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September 19, 2003


'tis nearing a sad day. I've tracked Galileo since '95, my freshmen year in college, check out the JPL Galileo site for some pretty pictures....

Also, Cassini is almost at Saturn.

Posted by razib at 01:13 PM

Very cool site. I always loved the idea of going to Jupiter (yeah I'm an old 2001 fan.)
Question: there is an image on the site, an overhead view of Earth and Jupiter. It shows a kind of halo around the Sun extending out beyond the Earth's orbit but probably not as far as Mars. Is that a real phenomenon and if so what is it?


Posted by: John Purdy at September 19, 2003 02:16 PM

weird-shouldn't anything that's emitted by the sun follow the inverse square law? gamma rays? ions?

Posted by: razib at September 19, 2003 06:35 PM

That image is a computer-generated simulation; I think the circumsolar glow is an artifact of the artist's imagination, because it closely corresponds to nothing I'm aware of.

It's possible that it was intended to be dust in the inner system (visible on dark nights as the Zodiacal Light (good photo is here) -- that dust is mostly in the ecliptic plane, probably most dense near the Sun and extending well past Mar's orbit. But the dust is also thin enough that it isn't easily visible off-plane: we only see the Zodiacal Light because we're looking through the plane and thus seeing much more dust thickness than would be visible from the perpendicular.

The only other think I can think of is that the artist was intending to show the inverse-square intensity of solar illumination (as hinted at by razib), and got too literal in his interpretation -- the eye's response is far from linear.

Whatever it is, I think it's wrong...

Posted by: Troy at September 21, 2003 11:41 PM