GK
SOLAR SYSTEM
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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True, what makes a planet a planet has always been the same
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False, the standards for what makes a planet a planet has changed several times
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Either A or B
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None of the above
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Detailed explanation-1: -Final definition (1) A planet [1] is a celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (c) has cleared the neighbourhood around its orbit.
Detailed explanation-2: -This definition, which applies only to the Solar System (though exoplanets had been addressed in 2003), states that a planet is a body that orbits the Sun, is massive enough for its own gravity to make it round, and has “cleared its neighbourhood” of smaller objects approaching its orbit.
Detailed explanation-3: -The International Astronomical Union (IAU) downgraded the status of Pluto to that of a dwarf planet because it did not meet the three criteria the IAU uses to define a full-sized planet.