You all probably know the famous The day the Earth Smiled image. For the life of me I can't understand what's going on with the rings there. Seems like the "bottom" half of the rings is the half that goes "behind" Saturn (relative to the camera), but then what's going on with the distortion of the rings on the upper half when they (presumably) cross in front of Saturn? I can't make sense of of this image.

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Higher resolution and annotated versions available

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    $\begingroup$ Upvote because I didn't even know this amazing picture. Thanks for sharing. $\endgroup$
    – Nico
    Dec 31, 2015 at 8:09

2 Answers 2


What's going on with the distortion of the rings on the upper half when they (presumably) cross in front of Saturn?

The brownish areas you see on Saturn are ring light, analogous to seeing the Earth by moonlight. Saturn's rings light up Saturn's night sky, particularly just after sunrise and just before sunset. The two dark bands across the face of Saturn are the A ring (upper dark band) and B ring (lower dark band). Of all of Saturn's rings, these two are the most opaque. The parts of Saturn underneath those two dark bands are brilliantly lit by ring light, but Cassini can't see those parts of Saturn because the opaque A and B rings block that light.

For a much better and more thorough explanation of all of the features in this incredible image, I suggestion you spend eleven minutes watching this youTube video by Emily Lakdawalla.

This is one of the very few times I will post a link to a youTube video. It is worth every eleven minutes.

  • $\begingroup$ A great analogy for ring light by moonlight; gotta remember it for the next time I'm explaining the phenomenon to somebody. $\endgroup$
    – V-J
    Jan 2, 2016 at 14:17

Saturn's ring

As you can see, Saturn is eclipsing the sun in this image. This eclipsing causes the white outlining of the planet in this photo. The bottom ring is indeed passing on the other side of Saturn which would explain why it is not visible in this image. However, the ring passing in front of Saturn is being cast in the shadow of the planet. The light cast on the planet, which could be the cause of this "distortion" is the light reflected from the Rings of Saturn. Since the Sun is being eclipsed, the ring passing in front is not receiving the light from the Sun causing it to look like a black shadow band across the planet.

  • $\begingroup$ The part of Saturn that is illuminated by the Sun is not visible in this image. $\endgroup$ Dec 31, 2015 at 17:33
  • $\begingroup$ The Rings are being illuminated by the light that is slipping around the planet. I'll try to be more descriptive in my answer. $\endgroup$
    – TechSam
    Jan 1, 2016 at 1:12
  • $\begingroup$ This answer is still wrong. You need to be able to explain why Saturn is not pure black. The parts of Saturn that are not black is not "light slipping around the planet". The "light that is slipping around the planet" -- that's the very bright white ring around Saturn. $\endgroup$ Jan 1, 2016 at 4:11
  • $\begingroup$ I understand what you are getting at. The light shown on Saturn is the reflection of the Rings. Is that what you are saying? $\endgroup$
    – TechSam
    Jan 1, 2016 at 4:23

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