Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

How the planets get their spherical shape

  1. Jun 13, 2013 #1
    how the planets get in spherical shape if the they are formed by a big explosion ?
  2. jcsd
  3. Jun 13, 2013 #2


    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Spheres of matter are the most stable shapes when pitted against the relentless force of gravity.

    - Warren
  4. Jun 13, 2013 #3


    User Avatar
    Science Advisor
    Gold Member
    2017 Award

    and they werent formed by a big explosion :)

    google accretion disk and solar system formation

  5. Aug 24, 2013 #4
    Planets get a spherical shape from gravity. Once a protoplanet (Baby Planet) reaches a certain radius, gravity crushes it into a spherical shape.
  6. Feb 23, 2014 #5
    The key concept you're looking for is hydrostatic equilibrium. If a celestial body is massive enough, its gravity will cause it to assume the optimal shape which balances gravity and pressure. This is a spheroid.
  7. Feb 23, 2014 #6


    User Avatar
    Staff Emeritus
    Science Advisor
    Homework Helper

  8. Feb 24, 2014 #7
    If I remember correctly, there was an experiment with particles in the space station (wasn't it salt?) and the particles formed together in a spheroid shape.

    It is natural.
  9. Feb 24, 2014 #8


    User Avatar
    Gold Member

    I thought that planets needed an explosion (shockwave) to be formed out of nebulae... for example an explosion would allow a condensate (not like the boson ones) to be formed -as an origin of initial gravitational attraction- and thus the whole gas around would start "falling" into that and form the planet.
    Due to the geometry of a sphere, it's the most favorable (energetically) shape to be formed... of course it's not a perfect sphere (for example the spin makes it more like an oval).
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook