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Is it true that gravitation on the full moon day is less than other days?

  1. May 10, 2010 #1
    On the full moon day the moon is closer to earth so the gravitation of the moon make the gravitation of the earth on us less strong.
    Is it true ?
    Thanks !
     
  2. jcsd
  3. May 10, 2010 #2

    Cyosis

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    Since the force of gravity is inversely proportional to the radius squared the gravitational attraction of the moon on you will be larger when the moon is close. This difference is very small. If the moon would be directly overhead at both apogee and perigee the difference in gravitational acceleration would be of the order 10^-5 m/s^2.
     
  4. May 10, 2010 #3

    HallsofIvy

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    That depends upon what you mean by "gravitation". The gravitational pull of the earth is the same wherever the moon is. If the moon is directly above you then the actual force pulling down on you, due to both moon and earth, would slightly less since the moon's pull very slightly offsets the eath's.

    But that has nothing to do with there being a full moon. The full moon occurs when the moon is on the opposite side of the earth from the sun and you can have a full moon with the "sun, center of earth" line and "center of earth, moon" lines are not on the same line and neither goes through you.
     
  5. May 10, 2010 #4
    But then what is the energy on the full moons ?
     
  6. May 10, 2010 #5

    Janus

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    The only practical difference between a full moon and any other is that a full moon reflects the most sunlight, which makes it easier to see at night without artificial lighting.
     
  7. May 10, 2010 #6
    Ok. But i know that moon phases have an influence on tides. Which is that ?
     
  8. May 10, 2010 #7
  9. May 10, 2010 #8

    D H

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    During a full moon, and a new moon as well, the tidal influences of the Sun and Moon are aligned. During quarter moons the tides are out of phase and partially cancel.

    The tidal forces are very, very small. Assuming you weigh 150 lb, the tidal forces from the Moon decrease your weight by about 1.7×10-5 lbf when the Moon is directly overhead/underfoot, and increase your weight by about 8×10-6 lbf when the Moon is on the horizon.
     
  10. May 10, 2010 #9
    I'm sure that is an energy that grows and decreases with the moon phases. But i don't know what it is ?
     
  11. May 10, 2010 #10

    Janus

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    Other than the insignificant effect due to tides and the increase in lighting already discussed, there is nothing else.
     
  12. May 10, 2010 #11
    You might be thinking of the loonies becoming more energetic around full moon. You could check this by looking up emergency room statistics.
     
  13. May 10, 2010 #12
  14. May 11, 2010 #13
    Sorry, what are loonies ?
     
  15. May 11, 2010 #14
    When the moon - earth - sun are aligned at the full moon, is the gravitation on earth less ?
     
  16. May 11, 2010 #15

    Borg

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    Last edited by a moderator: Apr 25, 2017
  17. May 11, 2010 #16

    Janus

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    If you mean that someone would weigh less, then it depends. If the local time was around noon or midnight (give or take a couple of hrs), then yes. If it were around sunrise or sunset, then you would weigh more. But as pointed out in an earlier post, this difference would be very,very small; the difference in weight being about the equivalent of a large grain of sand.
    The size of this difference would also depend on what latitude you were at and the time of year.

    Also, this is not restricted to the times of a full moon. You get the same thing on the times of a new moon, when the Sun and moon also align, but this time on the same side of the Earth.

    Your weight also would vary over the course of a day during other phases of the moon, just not by as much.
     
  18. May 11, 2010 #17
    I noticed that around full moon i have a better concentration, and on the descending moon to new moon i have a less concentration. (the same with memory, energy, gain weight ...)
     
  19. May 11, 2010 #18

    D H

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    This is a scientific forum, mreq. You are spouting either new age woo-woo nonsense or old (very old) pseudoscientific nonsense.
     
  20. May 11, 2010 #19
    Where i can find my answers ?
     
    Last edited: May 11, 2010
  21. May 11, 2010 #20

    Cyosis

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    Your sensible questions have been answered multiple times. Your nonsensical questions cannot be answered because an answer does not exist. In post #17 you haven't even asked a question just stated some mumbo jumbo. I wonder are you trying to pull our leg?
     
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