Tag Archives: Jupiter

Juno finds Jupiter’s core more extended and less dense than predicted

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.

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Jupiter’s changing Great Red Spot, as seen by Juno

Montage of Jupiter's Great Red Spot since 2017
Click for full image.

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.

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New Hubble image of Jupiter

Jupiter as seen by Hubble in 2019
Click for full image.

The Hubble science team today released a new global image the telescope took of Jupiter on June 27, 2019. The photograph on the right is that image, reduced and cropped to post here. As noted by the press release about the Great Red Spot,

The Great Red Spot is a towering structure shaped like a wedding cake, whose upper haze layer extends more than 3 miles (5 kilometers) higher than clouds in other areas. The gigantic structure, with a diameter slightly larger than Earth’s, is a high-pressure wind system called an anticyclone that has been slowly downsizing since the 1800s. The reason for this change in size is still unknown.

A worm-shaped feature located below the Great Red Spot is a cyclone, a vortex around a low-pressure area with winds spinning in the opposite direction from the Red Spot. Researchers have observed cyclones with a wide variety of different appearances across the planet. The two white oval-shaped features are anticyclones, like small versions of the Great Red Spot.

Another interesting detail is the color of the wide band at the equator. The bright orange color may be a sign that deeper clouds are starting to clear out, emphasizing red particles in the overlying haze.

In many ways Hubble’s images of Jupiter are comparable to those taken by Juno, except that Hubble can’t zoom in as close.

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The great storms of Jupiter

The Great Red Spot and its trailing storms
Click for full image.

Close-up

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.

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Jupiter’s changing Great Red Spot

The changing Great Red Spot
Click for full resolution image.

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.

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Jupiter in 3D

Jupiter in 3D

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.

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Jupiter’s atmosphere reacts quickly to the solar wind

New data from ground-based telescopes show that the atmosphere of Jupiter quickly changes due to changes in the solar wind, and that these changes descend deeper into the atmosphere than expected.

Auroras at Earth’s poles (known as the aurora borealis at the North Pole and aurora australis at the South Pole) occur when the energetic particles blown out from the Sun (the solar wind) interact with and heat up the gases in the upper atmosphere. The same thing happens at Jupiter, but the new observations show the heating goes two or three times deeper down into its atmosphere than on Earth, into the lower level of Jupiter’s upper atmosphere, or stratosphere.

…”What is startling about the results is that we were able to associate for the first time the variations in solar wind and the response in the stratosphere – and that the response to these variations is so quick for such a large area,” said JPL’s Glenn Orton, co-author and part of the observing team.

Within a day of the solar wind hitting Jupiter, the chemistry in its atmosphere changed and its temperature rose, the team found. An infrared image captured during their observing campaign in January, February and May of 2017 clearly shows hot spots near the poles, where Jupiter’s auroras are.

Considering Jupiter’s size, for these effects to extend so quickly really is startling.

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The eye of a storm on Jupiter

Storm on Jupiter

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.

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The Great Red Spot from Juno

Jupiter's Great Red Spot

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

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Juno images volcano plume on Io

Volcano plume on Io

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.

This image is not the first time a spacecraft has caught an active volcanic plume on Io. In fact, practically the very first good images of Io during the Voyager 1 fly-by did this, confirming then that volcanoes are active on the Jupiter moon.

What this image further confirms however is how active Io really is. Volcanoes erupt there so continuously that it apparently isn’t that hard to catch one as it happens.

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Movie of Juno’s October 29, 2018 Jupiter fly-by

Cool movie time! Citizen scientist Gerald Eichstädt has created a time lapse movie using the images taken by Juno during its sixteenth close fly-by of Jupiter on October 29, 2018.

The movie is embedded below the fold. Quite spectacular. The colors are enhanced to bring out the details, and begins looking down at Jupiter’s north hemisphere at night.
» Read more

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Jupiter’s upper clouds

Jupiter's upper clouds

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.

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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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Radiation maps of Europa

By culling together data from Voyager 1 and the Galileo orbiter, scientists have created a radiation map of the surface of Europa.

Using data from Galileo’s flybys of Europa two decades ago and electron measurements from NASA’s Voyager 1 spacecraft, Nordheim and his team looked closely at the electrons blasting the moon’s surface. They found that the radiation doses vary by location. The harshest radiation is concentrated in zones around the equator, and the radiation lessens closer to the poles.

Mapped out, the harsh radiation zones appear as oval-shaped regions, connected at the narrow ends, that cover more than half of the moon.

…In his new paper, Nordheim didn’t stop with a two-dimensional map. He went deeper, gauging how far below the surface the radiation penetrates, and building 3D models of the most intense radiation on Europa. The results tell us how deep scientists need to dig or drill, during a potential future Europa lander mission, to find any biosignatures that might be preserved.

The answer varies, from 4 to 8 inches (10 to 20 centimeters) in the highest-radiation zones – down to less than 0.4 inches (1 centimeter) deep in regions of Europa at middle- and high-latitudes, toward the moon’s poles.

This model, which by the way probably has large margins of error, will be used as a guide by the Europa Clipper scientists now planning that orbiter’s mission.

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Astronomers discover 10 more Jupiter moons

Worlds without end: Astronomers, while searching for objects in the Kuiper Belt, have discovered 10 more Jupiter moons.

All the newfound moons are small, between about 1 and 3 kilometres across. Seven of them travel in remote orbits more than 20 million kilometres away from Jupiter, and in the opposite direction from the planet’s rotation. That puts them in the category known as retrograde moons.

The eighth moon stands out because it travels in the same region of space as the retrograde moons, but in the opposite direction (that is, in the same direction as Jupiter’s spin). Its orbit is also tilted with respect to those of the retrograde moons. That means it could easily smash into the retrograde moons, pulverizing itself into oblivion. It may be the leftovers of a bigger cosmic collision in the past, Sheppard says.

Jupiter’s moons are named after gods with connections to the mythological Jupiter or Zeus. Sheppard has proposed naming the oddball Valetudo, after one of Jupiter’s descendants, the Roman goddess of hygiene and health.

The ninth and tenth newfound moons orbit closer to Jupiter, moving in the same direction as the planet.

I predict that these are not the last moons of Jupiter to be discovered. As our observing skills improve, more are certain to pop up.

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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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Europa water plume detected in old Galileo data

Using old Galileo data and new techniques of analysis scientists have uncovered a water plume on Europa that the spacecraft flew through in 1997.

Over the course of 5 minutes, spikes the spacecraft recorded with its magnetic and plasma sensors reflected the alterations that a veil of ejected water, from one or many vents, could cause in a region matching the telescope observations, they report today in Nature Astronomy. This indicates that a region of the moon potentially 1000 kilometers long could host such activity, though it is impossible to say whether this is a single plume or many, like the complex system of fractures and vents seen on Enceladus. Indeed, on its own, this evidence was too weak to tie to erupting water in a 2001 study describing it, the authors add, but it fits well with the Hubble and modeled evidence.

As indicated by the quote above, the result has a lot of uncertainty.

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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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Scientists catch a big volcano eruption on Io

Scientists reviewing twenty year old data from the Galileo orbiter that studied Jupiter and its moons in the 1990s have identified the most intense volcanic eruption yet found on Io.

While looking through the NIMS temperature data, Davies and his colleagues spotted a brief but intense moment of high temperatures that cooled oddly quickly. This signal showed up as a spike in heat from a region in the southern hemisphere called Marduk Fluctus. First, the researchers saw a heat signal jump to 4–10 times higher than background, or relatively normal, levels. Then just a minute later, the signal dropped about 20%. Another minute later, the signal dropped another 75%. Twenty-three minutes later, the signal had plummeted to the equivalent of the background levels.

This signature resembled nothing Davies had seen before from Io. The lava flows and lava lakes are familiar: Their heat signals peter out slowly because as the surface of a lava flow cools, it creates a protective barrier of solid rock over a mushy, molten inside. Heat from magma underneath conducts through this newly formed crust and radiates from Io’s surface as it cools, which can take quite a long time.

This new heat signature, on the other hand, represents a process never before seen on Io, Davies said: something intense, powerful, and—most important—fast.

There’s only one likely explanation for what the instruments saw, explained Davies, whose volcanic expertise starts here on Earth. Large, violent eruptions like those seen at Stromboli are capable of spewing huge masses of tiny particles into the air, which cool quickly.

The article makes it sound like we’ve never seen this kind of eruption on Io before, which isn’t really true. Such eruptions have been imaged, but this is the first time that infrared data of their temperature spike was captured, thus confirming its nature.

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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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