NASA’s Cassini spacecraft recently captured new images of Saturn’s moon, Titan. After review, NASA discovered that Titan’s atmosphere is actually filled with mysterious clouds. It isn’t the existence of the clouds that’s so mind-boggling but, rather, that the clouds are sometimes visible in one image but not in another. This, friends, is the case of Titan ghost clouds. Cue the Scooby Doo music, please.
NASA said the pictures were snapped around the same time and in the same conditions, so those two variables don’t quite explain why there’s a discrepancy in the photos. It has an idea of what’s going on, but since NASA can it explain it better than I can, here’s what’s what:
The answer to what could be causing the discrepancy appears to lie with Titan’s hazy atmosphere, which is much easier to see through at the longer infrared wavelengths that VIMS is sensitive to (up to 5 microns) than at the shorter, near-infrared wavelength used by ISS to image Titan’s surface and lower atmosphere (0.94 microns). High, thin cirrus clouds that are optically thicker than the atmospheric haze at longer wavelengths, but optically thinner than the haze at the shorter wavelength of the ISS observations, could be detected by VIMS and simultaneously lost in the haze to ISS — similar to trying to see a thin cloud layer on a hazy day on Earth. This phenomenon has not been seen again since July 2016, but Cassini has several more opportunities to observe Titan over the last months of the mission in 2017, and scientists will be watching to see if and how the weather changes.
Titan has ghost clouds
In other words, one camera was able to capture the images because it was using different wavelengths than another one. At least that’s how I understand it. I’m sticking to my ghost cloud theory, though. Check out the image above and hit the source link for a deeper dive into the mystery clouds.