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B Significance of a planet's "surface gravity"

  1. Jan 11, 2017 #1
    I was just looking at list of solar system objects and was surprised to see that the surface gravity of Uranus is only 90% that of Earth's. I get it that the "surface" of a gas planet is further from that planet's core than is the case for Earth.
    But does surface gravity really have any effect on a planet's overall gravitational force toward other objects? For example, would Uranus still have a considerably greater tug on an asteroid passing 100,000 miles away from it than the Earth would have on an asteroid passing by Earth at the same distance?
    Last edited: Jan 11, 2017
  2. jcsd
  3. Jan 11, 2017 #2


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    At equal distances, Uranus would have a greater pull on the object. The reason that Uranus has a lesser surface gravity is because it is much less dense than the Earth (about 24% that of the Earth's). This increases the distance the surface has from the center even more than what it would have been if the densities had been equal.
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