International Observatories Unite to Solve Energy Crisis on Jupiter
Located more than five times the distance from the Sun as Earth, Jupiter is not presumed to be particularly warm. Based on the quantity of sunlight received, the average temperature level in the planet’s upper atmosphere should be around minus 100 degrees Fahrenheit or a freezing minus 73 Celsius. Instead, the measured value rises to around 800 degrees Fahrenheit or 426 Celsius. The source of this heat surplus has stayed intangible for half a century, causing researchers to describe the inconsistency as an “energy crisis” for the planet.
Recently, a worldwide team put together monitorings from a trio of observatories– NASA’s Juno spacecraft, W. M. Keck Observatory on Maunakea in Hawaiʻi, as well as the Hisaki satellite from the Japan Aerospace Expedition Agency (JAXA)– to find the most likely source of Jupiter’s thermal boost.
“We discovered that Jupiter’s intense aurora, the most robust in the solar system, is responsible for heating the whole earth’s top atmosphere to shockingly high temperatures,” stated James O’Donoghue of the JAXA Institute of Space and Astronautical Science, Sagamihara, Japan. O’Donoghue started the research study at NASA’s Goddard Space Flight Facility in Greenbelt, Maryland, and is the lead author of a paper concerning this study released in the journal Nature.
Auroras happen when electrically charged fragments are captured in a planet’s magnetic field. These spiral along undetectable lines of force in the electromagnetic field towards the planet’s magnetic poles, hitting atoms and particles in the atmosphere to release light and energy. This causes the colorful light show on Earth that creates the Aurora Borealis and Australis, also known as the northern and southern lights. At Jupiter, material emerging from its volcanic moon, Io, causes the strongest aurora in the solar system and gigantic heating in the upper atmosphere over the polar areas of the planet.
The suggestion that the aurora might be the resource of Jupiter’s strange energy had been proposed previously, but monitorings have not been able to validate or refute this until now.
Global models of Jupiter’s upper environment proposed that winds heated up by the aurora and also headed to the equator would undoubtedly be overwhelmed and redirected by westward winds propelled by the planet’s rapid rotation. This would deter the auroral energy from getting away from the polar regions and warming the entire atmosphere. But, this brand-new observational result hints that such trapping is not happening, which the westward winds might be reasonably weaker than predicted compared to equatorward winds.
High-resolution temperature level maps from Keck Observatory, along with magnetic field data from Hisaki and Juno, enabled the team to capture the aurora in the act of sending what appears to be a pulse of heat toward Jupiter’s equator.
The group observed Jupiter with the Keck II telescope for 5 hours on two different evenings in April 2016 and January 2017. Using the Near-Infrared Spectrograph (NIRSPEC) on Keck II, heat from electrically charged hydrogen particles (H3+ ions) in Jupiter’s environment was traced to the equator from the planet’s posts. Earlier maps of the upper climatic temperature level were made using pictures containing only several pixels. That is insufficient resolution to see how the temperature level may be shifting throughout the planet, giving few ideas about the origin of the heat surplus.
To better the circumstance, the team used the power of Keck II to take more temperature measures throughout the face of the planet and only added measurements with uncertainty in the recorded value of less than 5 percent. This took years of meticulous work and produced temperature maps with over 10,000 distinct data points, the highest resolution to date.
“We have tried this numerous times with other instruments; however, with Keck’s NIRSPEC, we measured for the first time the light from Jupiter to the equator fast enough to allow us to map out the temperature and also ionospheric density,” claimed Tom Stallard, a co-author of the paper at the College of Leicester, Leicester, United Kingdom.
These detailed maps revealed that the heat in the upper atmosphere was more extensively distributed, with a slow decrease in temperature closer to the equator, opposing the predictions that only near the aurora could high temperatures be found if the heat is caught there.
“We also exposed a strange specific region of heating far away from the aurora– a long bar of heating unlike anything we have seen before,” stated Stallard. “Though we cannot make sure what this peculiarity is, I believe it is a rolling wave of heat flowing equatorward from the aurora.”
Additionally, monitorings from JAXA’s Hisaki satellite revealed that conditions at the time of the Keck II temperature level monitorings could produce an intense aurora on Jupiter. Hisaki has observed the aurora-generating electromagnetic field around Jupiter from orbit around Earth since the mission’s launch in 2013. This long-term surveillance has shown that Jupiter’s electromagnetic field is strongly affected by the solar wind, a flow of high-energy particles that emanates from the sunlight. The solar wind carries its electromagnetic field, and also, when this reaches Jupiter’s planetary field, the latter is compressed. At the Keck II monitorings, Hisaki showed that pressure from the solar wind was exceptionally high at Jupiter. The field compression is most likely to have produced an improved aurora.
Lastly, observations from Juno in orbit around Jupiter gave the specific area of the aurora in the planet.
“Juno’s electromagnetic field information gave us a ‘ground truth’ as to where the aurora was. This info is not readily available from heat maps, as warmth oozes from many directions,” said O’Donoghue. “Imagine this like a beach: if the hot atmosphere is water, the electromagnetic field mapped by Juno is the shoreline, and also the aurora is the sea, we found that water left the sea and flooded the land, and also Juno exposed where that coastline was to assist us in understanding the degree of flooding.”
“It was pure luck that we recorded this potential heat-shedding event,” adds O’Donoghue. “If we had observed Jupiter on a different night when the solar wind pressure had not just recently been high, we would certainly have missed it!”
The group will continue to evaluate the data and generate even more maps; their objective is to catch Jupiter’s aurora gushed an additional hot spot, this time around observing it over a 2-3 day duration so they can track its energy as it moves around the planet.
“Can we observe one of these functions relocating? Will it reveal the circulation of auroral heat in action? Exactly how does this circulation of energy after that affect the adjacent magnetic fields that we currently recognize are so complicated? It is an exhilarating set of study inquiries in a region of Jupiter’s ionosphere that, five years back, we believed to be mundane,” stated Stallard.
See Secret Behind Jupiter’s “Energy Crisis” Revealed for more on this study.
Originally published on Scitechdaily.com. Read the original article.
