids, we have always believed that the Solar System has nine planets: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune and Pluto. It was what it was until 2006, however, when Pluto got kicked out of the planet club, leaving us wondering whatever happened to the poor little thing.
According to BBC, Pluto was discovered as a planet in 1930, with an itsy bitsy size of 1,430 miles (2,302 kilometers) in diameter and a distance of 3.7 billion miles (5.9 billion kilometers) away from the Sun. These measurements make Pluto smaller than the Earth's Moon and located 40 times the Sun and Earth's distance.
Shortly after the launch of NASA's New Horizons mission in 2006, the International Astronomical Union developed new criteria on what makes a planet actually a planet.
Although Pluto does orbit the Sun, has moons, has enough mass to be considered round and is warmer than -220 degrees Celsius (it has a temperature of -233 degrees Celsius, which makes it even warmer than Neptune), Pluto did not pass the cleared orbit criterion because of the small objects scattered around it.
In other words, Pluto did not have the required gravitational force for it to clear the orbits near it.
Pluto was then considered as a dwarf planet, along with other dwarf planets named Eris -- the largest and farthest of all dwarf planets named after the Greek goddess of discord; Ceres -- the smallest dwarf planet also discovered with Eris and Pluto in 2006; Haumea -- the egg-like shaped planet that rotates its axis every 4 hours; and Makemake -- which has no moons and would take 310 Earth years to orbit the Sun.
This does not complete the list of dwarf planets, however, according to astronomer Mike Brown from the California Institute of Technology in Pasadena
"We know of 44 [so far]," Brown told National Geographic News. "We will find hundreds. It's a very huge category."
This means that Pluto is not that lonely after all.