The decrease in size hasn’t been constant, though. Back in the 1920s, the storm actually grew for a short period of time before continuing to shrink again. “There is evidence in the archived observations that the Great Red Spot has grown and shrunk over time,” said Reta Beebe, an emeritus professor at New Mexico State University in Las Cruces and co-author of the paper. “However, the storm is quite small now, and it’s been a long time since it last grew.”
The strange storm travels westward, opposite Jupiter’s eastward rotation. It was previously believed to move at a constant rate; however, the study found that it’s traveling through Jupiter’s atmosphere faster now than in the past. Researchers also discovered, surprisingly, that no change in internal wind speed has occurred over time. Since the storm is becoming more compact, they expected the winds to become stronger, but found that the wind is traveling at the same speed that it was before. Rather than gusting more fiercely at its base, the storm is instead growing taller.
Another noteworthy development is that the Great Red Spot isn’t so red anymore — it’s actually been turning a deep orange since 2014. The researchers think that the increasingly tall storm could be carrying the chemicals responsible for its color higher into Jupiter’s atmosphere, increasing their exposure to UV radiation and causing their color to change. However, further research is needed to corroborate this theory.
Although the increase in height is pretty small compared to its steady decrease in length, and its change in color isn’t
too drastic, the study gives decent clues as to what the storm’s next move might be. For now, though, all we can do is sit back and enjoy the powerful storm while it lasts, because
with a history of unexpected behavior and disproven predictions, the Great Red Spot’s ultimate fate still remains a mystery.
“If the trends we see in the Great Red Spot continue, the next five to 10 years could be very interesting from a dynamical point of view,” said co-author Rick Cosentino of NASA’s Goddard Space Flight Center. “We could see rapid changes in the storm’s physical appearance and behavior, and maybe the Red Spot will end up being not so great after all.”