In natural colors, Jupiter looks pretty pale. Therefore, the still images are approximately illumination-adusted, i.e. almost flattened, and consecutively gamma-stretched to the 4th power of radiometric values, in order to enhance contrast and color.
Like for all its previous flybys, Juno approached Jupiter roughly from north, and left Jupiter looking towards the soutern hemisphere. Closest approach to Jupiter was 3,500 km above the nominal IAU 1-bar level, and near 25.3 degrees north (planetocentric), according to long-term planning of November 2017.
Using data from Juno, scientists now theorize that Jupiter produces what they dub “shallow lightning” as well as ammonia-water hailstones dubbed “mushballs.”
The image to the right, cropped and reduced to post here, is only an artist’s illustration of the lightning. Sadly Juno’s camera doesn’t have the resolution to capture such flashes.
An unexpected form of electrical discharge, shallow lightning originates from clouds containing an ammonia-water solution, whereas lightning on Earth originates from water clouds.
Other new findings suggest the violent thunderstorms for which the gas giant is known may form slushy ammonia-rich hailstones Juno’s science team calls “mushballs”; they theorize that mushballs essentially kidnap ammonia and water in the upper atmosphere and carry them into the depths of Jupiter’s atmosphere.
As with the InSight results below, there is much uncertainty with these results, especially the hypothesis of mushballs. These features fit their present data from Juno, but we must remember that the data is still somewhat superficial.
Cool image time! The photo to the right, rotated and reduced to post here, was taken by Juno during its 28th close orbital fly-by of Jupiter, and then processed by citizen scientist Hemant Dara.
While not the first Juno image of the poles of Jupiter, this photo illustrates very well the evolution of the gas giant’s deep atmosphere as you move from the equator to the pole. From the equator to the high mid-latitudes the planet’s rotation, producing a day only 10 hours long, organizes that atmosphere into jet streams that form the bands that astronomers have spied from Earth since the first telescopes.
At the pole the influence of that rotation seems to wane, or at least influence the atmosphere differently, so that the storms seem to form randomly and incoherently.
The image also shows that there appear to be several types of storms at the south pole. Some appear as tight spirals, similar to hurricanes. Others appear chaotic, with no consistent shape, almost like clouds on Earth.
The processes that would explain all this are not yet understood, in the slightest, and won’t be until we get orbiters at Jupiter able to watch the atmosphere continuously, as we do here on Earth. Then it will be possible to assemble movies of the formation and dissipation of these storms, and begin (only begin) to decipher what causes them.
A new storm, dubbed Clyde’s spot after its discoverer, developed suddenly in late May on Jupiter, and has been imaged by Juno during its most recent close fly-by of the gas giant planet.
The image to the right, cropped to post here, focuses in on this spot. It is the feature in the center of the full image, with the Great Red Spot to the upper left.
The new feature was discovered by amateur astronomer Clyde Foster of Centurion, South Africa. Early on the morning of May 31, 2020, while imaging Jupiter with his telescope, Foster noticed a new spot, which appeared bright as seen through a filter sensitive to wavelengths of light where methane gas in Jupiter’s atmosphere has strong absorption. The spot was not visible in images captured just hours earlier by astronomers in Australia.
On June 2, 2020, just two days after Clyde Foster’s observations, Juno performed its 27th close flyby of Jupiter. The spacecraft can only image a relatively thin slice of Jupiter’s cloud tops during each pass. Although Juno would not be travelling directly over the outbreak, the track was close enough that the mission team determined the spacecraft would obtain a detailed view of the new feature, which has been informally dubbed “Clyde’s Spot.”
The feature is a plume of cloud material erupting above the upper cloud layers of the Jovian atmosphere. These powerful convective “outbreaks” occasionally erupt in this latitude band, known as the South Temperate Belt
The coolest thing about this is that the storm was spotted by an amateur, using a ground-based telescope, within hours of its inception.
Cool image time! The photograph on the right, reduced to post here, was color enhanced by citizen scientist Emma Walimaki from the original Juno image in order to bring out the features and storms visible in the upper storm layers of Jupiter.
The photo was taken during Juno’s 25th close fly-by of the gas giant, and thus we are only seeing a small portion of Jupiter’s sphere.
In comparing this image with the original, it appears that Walimaki simply made the colors that were already there brighter and more distinctive. Thus, these colors represent real data. Jupiter’s cloud tops are really blue, orange, tan, and brown, unlike Earth’s consistently and boringly white water clouds.
The uncertainty of science: Scientists today released their first measurements from Juno of the amount of water found in Jupiter’s atmosphere.
The Juno science team used data collected during Juno’s first eight science flybys of Jupiter to generate the findings. They initially concentrated on the equatorial region because the atmosphere there appears more well-mixed, even at depth, than in other regions. From its orbital perch, the radiometer was able to collect data from a far greater depth into Jupiter’s atmosphere than the Galileo probe – 93 miles (150 kilometers), where the pressure reaches about 480 psi (33 bar).
“We found the water in the equator to be greater than what the Galileo probe measured,” said Cheng Li, a Juno scientist at the University of California, Berkeley. “Because the equatorial region is very unique at Jupiter, we need to compare these results with how much water is in other regions.”
These results remain very preliminary, especially because they have not yet gathered data at higher latitudes. Regardless the amount so far detected, 0.25% of all molecules in Jupiter’s atmosphere. seems remarkably small, suggesting that Jupiter has relatively little hydrogen or oxygen in its atmosphere.
Citizen scientist Brian Swift has created a new movie from images taken by Juno during its December 25th close pass of Jupiter, the 24th such flyby of the spacecraft’s mission.
I have embedded the movie below. While it isn’t as spectacular as previous movies (see here, here, here, and especially here and here), as it appears that either Juno did not get quite as close, or Swift did not shape it to give that impression, it is still most breathtaking.
During Juno’s 24th close approach to Jupiter the spacecraft was able to take the first images ever of the north pole of Ganymede, the largest moon in the solar system. The image to the right was processed by citizen scientist Roman Tkacenko, and shows a variety of light and dark features.
In either case, however, the fuzziness of the image reminds me of planetary astronomy in my early childhood. Images like this, taken by telescopes on Earth, were the best we had of any planet beyond the Moon. Made it very hard to understand what was there, or what it meant.
Cool image time! Citizen scientist Gerald Eichstädt has used images taken by Juno of Jupiter’s south polar storms to produce an animation that shows the evolution of those storms over a short time period.
The movie is more a computer model than an assemblage of images.
A fluid dynamical 2D model rotating with Jupiter’s System III rotation rate is started with a map of PJ19 (Juno’s 19th close approach) vorticity measurements of the south polar region between 75 and 90 degrees south (azimuthal, equidistant, planetocentric) as initial condition. The vorticity map is based on a sequence of PJ19 JunoCam images.
Relative vorticities are encoded in color, blue for cyclonic, orange for anticyclonic relative vorticity. The animated gif covers 48 hours, with one frame per real-time hour. Played with 25 fps, the result is a 90,000-fold time-lapsed animation.
I have embedded the animation below the fold. It is quite impressive. » Read more
New images from Juno have revealed the formation of a new Texas-sized cyclone joining the circle of storms around Jupiter’s south pole.
In the infrared Juno image to the right, the new storm is the small bright cyclone in the lower right.
[D]uring Juno’s 22nd science pass [on November 3], a new, smaller cyclone churned to life and joined the fray. “Data from Juno’s Jovian Infrared Auroral Mapper [JIRAM] instrument indicates we went from a pentagon of cyclones surrounding one at the center to a hexagonal arrangement,” said Alessandro Mura, a Juno co-investigator at the National Institute for Astrophysics in Rome. “This new addition is smaller in stature than its six more established cyclonic brothers: It’s about the size of Texas. Maybe JIRAM data from future flybys will show the cyclone growing to the same size as its neighbors.”
Probing the weather layer down to 30 to 45 miles (50 to 70 kilometers) below Jupiter’s cloud tops, JIRAM captures infrared light emerging from deep inside Jupiter. Its data indicate wind speeds of the new cyclone average 225 mph (362 kph) – comparable to the velocity found in its six more established polar colleagues.
Because of Juno’s orbit we do not get continuous views of the gas giant’s cloud-tops, so we can’t see the moment-by-moment evolution of these storms, which makes it impossible to obtain a full understanding of their formation or disappearance. Even then it will likely take centuries of observations to even begin to get a fuller understanding of the meteorology of Jupiter.
Cool image time! The photo to the right, taken by Juno on November 3, was enhanced by citizen scientist Björn Jónsson to bring out the colors. It shows a band of repeating large storms, with tiny white thunderheads popping up within them.
The dark areas at the edges of the swirls are likely not an aspect of the clouds but shadows created because the white swirls sit higher than the surrounding gases.
Sadly the press release does not give us a scale. The image was taken from a distance of 3,200 miles. I suspect each cloud swirl would likely cover much of the Earth.
Using raw Juno images, citizen scientist Gerald Eichstädt has created the processed and color enhanced image to the right, cropped to post here. From the Juno press release:
This view from NASA’s Juno spacecraft captures colorful, intricate patterns in a jet stream region of Jupiter’s northern hemisphere known as “Jet N3.”
Jupiter’s cloud tops do not form a simple, flat surface. Data from Juno helped scientists discover that the swirling bands in the atmosphere extend deep into the planet, to a depth of about 1,900 miles (3,000 kilometers). At center right, a patch of bright, high-altitude “pop-up” clouds rises above the surrounding atmosphere.
Some of the darker areas are darker mostly because they are lower and therefore in shadow.
The raw image was taken on May 29, 2019 when Juno was about 6,000 miles away. Unfortunately, they do not provide a scale, but I suspect that the image is probably close to the size of the entire Earth.
In order to avoid a twelve-hour plunge through Jupiter’s shadow that would have likely sucked all power from Juno’s solar powered systems and killed the spacecraft, mission engineers have successfully used its attitude thrusters to complete a 10.5 long engine burn.
Juno began the maneuver yesterday, on Sept. 30, at 7:46 p.m. EDT (4:46 p.m. PDT) and completed it early on Oct. 1. Using the spacecraft’s reaction-control thrusters, the propulsive maneuver lasted five times longer than any previous use of that system. It changed Juno’s orbital velocity by 126 mph (203 kph) and consumed about 160 pounds (73 kilograms) of fuel. Without this maneuver, Juno would have spent 12 hours in transit across Jupiter’s shadow – more than enough time to drain the spacecraft’s batteries. Without power, and with spacecraft temperatures plummeting, Juno would likely succumb to the cold and be unable to awaken upon exit.
“With the success of this burn, we are on track to jump the shadow on Nov. 3,” said Scott Bolton, Juno principal investigator at the Southwest Research Institute in San Antonio.
This burn did not use the spacecraft’s main engine, which they fear has a problem that would produce a catastrophic failure if fired. Instead, they used Juno’s small attitude thrusters, which explains the length of the maneuver. In fact, this 10.5 hour burn might actually be the longest chemical engine burn in space ever. While ion engines routinely fire for this long or longer, as far as I can remember no chemical engine in space has ever fired even close to this length of time.
As he has done previously, citizen scientist Gerald Eichstädt has created a movie using Juno images of the spacecraft’s twenty-second fly-by of Jupiter.
I have embedded the movie below the fold. This fly-by included the images of Io’s shadow posted by other citizen scientists earlier. Because the movie shows this shadow in the context of the fly-by (near its lowest altitude), it illustrates why the shadow appears far larger than it is, relative to the entire planet.
The image on the right, reduced to post here, was created by Citizen scientist Kevin Gill from recent Juno images taken of Jupiter, and shows in detail some of the many storms that fill Jupiter’s many bands of color.
We do not have a scale, but my guess is that these storms are probably about the size of the Earth, which means these storms are bigger than any hurricane you can imagine. If you click on the image to look at the full resolution photograph, you can see there are tiny white clouds clumped in the middle of the picture’s three biggest storms. Those clumps are probably also bigger than any single clouds you could find anywhere on Earth.
What should fill us with even more awe is that this only covers a very thin slice of the top of Jupiter’s deep atmosphere. The planet itself is about 89,000 miles in diameter, more than ten times larger than Earth. The depth of its atmosphere is not really known, but it must be deeper than several Earths, piled on top of each other. In that depth there must be many atmospheric layers, each thicker and denser than the one above, and each with its own weather systems and complexities.
It will take centuries of research, including the development of new engineering capable of accessing this place, to even begin to map out its meteorology. And this is only one gas giant, of what we now know must be millions and millions throughout the galaxy.
If we have the nerve and daring, the human race has the opportunity to go out there and never be bored. There will always be something unknown to discover.
All that still applies. We have only just begun our journey exploring the universe.
Citizen scientists Kevin Gill and Tanya Oleksuik have used raw images from Juno to create several really cool images of the eclipse shadow of Io moving across the face of Jupiter. The image above, by Gill, is what I think is the most dramatic. The other images are here, here, here, here, and here.
Oleksuik notes that the colors are not true, and are enhanced for drama. Also, the shadow in many of the images are much too large relative to the globe of Jupiter. The last link above gives a better sense of the true size of that shadow against Jupiter’s giant sphere. Io’s shadow only covers a tiny part of the surface. The reason it appears larger is that the whole image does not see the entire hemisphere.
My headline above focuses on the real story here, that Juno has found that Jupiter’s solid core is more fuzzy and extended.
Unfortunately, the press release instead focuses on one theory, based on computer models, that might explain this discovery.
The research team ran thousands of computer simulations and found that a fast-growing Jupiter can have perturbed the orbits of nearby “planetary embryos,” protoplanets that were in the early stages of planet formation.
Liu said the calculations included estimates of the probability of collisions under different scenarios and distribution of impact angles. In all cases, Liu and colleagues found there was at least a 40% chance that Jupiter would swallow a planetary embryo within its first few million years. In addition, Jupiter mass-produced “strong gravitational focusing” that made head-on collisions more common than grazing ones.
Isella said the collision scenario became even more compelling after Liu ran 3D computer models that showed how a collision would affect Jupiter’s core. “Because it’s dense, and it comes in with a lot of energy, the impactor would be like a bullet that goes through the atmosphere and hits the core head-on,” Isella said. “Before impact, you have a very dense core, surrounded by atmosphere. The head-on impact spreads things out, diluting the core.”
This theory is all well and good, but we mustn’t take it too seriously. It relies entirely on computer models, and carries with it enormous assumptions about the early solar system that are as yet unproven.
That Jupiter’s core however is fuzzy and extended however is quite fascinating, highlighting once again how little we know about the universe.
Citizen scientist Björn Jónsson has compiled the montage to the right, reduced to post here, of the five times Jupiter’s Great Red Spot (GRS) was imaged by Juno during its repeated orbital fly-bys.
The mosaics show how the GRS and nearby areas have changed over the course of the Juno mission. The mosaics cover planetographic latitudes 4.7 to 38 degrees south.
The resolution of the source data is highly variable and this can be seen in some of the mosaics. The viewing geometry also varies a lot. Some of the images were obtained almost directly above the GRS (in particular some of the perijove 7 images) whereas other images were obtained at an oblique viewing angle (in particular the perijove 17 images).
These are approximately true color/contrast mosaics but there may be some inaccuracies in areas where the original images were obtained at a highly oblique angle. The contrast is also lower in these areas.
Some of the changes are remarkable, considering the short time involved. For example, note the appearance of the large white storm below the Spot in the third image, taken in December 2018. It wasn’t there in April 2018, and was gone by Feburary 2019. This doesn’t mean it had dissipated. Instead, the storm is in a different band which moves at a different speed than the band that the Spot is in. It has thus simply moved away.
This movement is even more remarkable when we remember that the Great Red Spot is about the width of the Earth.
During its most recent close approach of Jupiter, Juno took the above image of the gas giant’s Great Red Spot from a distance of 26,697 miles above the cloud tops. As noted at the link,
This view highlights the contrast between the colorful South Equatorial Belt and the mostly white Southern Tropical Zone, a latitude that also features Jupiter’s most famous phenomenon, the persistent, anticyclonic storm known as the Great Red Spot.
Just for fun, I cropped out at full resolution the bright storm just to the west of the Great Red Spot, as shown on the right.
It is important to understand the vastness of this image’s scale. You could almost fit two full Earths within the Great Spot. The close-up covers only a slightly smaller range of size. Thus, that tiny bright storm would be the largest hurricane ever seen on Earth, able to cover almost the entire Pacific Ocean.
Using Juno images produced during four different orbits, beginning in July 2017 through February 2019, citizen scientist Björn Jónsson has created a montage, reduced in resolution to post on the right, that shows the changes that have occurred in Jupiter’s Great Red Spot during that time. As he writes,
This is a montage of four map-projected [Spot] mosaics processed from images obtained during these perijoves (at the time of this writing perijove 20 is the most recent perijove). The mosaics show how the [Spot] and nearby areas have changed over the course of the Juno mission. The mosaics cover planetographic latitudes 4.7 to 38 degrees south.
The resolution of the source data is highly variable and this can be seen in some of the mosaics. The viewing geometry also varies a lot. Some of the images were obtained almost directly above the [Spot] (in particular some of the perijove 7 images) whereas other images were obtained at an oblique viewing angle (in particular the perijove 17 images).
These are approximately true color/contrast mosaics but there may be some inaccuracies in areas where the original images were obtained at a highly oblique angle. The contrast is also lower in these areas.
What strikes me the most is how the Spot itself seems relatively unchanged, while the bands and surrounding cloud formations changed significantly during this time.
Cool image time! Using images from Juno, a citizen scientist going under the nom de plume YobiRoby has created the height map image to the right, showing three-dimensionality of the cloud surface of Jupiter.
Though they provide no details to go with this image, it appears it is centered on Jupiter’s Great Red Spot, the larger of the two big storms that are visible. While the smaller storm appears raised like a mound above the surrounding cloudtops, the Great Red Spot instead appears to be a mound that is depressed below the cloudtops.
The image on the right, cropped to post here, was taken by Juno on February 12, 2019 as the spacecraft made its 17th close approach of Jupiter. The Juno science team today has highlighted this version, processed by citizen scientists Gerald Eichstädt and Seán Doran to enhance the details therein. They note how the white clouds can clear be seen sitting above the colored clouds below.
I cropped it to show the center of the storm. The full image is equally spectacular, as it shows the full storm. Unfortunately, there is no scale, but I suspect you could probably fit the entire Earth several times across the diameter of the storm.
Cool image time! Citizen scientists Gerald Eichstädt and Seán Doran have released two new images that they have processed from the Juno raw image archive that were taken during the most recent spacecraft fly-by of Jupiter. The image to the right, cropped and reduced to post here, shows the Spot as the spacecraft was flying past. If you click on the image you can see their full image, processed by them to bring out the details and colors.
Even more spectacular, though unfortunately much too short, is the gif animation they have produced combining a number of images from this fly-by. I have embedded this animation below the fold. If you watch closely, you can see the rotation of this gigantic storm, including the motion of the jet streams within it. » Read more
Using several instruments, the Juno science team has successfully photographed an active volcano plume in Io’s polar regions. Two instruments measured the plume’s heat and radiation. Juno’s cameras meanwhile took the color image on the right. The bright spot on Io’s night side matches the location of the heat and radiation signatures from the other instruments.
JunoCam acquired the first images on Dec. 21 at 12:00, 12:15 and 12:20 coordinated universal time (UTC) before Io entered Jupiter’s shadow. The Images show the moon half-illuminated with a bright spot seen just beyond the terminator, the day-night boundary. “The ground is already in shadow, but the height of the plume allows it to reflect sunlight, much like the way mountaintops or clouds on the Earth continue to be lit after the sun has set,” explained Candice Hansen-Koharcheck, the JunoCam lead from the Planetary Science Institute.
Cool image time! The photograph on the right, reduced to post here, was created by citizen scientists Gerald Eichstädt and Seán Doran from the raw images taken by Juno during the spacecraft’s 16th close fly-by of Jupiter on October 29, 2018. If you click on it you can see the full resolution image.
At the time, Juno was about 4,400 miles (7,000 kilometers) from the planet’s cloud tops, at a latitude of approximately 40 degrees north.
What attracts me to this image is its dimensionality. First, it looks at Jupiter from an oblique angle. Second, the shadows of the upper clouds can clearly be seen being cast on the lower clouds. Third, if you look at the full resolution image you can even see this effect in the middle of the big white storm in the image’s top left.
What frustrates me about this image is that Juno is not in an orbit around Jupiter allowing it to make extended movies of the evolution of these cloud features. Gaining even a limited understanding the meteorology of this gas giant will simply not be possible until we can do this, and that will require many satellites orbiting the planet.
New data from Juno has revealed that Jupiter’s magnetic field acts like it has three poles, one at each pole and another near the equator.
If Earth’s magnetic field resembles that of a bar magnet, Jupiter’s field looks like someone took a bar magnet, bent it in half and splayed it at both ends. The field emerges in a broad swath across Jupiter’s northern hemisphere and re-enters the planet both around the south pole and in a concentrated spot just south of the equator, researchers report in the Sept. 6 Nature.
“We were baffled” at the finding, says study coauthor Kimberly Moore, a graduate student at Harvard University.
They think the multiple poles are a result of the complexity of Jupiter’s inner core, which likely does not have the same kind of organization as a rocky terrestrial planet.
Cool image time! The image on the right, cropped to post here, shows the white center of one of the smaller giant storms on Jupiter, taken by Juno. The image was processed by citizen scientists Gerald Eichstädt and Seán Doran. If you click on the image you can see the entire picture, which has a host of spectacular details surrounding the white spot.
Unfortunately, they do not provide a scale. Based on past experience, I would guess that this tiny storm probably exceeds the size of the Earth. What makes the image so impressive however are the white cloudtops visible as they swirl around the storm’s center. Sunlight shadows clearly shows that these thunderheads rise above rest of the storm.
The full image shows even more fascinating details. It is worthwhile studying, though one can certainly get lost in that vast and turbulent Jupiter atmosphere.
The uncertainty of science: New computer models, combined with new data from Juno, suggest that magnetism explains why Jupiter’s colored jet stream bands go as deep below the visible cloud-tops as they do.
Dr Navid Constantinou from the ANU Research School of Earth Sciences, one of the researchers on the study, said that until recently little was known about what happened below Jupiter’s clouds. “We know a lot about the jet streams in Earth’s atmosphere and the key role they play in the weather and climate, but we still have a lot to learn about Jupiter’s atmosphere,” he said. “Scientists have long debated how deep the jet streams reach beneath the surfaces of Jupiter and other gas giants, and why they do not appear in the sun’s interior.”
Recent evidence from NASA’s spacecraft Juno indicates these jet streams reach as deep as 3,000 kilometres below Jupiter’s clouds.
Co-researcher Dr Jeffrey Parker from Livermore National Laboratory in the United States said their theory showed that jet streams were suppressed by a strong magnetic field. “The gas in the interior of Jupiter is magnetised, so we think our new theory explains why the jet streams go as deep as they do under the gas giant’s surface but don’t go any deeper,” said Dr Parker.
This theory is intriguing, but very tentative, to put it mildly.