A false color image of Saturn composed of frames taken in the green, red, and CB2 filters. Taken by Cassini on July 16, 2017, processed by me.
Soooo, while I was playing around with an image of Saturn yesterday (which you can find here), where I experimented with using different frames than I usually would to create a color composite image, I decided to be a bit daring and try the same with another image. I say daring because here, I only had images in the green, red, and CB (Continuum Band) filters, so I knew I was pushing it. It’s certainly not the best image I’ve processed (ahem, oh and ahem! And there’s more!), but there’s a reason I decided I had to process this image. If you take yet another look at the image above, two things should pop out at you: first, Saturn’s atmosphere is clearly visible near its limb; second, its atmosphere is causing its rings to look like they bend slightly upward! This isn’t the first time we’ve seen this. In fact, you probably remember seeing an image of Saturn with its rings appearing warped (far more than the above image) last year. But, let’s be honest: does seeing physics in action ever get old, especially when it happens on another planet?! OF COURSE NOT.
Atmospheric bending of light causes Saturn’s rings to appear warped in the above image, taken by Cassini on June 9, 2016. Credit: Nasa/JPL-Caltech/SSI
Saturn’s rings are highly reflective because they’re composed of mostly ice, and ice tends to reflect most of the light incident upon it. But Saturn’s rings are also extremely flat, so, why the bend? Well, Saturn has a lot of atmosphere. Its atmosphere does a pretty good job of absorbing a lot of the light reflected off of Saturn’s rings, but, like any atmosphere, or fluid like water, it also acts as a lens, and bends light as it passes through it. So, from the right vantage point, one can observe the awesomeness of Saturn’s atmosphere bending, or refracting, the light that Saturn’s rings of ice particles galore reflect back into space, or in this case, into Cassini’s eye. And that’s why Saturn’s rings look bent in some images, like the ones above. You can read more about Saturn’s rings in a previous blog post here, and about other cool phenomena that happen in Saturn’s rings, like spokes and rainbows (or the opposition effect), here.
Stay tuned for more on Saturn and the Cassini Spacecraft. There’s a lot that’ll be coming from me about everyone’s favorite eye in space, giving us beautiful views of Saturn till the very end*.
*The end for Cassini is sadly very near. The spacecraft will dive into Saturn’s atmosphere on September 15, 2017, becoming one with the planet forever.