Why Pluto is No Longer a Planet and What it Means to You?

Story Highlights
  • The Discovery of the Solar System
  • The Definition of a Planet
  • The Test of Time
  • The Outrage

Anyone born before 2005 will remember studying about nine planets in a milky way. This changed, however, in 2006 when the farthest one from the sun—the icy dwarf, Pluto—lost its planetary status, leading to our current eight-planet solar system. Pluto’s story is fascinating and involves a fair bit of twists and turns, so it would be best to start from the beginning.

The Discovery of the Solar System

Humanity’s obsession with space began with Galileo, who used his telescope to look out into space and was responsible for many discoveries. In those times, it was thought that everything that orbited the sun was a planet. Further down the line, a small body, about half the radius of the Earth’s moon, was found between Jupiter and Mars in 1801 and was named Ceres. The following year another was found, and this number increased to hundreds in the subsequent years. Thus, asteroids and the asteroid belt were discovered.

The Definition of a Planet

Asteroids were quickly removed from the list of planets, limiting this to mainly large spherical objects with their satellites. Finally, in 1930, Pluto was discovered, and it fit the description of a planet. It was large, spherical, and had a moon. But as visible space continued to expand, it was realized that planets needed a new definition.

Scientists finally settled on bodies that orbited the sun, were spherical, and “cleared their neighborhood”; more on this in a while.

The Test of Time

As the years passed, scientists realized Pluto was smaller than they had initially calculated. The new scale would continue to shrink over the years until, by 2006, it was found to be smaller than the moon and 1/459th the size of the Earth. Now, for its moon. It is half of Pluto’s

size, which happens to be enough mass to disturb Pluto’s orbit, and instead of having Pluto act as an anchor, they both share a mutual axis to revolve around.

Along with this, other large spherical bodies continued to be discovered, many of which were close to Pluto. So, considering these discoveries, Pluto did not strictly orbit the sun. Also, considering the other similar objects around Pluto, many of which successfully disturbed it, it failed to clear its neighborhood. And thus, in 2006, Pluto was finally stripped of its planetary status, and the Milky way was left with eight planets in total.

The Outrage

Surprisingly, many people campaigned to have this status reinstated as it was an “injustice” to the dwarf. Many joined this protest as a joke, some very seriously. Some even argued that Pluto is more like Earth than Jupiter (a gas giant). But it could not be denied that Pluto was no longer fit to stand among the mighty planets.

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