How many Planets are Oblate Spheroids??

Question

I know that Saturn and Earth are oblate spheroids; but what about the other 5 planets? Are they Prolate spheroids, spheres, or oblate spheroids and what are they?

Answer 1

Jupiter is oblate, as are the other gas giants.  The oblate shape of the earth and these other planets is due to the bulging of their equatorial diameter compared to their polar diameter because of their rotational velocity.  Planets with little or no spin (Mercury, Venus for example) would not have noticable oblateness, Earth is oblate by 1/297, and I suspect Jupiter would be most oblate given its fast rotational speed (1 rotation every 10 hours or so).

Answer 2

All

Answer 3

They are all oblate spheroids to varying degrees.  The gas giants are the most oblate, being gaseous and having high rotational speeds. (Jupiter, Saturn, Uranus, and Neptune.)  This slight bulge is caused by the centrifugal force of the rotation.  Since Venus and Mercury have such slow rotational periods, they would not demonstrate any significant oblateness, but there is probably some tiny bit.  

None of them are prolate.  That would be contrary to the physics.