It can feel like astronomy discoveries all took place decades, if not centuries, ago. Which is why things like “Clyde’s Spot” stand out. Informally named for the South African amateur astronomer who found it, this swirling spot on Jupiter’s surface was first observed by Clyde Foster in 2020.
Because Jupiter is a giant ball of gas, it has a constant blanket of clouds to observe. Just like our atmosphere, convection and air current, upwellings and all other manner of gaseous phenomena change the shape of this cloud layer constantly.
Great Red Storm
Sometimes, though, these phenomena stick around. The Great Red Spot is probably the most famous of Jupiter’s atmospheric anomalies.
The Great Red Spot is a storm in Jupiter's southern hemisphere with crimson-colored clouds that spin counterclockwise at wind speeds that exceed those in any storm on Earth. The Great Red Spot has slowly changed over the years, and is currently about 1.3 times as wide as our planet.
A Juno assist
Clyde’s Spot is a little different and luckily NASA’s Juno spacecraft was around to give us a close look at it. On June 2, 2020, just two days after Foster's initial discovery, Juno provided detailed observations of Clyde's Spot, which scientists determined was a plume of cloud material erupting above the top layers of the Jovian atmosphere just southeast of the Great Red Spot.
These powerful convective outbreaks occasionally occur in this latitude band, known as the South Temperate Belt. The initial plume subsided quickly, and within a few weeks it was seen as a dark spot.
Many features in Jupiter's highly dynamic atmosphere are short lived, but the April 2021 observation from Juno revealed that nearly one year after its discovery, the remnant of Clyde's Spot had not only drifted away from the Great Red Spot but had also developed into a complex structure that scientists call a folded filamentary region.
This region is twice as big in latitude and three times as big in longitude as the original spot, and has the potential to persist for an extended period of time.