26 thoughts on “Gas Giant pr0n

      1. They are all in visible or near visible, AFAIK. Not part of the scientific mission- you just can't send a spacecraft out there without putting a camera on it for some goodies for the taxpayers. Nice to see (in many ways).

  1. Remember, in these images you are not seeing the surface of Jupiter; the gas giant has none, as such.

    Earlier this year I learned that the arbitrary definition of the "surface" of a gas giant used by astronomers is that layer of gas where the ambient pressure is 1 bar (i.e. the earth standard pressure we all know and love). So now I'm curious which clouds we're seeing are at "shirt sleeve" altitudes.

    1. Wow that’s arbitrary. How about when the gases are the same density as their liquids? The photosphere of the sun is less dense than 1 atm gas, IIRC…

      Edit- just looked it up- the sun’s photosphere has a density of 2×10^-4 kg/cubic meter, or about 1/6000th the density of our atmosphere at sea level

      1. I'm just repeating what the Great Green Book of Everything says the Astronomical Almanac uses for its listed values. Apparently different values are used for different purposes, but it seems a reasonable starting point for things like semidiameters and eclipse timings.

        1. On my astrophysics final we had one question: assume Saturn is 3/4 hydrogen, 1/4 helium by volume, evenly mixed. What is the gravitational potential energy given off as the helium settles to an ever expanding pure helium core?

          1. The gas giants have 1% of the mass of of the solar system, but 99% of its angular momentum. Discuss.

          2. The GPE released will be converted to the increase in angular momentum; L=I(w2-w1) where I = 2/5*m(R2^2-R1^2), R1 is the geometric mean radius of the distributed helium mass before the collapse and R2 is the geometric mean radius of the condensed helium core, w1 is the initial angular momentum and w2 is the angular momentum after the collapse.

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