Last year, Saturn's ordinarily serene surface was torn apart by a storm that grew within a month to cover an entire hemisphere with howling winds, enormous "beacons" of infrared light, and even icier cold than usual. Now scientists take us inside that storm for the first time, using satellite images.
The storm affected several layers in Saturn's thick, gas atmosphere, and its clouds whirled around a central core that was intensely cold.
In the top series of images, you can see Saturn's version of lighting: beacons of infrared light glow in the second image (the first image is visible light, where the beacons aren't visible). In the second and fourth images, you can see what the researchers call "churning storm clouds," which swirl around "the central dark/cold vortex." In the third and fifth images, more beacons: in the upper part of the atmosphere, the stratosphere, there are "beacons of infrared emission from ethane and methane." Basically, the sky is exploding. Images via ESO/University of Oxford/L.N. Fletcher/T. Barry.
In the lower series of images, you can see the evolving storm in infrared. At the far left, you can see the pre-storm Saturn. And then you see more of the upper atmosphere infrared beacons moving across the face of the hemisphere. Images via ESO/VLT.
This was such an enormous storm that the entire planet's atmosphere was disrupted, say the scientists, who published an analysis of these images and the storm this week in Science.
Here's how the researchers explain the sequence of events:
On 5 December 2010 a plume of bright cloud material in Saturn's northern springtime hemisphere created an expanding system of white cloud material that was spread east and west by the prevailing winds. Although previous disturbances have been intensively studied in reflected sunlight, their effect on the atmospheric thermal structure, chemistry and circulation patterns has never been measured. Leigh Fletcher and colleagues used satellite and ground-based observations to characterize the storm and its effects on the atmosphere. They report that within a month of the storm's onset, the storm had intensely perturbed the atmosphere's temperature, winds and composition between 20 and 50 degrees N over an entire hemisphere. The storm produced effects that penetrated hundreds of kilometers into Saturn's stratosphere, generated beacons of bright infrared emission, altered atmospheric circulation, modified stratospheric zonal jets and other wind patterns, and generated a new, cold vortex in the middle of the disturbance.
It's the biggest storm we've ever seen on Saturn, and gives us a fascinating glimpse of disaster weather on another planet.
Read the full scientific article via Science.