A study published this week in the journal Nature reveals that Jupiter's upper atmosphere is heating up and the culprits for this are thunder that rises from the Great Red Spot. Prof. Yoav Yair, an expert on the atmosphere, says that it is possible that thunder is the cause of the warming, but it almost certainly originates in other areas of the atmosphere and in the Great Red Spot
The Great Red Spot of Jupiter - a hurricane three times larger than Earth's, "shelling" Jupiter's upper atmosphere with heat. This is according to a publication by an international group of researchers.
Using measurements made with an infrared telescope in Hawaii, members of a team of astronomers from Britain and the United States found evidence of high temperatures, likely 1,500 degrees Celsius, a hundred degrees more than anywhere else in the planet's high atmosphere. According to them, the warm layer was created by sound waves - thunder - that broke in the high and thin layers of Jupiter's upper atmosphere. The study was published in the journal Nature.
This discovery is made possible by a mystery that planetary science experts have called an "energy crisis" for a gas giant like Jupiter: the temperatures in its upper atmosphere reach much higher temperatures than can be explained by solar energy - especially in light of its enormous distance from the sun. Thus, if it turns out that the mysterious heat is generated by local sources, like Jupiter's famous storm, then the puzzle will be solved - and these measurements are the first direct evidence of any such activity.
Dr. Thom Stollard from the University of Leicester in the UK, one of the authors of the study, said that this is a big step forward to try and understand the flow of heat on Jupiter. "Since Voyager, we've had measurements of the temperature in Jupiter's upper atmosphere, and it turns out that it's all hot from the poles to the equator.
Jupiter's enormous aurora can explain the high temperature in the polar regions, but for the heat to reach the equator as well, an incredibly dramatic mixing of the atmosphere is required, and so far no research has supported its existence. "There's no real excuse for it being so hot," said Dr. James O'Donoghue of Boston University, lead author of the paper.
lightning and thunder
After mapping Jupiter's top temperature using NASA's Infrared Telescope Facility (IRTF) at Mauna Kea, Hawaii, the researchers propose a solution: just a few hundred kilometers above the clouds of the Great Red Spot, the highest temperatures were measured and the heat at high altitude probably originated Somehow from the instability below. The warming was measured by detecting the radiation from hydrogen H3+ - a hydrogen molecule that is the main component of Jupiter's atmosphere, to which a proton (carrier of a positive charge) was added.
"There were scientists who argued that it was likely that the heat was coming from below, but the observations never supported that," said Dr. Stollard.
He and his colleagues don't know exactly what causes heat to rise in temperature, but they have some ideas. It may have originated from powerful thunderstorms rising above the largest storm in the solar system. In such a case, an acoustic event is created, thunder that spreads vertically, that is, energy that originates from sound waves that spread directly upwards. "The wave will continue upwards until it reaches an area where the density of the atmosphere is low in the upper part of the atmosphere, and then it discharges all its energy to the upper part of the atmosphere, like waves breaking on the shore, when the water becomes shallower and the wave is unable to rise and therefore it breaks and releases a lot of energy."
According to Dr. Adono, there is a precedent for warming that originates from a sound phenomenon much closer to home. "There is evidence in the Earth's atmosphere, above storms and above mountain peaks - the Andes Mountains for example, that create acoustic waves in the air that rise into the atmosphere and heat it locally," he said.
Prof. Yoav Yair, currently head of the School of Sustainability at the Interdisciplinary Center in Herzliya and a veteran researcher of atmosphere and space says:
"According to their explanation, the energy of sound waves that spread from great depths in Jupiter, where the lightning storm clouds are located above to areas where the density is very low, is converted from acoustic energy to thermal energy and this causes the temperatures in the upper atmosphere to rise."
"The researchers hypothesize that these acoustic waves could be thunder as a result of lightning storms and claim that they originate from the largest vortex in the solar system, i.e. the Great Red Spot. After reading the article in Nature, I corresponded with my colleagues from Japan, England and Austria about the published study, and we came to an agreement that there is certainly warming and that its origin may be acoustic, but that the Great Spot is probably not responsible for it. This is because it is a vortex where the vertical movements are from top to bottom, and the air sinks and prevents the development of large storm clouds. Indeed, lightning (and therefore thunder) has never been observed above the Great Spot on Jupiter, but only at other latitudes.
"The Great Red Spot known as GRS (Great Red Spot) is a huge storm with an oval (elliptical) shape whose horizontal axis is 22 kilometers and the vertical axis is about 12 kilometers, it is a huge volume that can fit the Earth several times. As mentioned, this is an area where the air actually lowers and sinks deep into the atmosphere. These are not the optimal conditions for the formation of lightning, because they usually look for the opposite conditions - areas where the air rises and then there is condensation of water vapor that creates huge clouds."
Prof. Yair adds: "On these clouds I did my doctorate at Tel Aviv University in 1994. These are clouds 50-60 kilometers thick that create lightning at a crazy rate, and they are found at a great depth, below the colorful layer of clouds that you see in the beautiful photographs of Jupiter. Jupiter's lightning is 100 times more energetic than Earth's, and therefore naturally creates very strong thunder - and these can indeed explain the observed warming."
"As mentioned, in the Great Red Spot we never saw lightning and there were several spacecraft that photographed Jupiter - Voyager 1 and 2, Galileo, Cassini and also "New Horizons" and none of the spacecraft saw lightning in the Great Red Spot but in other places at high latitudes More. Our conclusion is that their explanation may be correct but is not supported by the observations."
"One of the reasons for our skepticism is the great storm that was on Saturn several years ago that created a great white spot, and occurred in 2010. This huge storm was so strong that the clouds in it spread and surrounded the entire planet. In that storm hundreds of thousands of lightning were observed and as a result a warming was seen in the upper atmosphere. There the explanation makes more sense because detectors on the Cassini spacecraft which was in the coffee orbit around Saturn at that time indeed picked up the lightning optically and electromagnetically, and where there is lightning there is also thunder. Therefore, it is likely that the name of the physical mechanism they proposed is correct - but as for Tzedek, there is a lack of evidence for lightning in the Great Spot."
Can Juno test which of the theories is correct?
Prof. Yair: "Juno entered the coffee orbit around Jupiter a few weeks ago and if NASA decides that it is their priority to look for lightning in the depth of Jupiter's atmosphere (and I really hope they do) - theoretically they can do it even though this was not the goal the main task. This is the kind of mystery that a spacecraft like Juno can solve, so we just have to be patient."
