Image credit: International Gemini Observatory/NOIRLab/NSF/AURA/NASA/ESA, M. H. Wong and I. de Pater (UC Berkeley) et al. NASA's Juno mission to Jupiter has produced new images of the gas giant, showing new detail of the planet's atmosphere and uncovering new depth data about Jupiter's famous Great Red Spot.
The Juno mission is, unsurprisingly, aimed at observing Jupiter and learning more about the planet. One of Jupiter's most famous features, the Great Red Spot, has long been shrouded in mystery. The planet's observable features alone are the source of much intrigue. The Juno probe has recently made significant observations that have helped scientists back on Earth better understand Jupiter's colorful atmospheric characteristics and gain insight into what's happening beneath the clouds that cover the planet. Much like Earth's atmosphere includes belts and zones, it seems that Jupiter's does, too.
Artist's rendition of Juno orbiting Jupiter. Credit: NASA
'These new observations from Juno open up a treasure chest of new information about Jupiter's enigmatic observable features,' said Lori Glaze, director of NASA's Planetary Science Division at the agency's headquarters in Washington. 'Each paper sheds light on different aspects of the planet's atmospheric processes – a wonderful example of how our internationally-diverse science teams strengthen understanding of our solar system. '
Juno has been in Jupiter's orbit since 2016 and has made 37 passes of the planet since then. Each time Juno rounds the planet, the probe's specialized instruments look beneath the planet's cloudy surface. With Juno's microwave radiometer (MWR), scientists can look beneath Jupiter's clouds and get new information about the planet's vortex storms, including the anticyclone vortex storm that forms the Great Red Spot. MWR findings indicate that the storms are much taller than previously expected, with some of them extending a staggering 100km (60 mi) below the cloud tops, and others, like the Great Red Spot, extending over 350km (200 mi). NASA writes, 'This surprise discovery demonstrates that the vortices cover regions beyond those where water condenses and clouds form, below the depth where sunlight warms the atmosphere. '
'Jupiter's banded appearance is created by the cloud-forming 'weather layer. ' This composite image shows views of Jupiter in (left to right) infrared and visible light taken by the Gemini North telescope and NASA’s Hubble Space Telescope, respectively. '
Credits: International Gemini Observatory/NOIRLab/NSF/AURA/NASA/ESA, M. H. Wong and I. de Pater (UC Berkeley) et al.
' Previously, Juno surprised us with hints that phenomena in Jupiter's atmosphere went deeper than expected,' said Scott Bolton, principal investigator of Juno from the Southwest Research Institute in San Antonio and lead author of the Journal Science paper on the depth of Jupiter's vortices. 'Now, we're starting to put all these individual pieces together and getting our first real understanding of how Jupiter's beautiful and violent atmosphere works – in 3D. '
Juno travels low over Jupiter's cloud deck at about 209,000 kph (130,000 mph). Even at this speed, Juno scientists can measure velocity changes as small as 0. 01 millimeters per second with NASA's Deep Space Network tracking antenna from a distance of more than 650,000,000 km (400,000,000 mi). With this high-tech tracking technology, the team was able to ascertain the depth of the Great Red Spot.
'This illustration combines an image of Jupiter from the JunoCam instrument aboard NASA's Juno spacecraft with a composite image of Earth to depict the size and depth of Jupiter's Great Red Spot. '
Credits: JunoCam Image data: NASA/JPL-Caltech/SwRI/MSSS; JunoCam Image processing by Kevin M. Gill (CC BY); Earth Image: NASA
'The precision required to get the Great Red Spot's gravity during the July 2019 flyby is staggering,' said Marzia Parisi, a Juno scientist from NASA's Jet Propulsion Laboratory in Southern California and lead author of a paper in the Journal Science on gravity overflights of the Great Red Spot. 'Being able to complement MWR's finding on the depth gives us great confidence that future gravity experiments at Jupiter will yield equally intriguing results. '
In addition to cyclones and anticyclones, Jupiter also includes belts and zones, which are the white and reddish-colored bands that envelop the planet. Thanks to Juno, scientists previously learned that the jet streams on Jupiter reach depths of about 3,200 km (2,000 mi). However, scientists are still trying to figure out how the jet streams form. However, recent Juno passes offer a new clue, ammonia gas in the atmosphere that travels up and down in 'remarkable' alignment with the jet streams.
'By following the ammonia, we found circulation cells in both the north and south hemispheres that are similar in nature to 'Ferrel cells,' which control much of our climate here on Earth', said Keren Duer, a graduate student from the Weizmann Institute of Science in Israel and lead author of the Journal Science paper on Ferrel-like cells on Jupiter. 'While Earth has one Ferrel cell per hemisphere, Jupiter has eight – each at least 30 times larger. '
An overview of the Juno spacecraft and its onboard instruments. Credit: NASA. Click to enlarge.
MWR data shows that Jupiter's belts and zones transition around 65km (40 mi) beneath the planet's water clouds. The belts are brighter in microwave light at shallow depths, and the opposite is true when observing deeper depths. This is similar to oceans on Earth, so scientists refer to the transition as 'Jovicline,' which is analogous to the thermocline transition in Earth's oceans.
In Juno's first year observing Jupiter, we saw that the giant cyclones at both of Jupiter's poles were arranged in an octagonal pattern in the north and a pentagonal pattern in the south. Five years later, using Juno's Jovian Infrared Auroral Mapper (JIRAM), it seems that the atmospheric phenomena are in the same location. Each cyclone affects the other cyclones, and they're oscillating in an equilibrium position. Slow oscillation suggests the cyclones have what NASA refers to as 'deep roots. ' It will be interesting to see what else Juno can learn about these relatively stationary storms.
If you want to check out a great overview of what we currently know about Jupiter and see some of Juno's previous discoveries, check out the video below.
The Juno mission has been extended to at least 2025, so there's much more to learn about the mysterious planet. Earlier this year, NASA published a stunning new image of Jupiter and even new photos of one of Jupiter's famous moons, Ganymede.
. dpreview.com2021-11-2 17:42
