Photo by NASA Hubble Space Telescope on Unsplash
Do you ever think about the Great Red Spot of Jupiter? About exactly what that storm represents?
It’s Geeking Cool!
Our brains are pretty hard-wired that planetary surface stay the same. It’s a planet right? Sure Jupiter is a gas giant and we take lots of pictures of the swirling gases, but that Great Red Spot reassures our instinctive assumption that planets are still fixed even when gaseous.
Except, no, it isn’t the case.
“The first record of the Great Red Spot is a drawing made in 1831 by German amateur astronomer Samuel Heinrich Schwabe of the “Hollow” in which the spot sits.” (Britannica) And the spot has been continuously observed ever since 1878.
There was a storm recorded in 1665 by Italian astronomer Gian Domoenico Cassini, of which records stopped in 1713. Some scientist think it may have been the Great Red Spot, but more likely the “Permanent Spot” storm subsided and a new storm arose a hundred and sixty years later. Further supporting evidence of a new storm is the Great Red Spot is in the Southern Hemisphere and the drawn records of the Permanent Spot seem to place the phenomenon in the Northern Hemisphere.
Whether long-lived storms flowed over Jupiter’s surface before 1665 can only be speculation. Use of concave lenses to study the sky is recorded in the very early 1600 in Western Europe and spread to China within a decade. (Wikipedia: History, Wikipedia: Chinese) These solidified into telescopes by mid-1600s. Scientists long journaled and drew about the dance in the heavens, but telescopes took the images possible to a whole new level. Before then, while Jupiter is visible to the naked eye, details would not have been able to be picked out.
Having been visible 194 years at this point (oh, do you think we can have a 200-year anniversary in 2031?), the storm has started to shrink, presently a third of its largest size. A “mere” 16,000 kilometers long (still larger than Earth), down from 48,000 kilometers. (Ashford) Scientists are not sure if the storm is winding down, or just changing its shape.
On Earth, when large storms reduce in size over the ocean feeding them energy, the eye of the storm solidifies into hurricanes, the winds increase, and the damage once it makes landfall kicks up the ranking on the Saffir-Simpson hurricane wind scale. On land, hurricanes are cut off from their energy and disperse – growing wider, weaker, until they fall apart.
The Great Red Spot is clearly the eye of a storm, a nearly 200-year-old hurricane the size of the Earth. But modeling it off of Earth weather gets weird because the planet’s atmosphere runs on liquid ammonia not liquid water, and doesn’t have solid ground reducing the power of storms. The mechanism of shrinking storms getting faster winds hasn’t proved to be the case based on data being gathered from satellites in Jupiter’s orbit. Instead, the Spot is deepening, like a swirling funnel cloud forming in green clouds, then lowering down through the atmosphere until it hits the ground as it gets smaller and faster. Jupiter has no ground; how far down can the Great Red Spot go?
Okay, I need a second to recover from the image of a tornado the size of Earth dropping a funnel cloud through layer after layer of Jupiter’s atmosphere. Don’t ask me why an Earth-sized tornado is scarier than an Earth-sized hurricane, but it just is.
I am curious to see if Jupiter’s Forever Storm will dissipate in my lifetime, like a tornado falling apart. If it does fall apart, is Jupiter in “hurricane season” and the atmospheric energy will make a new one or even a chain of new ones? In the meantime, will the deepening of the storm bring new materials from the lower atmospheric levels to the top of Jupiter’s atmosphere for us to study?
The Great Red Spot, so geeking cool.
Bibliography
Ashford, Ade. “Don’t miss Jupiter’s ‘unravelling’ Great Read Spot.” Astronomy Now. 2019 June 6. https://astronomynow.com/2019/06/06/observers-urged-to-monitor-jupiters-unravelling-great-red-spot/ last viewed 6/13/2025.
Britannica. “Great Read Spot.” (undated). https://www.britannica.com/place/Great-Red-Spot last viewed 6/13/2025.
NASA Goddard. “Jupiter’s Great Red Spot Shrinks and Grow.” YouTube. 2018(?). https://www.youtube.com/watch?v=JDi4IdtvDVE&t=126s last viewed 6/13/2025.
Wikipedia. “Chinese astronomy.” (undated). https://en.wikipedia.org/wiki/Chinese_astronomy last viewed 6/13/2025.
Wikipedia. “History of the telescope.” (undated). https://en.wikipedia.org/wiki/History_of_the_telescope last viewed 6/13/20256.