UNIVERSE
COMETS
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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Be in orbit around the Sun
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Be massive enough to assume a nearly round shape
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Clear the neighborhood around its orbit
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Be massive enough that its gravity keeps it spherical
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none of these
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Detailed explanation-1: -It states that a planet is a celestial body that (a) is in orbit around one or more stars or stellar remnants, (b) has sufficient mass to clear the neighborhood around its orbit and (c) has a mass below 13 Jupiter masses.
Detailed explanation-2: -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. Essentially Pluto meets all the criteria except one-it “has not cleared its neighboring region of other objects.”
Detailed explanation-3: -Dwarf planets orbit the Sun, and unlike smaller objects such as asteroids, they also have enough mass to form a sphere; however they don’t have the gravity needed to clear their orbits of other objects and debris.
Detailed explanation-4: -Because they are smaller, dwarf planets lack the gravitational forces needed to pull in and accumulate all of the material found in their orbits.