NASA’s Juno reveals the dark origin of one of Jupiter’s large light shows

NASA's Juno reveals the dark origin of one of Jupiter's large light shows

This illustration depicts ultraviolet polar aurorae on Jupiter and Earth. Credit: NASA / JPL-Caltech / SwRI / UVS / STScI / MODIS / WIC / IMAGE / ULiège

New results from the Ultraviolet Spectrograph instrument on NASA’s Juno mission reveal for the first time the birth of the day after tomorrow in the dawn – the early morning that is clearly unique to Jupiter’s spectacular aurorae. These enormous, momentary appearances of light occur at both Jovian poles and have previously been observed only by observatories on Earth and around the Earth, especially NASA’s Hubble Space Telescope. The results of this study were published in the journal on March 16. AGU advances.

Dawn Storms, first discovered by Hubble’s Faint Object Camera in 1994, consists of a momentary but intense illumination and widening of Jupiter’s main-oval – an elongated curtain of light surrounding both poles – near where the atmosphere emerges from the darkness in the early morning region. . Before Juno, observations of the Jovian ultraviolet aurora presented only side views, hiding everything that happened on the other side of the planet.

“By observing Jupiter’s aurora from Earth, you can see no further than the limb in the night side of Jupiter’s poles. Exploration by other spacecraft – Voyager, Galileo, Cassini – took place from relatively great distances and did not flew over the poles so that they could not see the complete picture, ‘says Bertrand Bonfond, a researcher at the University of Liège in Belgium and lead author of the study. “Therefore, the Juno data is a real changer, which we have a better understanding of what happens at night, where the dawn storms are born. “







This video clip shows the evolution of a dawn storm in Jupiter’s polar aurorae. The footage for the video was collected using data from the Ultraviolet Spectrograph instrument aboard NASA’s spacecraft Juno. Credit: NASA / JPL-Caltech / SwRI / UVS / ULiège

Researchers have found that dawn storms are born on the night side of the gas giant. As the planet rotates, the soon-to-be-dawn storm turns into day with it, where these intricate and bright auroral features become even brighter and radiate space between hundreds and thousands of gigawatts of ultraviolet light. The brightness jump implies that dawn storms dump at least ten times more energy into Jupiter’s upper atmosphere than typical aurora.

“When we looked at the whole dawn storm sequence, we could not help but notice that it is very similar to a kind of terrestrial auroras called substorms,” ​​said Zhonghua Yao, co-author of the study at the University of Liege, said.

Substorms are the result of short-circuits in the Earth’s magnetosphere – the area of ​​space controlled by the planet’s magnetic field – that releases energy high into the planet’s ionosphere. The similarity between terrestrial and Jovian sub-storms is surprising because the magnetospheres of Jupiter and Earth differ radically. On Earth, the magnetosphere is essentially controlled by the interaction of the solar wind – the stream of charged particles flowing from the sun – with the Earth’s magnetic field. Jupiter’s magnetosphere is mostly populated by particles escaping from the volcanic moon Io, which are then ionized and trapped by the magnetic field around the gas giant.

These new findings will enable scientists to further study the differences and similarities that drive the formation of aurora, thus giving a better understanding of how these most beautiful of planetary phenomena occur in worlds inside and outside our solar system.

“The power that Jupiter possesses is incredible. The energy in this dawn light is another example of how powerful this giant planet really is,” said Scott Bolton, chief researcher at Juno of the Southwest Research Institute in San Antonio. “The revelations of the dawn storm are another surprise of the Juno mission, which is constantly rewriting the book on how the giant planet works. With NASA’s recent mission expansion, we look forward to many more new insights and discoveries.”


NASA Juno takes first photos of Jovian moon Ganymede’s north pole


More information:
B. Bonfond et al., Is Dawn Storms Jupiter’s Auroral Substorms? AGU advances, First published: 16 March 2021 doi.org/10.1029/2020AV000275

Quotation: NASA’s Juno reveals the dark origins of one of Jupiter’s major light shows (2021, March 16) on March 16, 2021 from https://phys.org/news/2021-03-nasa-juno-reveals-dark-jupiter. html

This document is subject to copyright. Except for any fair trade for the purpose of private study or research, no portion may be reproduced without the written permission. The content is provided for informational purposes only.

Source