The Oxford Science blog turns some recent research into a nifty thought experiment. If you could skydive on Saturn, what would you see?
… the first question when imagining a Saturn skydive is: where do you start?
Like the Earth, Saturn's upper atmosphere – its stratosphere – is relatively stable. This stratosphere extends way above the troposphere and the visible cloud deck, radiating energy generated within the planet out into space. But whilst Earth's stratosphere starts around 10km above the surface of our planet (a few kilometres above the clouds) on Saturn the stratosphere extends hundreds of kilometres above the clouds.
Saturn's stratosphere should be a 'weather-free' zone, relatively unaffected by the turmoil of storm clouds churning deep below, 'but this turns out to be completely wrong' Leigh explains. Instead, the new observations spotted 'beacons' in the stratosphere that, at 15-20 degrees Kelvin hotter than their surroundings (120-140 Kelvin), stand out like the beacons of a lighthouse. In fact, the spectacular effects of Saturn's giant storm were being felt in the stratosphere almost 300km above the visible clouds, 'that's almost as far as the International Space Station orbits above the surface of the Earth' Leigh adds.
These beacons are thought to be created when 'air' (87% hydrogen, 12% helium, 1% other trace gases) wells up and then descends; becoming compressed and heating up like the air in a bicycle pump. It's the emission from the other 1%, gases such as methane, ethane, and acetylene, which makes the beacons visible.
Our skydiver would have to plummet some 300kms from the stratospheric beacons to reach the troposphere where convection rules and energy is turned into powerful air currents.
Via Phil Plait
Image: Saturn and Earth, a Creative Commons
Attribution (2.0) image from lunarandplanetaryinstitute's
photostream
