Over the last few days, the amateur astronomer community has been buzzing with news: the Great Red Spot, Jupiter’s humungous storm, appears to be unraveling.
Sky observers worldwide have reported a long stream of gas stretching from the Great Red Spot. Infrared observations taken by Clyde Foster from Centurion, South Africa, that focus on the planet's methane emissions reveal a hook-like structure of gas. The structure, extending from the western lobe, appears to be roughly the same size as the Great Red Spot, which is 16,350 kilometers (10,160 miles) in width.
Astronomers (professional and non-professional) have been observing the gas giant in many different wavelengths. This allows them to see various elements and structures within the clouds. While the methane observations show the extended hook, photos at different wavelengths don't show the same structure. This suggests movements within the turbulent Jovian atmosphere affect its features in different ways.
We have known for a few years that the Great Red Spot is a complex and chaotic system. It is the largest anti-cyclonic storm in the Solar System and could comfortably fit our planet inside it. The storm has swirling structures within and waves that extend from the eastern side. Observations in 2017 from the Gemini Observatories spotted a much smaller hook-like structure stretching out west from the Spot.
Given the location, what we see today could be the continuation of what we saw in 2017 or have the same origins. We looked online for methane observations of the Great Red Spot in 2018, but we couldn’t find one that clearly showed whether or not the 2017 hook was still there.
Clarifying observations might come from NASA’s Juno spacecraft currently orbiting Jupiter, whose primary mission is to study the planet's clouds and upper atmosphere. The space probe is in an elongated orbit around the gas giant, which takes it close to the planet every 52 days. The next perijove is in a week (May 29) and may be in the right position to study these changes.
The Great Red Spot has existed for up to 350 years and is actively shrinking and changing. It is now less than half the width it used to be a century ago.