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Sun's tidal force on earth

  1. Mar 30, 2014 #1
    Hello,
    My question is regarding effect of sun's gravity on earth. I want to know that if sun's gravity can change earth's landscape in long duration (i.e. billion of years ) or not?? Means if earth is dead planet and all other planets are not present in the solar system and earth is as near as sun as mercury currently orbiting. And also suppose earth's surface is not smooth (because of hitting with other small bodies at regular interval) then can earth's surface can be smooth in long duration by gravity of sun or not??
     
  2. jcsd
  3. Mar 30, 2014 #2

    Nugatory

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    Staff: Mentor

    Google for "tidal lock", see what you find. That's by far the most prominent tidal effect in planetary motion. Earth has tidal-locked the moon and in principle the sun could tidal lock the earth if we were to wait long enough.

    Two exercises you might find worthwhile:
    1) estimate how long "long enough" in the previous sentence is.
    2) consider a lump of rock one kilometer across, sitting on the surface of the earth (that's sometimes called a "mountain":smile:). Roughly, what is the magnitude of the earth's gravitational force on it? How does it compare with the the tidal forces from the sun?
     
  4. Mar 30, 2014 #3

    russ_watters

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    Bit of a mismatch of separate thoughts here:
    Beyond the tides, no -- all of the Earth is in orbit, so it is all in freefall around the sun, feeling no force.
    Not sure if I follow - what do you mean by that? If earth were where Mercury is, it would be hot.
    Earth is smoother than a bowling ball. Generally, the more gravity, the better it can pull itself back into a spheroid.
     
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