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

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.

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

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.

Juno completes its closest approach of the Jupiter moon Io

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.

The Surt volcano on Io

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.

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

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.

Jupiter’s Great Red Spot continues to shrink, possibly to its smallest size ever measured

Jupiter, as seen by Hubble in 2020
A 2020 Hubble picture of Jupiter.
Click for full image.

Long term data from numerous observatories shows that the Great Red Spot on Jupiter, the largest and longest lasting storm in the solar system, has been continuously shrinking for decades, and appears approaching this year its smallest size ever measured.

Despite so many factors working to keep it “alive” the Spot may be in need of life support. It’s been shrinking for decades. In 2012 the rate of shrinkage abruptly accelerated, something many amateur observers have commented on since that time. Several years later, while still shrinking in diameter, it expanded in latitude becoming more circular. Now it’s narrowed again and continues to diminish in both axes. This observing season I’ve been struck by the Spot’s unusually small size. That, along with its pale pink color and turbulent environment, have made it less obvious than ever.

…Using the WinJUPOS program and one of his recent high-resolution images, Peach measured the Great Red Spot’s diameter on November 6, 2023, at 12,500 kilometers or about 7,770 miles across. If confirmed it would make this season’s GRS not only smaller than the Earth (12,756 kilometers or 7,926 miles across) but the smallest size in observational history. A British Astronomical Association Jupiter section bulletin on October 30th described it as “the smallest it has ever been.” That’s a far cry from the late 1800s when the Spot ballooned to 41,000 kilometers (25,500 miles) — big enough to swallow three Earths with room to spare. Now it can barely contain one!

No one knows if this shrinkage is merely a normal long term fluctuation, or a sign that this many-centuries-old storm is finally dissippating. When it comes to the solar system’s gas giants, their size and long orbits make any firm conclusion difficult in only a few centuries of observation. To understand them properly will likely require thousands of years of observations, covering many orbits and seasons.

Hubble snaps an ultra-violet view of Jupiter

Jupiter in ultra-violet

Cool image time! Using the Hubble Space Telescope, scientists have taken a false-color ultra-violet image of Jupiter. That picture is to the right, cropped, reduced and sharpened to post here.

This newly released image from the NASA Hubble Space Telescope shows the planet Jupiter in a color composite of ultraviolet wavelengths. Released in honor of Jupiter reaching opposition, which occurs when the planet and the Sun are in opposite sides of the sky, this view of the gas giant planet includes the iconic, massive storm called the “Great Red Spot.” Though the storm appears red to the human eye, in this ultraviolet image it appears darker because high altitude haze particles absorb light at these wavelengths. The reddish, wavy polar hazes are absorbing slightly less of this light due to differences in either particle size, composition, or altitude.

The data used to create this ultraviolet image is part of a Hubble proposal that looked at Jupiter’s stealthy superstorm system. The researchers plan to map deep water clouds using the Hubble data to define 3D cloud structures in Jupiter’s atmosphere.

By comparing this ultra-violet image with Hubble’s optical view as well as Webb’s infrared view, scientists can study Jupiter’s atmosphere much like meteologists study the Earth’s, using multi-wave satellite observations.

Scientists detect salts and carbon-based molecules on Ganymede

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.

More Io images by Juno, enhanced by citizen scientists

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.

Webb detects high altitude jet stream above Jupiter’s equatorial band

Jupiter's newly discovered jet stream
Click for original false-color infrared image.

Using the Webb Space Telescope’s infrared capability, scientists have now detected a high altitude jet stream that flows above the equatorial band of Jupiter at speeds estimated to 320 miles per hour.

The false-color infrared image to the right shows evidence of this jetstream in three places by the brightest features seen there. From the caption:

In this image, brightness indicates high altitude. The numerous bright white ‘spots’ and ‘streaks’ are likely very high-altitude cloud tops of condensed convective storms. Auroras, appearing in red in this image, extend to higher altitudes above both the northern and southern poles of the planet. By contrast, dark ribbons north of the equatorial region have little cloud cover. In Webb’s images of Jupiter from July 2022, researchers recently discovered a narrow jet stream traveling 320 miles per hour (515 kilometers per hour) sitting over Jupiter’s equator above the main cloud decks.

These features sit about 25 miles higher than the planet’s previously detected cloudtops.

This discovery only proves what has always been evident, that Jupiter’s atmosphere is very complex with many features earlier optical observations could not see. It also only gives us a hint of that complexity. It will take numerous Jupiter orbiters observing in all wavebands, not just Webb in the infrared millions of miles away, to begin to untangle that complexity. And that untangling will take decades as well, since global weather unfolds over time. You can’t understand it simply by one snapshot. You have to watch the changes from season to season and from year to year. As Jupiter’s year is 12 Earth-years long, this research will take many lifetimes.

Webb infrared data suggests Europa’s C02 comes from within

Europa as seen by Webb's near-infrared camera
Europa as seen by Webb’s near-infrared camera.
Click for original image.

Two different research papers, using infrared data from the Webb Space Telescope, have independently concluded that the carbon dioxide previously detected on the surface of Europa is found concentrated in the same region, and has the earmarks of coming from beneath the surface.

In one study, Samantha Trumbo and Michael Brown used the JWST [Webb] data to map the distribution of CO2 on Europa and found the highest abundance of CO2 is located in Tara Regio – a ~1,800 square kilometer region dominated by “chaos terrain,” geologically disrupted resurfaced materials. According to Tumbo and Brown, the amount of CO2 identified within this recently resurfaced region – some of the youngest terrain on Europa’s surface – indicates that it was derived from an internal source of carbon. This implies that the CO2 formed within Europa’s subsurface ocean and was brought to the surface on a geologically recent timescale. However, the authors say that formation of CO2 on the surface from ocean-derived organics or carbonates cannot be entirely ruled out. In either interpretation, the subsurface ocean contains carbon.

In an independent study of the same JWST data, Geronimo Villanueva and colleagues found that the CO2 on Europa’s surface is mixed with other compounds. Villanueva et al. also find the CO2 is concentrated in Tara Regio and interpret that as demonstrating that the carbon on the moon’s surface was sourced from within. The authors measured the ice’s 12C/13C isotopic ratio, but could not distinguish between an abiotic or biogenic source. Moreover, Villanueva et al. searched for plumes of volatile material breaching moon’s icy crust. Although previous studies have reported evidence of these features, the authors did not detect any plume activity during the JWST observations. They argue that plume activity on Europa could be infrequent, or sometimes does not contain the volatile gasses they included in their search.

As always, these conclusion must be viewed with some skepticism, as the data is somewhat sparse and coarse. Webb’s resolution is not enough to truly pinpoint the source location with great accuracy, and the conclusion that the CO2 comes from underground depends on many assumptions. For example, in the image above, the white area roughly corresponds to Tara Regio, but with very large margins.

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

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.

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

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.

Lightning on Jupiter

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.

The grooved surface of Ganymede

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.

Engineers free stuck radar antenna on Juice probe to Jupiter’s big moons

Engineers have successfully freed the 52-foot wide radar antenna on the Juice probe to Jupiter, shaking it enough to release a pin that was blocking deployment.

The pin was freed by employing “back-to-back jolts”. Imagine when you roll your car back and forth to get it freed from mud or snow. It appears this is what they did with the pin.

Juice will arrive in Jupiter orbit in 2031, where it will make numerous fly-bys of Europa, Calisto, and Ganymede, and then settle into an orbit around Ganymede alone. The radar antenna was essential for probing the ice content of these worlds, below the surface.

Hat tip to reader Mike Nelson.

Jupiter’s clouds in 3D

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.

Radar antenna on Europe’s JUICE probe to Jupiter stuck

European Space Agency officials revealed yesterday that the 52-foot radar antenna on its JUICE probe to Jupiter has failed to deploy as planned, and that they are attempting to shake what they think is a small pin free that is in the way.

Engineers suspect a tiny pin may be protruding. Flight controllers in Germany plan to fire the spacecraft’s engine in hopes of shaking the pin loose. If that doesn’t work, they said they have plenty of time to solve the problem.

Juice, short for Jupiter Icy Moons Explorer, won’t reach the giant planet until 2031. It’s taking a roundabout path to get there, including gravity-assist flybys of Earth and our moon, and Venus.

The radar antenna is needed to peer beneath the icy crust of three Jupiter moons suspected of harboring underground oceans and possibly life, a major goal of the nearly $1.8 billion mission. Its targets include Callisto, Europa and Ganymede, the largest moon in the solar system.

If this antenna cannot be freed, it will prevent JUICE from doing one of its prime missions.

Arianespace launches JUICE mission to Jupiter

Arianespace early today used its Ariane-5 rocket, on its next-to-last launch, to send the European Space Agency’s (ESA) JUICE mission on its way to Jupiter to study its large moons.

It will take eight years for JUICE to get to Jupiter, using flybys of the Earth, Moon, and Venus along the way. This journey might also include a flyby of an asteroid, depending on orbital mechanics and the spacecraft’s condition.

Once at Jupiter it will, from ’31 to ’34, do thirty-five flybys of the Ganymede, Callisto, and Europa, and then enter orbit around Ganymede for most of 2035, before being sent to crash onto the planet to end its mission.

Ariane-5 meanwhile has one more launch, in June. After this Arianespace will not at present have an active large rocket, as its Ariane-6 replacement is not yet flying, its maiden flight presently scheduled for the fourth quarter of this year.

This was also Europe’s first launch in 2023, so it does not get listed on the leader board. The leaders of the 2023 launch race are as follows:

23 SpaceX (with a launch scheduled for tonight)
15 China (with a launch scheduled for tomorrow)
6 Russia
3 Rocket Lab

American private enterprise still leads China 26 to 15, but is now tied with the entire world combined 26 all.

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

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.

Astronomers discover twelve more Jupiter moons

In reviewing ground-based data from 2021 and 2022, astronomers have discovered another twelve Jupiter moons, bringing that planet’s total moon population to 92.

All of the newly discovered moons are small and far out, taking more than 340 days to orbit Jupiter. Nine of the 12 are among the 71 outermost Jovian moons, whose orbits are more than 550 days. Jupiter probably captured these moons, as evidenced by their retrograde orbits, opposite in direction to the inner moons. Only five of all the retrograde moons are larger than 8 kilometers (5 miles); Sheppard says the smaller moons probably formed when collisions fragmented larger objects.

One newly discovered moon, dubbed Valetudo, is about 3,000 feet across and orbits in a retrograde orbit that crosses the orbits of several other moons that orbit in the opposite direction. As the article notes, “This highly unstable situation is likely to lead to head-on collisions that would shatter one or both objects.”

Juno’s camera experiences temperature problem

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.

Jupiter and two of its Moons, as seen by Cassini during 2018 fly-by

Cool video time! Back in December 2000 the spacecraft Cassini made a fly-by of Jupiter on its way to Saturn, which it then orbited from 2004 to 2017. In 2018 JPL scientist Kevin Gil took the images from that flyby to create a short movie, first showing two of Jupiter’s moons, Io and Europa, as they drifted above the Great Red Spot.

Then, for the second half of the movie Gil used Cassini images taken when in orbit around Saturn to show the moon Titan moving across the rings of Saturn.

I have embedded this short video below. If I had posted this back in 2018, I don’t remember. No matter. It is amazing enough to watch again.

Hat tip BtB’s stringer Jay.
» Read more

Animation of Jupiter’s clouds

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.
» Read more

Lucy team suspends efforts to complete deployment of unlatched solar panel

Lucy's planned route
Lucy’s planned route to explore the Trojan asteroids

The Lucy science team has decided to suspend its efforts to complete the deployment of the unlatched solar panel that failed to fully open shortly after launch, having determined that little can be accomplished while the spacecraft is so far from the Sun.

A series of activities in 2022 succeeded in further deploying the array, placing it into a tensioned, but unlatched, state. Using engineering models calibrated by spacecraft data, the team estimates that the solar array is over 98% deployed, and it is strong enough to withstand the stresses of Lucy’s 12-year mission. The team’s confidence in the stability of the solar array was affirmed by its behavior during the close flyby of the Earth on Oct. 16, 2022, when the spacecraft flew within 243 miles (392 km) of the Earth, through the Earth’s upper atmosphere. The solar array is producing the expected level of power at the present solar range and is expected to have enough capability to perform the baseline mission with margin.

The team elected to suspend deployment attempts after the attempt on Dec. 13, 2022, produced only small movement in the solar array. Ground-based testing indicated that the deployment attempts were most productive while the spacecraft was warmer, closer to the Sun. As the spacecraft is currently 123 million miles (197 million km) from the Sun (1.3 times farther from the Sun than the Earth) and moving away at 20,000 mph (35,000 km/hr), the team does not expect further deployment attempts to be beneficial under present conditions.

The spacecraft will do another Earth fly-by on December 12, 2024, which will send it to the Trojans on the left side of the map above. Before that Lucy will do a mid-course correction in February 2024, at which time the engineers will reassess whether to try again to latch the panel, when Lucy is closer to Earth and thus also closer to the Sun.

Racing above the clouds of Jupiter

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.

A new hotspot map of Io, based on Juno data

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.

Largest volcanic eruption in years detected on Io

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.

Juno snaps heat image of Jupiter’s volcano-covered moon Io

Io's volcanoes
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The image to the right, cropped and reduced to post here, was taken on July 5, 2022 by one of the infrared instruments on the Jupiter orbiter Juno of the moon Io, known for having many many active volcanoes.

This infrared image was derived from data collected by the Jovian Infrared Auroral Mapper (JIRAM) instrument aboard Juno. In this image, the brighter the color the higher the temperature recorded by JIRAM.

Each bright spot is an active volcano, some of which have been in the past photographed during eruptions. In fact, the first such photo was taken in March 1979 by the Voyager-1 spacecraft just after its fly-by of Jupiter, and was the first time any active volcano outside of Earth had ever been identified.

What made that discovery more profound was that only a week earlier scientists had published a paper predicting active volcanoes on Io, caused by the strong tidal forces from Jupiter’s gravity.

Since then planetary scientists have been studying Io’s volcanism repeatedly, tracking the evolution of specific volcanoes over time as they erupt and then become dormant.

A pseudo-oblique view of Jupiter’s cloud-tops

A pseudo-oblique view of Jupiter's cloud-tops
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Cool image time! The image to the right, cropped, reduced, and annotated to post here, was created on October 18, 2022 by citizen scientist Thomas Thomopoulos from one of the photos taken by Juno during its close fly-by of Jupiter in May 2018.

He created this three dimensional relief by assigning different elevation values across the image’s greyscale, with white having the highest elevation. This relief is thus not based on actual topography, but it provides a nice way to illustrate the cloud structures of Jupiter’s cloud tops. It also, as Thomopoulos notes, provide a good way to possibly “see a representation in relief of surface movements.” Nor is his topography based on greyscale far wrong, since in many Jupiter images the lighter colored clouds are generally higher because the darker ones are in shadow.

The map below provides the context and scale of this image.
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