If you are 16 years old or above now, most probably you have noticed a conflict in our solar system. Since you first entered school and started taking information about planets and stars until 2006, you were told by your tutors that the solar system consists of 9 planets, starting with Mars and ending with Pluto. From 2006 and until now, you have been told that the solar system consists of 8 planets, starting with Mars and ending with Neptune. So, what happened!! What has changed about Pluto?!
The answer is nothing; Pluto is the same planet it used to be eleven years ago, but actually the scientists’ perspective did change.
In 1930, an American astronomer, Clyde Tombaugh, discovered Pluto. From 1930 until 2006, Pluto sat comfortably beyond Neptune as the ninth planet in our solar system. In 2006, the definition of a planet did change.
According to new rules adopted by the International Astronomical Union, a celestial body must meet the following criteria in order to qualify as a planet:
•A planet must be round.
•A planet must orbit the sun.
•A planet must have “cleared the neighborhood" of its orbit. This means that as a planet travels, its gravity sweeps and clears the space around it of other objects. Some of the objects may crash into the planet, others may become moons.
Pluto follows the first two rules: It is round, and it orbits the sun. It does not, however, follow the third rule. It has not yet cleared the neighborhood of its orbit in space. Because it does not follow this rule, Pluto is no longer considered a planet.
Written by Ahmed alaa
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Why Is Not Pluto A Planet Anymore?!
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