Saturn

saturn_cassini.jpg (17043 bytes) saturn-shani.jpg (20162 bytes)

(to left, from NASA, Cassini Project; above, Shani, the planet Saturn, from from The Black Peacock, http://www.goloka.com/index.html))
gianplan.jpg (148474 bytes) Saturn, another giant planet, is very similar to Jupiter in many respects:
  • Its composition is mainly H and He
  • If rotates very rapidly, in 10 and half hours
  • It is large, with very low density
  • Its atmosphere has colored bands, high winds, violent storms
  • It has an internal energy source (but why is it so strong; Saturn being smaller than Jupiter should have cooled off more) 

Saturn differs from Jupiter in ways which reflect either its lower temperature or smaller size:

  • Atmospheric bands have weaker coloring due to lower temperatures
  • Weaker magnetic field due to a smaller proportion of metallic hydrogen in its interior
Saturn's cloud deck Artist's concept of flying through Saturn's clouds
Limb of Saturn (left) and artist's impression of the view over Saturn's cloud tops (right; Don Dixon)

Uranus and Neptune

Uranus

Neptune
Uranus Neptune
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But the two planets are not completely identical:

Bands show Uranus' axial tilt  
  • As shown by the bands in its atmosphere, Uranus has a curious tilt of its rotational axis (nearly in the plane of its orbit; a pole will be sun lit for 42 years at a time!).

Nonetheless, the surface temperature is uniform implying that winds stir the atmosphere.