The Great Red Spot: a storm of uncertain age
The Great Red Spot is a huge anticyclonic vortex in Jupiter’s atmosphere. Its modern appearance is reliably tracked at least since the nineteenth century, and it has been shrinking. Current measurements show it is only slightly wider than Earth’s diameter.
Illustration is AI-generated and conceptual, not a telescope image.
In the seventeenth century, astronomers described another long-lived dark spot. An analysis of historical records published in 2024 suggests that the “Permanent Spot” observed from 1665 to 1713 was probably not the same vortex as today’s Great Red Spot. Its exact age and time of formation therefore remain unknown.