Generations of students were taught: “Pluto is the ninth planet of the solar system.” This was believed for 76 years. In 2006, out of the blue, the International Astronomical Union (IAU) threw Pluto out of the solar system without warning. The astronomers said that it was a dwarf planet – not large enough to matter. Unfortunately, Pluto is small. It has a radius close to 750 miles — about one-fifth the size of Earth’s. August 24 is the day Pluto suffered demotion and so that day is remembered as Pluto Demoted Day.
Scientists discovered 4 other planetary bodies, larger than Pluto, revolving around the sun. If Pluto remained a planet, we would have 13 in our solar system. Ah, 13 is unlucky! Plus, having 13 planets is too much of a change for the scientists (and their calculations), so Pluto was put on the bench. We have 8 planets now.
August 24 is the day Pluto suffered demotion and so that day is remembered as Pluto Demoted Day.
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