Yesterday at the annual American Geophysical Union meeting the new discoveries concerning Jupiter’s Great Red Spot of Jupiter and a new radiation area were announced. The data collected by NASA’s space probe Juno during a flyby on July 11, 2017 allowed to discover something new about that storm bigger than Earth, for example finding an answer to one of the crucial questions about it establishing that it’s about 300 kilometers (200 miles) deep.
The Microwave Radiometer (MWR) instrument of the Juno space probe is the one that allowed to investigate the depths of the Great Red Spot. It’s an instrument designed specifically for that purpose and can perform measurements at much greater depth than those of any other space probe or Earth-based.
Andy Ingersoll, professor of planetary science at Caltech and one of the investigators of the Juno mission, explained that the giant storm has “roots” that are warmer at their base. Winds are associated with the differences in temperature and the heat of the Great Red Spot’s base explains the existence of the fierce winds visible at the top of Jupiter’s atmosphere.
The new knowledge of the Great Red Spot’s structure and a monitoring that’s more in-depth thanks to the Juno space probe could also allow to understand why it’s shrinking. Its size has been regularly monitored since 1830, showing its reduction, which has recently become very quick.
During the 19th century the astronomers of the time reported that the Great Red Spot’s size was well over twice the Earth’s. Still in 1979, the Voyager 1 and 2 space probes flew by Jupiter and showed that the storm was about twice the Earth’s size. Today its width has decreased by about 33% while its height has decreased by just over 12% compared to 1979.
The Juno space probe also discovered two radiation areas that were still uncharted, one of them unknown just above Jupiter’s atmosphere, near its equator, indicated in the image below as a glowing blue area. That area includes energetic hydrogen, oxygen, and sulfur ions moving at speeds close to the light’s. It was identified by the Jupiter Energetic Particle Detector Instrument (JEDI) instrument during flybys.
According to the scientists of the Juno mission in that region there are energetic neutral atoms coming from the thin gas around Io and Europa, two of Jupiter’s moons. These atoms get ionized when their electrons are stripped away by the interaction with the planet’s upper atmosphere.
Again the Juno space probe can perform otherwise impossible measurements. Heidi Becker, another scientist of the Juno mission, explained that the discovery of a new radiation area was possible thanks to the orbit that leads Juno very close to the top of Jupiter clouds.
These discoveries offer new information on various types of phenomena occurring on Jupiter. This gas giant keeps on offering surprises and there’s still a lot of work to do to discover all its secrets and to understand everything that happens on the planet and around it, in its huge and powerful magnetosphere.