If there is a famous image for Jupiter, it’s for sure the one of its Great Read Spot, which is a giant, spinning, fast travelling storm in Jupiter’s atmosphere – a sort of huge hurricane, about twice the size of Earth and whose winds reach speeds of about 270 miles per hour. The interesting part is that the storm has been changing (and shrinking) for the last thirty years, like the imagery over time has shown. More surprises have been awaiting scientists in these last days, when NASA’s scientists have used Hubble Space Telescope to produce updated maps of Jupiter.
“Every time we look at Jupiter, we get tantalising hints that something really exciting is going on. (…) This time is no exception.” (Amy Simon, NASA).
NASA’s report explains with more details what is special about these new images just collected, and namely that they have confirmed that “the Great Red Spot continues to shrink and become more circular, as it has been doing for years. The long axis of this characteristic storm is about 150 miles (240 kilometers) shorter now than it was in 2014. Recently, the storm had been shrinking at a faster-than-usual rate, but the latest change is consistent with the long-term trend. The Great Red Spot remains more orange than red these days, and its core, which typically has more intense color, is less distinct than it used to be. An unusual wispy filament is seen, spanning almost the entire width of the vortex. This filamentary streamer rotates and twists throughout the 10-hour span of the Great Red Spot image sequence, getting distorted by winds blowing at 330 miles per hour (150 meters per second) or even greater speeds.
In Jupiter’s North Equatorial Belt, the researchers found an elusive wave that had been spotted on the planet only once before, decades earlier, by Voyager 2. In those images, the wave is barely visible, and nothing like it was seen again, until the current wave was found traveling at about 16 degrees north latitude, in a region dotted with cyclones and anticyclones. Similar waves – called baroclinic waves – sometimes appear in Earth’s atmosphere where cyclones are forming.”
In order to compare the spot over time, I have collected here some images from NASA pages – and it’s amazing to notice the difference in size.
Finally, for a video in high-resolution from Hubble Space Telescope, have a look at this: