Tag: Juno

Juno enters and then recovers from safe mode

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During its most recent close fly-by of Jupiter on April 4, 2025 — its 71st — the orbiter Juno went into safe mode two different times, causing its science instruments to shut down.

The mission operations team has reestablished high-rate data transmission with Juno, and the spacecraft is currently conducting flight software diagnostics.The team will work in the ensuing days to transmit the engineering and science data collected before and after the safe-mode events to Earth.

Juno first entered safe mode at 5:17 a.m. EDT, about an hour before its 71st close passage of Jupiter — called perijove. It went into safe mode again 45 minutes after perijove. During both safe-mode events, the spacecraft performed exactly as designed, rebooting its computer, turning off nonessential functions, and pointing its antenna toward Earth for communication.

Since arrival in its present Jupiter orbit in 2016 Juno has operated almost perfectly, having experienced only two other safe mode events, once in 2016 and a second in 2022. The two recent events on this most recent fly-by suggest however that the harsh environment surrounding Jupiter might be beginning to impact the spacecraft.

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Juno data proves volcanism on Io involves numerous lava lakes

11:47 am

The lava lakes of Io
A global map of Io’s lava lakes. Click for original figure.

Based on data and imagery produced by the Jupiter orbiter Juno as it made a series of fly-bys of the moon Io from 2022 to 2024, scientists have now mapped at least 40 lava lakes amid the numerous volcanoes on the planet. The map above, figure 2 of the paper, shows their location and approximate relative size across Io’s surface. From the paper’s abstract:

Recent observations from the Juno spacecraft have revealed at least 40 lava lakes on Io, one of Jupiter’s moons, using the JIRAM (Jovian InfraRed Auroral Mapper) imager. Most of the large depressions on Io, known as paterae, show signs of heat, indicating that lava lakes are common. The lava lakes vary in size from 10 to 100 km in diameter and have a thin crust, about 5–10 m thick, that appears to be a few years old. The heat observed mainly comes from the larger crust, not the small exposed lava, so it is hard to measure the total heat output from just the thermal data. Additionally, eight of these lava lakes are new discoveries and were not previously known as active hotspots.

One aspect of these lakes found repeatedly in this new data is that their lava appears to rise and fall as a unit, as if the lake’s floor bed acts like a huge piston pushing the whole lake up and down from below, rather than lava entering in or draining out from a central vent. This conclusion appears to settle the debate between these models for explaining why the lava almost never rises high enough to pour out from the lake. Instead, the lakes themselves appear to be stable features, not volcanic calderas from which lava flows to build a mountain.

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Juno detects the largest volcanic event on Io yet

9:51 am

Changes on Io since April 2024
Changes on Io since April 2024. Click for original image.

Infrared detection of volcanic hot spot
Infrared detection of volcanic hot spot.
Click for original image.

Using Juno’s Italian JIRAM infrared instrument image as well as its optical camera, scientists have detected what appears to be the largest volcanic event yet measured on the Jupiter moon Io, covering an area larger than Lake Superior,

Scientists with NASA’s Juno mission have discovered a volcanic hot spot in the southern hemisphere of Jupiter’s moon Io. The hot spot is not only larger than Earth’s Lake Superior, but it also belches out eruptions six times the total energy of all the world’s power plants.

…The JIRAM science team estimates the as-yet-unnamed feature spans 40,000 square miles (100,000 square kilometers). The previous record holder was Io’s Loki Patera, a lava lake of about 7,700 square miles (20,000 square kilometers). The total power value of the new hot spot’s radiance measured well above 80 trillion watts.

The pictures above were taken by Juno’s optical camera during the last three close flyby’s, looking down at the south pole, with the red arrows indicating the change to the pole’s right during each pass. The infrared image to the right shows a similar view during the fly-by, and shows that same hot spot as the bright area to the pole’s right.

Juno will do another fly-by of Io in March, though from a greater distance. Scientists plan to use both instruments to see how this hot spot has changed again since the end of December.

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Juno spots changes on Io’s surface in just a two-month span

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Before and after images by Juno of volcanic ring on Io
Click for original image.

New photos taken just two months apart by Juno of a region dubbed Nusk Patera on the Jupiter moon Io showed the appearance of a distinct ring that had hardly been there before.

The pictures, taken during two recent fly-bys of the moon, are above, and show the change. From the caption:

A red ring formed around Nusku Patera in the two months between the spacecraft’s 58th flyby on Feb. 3, 2024, and its 60th on April 9, 2024. The ring obscures some nearby features like Creidne Patera. This ring, 683 miles (1,100 kilometers) wide is likely from a Pele-type plume rich in sulfur. Similar transient red rings were observed by NASA’s Galileo mission around Grian Patera and Surt and were associated with intense but short-lived thermal “outburst” eruptions.

In other words, sulfur from eruption from the central vent/caldera was flung into the sky enough that when it eventually settled back down it landed in a ring about 340 miles away from the center.

Other data from Juno, also released this week here and here, detected fresh lava flows at another volcanic region of Io dubbed, Zal Patera.

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Io’s volcanoes get their lava from separate magma chambers, not a global underground ocean of magma

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Io's interior as presently theorized
Click for original animation.

Using data collected from Juno’s multiple fly-bys of the Jupiter moon Io, scientists now hypothesize that the moon does not have a global underground ocean of magma, feeding its many volcanoes, but that instead each volcano is fed its lava from a separate magma chamber.

The graphic to the right illustrates the present conclusion. You can read the paper here [pdf]. From the press release:

The Juno team compared Doppler data from their two flybys with observations from the agency’s previous missions to the Jovian system and from ground telescopes. They found tidal deformation consistent with Io not having a shallow global magma ocean.

“Juno’s discovery that tidal forces do not always create global magma oceans does more than prompt us to rethink what we know about Io’s interior,” said lead author Ryan Park, a Juno co-investigator and supervisor of the Solar System Dynamics Group at JPL. “It has implications for our understanding of other moons, such as Enceladus and Europa, and even exoplanets and super-Earths. Our new findings provide an opportunity to rethink what we know about planetary formation and evolution.” [emphasis mine]

The highlighted words indicate the significance of this data. It possibly suggests that the underground oceans of water that have been theorized for these other moons — where life could possibly exist — might be mistaken. Instead, they might have smaller pockets of water, similar to Io’s many magma chambers.

Everything here however is uncertain, including these new conclusions about Io. We just don’t have enough data from any of these moons to make any definitive conclusions.

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A map of Io’s hot spots based on Juno data

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The hot spots on Io
Click for original image.

The uncertainty of science: Using the JIRAM infrared camera on the Jupiter orbiter Juno, scientists have now created a global map of volcanic activity, showing where it appears the hottest and greatest activity is located.

That data is illustrated by the graphic to the right, taken from figure 1 of the paper. The top row shows the coverage of the planet, with Io’s southern hemisphere getting the fewest observations. The bottom row shows the observed regions with the greatest heat. This quote from the abstract is most revealing:

Using JIRAM, we have mapped where volcanoes are producing the most power and compared that to where we expect higher heat flow from the interior models. Our map doesn’t agree with any of these models very well. JIRAM observed more volcanic activity at the poles than we expected to see based on previous observations. However, since the south pole was only observed twice, it’s possible that these observations don’t represent the average volcanic activity of the south pole. Very bright volcanoes that may have been continuously active for decades were also imaged during these Juno fly-bys, some of which are nearer the poles than the equator.

The conflict between the data and the theories could very well be explained simply by the short term nature of these observations. The models could very well be right, over centuries. For example, the new volcano discovered by Juno is near the equator, suggesting with time those models will turn out to be correct.

Or not. A lot more observations will have to be made of Io before any model of its volcanic activity can be considered trustworthy.

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Juno discovers new volcano on Io

10:24 am

New volcano on Io
Click for original image.

By comparing images taken twenty-seven years apart by the the Jupiter orbiters Galileo and Juno, scientists have discovered that during that time a new volcano appeared on the volcano-strewn Jupiter moon Io.

The two pictures to the right show the surface change on Io during those 27 years.

Analysis of the first close-up images of Io in over 25 years, captured by the JunoCam instrument on NASA’s Juno mission, reveal the emergence of a fresh volcano with multiple lava flows and volcanic deposits covering an area about 180 kilometres by 180 kilometres. The findings have been presented at the Europlanet Science Congress (EPSC) in Berlin this week.

The new volcano is located just south of Io’s equator. Although Io is covered with active volcanoes, images taken during NASA’s Galileo mission in 1997 did not see a volcano is in this particular region – just a featureless surface.

If anything, it has been somewhat surprising how little change the new Juno images have found on Io’s surface, considering its intensely active volcanic geology, with volcano plumes from eruptions captured in images repeatedly. Some volcanoes have shown change, but new features such as this new volcano have not previously been identified.

At the same time, the amount of high resolution imagery of the planet’s surface has been somewhat limited. Galileo sent back far fewer pictures than planned because its main antenna never deployed, and Juno had only a handful of close fly-bys. It will take a mission dedicated to studying Io to better map its violent surface.

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Juno infrared data confirms existence of at least eleven lava lakes on Io

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Cartoon describing Io's lava lakes
Click for original image.

Using infrared data from the Jupiter orbiter Juno, obtained during a close fly-by in May 2023 of the moon Io, scientists have identified what appear to be at least eleven active lava lakes, all filled with liquid magma under a surface crust and having a stable perimeter that apparently does not overflow the rim.

You can read the research paper here. The graphic to the right is figure 6 from the paper, describing two models for explaining why the lava in these lakes never rises high enough to pour out.

Unlike the April fly-by, which got as close as 10,777 miles and produced some amazing imagery, the May fly-by only got within 22,000 miles, but its course allowed Juno’s infrared instruments to collect good global data for six hours.

The JIRAM data reveal a common set of thermal characteristics for at least ten patera, with bright “thermal rings” around the perimeter of their floors. Loki, Surt, Fuchi, Amaterasu, Mulungu, Chors, and Dazhbog paterae, two unnamed paterae (here referred to as UP1 and UP2), and two other potential additional paterae (not discussed further because the spatial resolution is poor), all show the same pattern of surface temperatures.

That data suggested that each patera was a hot lava lake, with a stable rim in which little magma ever overflowed. As the scientists conclude in their paper, “Present findings highlight Io’s abundant lava reserves, resembling lava lakes on Earth in some ways, yet distinctly different from any other phenomena observed in the Solar System.” The scientists also note that no missions are being planned right now to get a better look at Io.

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Juno looks down at Jupiter

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Jupiter as seen by Juno on May 12, 2024
Click for original image.

Cool image time! The picture to the right, rotated, reduced, and annotated to post here, was taken on May 12, 2024 by the camera on the Jupiter orbiter Juno during its most recent close-fly of the gas giant, its sixty-first since it arrived in 2016. The picture was snapped when Juno was about 34,674 miles away from Jupiter as it flew over the northern hemisphere.

Citizen scientist Thomas Thomopoulos then took that raw image and enhanced and enlarged it to bring out the storm details. You can see the distinct bands that cut across Jupiter’s equatorial and mid-latitudes. The reddish band is where the Great Red Spot is located, though that spot is not seen in this picture.

As we move north those bands slowly transition into the chaotic storms of the polar regions, which also circle the pole but do not form bands.

For scale I have added a circle that approximates the Earth’s size in comparison to Jupiter. You will notice that some of those polar storms are as big if not bigger than the Earth itself. To think we presently have any real understanding of the processes that create Jupiter’s climate and weather systems is to be arrogant beyond belief.

Fortunately, the scientists who study Jupiter are not that arrogant, though they often can’t admit it and are forced to sound otherwise when ignorant journalists and NASA managers demand more answers from them then are possible. The scientists understand that what makes pictures like this intriguing is not what it tells us but the amount of ignorance it reveals. To get funding for future research however sometimes requires they sound more knowledgeable than they are.

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Io on Juno’s 60th close fly-by of Jupiter

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Volcano Plumes on Io
Click for original image.

Io as seen by Juno
Click for original image.

The photos above and to the right were both taken by Juno during its 60th close fly-by of Jupiter on April 9, 2024. The image above, cropped slightly to post here, was processed by citizen scientist Gerald Eichstädt, who states the following:

The stretched and enlarged crop is derived from a reprojected Io image with a margin of 100 km greater than Io’s nominal radius. Two plumes are obvious. The plume on the night siide is visible in several frames of the PJ60 Io sequence.

That Juno captures plumes like this on every close fly-by tells us the extent of activity that is on-going on the moon. Basically, eruptions are continuous and never ending.

The image to the right, reduced and sharpened to post here, was processed by Eichstädt and enhanced by citizen scientist Thomas Thomopoulos. It gives us a global view of Io’s many volcanoes and flood lava plains.

During that 60th fly-by Juno’s closest approach to Io was 10,778 miles. Though close, this is not as close as the approach of 930 miles during the 57th and 58th fly-bys. Nor will future fly-bys be as close again. This is essentially Juno’s last close look at the volcano world.

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Scientists: Europa produces oxygen on its surface, but less than expected

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Graphic of Europa
Click for original image.

The uncertainty of science: Scientists using data from a 2022 flyby of the Jupiter moon Europa by the orbiter Juno have determined that the moon produces about 1,000 tons of oxygen every 24 hours on its surface, a large amount but less than most predictions based on previous indirect observations.

The paper’s authors estimate the amount of oxygen produced to be around 26 pounds every second (12 kilograms per second). Previous estimates range from a few pounds to over 2,000 pounds per second (over 1,000 kilograms per second). Scientists believe that some of the oxygen produced in this manner could work its way into the moon’s subsurface ocean as a possible source of metabolic energy.

You can read the paper here. The graphic shows the basic process, as presently theorized. What remains unknown is how or even if that oxygen is transported downward to the theorized underground ocean of liquid water. That the amount created is on the very low end of previous estimates suggests that there will be less free oxygen to support life in that ocean than expected.

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The volcanic world of Io, as seen by Juno in all its fly-bys

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Map of Io
Click for full resolution image.

The mosaic of images above, reduced and sharpened to post here, was compiled by citizen scientists Gerald Eichstädt, Jason Perry, and John Rogers from images taken of the Jupiter moon Io during the three close fly-bys by the orbiter Juno that occurred during its 55th, 57th, and 58th orbits. From the caption:

Global map of Io by JunoCam, combining maps from PJ55, PJ57 and PJ58. Both the sunlit side and the Jupiter-lit-dark side are included. PJ55 map by Gerald Eichstädt; PJ57 map by Jason Perry; PJ58 map by Gerald Eichstädt and John Rogers. Some scaling and shifting was performed in order to align the maps with each other and with the USGS Voyager/Galileo map. Colours were adjusted for better compatability. –John Rogers.

A labeled version, showing the names of many volcanoes but only of the areas photographed during the most recent 58th orbit fly-by on February 3, 2024, can be seen here.

As Juno’s later fly-bys will be progressively farther away, we will no longer get better views of Io until another spacecraft arrives in a Jupiter orbit capable to returning to Io, possibly decades from now. Though Europa Clipper will arrive in Jupiter orbit April 2030, that orbit is designed to repeatedly fly close past Europa, and will likely never get close to Io.

Thus, this map provides a baseline for determing any changes that occur on Io in the coming years.

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Juno completes its closest approach of the Jupiter moon Io

9:53 am

Io on February 3, 2024
Click for full image.

The Jupiter orbiter Juno successfully completed its 58th close fly-by of the gas giant, during which it also made its closest approach to the volcanic moon Io, zipping past at a distance of 932 miles. The image of Io to the right, cropped and reduced to post here, was taken at that closest Io approach, and shows a mountain on the horizon as well as a large shield volcano in the center (the dark splotch), with a major lava flow to the south. The picture was processed by citizen scientist Brian Swift.

Another image, processed by Björn Jónsson, shows the differences at one volcano dubbed Loki between the December 30, 2023 and the February 3, 2024 flybys. It appears that the brightness of the apron of lava that surrounds the volcano changes significantly depending on the lighting and the angle of view. In December it was almost black. In February it was greyish silver, almost shiny.

Another image, processed by Andrea Luck, captured faint eruption plumes on Io’s edge, caused by an ongoing eruption just beyond the horizon.

Juno still has four more flybys of Io coming up, but none will be as close as the February 3rd approach.

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The Surt volcano on Io

1:19 pm

The Surt volcano on Io in close-up
Click for original image.

Cool image time! The picture to the right, rotated, reduced, and sharpened to post here, was taken by Juno during its 57th close-fly of Jupiter on December 30, 2023. It shows of one of the many volcanoes that cover and continually recoat the surface of the Jupiter moon Io.

The picture was initially processed by citizen scientist Gerald Eichstädt. Thomas Thomopoulos then zoomed in and added additional enhancements to this particular area. (I thank Thomas for his additional help in making this post happen.)

The location is an active volcano named Surt, which has been observed to erupt several times since the 1970s, with its February 2001 eruption the most powerful yet observed on Io, though the pictures by the Jupiter orbiter Galileo taken before and after revealed few significant surface changes.

The picture itself shows a region where major changes have definitely occurred. The large arc of mountains across the photo’s center suggests the remaining half of a large caldera, its northern half now either buried or destroyed. The deep obvious hole inside that crescent appears to be the main vent from which the recent eruptions have spewed, as indicated by the light-colored apron surrounding it.

In the southwest section of that large mountain arc is a distinct ridgeline with a small circular curve in its middle that suggests a former volcanic cone, its northern half now gone.

To put it mildly, Io appears a very alien place, shaped entirely and continuously by endlessly volcanic eruptions that spread lava across its entire surface repeatedly.

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First Juno images of Io from December 30th fly-by

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Io as seen by Juno on December 30, 2023
For original global image go here. For original of inset go here.

The first raw Juno images taken of the Jupiter moon Io during its close fly-by on December 30, 2023, the closest in more than twenty years, have been released by the science team and citizen scientists have begun processing them.

The global picture to the right, rotated and reduced to post here, was processed by Kevin Gill. The inset of the volcanic mountains near the terminator was processed by Thomas Thomopoulos. As he notes, to obtain better detail he enhanced the colors and image and then zoomed in.

In the inset, note the northeast flows coming off the two mountains near the center. With the lower mountain, this flow appears to lie on top of a larger flow that extended out almost to the mountain to the right.

Io is a planet of continuous volcanic activity. For example, when the global image above was taken, the plume of a volcano eruption was visible on the right horizon, as shown in this version, its exposure adjusted by Ted Stryk. Catching such eruptions on Io is not unusual, considering its continuous volcanic activity generated by the tidal forces the planet undergoes from its orbit around Jupiter. In fact, the very first plume was imaged in 1979 by Voyager 1 during its short fly-by, and proved a hypothesis of such activity that scientists had only published one week earlier.

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Juno’s closest image of Europa suggests recent surface activity

11:18 am

Juno's best image of Europa
Click for original image.

Analysis by scientists of the closest image of Europa taken during Juno’s close-fly on September 29, 2022 suggests that a particular strange feature, dubbed the “platypus” due to its shape, might be very young and indicate recent surface activity that could be related to underground liquid water.

That picture, reduced and sharpened to post here, is to the right. It is figure 2 of the paper. The description of this photo from the abstract:

Intricate networks of cross-cutting ridges and lineated bands surround an intriguing 37 km (east-west) by 67 km (north-south) chaos feature with a concentric fracture system, depressed matrix margins, and low-albedo materials potentially associated with brine infiltration. The morphology and local relief of the chaos feature are consistent with formation in the collapse of ice overlying a salt-rich lens of subsurface water. Low-albedo deposits, similar to features previously associated with hypothesized cryovolcanic plume activity, flank nearby ridges. The SRU’s high-resolution view of many types of features in a single image allows us to explore their regional context and greatly improve the geologic mapping of this part of Europa’s surface. The image reveals several relatively youthful features in a potentially dynamic region, providing baselines for candidate locations that future missions can investigate for present day surface activity.

SRU is Juno’s Stellar Reference Unit camera, designed to take pictures using only the low light of Jupiter reflected onto nighttime surfaces of Jupiter’s moons. It took this photo when Juno was only 256 miles above the surface.

This feature will obviously become a prime target for Europa Clipper when it arrives into orbit around Jupiter in April 2030. From this vantage point — safer than continuous exposure to Jupiter’s magnetosphere while in orbit around Europa — the spacecraft will do 44 close-flys of the moon.

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Scientists detect salts and carbon-based molecules on Ganymede

8:47 am

Ganymede as seen by Juno
A close-up image taken during the June 7, 2021
Juno fly-by of Ganymede Click for original image.

Using data obtained during a close fly-by of Ganymede by Juno in June 2021, scientists have detected evidence of salts and organic carbon-based molecules.

On June 7, 2021, Juno flew over Ganymede at a minimum altitude of 650 miles (1,046 kilometers). Shortly after the time of closest approach, the JIRAM instrument acquired infrared images and infrared spectra (essentially the chemical fingerprints of materials, based on how they reflect light) of the moon’s surface. Built by the Italian Space Agency, Agenzia Spaziale Italiana, JIRAM was designed to capture the infrared light (invisible to the naked eye) that emerges from deep inside Jupiter, probing the weather layer down to 30 to 45 miles (50 to 70 kilometers) below the gas giant’s cloud tops. But the instrument has also been used to offer insights into the terrain of moons Io, Europa, Ganymede, and Callisto (known collectively as the Galilean moons for their discoverer, Galileo).

The JIRAM data of Ganymede obtained during the flyby achieved an unprecedented spatial resolution for infrared spectroscopy – better than 0.62 miles (1 kilometer) per pixel. With it, Juno scientists were able to detect and analyze the unique spectral features of non-water-ice materials, including hydrated sodium chloride, ammonium chloride, sodium bicarbonate, and possibly aliphatic aldehydes.

The data indicated that the salts and organics were most concentrated in Ganymede’s equatorial regions, which are less impacted by Jupiter’s strong magnetic field. The scientists think these materials originally came from the brine of an underground ocean that somehow reached the surface, though this hypothesis remains unconfirmed.

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More Io images by Juno, enhanced by citizen scientists

1:27 pm

Io in natural and enhance colors
Click here for original of top image,
here for bottom.

Since Juno completed its 55th close swing past Jupiter on October 15, 2023, including the closest fly by of its volcano-covered moon Io since the 1990s, citizen scientists have been grabbing the spacecraft’s raw images of the moon and enhancing them to bring out the details.

Immediately after the fly-by I posted on October 17, 2023 the top image to the right, processed by Ted Stryk. This version attempted to capture the view of Juno is natural color. As I noted then, “The dark patches are lava flows, with the dimensions of mountains along the terminator line between night and day clearly distinguishable.”

The bottom picture to the right was first processed by citizen scientist Gerald Eichstädt, who like Stryk attempted to capture Io’s natural colors. Thomas Thomopoulos then took Eichstädt’s image and enhanced the colors as well as reduced the brightness, in order to bring out the details as much as possible.

I have rotated, cropped, and reduced this bottom image further to post it here.

In comparing this image with earlier pictures of Io, taken by both Juno and Galileo in the 1990s, there is evidence that some of the lava flows visible now have changed significantly in the intevening time. This is not a surprise, as volcanic eruptions take place on Io so frequently that it has not unusual to capture one in the rare times close up images are possible, going back to the discovery of volcanic activity by Voyager-1 in 1979.

It will take a bit of time for scientists, both professional and amateur, to pick out the specific changes. That work will be further aided by Juno’s next fly-by on December 30, 2023, where it will dip to less than 1,000 miles of the surface.

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New Io images from Juno

9:43 am

Io as seen on October 15, 2023 by Juno
Click for original image.

The Jupiter orbiter Juno completed its 55th close pass of the gas giant on October 15, 2023, which also included a close pass of the Jupiter moon Io. The science team has now released the first images of Io from that fly-by, and several citizen scientists have released their processed versions.

The picture to the right, cropped, reduced, and sharpened to post here, was processed by Ted Stryk. It is the best view seen of this volcano-covered world since the Galileo orbiter in the 1990s. The dark patches are lava flows, with the dimensions of mountains along the terminator line between night and day clearly distinguishable.

An even closer look will occur during Juno’s 57th Jupiter orbit on December 30, 2023, when it will get within 1000 miles of Io’s surface, crossing the mid- to high latitudes of the planet’s western hemisphere.

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Juno gets new close-up images of Jupiter’s moon Io

9:57 am

Io as seen by Juno in July 2023
Click for original image.

During its July close fly-by of Jupiter the orbiter Juno also flew past the moon Io, getting within 14,000 miles. The picture to the right, cropped and reduced to post here, was one of the images taken during that fly-by and subsequently processed and color enhanced by citizen scientist Thomas Thomopoulos.

The picture was taken at about the spacecraft’s closest point. It shows the splotched and volcanic surface of Io, which because it orbits close to Jupiter tidal forces cause it to have an intensely active volcanic surface. All the black features are either volcanoes or lava flows. This set of all of Juno’s Io images taken during the fly-by, enhanced by citizen scientist Gerald Eichstädt, also shows a volcanic plume in the shadowed portion of the planet, just beyond the terminator, which Eichstädt believes is a mountain dubbed Tohil Mons.

Even closer flybys are scheduled for December ’23 and February ’24, both getting within 1,000 miles of the surface.

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Juno’s next fly-by of Io coming on July 30

9:54 am

Io as seen by Juno
An image of Io from the March fly-by

The Juno science team is gearing up for the spacecraft’s next fly-by of the Jupiter moon Io, scheduled for July 30, 2023.

When NASA’s Juno mission flies by Jupiter’s fiery moon Io on Sunday, July 30, the spacecraft will be making its closest approach yet, coming within 13,700 miles (22,000 kilometers) of it. Data collected by the Italian-built JIRAM (Jovian InfraRed Auroral Mapper) and other science instruments is expected to provide a wealth of information on the hundreds of erupting volcanoes pouring out molten lava and sulfurous gases all over the volcano-festooned moon.

The image to the right was taken from 33,000 miles during the March fly-by, almost three times farther away. The dark spots are volcanoes, and some showed significant change from earlier images.

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Lightning on Jupiter

10:53 am

Lightning on Jupiter
Click for original image.

Cool image time! The picture to the right, cropped and reduced to post here, was taken on December 30, 2020 by Juno during its 31st close fly-by of Jupiter, and was enhanced and processed by citizen-scientist Kevin Gill.

In this view of a vortex near Jupiter’s north pole, NASA’s Juno mission observed the glow from a bolt of lightning. On Earth, lightning bolts originate from water clouds, and happen most frequently near the equator, while on Jupiter lightning likely also occurs in clouds containing an ammonia-water solution, and can be seen most often near the poles.

Juno was about 20,000 miles above Jupiter’s clouds when it took this picture, located at about 78 degrees north latitude.

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The grooved surface of Ganymede

9:39 am

The grooves of Ganymede
Click for original image.

Cool image time! The picture to the right, reduced to post here, was taken on June 7, 2021 when the Jupiter orbiter Juno did a close flyby of the moon Ganymede, taking four pictures.

Citizen scientists Gerald Eichstädt and Thomas Thomopoulos have now reprocessed parts of those images to bring out the details more clearly (the other new versions available here, and here).

I have chosen to highlight the picture to the right however because it so clearly shows the puzzling grooves that cover much of Ganymede’s surface. While these parallel grooves in many ways mimic the grooves often seen on top of valley glaciers on Earth and Mars, on Ganymede they do not follow any valley floor. Instead, they form patches of parallel grooves that travel in completely different directions, depending on the patch. At the moment their origin is not understood.

These grooves are one of the mysteries that Europe’s Juice probe will attempt to solve when it arrives in orbit around Jupiter in 2031.

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Jupiter’s clouds in 3D

12:37 pm

Jupiter's clouds in 3D
Click for original image.

Another cool image! The picture to the right, cropped and reduced to post here, was created by a team of citizen scientists from a raw Juno image during its 40th close fly-by of Jupiter. From the caption:

Visual interpretation of relief (exaggerated) on Jupiter based on depth estimation from a single image

2D process: Enhanced RGB, enlargement and crop of image taken on 2022-02-25 02:21 UT – perijove 40 – Junocam

Process on 3d image : not based on a DTM, but a visual interpretation of the surface by depth estimation from a single image

The white box on the global image on the upper left marks the approximate area coverd by the oblique 3D picture. Though the vertical relief is greatly exaggerated as well as simulated from a flat image, it provides us a nice sense of the turbulent nature of Jupiter’s more active bands. The larger structures in the colored band appear to act like giant waves in a river rapids. And for reasons not yet understood, the more active areas of that upper atmosphere is divided into bands determined by latitude.

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Juno captures close-up images of Jupiter’s moon Io

10:25 am

Io as seen by Juno

On March 1, 2023 the Jupiter orbiter Juno passed within 33,000 miles of the gas giant’s moon Io, getting its first close-up images.

Several citizen scientists have processed those images. The photo to the right, cropped and reduced to post here, was created by Andrew R Brown. This particular picture was one of five taken by Juno during the fly-by. Jason Perry processed all five here, with this caption:

Most of the dark spots seen across Io’s surface are the result of volcanic eruptions. These include East Girru, a dark spot that was not seen the last time Io was seen at this resolution during the New Horizons encounter with Jupiter in February 2007. East Girru was undergoing a major eruption at the time but hadn’t had time to produce a new lava flow before the end of the week-long encounter. This small flow field, measuring 3,200 square kilometers (1,390 square miles) in size, may have also been reactivated during an eruption in October 2021, as seen by Juno JIRAM.

Another apparent surface change is at Chors Patera, which has undergone a significant reddening since Galileo last observed it in October 2001. Reddish materials on Io are indicative of the presence of short-chain sulfur and are often associated with high-temperature, silicate volcanism. Additional dark spots near the terminator, the boundary between Io’s day and night sides, are the shadows of tall mountains. The dark spot at middle right in the upper right image may be due a mountain 5500 meters (18,000 feet) tall.

The smallest object resolved in this image is about 22 miles across.

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Juno’s camera experiences temperature problem

8:57 am

Because of an unexpected rise in its temperature, Juno’s camera was unable to take its full schedule of planned images during its January 22, 2023 close approach of Jupiter.

The JunoCam imager aboard NASA’s Juno spacecraft did not acquire all planned images during the orbiter’s most recent flyby of Jupiter on Jan. 22. Data received from the spacecraft indicates that the camera experienced an issue similar to one that occurred on its previous close pass of the gas giant last month, when the team saw an anomalous temperature rise after the camera was powered on in preparation for the flyby.

However, on this new occasion the issue persisted for a longer period of time (23 hours compared to 36 minutes during the December close pass), leaving the first 214 JunoCam images planned for the flyby unusable. As with the previous occurrence, once the anomaly that caused the temperature rise cleared, the camera returned to normal operation and the remaining 44 images were of good quality and usable.

Engineers are analyzing the issue to try to determine its cause, as well as a fix. The camera at this moment appears to be operating properly, with the next close fly-by occurring on March 1, 2023.

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Animation of Jupiter’s clouds

9:19 am

Cool video time! Using a photo taken by Juno during its 2018 fly-by of Jupiter, citizen scientist Thomas Thomopoulos has created a short animation showing the flow of Jupiter’s clouds. He also added some 3D relief by assigning elevation to the image’s greyscale, with lighter regions assigned higher altitudes.

I have embedded the animation below. Run it at the slowest speed for the best effect. It is quite spectacular, though it is also important to note that it is not reality. Thomopoulos is simply giving us a hint of the natural evolution of the cloud structures, both in elevation and in time.

You can see another equally impressive animation by Thomopoulos here of several of Jupiter’s polar storms, using AI technology to smooth out the loop.
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Racing above the clouds of Jupiter

11:28 am

Racing above the clouds of Jupiter
Click for full image.

Cool image time! The photo above, reduced in size to post here, was created from a raw Juno image by citizen scientist Kevin Gill. From his caption:

A low perspective over Jupiter’s North Polar Storms. Used imagery from the Juno spacecraft’s recent Perijove 47 to render a simulated view as if the viewer were only a few thousand kilometers above the clouds. Applied simulated altimetry, shadowing, and upper atmospheric transparency depth in Blender and Photoshop to render this.

To get some perspective on how large Jupiter is, the planet’s curve is about comparable to the same curve seen by astronauts of the Earth at a height of about 300 to 400 kilometers. In this image however we are about ten times higher.

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A new hotspot map of Io, based on Juno data

11:52 am

Hot spot map of Io
Click for original figure.

Scientists have compiled a new map of the many volcanic hotspots on the Jupiter moon Io, based on data obtained by Juno, including 23 spots previously undetected. From the paper’s abstract:

We mapped the hot spot distribution on Io’s surface by analyzing the images acquired by the JIRAM instrument onboard the Juno spacecraft. We identified 242 hot spots, including 23 not present in other catalogs. A large number of the new hot spots identified are in the polar regions, specifically in the northern hemisphere. The comparison between our work and the most recent and updated catalog reveals that JIRAM detected 82% of the most powerful hot spots previously identified and half of the intermediate-power hot spots, thus showing that these are still active. JIRAM detected 16 out of the 34 faint hot spots previously reported.

The map above is taken from figure 2 of the paper. The data, when compared to other earlier data, confirms that many of these hot spots are long-lived, and have been erupting now for decades.

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Largest volcanic eruption in years detected on Io

9:49 am

Using instruments on a ground-based telescope, one scientist based at the Planetary Science Institute (PSI) in Arizona has detected the largest volcanic eruption in years on the Jupiter moon Io.

PSI Senior Scientist [Jeff] Morgenthaler has been using IoIO, located near Benson, Arizona to monitor volcanic activity on Io, since 2017. The observations show some sort of outburst nearly every year, but the largest yet was seen in the fall of 2022. Io is the innermost of Jupiter’s four large moons and is the most volcanic body in the Solar System thanks to the tidal stresses it feels from Jupiter and two of its other large satellites, Europa and Ganymede.

IoIO uses a coronagraphic technique which dims the light coming from Jupiter to enable imaging of faint gases near the very bright planet. A brightening of two of these gases, sodium and ionized sulfur, began between July and September 2022 and lasted until December 2022. The ionized sulfur, which forms a donut-like structure that encircles Jupiter and is called the Io plasma torus, was curiously not nearly as bright in this outburst as previously seen. “This could be telling us something about the composition of the volcanic activity that produced the outburst or it could be telling us that the torus is more efficient at ridding itself of material when more material is thrown into it,” Morgenthaler said.

The material released by this eruption could impact Juno during future close approaches of Jupiter.

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