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Earth rotation speed if it was tidal locked to the Sun

  1. Dec 13, 2016 #1
    Dear Forum,

    I am filmmaker from Berlin and despite physics focus back in high school I am really bad at it. I am trying to get my head around some ideas I am working on and would kindly ask you for some tiny calculations. I hope this is OK and maybe even fun for someone here?

    So my questions are:
    The earth spins at a speed of 465,1 m/s (A) at the equator, right?

    How fast would the Earth spin at the equator if it would be tidal locked to the Sun (B)?

    If the negative acceleration from A to B would take 20 years how many m/s slower the Earth would spin in a year?

    Would the negative acceleration be linear or exponential if one passing object would "steal" the rotational energy through its own gravitational force. Like the moon does for example but much heavier of course.

    What mass would such an object need to decelerate the Earth like this if it passes let's say about the distance of the moon?

    I know it is nonsense. But fun to think about it!

    I thank you so much.
  2. jcsd
  3. Dec 13, 2016 #2
    welcome to the forum
  4. Dec 13, 2016 #3
    Thank you hsdrop!
  5. Dec 13, 2016 #4
    are you writing a store based off the questions you asked??
    there is a separate forum for that on the site for writers and stories that they are writing about
  6. Dec 13, 2016 #5
    Yes I do. It it better to post/move there?
  7. Dec 13, 2016 #6
    in most creative writing storeys the writers forum is a bit more open to the "what if's" then the others just because the other deal in absolutes and lateral instead of the creative. throw i an looking up some of the answers to your questions now or at least the ones that i can explain some what easley
  8. Dec 13, 2016 #7
    for your first question
    yes the earth does spin at that speed hears a graph that shows a little more of how fast the earth spins according to where you live on the planet article-2546864-1B07A3AB00000578-149_634x365.jpg
    for your 2 question
    well if the earth was tidal locked to the sun that would mean that only one side of the earth would face the sun at all times so if you take the circumference of the earth and divide it by a year you would get your spin speed that comes out to about 4.57477.....km/h

    as for the other questions that you asked i would need a little help with answering them completely right
  9. Dec 13, 2016 #8


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  10. Dec 13, 2016 #9
    what exactly are you asking for? Are you asking how fast would the equator move if a day took 365 days or how close would the Earth have to be in order to tidally lock in the first place? That can't happen where it is, it's way too far from the sun.
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