Tag Archives: Juno

Jupiter’s weird magnetic field

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.

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One “tiny” storm on Jupiter

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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.

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Magnetism helps shape Jupiter’s colorful jet stream bands

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.

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Movie of Juno’s thirteenth fly-by of Jupiter

Cool image time. Mathematician and software programmer Gerald Eichstädt has released another movie using images from Juno’s thirteenth close fly-by of Jupiter.

I have embedded the movie below the fold. As he notes,

The movie covers two hours of this flyby in 125-fold time lapse, the time from 2018-05-24T04:41:00.000 to 2018-05-24T06:41:00.000. It is based on 27 of the JunoCam images taken during the flyby, and on spacecraft trajectory data provided via SPICE kernel files.

The view begins by looking down at the northern hemisphere, and gets to within 2,200 miles of the giant planet’s cloud tops.

» Read more

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Juno mission extended

NASA has extended the Juno mission through 2022 in order to complete its planned science.

NASA has approved an update to Juno’s science operations until July 2021. This provides for an additional 41 months in orbit around Jupiter and will enable Juno to achieve its primary science objectives.Juno is in 53-day orbits rather than 14-day orbits as initially planned because of a concern about valves on the spacecraft’s fuel system. This longer orbit means that it will take more time to collect the needed science data.

An independent panel of experts confirmed in April that Juno is on track to achieve its science objectives and is already returning spectacular results.The Juno spacecraft and all instruments are healthy and operating nominally.

NASA has now funded Juno through FY 2022. The end of prime operations is now expected in July 2021, with data analysis and mission close-out activities continuing into 2022.

I will admit that though Juno is clearly learning a great deal about Jupiter, such as this story about lightning there, its larger orbit makes it difficult to track the gas giant cloud structures as they evolve. This is unfortunate.

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Juno images processed by citizens highlighted at conference

Several Juno images that have been cleverly processed by citizen scientists are being highlighted at a Jupiter conference being held in London this week.

JunoCam images presented at the meeting by citizen scientists Gerald Eichstädt and Seán Doran include an animation showing the evolution of swirling features in the giant planet’s atmosphere and a composite image of Jupiter’s cloud tops.

Gerald Eichstädt, a mathematician working as a software professional, has taken two images from JunoCam and reprojected them to the same vantage point to enable a direct comparison between the images and show the subtle motions within the atmosphere. By modelling the movement of individual pixels in the images, he has created an animation that extrapolates the swirling evolution of the vortices in the atmosphere.

Eichstädt explains: “This animation represents a ‘feasibility test’. Building on this initial work, we can add in more variables that will give us a more detailed description and physical understanding of Jupiter’s atmosphere.”

Seán Doran, in collaboration with Eichstädt, has created a new composite image of Jupiter as seen by Juno as it swung away from Jupiter’s south pole on 1st April 2018. Because Jupiter was larger than JunoCam’s field of view when the main portion of the image was taken, Eichstädt rendered four other images to the same viewing geometry to reconstruct a mosaic of the whole planet. Doran then processed the composite image to balance and blend the overlapping components, sharpen the contrast, and fill gaps.

I have myself highlighted images by both previously at Behind the Black, here and here and here and here. This press release nicely places both in the limelight at last.

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Jupiter’s North Pole, as seen in infrared by Juno

The Juno science team has released an animation that shows, in infrared and in three dimensions, the storms of Jupiter’s north pole.

The link has three videos. One shows the gas giant’s surprisingly irregular magnetic field, as found by Juno. The first and third show a low and a high fly-over of the north pole, in infrared. I have embedded both fly-overs below the fold. First watch the high fly-over, which is the first video. This will make the low fly-over more understandable as it flies over the eight smaller storms that encircle the pole’s central vortex.
» Read more

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An even more spectacular movie of Jupiter’s storms

Cool image time! Yesterday I posted a short gif created by citizen scientist Gerald Eichstädt, using twelve Juno images, that showed some cloud changes over time. Today, I discovered that Eichstädt has created an even more spectacular movie, which I have embedded below the fold, based on images taken during Juno’s tenth close fly-by.

This movie shows the short-term dynamics Jupiter’s southern storms derived from raw JunoCam images of Juno’s Perijove-10 flyby on Dec 16, 2017.

You might also notice the effect of changing solar illumination on the appearance of the haze bands. JunoCam usually takes a time-lapse sequence of images during each perijove showing Jupiter’s polar regions. These images are taken from different perspectives along Juno’s trajectory. But it’s possible to reproject the JunoCam images to a common perspective. Displaying such a sequence rapidly reveals cloud motion in Jupiter’s storm systems.

This movie applies this technique. At the same time, it is changing the simulated perspective along Juno’s trajectory. The same short sequence of images is displayed in a loop, but due to the changing way of reprojecting the raw images, the shown surface area is changing more or less continuously.

Eichstädt warns that the blinking nature of the film might make it unsuitable for those with epilepsy. If this is not an issue for you, you should then definitely take a look.
» Read more

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A Juno movie of cloud motions

Cool image time! Citizen scientist Gerald Eichstädt, using twelve Juno images, has compiled a short gif movie that shows a tiny amount of cloud movement.

I think this is one of the first times Juno has show us even a tiny bit of cloud evolution, information that is essential for gaining a true understanding of Jupiter’s slightly less than 2000 mile deep atmosphere. To see it, go to the link. As Eichstadt notes, “Individual images are noisy, but we see cloud motion.”

When you watch, zoom in on the upper right quarter. This is the area that the cloud motion is seen best.

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Jupiter has a 1,900 mile deep atmosphere

The uncertainty of science: New results from Juno reveal that the jet-stream-type bands visible on the surface extend down to 1,900 miles, deeper than expected. Below that,

…the planet rotates nearly as a rigid body.”This is really an amazing result, and future measurements by Juno will help us understand how the transition works between the weather layer and the rigid body below,” said Tristan Guillot, a Juno co-investigator from the Université Côte d’Azur, Nice, France, and lead author of the paper on Jupiter’s deep interior. “Juno’s discovery has implications for other worlds in our solar system and beyond. Our results imply that the outer differentially-rotating region should be at least three times deeper in Saturn and shallower in massive giant planets and brown dwarf stars.”

Scientists had not expected the atmosphere go that deep.

Other results show that that the gas giant’s complex polar regions are surprising as well.

Its north pole is dominated by a central cyclone surrounded by eight circumpolar cyclones with diameters ranging from 2,500 to 2,900 miles (4,000 to 4,600 kilometers) across. Jupiter’s south pole also contains a central cyclone, but it is surrounded by five cyclones with diameters ranging from 3,500 to 4,300 miles (5,600 to 7,000 kilometers) in diameter. Almost all the polar cyclones, at both poles, are so densely packed that their spiral arms come in contact with adjacent cyclones. However, as tightly spaced as the cyclones are, they have remained distinct, with individual morphologies over the seven months of observations detailed in the paper.

“The question is, why do they not merge?” said Adriani. “We know with Cassini data that Saturn has a single cyclonic vortex at each pole. We are beginning to realize that not all gas giants are created equal.”

I am always baffled when scientists are surprised at the infinite variety of the universe. It is absurd to assume Jupiter and Saturn would be alike, especially considering the history of solar system exploration since the dawn of the space age. Since the first probe got a close look at the Moon, every single new object observed has been completely different from every other previously observed object. Every object has been unique. None have been the same.

Jupiter should be no different. And I guarantee that the next fifty gas giants we finally get a close look at out there among the stars will be as different from each other as they are from Jupiter. It is going to take a lot of exploration for us to finally get a handle on the overall patterns of planetary formation.

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A movie of Jupiter’s south polar region

Cool movie time! Using Juno images, a citizen scientist has created a short movie showing two complete rotations of Jupiter’s south polar regions. I have embedded the movie below the fold. It is definitely worth watching. As he notes,

Due to Jupiter’s low axial tilt we never see more than roughly one half of the area around the poles in sunlight at any given time. However, it is interesting to see what Jupiter’s polar regions would look like if things were different and a big area around the poles was illuminated. This rotation movie shows what Jupiter’s south polar region would look like near the time of southern summer solstice if Jupiter’s axial tilt was much greater than it is, i.e. comparable to Saturn’s axial tilt.

He also notes the puzzling fact that, though Jupiter and Saturn are both gas giants, unlike Saturn Jupiter does not have a vortex at its poles. In fact, he points out how none of Jupiter’s storms are centered at the pole. Why one gas giant should have such pole-centered vortexes while another does not is a big mystery that illustrates how very little we know about planetary formation and evolution.

The two rotations also do not show any changes in the storms, not because they aren’t changing but because the images used were taken over too short a time span to show this.
» Read more

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Flying through Jupiter’s Great Red Spot

Cool movie time! In conjunction with the release yesterday of data from Juno’s first close fly-over of Jupiter’s Great Red Spot, the science team also released an animation of what it would be like to fly down into the Spot.

You can also download the mp4 file here. It is definitely worth watching. It illustrates forcefully how daunting and challenging it will be for the human race to ever explore the vastness of Jupiter. This simulated plunge only goes into the Great Red Spot a few hundred miles, and barely touches its dynamics.

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Juno’s look at Jupiter’s Great Red Spot

The Juno science team released its results from the spacecraft’s first close fly over of Jupiter’s Great Red Spot in July 2017.

Jupiter’s Great Red Spot is a giant oval of crimson-colored clouds in Jupiter’s southern hemisphere that race counterclockwise around the oval’s perimeter with wind speeds greater than any storm on Earth. Measuring 10,000 miles (16,000 kilometers) in width as of April 3, 2017, the Great Red Spot is 1.3 times as wide as Earth.

“Juno found that the Great Red Spot’s roots go 50 to 100 times deeper than Earth’s oceans and are warmer at the base than they are at the top,” said Andy Ingersoll, professor of planetary science at Caltech and a Juno co-investigator. “Winds are associated with differences in temperature, and the warmth of the spot’s base explains the ferocious winds we see at the top of the atmosphere.”

The future of the Great Red Spot is still very much up for debate. While the storm has been monitored since 1830, it has possibly existed for more than 350 years. In the 19th century, the Great Red Spot was well over two Earths wide. But in modern times, the Great Red Spot appears to be diminishing in size, as measured by Earth-based telescopes and spacecraft. At the time NASA’s Voyagers 1 and 2 sped by Jupiter on their way to Saturn and beyond, in 1979, the Great Red Spot was twice Earth’s diameter. Today, measurements by Earth-based telescopes indicate the oval that Juno flew over has diminished in width by one-third and height by one-eighth since Voyager times.

The storm’s estimate depth, about 200 miles, seems gigantic, but then we must remember this storm is on a gas giant that is about 88k miles in diameter, about ten times larger than Earth. The relative size of this storm to the size of Jupiter therefore is really not that much different than the relative size of big hurricanes on Earth. At the same time, the realities here are daunting, filled with unknowns, chief of which is the fact that unlike Earth, the Great Red Spot is a storm that is floating high in the atmosphere with no solid surface below it.

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Another Juno fly-by movie of Jupiter!

Cool movie time! Using 125 Juno images taken when it flew past Jupiter on its third orbit in December 2016, citizen scientist Gerald Eichstädt has produced a beautiful short movie showing that flyby. I have embedded it below.

At the link he provides very specific details on how he created this move. I found this detail however most fascinating:

Most repetitive bright and dark camera artifacts are patched. Due to the intense radiation near Jupiter, several additional bright pixels occured. Those aren’t patched in this animation.

In rarer cases, lightnings on Jupiter might also show up as bright pixels. [emphasis mine]

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The fly-by anomaly returns with Juno

The uncertainty of science: An orbital discrepancy between where engineers predict where Juno should be and where it actually is suggests it represents the recurrence of an anomaly that has been seen with numerous past planetary spacecraft.

During the 1970s when the Pioneer 10 and 11 probes were launched, visiting Jupiter and Saturn before heading off towards the edge of the Solar System, these probes both experienced something strange as they passed between 20 to 70 AU (Uranus to the Kuiper Belt) from the Sun.

Basically, the probes were both 386,000 km (240,000 mi) farther from where existing models predicted they would be. This came to be known as the “Pioneer anomaly“, which became common lore within the space physics community. While the Pioneer anomaly was resolved, the same phenomena has occurred many times since then with subsequent missions.

…Another mystery is that while in some cases the anomaly was clear, in others it was on the threshold of detectability or simply absent – as was the case with Juno‘s flyby of Earth in October of 2013. The absence of any convincing explanation has led to a number of explanations, ranging from the influence or dark matter and tidal effects to extensions of General Relativity and the existence of new physics.

However, none of these have produced a substantive explanation that could account for flyby anomalies.

The article describes in detail an effort to pin down the extent of Juno’s orbital anomaly, and to use that information to develop a model that would explain the phenomenon. Not surprisingly, they have not really come up with a comprehensive explanation. To me, the variability of the phenomenon suggests that it isn’t real, that it is either an unmeasured instrument effect or an ordinary component of solar system travel and orbital mechanics that programmers have not yet pinned down. For example, the gravitational effect of every planet and rock in the solar system will influence the path of a spacecraft, though with most that influence will be very small. It would not surprise me if this anomaly is simply the consequence of missing some of this influence.

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A storm on Jupiter

A storm of Jupiter

Cool image time! The image above, reduced in resolution to post here, was taken during Juno’s ninth close fly-by of Jupiter in late October, and shows one particular storm swirl in the gas giant’s southern hemisphere.

The Juno team today highlighted an image taken during this fly-by of Jupiter’s entire southern hemisphere, but I find this close-up more interesting. Be sure to check out the full resolution version. It appears to me that the white swirls have risen up above the gold and blue regions, casting shadows down upon them.

Unfortunately, I cannot tell you the scale of this storm, as the release does not give any details, including where in the full hemisphere image it is located. I suspect, however, that it is large enough to likely cover the Earth.

Both the full hemisphere image and the image above were processed by citizen scientists Gerald Eichstädt and Seán Doran.

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Juno’s first hints of Jupiter’s interior

Data from Juno not only suggests that the gas giant has a small fuzzy core, its storms appear to extend thousands of miles into the interior.

By studying Jupiter’s gravitational field, researchers can probe thousands of kilometres into the planet. On each close fly-by, Juno measures the planet’s complex gravitational tug. These observations have already revealed that Jupiter has a small, ‘fuzzy’, poorly defined core.

The latest results show that Jupiter’s gravitational field is askew, with different patterns in its northern and southern hemispheres, said Tristan Guillot, a planetary scientist at the Observatory of the Côte d’Azur in Nice, France. That suggests that its hydrogen-rich gas is flowing asymmetrically deep in the planet. “This is something that was not expected,” Guillot said at the meeting. “We were not sure at all whether we would be able to see that.”

Another clue to the structure of Jupiter’s interior came from how the gravity field varies with depth. Theoretical studies predict that the bigger the gravity signal, the stronger the flow of gas deep down. That information is important for teasing out whether all of Jupiter’s interior is rotating as a single solid body, or whether different layers spin separately from one another, like a set of nesting Russian dolls moving within each other.

Juno detected a gravity signal powerful enough to indicate that material is flowing as far down as 3,000 kilometres. “We’re just taking the clouds and the winds and extending them into the interior,” Kaspi said. Future work could help to pinpoint how strong the flow is at various depths, which could resolve whether Jupiter’s interior really resembles Russian dolls.

What is especially fascinating is that this first study of Jupiter shows it to appear so very different than Cassini’s first look at Saturn. Their polar regions are completely different, their storms are different, even their horizontal bands behave and look different. As I’ve said numerous times, the one given in planetary exploration is that every single planetary object we look at will be completely different from every other object.

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3D image of Jupiter

Another citizen scientist who goes by the moniker of mesno has uploaded a spectacular 3D anaglyph of one of Juno’s images of Jupiter.

I could post it here, but I’d have to reduce its resolution, and I don’t think this will work well. If you have red-blue anaglyph 3D glasses the image does a great job of showing the differing vertical heights of Jupiter’s many horizontal bands, especially since it exaggerates the vertical scale significantly to bring out these differences.

Mesno has done three other anaglyphs. Check them out. The image of the Great Red Spot really shows how this is a vast whirlpool boring deep into Jupiter’s atmosphere.

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Movie of Juno’s September 1 fly-by of Jupiter

Citizen scientist Gerald Eichstädt has done it again, assembling and enhancing the images taken by Juno in its September 1, 2017 fly-by of Jupiter to produce a spectacular movie, embedded below.

In his words,

This animation reconstructs the two and a half hours from 2017-09-01T20:45:00 to 2017-09-01T23:15:00 in 125-fold time-lapse with 25 frames per second, using 20 raw JunoCam images. JunoCam is Juno’s optical and near infrared Education and Public Outreach camera.

Trajectory data are retrieved from SPICE kernels via the NAIF spy.exe tool. The NAIF/SPICE environment is the way NASA provides spacecraft navigation data.

The movie shows Jupiter in a heavily enhanced way, in order to reveal detail.

Some of the raw images cover only part of the area required to render a still of the movie. In these cases, you’ll see the border of the raw image.

Each image is rendered into a short scene. The scences overlap and are blended.

Rendering the movie took about five days. Any shortcomings of the movie are a result of imperfect image processing.

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First Juno movie of Jupiter’s changing weather

Gerald Eichstädt at the Juno image site has produced the first attempt to assemble a movie of Juno images of the same area on Jupiter in order to show its changing weather.

JunoCam has been seeing this scene about six times from very different perspectives between about 2017-09-01T22:03 and about 2017-09-01T22:19, hence a over a little more than 15 minutes.

This animation is a first attempt to reproject the six images to a similar common perspective in order to reveal some dynamical information.

An movie covering only 15 minutes won’t show much change, but it is a start. He also notes that in making the different images match up he likely introduced some artifacts that are not real.

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Juno finds mystery in Jupiter’s aurora

The uncertainty of science: Scientists analyzing the data sent back by Juno have found that the system for generating Jupiter’s aurora does not appear to be same as the process that creates auroras on Earth.

The science here is a bit complicated. Suffice it to say that Jupiter’s aurora seems produced by a much more complex process, which actually should not have surprised anyone, considering how much larger Jupiter is and more powerful its magnetic field.

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First images released from Juno’s seventh close fly-by of Jupiter

Jupiter's South pole, August 2017

Cool image time! The raw images taken during Juno’s seventh close fly-by of Jupiter have been released. The image on the right, reduced in resolution to post here, was reprocessed by Gerald Eichstädt and shows the gas giant’s south polar region.

It is worthwhile comparing this with previous south pole images, as well as other images from this fly-by reprocessed by Eichstadt. I want to know whether anyone can identify specific storms and show how they have changed over time. Unfortunately, Juno’s orbit is large, and so it only drops in close every 53 days, allowing for these storms to change a great deal, and thus making it more difficult to link images of the same changing storm. Moreover, the images don’t necessarily show the same longitudes on Jupiter, making this even more difficult.

Nonetheless, to gain a real understanding of Jupiter’s atmosphere will require a clear understanding of the pace in which its storms and atmosphere change. These images might give us our first glimpse of this process.

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First very short movie from Jupiter

Using two Juno images of the same area, taken at slightly different times, scientists have produced what might be the first very short gif animation showing the changing circulation patterns in Jupiter’s atmosphere.

The animation is only two images long, so in a sense it isn’t a movie but a blink comparison. Moreover, the difference in circulation patterns between the two images is not strongly evident, partly because the two images have different resolution and somewhat different lighting. Nonetheless, this animation foretells what will should become possible with time, as Juno’s mission continues. Eventually its images will show the changes in the gas giant’s storms.

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One of Jupiter’s mid-sized storms

One of Jupiter's mid-sized storms

Cool image time! The Juno image on the right, cropped to show here, focuses in on one of Jupiter’s mid-sized storms near its high northern latitudes and just on the edge of the chaotic polar region.

This storm is a long-lived anticyclonic oval named North North Temperate Little Red Spot 1 (NN-LRS-1); it has been tracked at least since 1993, and may be older still. An anticyclone is a weather phenomenon where winds around the storm flow in the direction opposite to that of the flow around a region of low pressure. It is the third largest anticyclonic oval on the planet, typically around 3,700 miles (6,000 kilometers) long. The color varies between red and off-white (as it is now), but this JunoCam image shows that it still has a pale reddish core within the radius of maximum wind speeds.

Be sure to take a look at the full image, which provides a bit of context.

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The Great Red Spot

The Great Red Spot

Cool image time! The image on the right, reduced in resolution to post here, shows one of the close-ups taken by Juno during its recent close fly-by of the Great Red Spot. What makes it different is its colors.

This image of Jupiter’s iconic Great Red Spot was created by citizen scientist Björn Jónsson using data from the JunoCam imager on NASA’s Juno spacecraft.

This true-color image offers a natural color rendition of what the Great Red Spot and surrounding areas would look like to human eyes from Juno’s position. The tumultuous atmospheric zones in and around the Great Red Spot are clearly visible.

Normally scientists enhance the colors to bring out the details. This version does not, which definitely makes it a little less dramatic but more accurate. Even so, the whirls and storms within the Spot are clearly visible.

The image was taken on July 10 from about 8,600 miles away. Note also that the entire Earth would fit inside the storm.

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Juno images of Great Red Spot released

The Juno science team has released the images taken by Juno as it flew past Jupiter’s Great Red Spot on June 11.

The three images at the link were all processed by citizen scientists, who took the raw images provided immediately and enhanced the colors. Not surprisingly, the images reveal that there are storms within storms within storms inside the Spot, which itself is a storm, the largest in the solar system.

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Juno completes close fly-by of Great Red Spot

Juno has successfully completed its sixth close fly-by of Jupiter, this time dipping down to within 2,200 miles of the gas giant’s cloud tops and about 5,600 miles above the Great Red Spot.

All science instruments worked flawlessly, according the NASA press release. Images should become available in the next few days.

The next close fly-by will occur in September.

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Jupiter’s cloud-tops, up close

Jupiter's cloud tops

Cool image time! On the right is a cropped and reduced resolution section from this image from Juno. It shows the top of some of Jupiter’s clouds, swirling about chaotically.

What I find most fascinating is how this image reveals the different elevations of some of these cloud belts. The swirling clouds on the left and bottom of the image are clearly higher than the dark areas to the top and right. They are in fact casting their shadows on those lower cloud-tops.

To really understand the interactions taking place here, however, will require satellites capable of continually tracking these clouds over time. Unfortunately, Juno cannot do this. Though it will provide us periodic snapshots of specific areas, its long 53-day orbit means that it will not return to view the same areas very frequently. Making movies of the evolution of these clouds will be difficult, if not impossible.

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Looking at Jupiter’s southern hemisphere

Jupiter's southern hemisphere

Cool image time! The image on the right, reduced to post here, shows Jupiter’s south pole and much of its southern hemisphere. It was taken during Juno’s last orbital fly-by of the gas giant’s cloud tops last week, and has been enhanced by Fevig-58, an ordinary citizen who downloaded the raw image and then uploaded his enhanced version to the Juno website.

It is definitely worthwhile taking a close look at the full resolution image. At the top its shows the horizontally banded Jupiter at equatorial- and mid-latitudes that has been that planet’s familiar face for centuries. In the middle is the transitional region from those horizontal bands to the chaotic polar regions. And at the bottom is the pole, where there the storms appear to follow no pattern and form a mish-mash.

One thing about Jupiter’s pole. It appears very different than Saturn’s. While I am certain they will find a vortex of some kind there, so far there is no indication of a coherent jet stream, as seen by Saturn’s hexagon. This once again demonstrates the one unbroken rule of planetary science that has been found with every planetary mission to every planetary body, whether they be pebbles, asteroids, dwarf planets, gas giants, or moons: Every single one of them is different and unique. They might fall into a single category, say gas giants, but each has its own unique features that make it different from every other member of that category.

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First science results from Juno

The Juno science team today released their first research results since the spacecraft entered orbit around Jupiter in July 2016.

“Although many of the observations have terrestrial analogs, it appears that different processes are at work creating the auroras,” said SwRI’s Dr. Phil Valek, JADE instrument lead. “With JADE we’ve observed plasmas upwelling from the upper atmosphere to help populate Jupiter’s magnetosphere. However, the energetic particles associated with Jovian auroras are very different from those that power the most intense auroral emissions at Earth.”

Also surprising, Jupiter’s signature bands disappear near its poles. JunoCam images show a chaotic scene of swirling storms up to the size of Mars towering above a bluish backdrop. Since the first observations of these belts and zones many decades ago, scientists have wondered how far beneath the gas giant’s swirling façade these features persist. Juno’s microwave sounding instrument reveals that topical weather phenomena extend deep below the cloudtops, to pressures of 100 bars, 100 times Earth’s air pressure at sea level.

“However, there’s a north-south asymmetry. The depths of the bands are distributed unequally,” Bolton said. “We’ve observed a narrow ammonia-rich plume at the equator. It resembles a deeper, wider version of the air currents that rise from Earth’s equator and generate the trade winds.”

Juno is mapping Jupiter’s gravitational and magnetic fields to better understand the planet’s interior structure and measure the mass of the core. Scientists think a dynamo — a rotating, convecting, electrically conducting fluid in a planet’s outer core — is the mechanism for generating the planetary magnetic fields. “Juno’s gravity field measurements differ significantly from what we expected, which has implications for the distribution of heavy elements in the interior, including the existence and mass of Jupiter’s core,” Bolton said. The magnitude of the observed magnetic field was 7.766 Gauss, significantly stronger than expected. But the real surprise was the dramatic spatial variation in the field, which was significantly higher than expected in some locations, and markedly lower in others. “We characterized the field to estimate the depth of the dynamo region, suggesting that it may occur in a molecular hydrogen layer above the pressure-induced transition to the metallic state.”

What I want to see is a depth map showing where Jupiter’s atmosphere ends and its solid core begins. I expect Juno will eventually be able to give us a first glimpse.

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