MIT researchers have unlocked the answer to the question that has been baffling scientists for years. What forms the cyclones observed at the poles of Saturn?
Initially, images beamed back to earth by NASA’s Cassini allowed a closer look at these phenomenons, yet it wasn’t until now that a real answer was prompted after new images triggered a hypothesis.
There are massive, long-lasting cyclones happening at the poles of Saturn? But what could trigger them and what fuels them for such a long time?
Evidence from Earth’s similar events is not helpful in unlocking the key to understanding the polar cyclones as on our planet the moisture blanket of the oceans is a great driving force.
But Saturn’s lack of wide surfaces of water like our oceans could not test the same conditions.
The MIT scientists used Saturn’s planetary model to incur hundreds of computer simulations that recreate the atmospheric conditions of the planet. Atmospheric dynamics, linked with geographical observations and the planet’s spin pooled together to indicate one answer.
The polar cyclones on Saturn are indeed a collection of smaller storms which are pulling Saturn’s atmoshperic gases towards both poles through ‘beta drifting’.
One after another these smaller storms build up a spin in Saturn’s atmosphere and due to beta drifting, they drag the gases and gather up sufficient circulation to push them towards Saturn’s poles.
Here, altogether they create the amazing cyclones which at the northern pole feature a hexagonal edge. The answer as to the hexagonal shape is still not yet clear. Yet, MIT researchers stated that turbulent eddies placed around the central vortex of the cyclone might give it this unique feature.
Nonetheless, the computer simulations based on the planetary model of Saturn was successful in showing what causes these large and long lasting cyclones to occur at the planet’s poles. Beta drifting is a phenomenon also observed with Earth hurricanes. This drives their motion, regardless of the lack or presence of water necessary for their initial spark.
Therefore, two conditions are factored in: the energy of Saturn’s atmosphere and the storms’ sizes relative to that of the planet. With larger storms and larger number of storms driven by the beta drift, the larger polar cyclones are noticed on Saturn, and the more extensive their life-time.
Morgan O’Neill, lead author of the research, former MIT Ph.D. student in the Department of Earth, Atmospheric and Planetary Sciences commented that:
“Before it was observed, we never considered the possibility of a cyclone on a pole. Only recently did Cassini give us this huge wealth of observations that made it possible, and only recently did we have to think about why polar cyclones occur.”
The research conducted on the planetary model of Saturn was replicated for Neptune and Jupiter as well. The results differed according to each planet’s specifics. Neptune for instance was found to feature polar cyclone, but not comparable in life-time with those of Saturn.
Jupiter on the other hand seems to not host these phenomenons at all. Yet, the computer models will be tested once more when Jupiter will be observed from closer thanks to Juno.
The exciting findings of the MIT research team are published in the Nature Geoscience journal.
Image Source: universetoday.com