Results 1 to 6 of 6

Thread: Friction in Space

  1. #1
    Join Date
    Jul 2020
    Posts
    6

    Friction in Space

    By the way, a curious observation concerning friction.

    Have you noticed the spin velocities of Jupiter and Saturn equal their orbital velocities?

    As an analogy, the spin velocity of your tire equals the linear velocity of your car -- the cause being friction between the pavement and tire.

    Do you think this is a coincidence?

  2. #2
    Join Date
    Apr 2007
    Location
    Nowhere (middle)
    Posts
    39,415
    Considering most other planets have radically non-matching spins to their orbits, yes, I'm willing to call it coincidence.
    "I'm planning to live forever. So far, that's working perfectly." Steven Wright

  3. #3
    Join Date
    Feb 2003
    Location
    Depew, NY
    Posts
    12,611
    Quote Originally Posted by marksthespot View Post
    By the way, a curious observation concerning friction.

    Have you noticed the spin velocities of Jupiter and Saturn equal their orbital velocities?

    As an analogy, the spin velocity of your tire equals the linear velocity of your car -- the cause being friction between the pavement and tire.

    Do you think this is a coincidence?
    I've noticed that they are not equal. For Saturn, it has an average orbital speed of 9.68 km/s and rotational velocity of 9.87 km/s. For Jupiter, it's an average of 13.07 km/s and 12.6 km/s. One number is an average speed and the other is a velocity. Speed is distance over time while velocity is displacement over time.

    What about Venus and Uranus?
    Solfe

  4. #4
    Join Date
    Jul 2020
    Posts
    6
    1) If this mechanism were possible, I would not expect it to be exact
    2) A coefficient of frictions goes from 0 to 1

  5. #5
    Join Date
    Jul 2005
    Posts
    20,743
    Orbital speeds are not constant, but vary throughout the planet's year, so at best the rotation speed matches the orbital speed twice a planetary year. And the rotation axes are inclined to the orbital plane--so the planet would be skidding rather than rolling in its revolution around the sun.

    Grant Hutchison

  6. #6
    Join Date
    Jul 2006
    Location
    Peters Creek, Alaska
    Posts
    13,887
    marksthespot,

    It almost sounds like you're making a claim and arguing against the answers. That's not what we do here. The Space/Astronomy Questions and Answers forum is where people get mainstream answers to their questions. One may not argue against those answers on an against-the-mainstream basis. Please read our rules, linked in my signature line below.
    Forum Rules►  ◄FAQ►  ◄ATM Forum Advice►  ◄Conspiracy Advice
    Click http://cosmoquest.org/forum/images/buttons/report-40b.png to report a post (even this one) to the moderation team.


    Man is a tool-using animal. Nowhere do you find him without tools; without tools he is nothing, with tools he is all. Thomas Carlyle (1795-1881)

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •