Smaller storms may be feeding Jupiter's Great Red Spot
Jupiter’s Great Red Spot may be stealing energy away from the smaller storms that careen into it on a regular basis, according to the results of a new study. While on the surface these dramatic interactions seem to be damaging the iconic atmospheric feature, they may actually be keeping it stable, and increasing its lifespan in the process.
The Great Red Spot (GRS) is, without question, one of the most awe-inspiring sights of our solar system. It is roughly twice the size of Earth, and astronomers know from telescopic observations that it has raged continuously for at least 150 years, though it has probably been around much longer than that.
It is in its most basic form a vast anticyclone spinning around a high atmospheric pressure center. It extends roughly 200 km (125 miles) below the cloud surface, and has peripheral winds on the outer edge of the storm that travel at an unearthly 540 km/h (335 mph).
In short, its a monster.
But despite its seemingly immutable stature, the GRS will not last forever. In 1879 the storm was estimated to be around 40,000 km (24,850 miles) in length. However, present day estimates place the size of the GRS at roughly 15,000 km (9,320 miles) from end to end.
Part of this apparent reduction in size may be down to its interactions with the many smaller storms that roam the cloud sea of Jupiter. Since 2019 dozens of storms have slammed into the GRS, apparently further threatening its survival, with the collisions often resulting in large ribbons of reddish cloud being shredded away from the great vortex.
However, according to a newly published study, these dramatic interactions may actually be helping to ensure the long term survival of the iconic storm. The authors of the paper drew on images captured by the Hubble Space Telescope, the Juno spacecraft (which is currently orbiting Jupiter), and a host of images captured by amateur astronomers.
An analysis of the images, and numerical simulations run by the team, revealed that the smaller storms first passed through the fast moving outer perimeter of the larger vortex before going on to circle around the vast structure.
According to the authors of the study, the physical damage observed wherein material is shredded away from the GRS is likely only surface deep, and is not heavily affecting the deeper structure of the storm.
However, the interactions did have other observable effects. For one the collisions led to a transient shift in the atmospheric feature’s usually steady 90-day longitudinal oscillation pattern.
Furthermore, it was observed that there was a transfer of energy between the larger and smaller storms. This resulted in the GRS’s internal rotation velocity increasing at the expense of the smaller vortexes. This increase in rotational energy could make the storm more stable, which in turn would help ensure the long-term survival of the great storm, which remains to this day one of the greatest mysteries of our solar system.
A paper on the research has been published in the Journal of Geophysical Research: Planets.
Source: American Geophysical Union