Tag: Jupiter

Dumb science: Researchers claim Jupiter is 0.0028% thinner than previously measured

9:29 am

Stupidity on display: According to researchers using data from the Jupiter orbiter Juno, Jupiter is a tiny bit thinner at the equator and flatter at the poles than previously measured.

Leading an international team from Italy, the United States, France and Switzerland, Weizmann Institute of Science researchers [Israel] have produced more precise measurements of Jupiter’s size and shape than ever before, using new data from NASA’s Juno spacecraft.

The peer-reviewed research, published today in Nature Astronomy, shows that the radius of Jupiter is about four kilometers (2.5 miles) thinner at its equator and 12 kilometers (7.5 miles) flatter at the poles than believed in earlier assessments. The scientists determined the planet has a radius of 71,484 kilometers (44,418 miles). Earlier data measured it at 71,492 kilometers (44,423 miles).

The absurdity of this research is galling. The revision they claim is tiny, a mere 0.0028% difference at the equator, and 0.0084% at the poles. These numbers are insignificant. Moreover, Jupiter is a gas giant. It has no precisely known surface. Instead, it has an atmosphere that gradually thins as you go up. To claim any precise diameter is absurd, especially because seasonally and over time that atmosphere will expand and shrink.

And of course, at least two mainstream news outlets, Scientific American and The Times of Israel (linked above), report this story without any skepticism, as if this is a Earth-shaking discovery. All that tells me is that when it comes to science, both are incompetent sources of information.

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Scientists produce new estimate of the thickness of Europa’s icy crust

5:23 pm

Europa in true color
Europa in true color, taken by Juno during that
September 2022 fly-by. Click for full image.

Using data produced by Juno during a 2022 close-fly of Jupiter’s moon Europa, scientists have made a new estimate of the thickness of Europa’s icy crust, approximately 18 miles thick with a 6-mile margin of error.

In other words, their estimate could be as small as 12 miles thick, or as large as 24 miles thick.

You can read their paper here. From their abstract:

For the idealized case of pure water ice, the data are consistent with the existence of a thermally conductive ice shell with a thickness of 29 ± 10 km [18 ± 6 miles] and with the presence of cracks, pores or other scatterers extending to depths of hundreds of metres below the surface with a characteristic size smaller than a few centimetres in radius. An ice-shell salinity of 15 mg kg−1, as indicated by models based on terrestrial marine ice, would reduce our estimate of the thickness of the ice shell by about 5 km, substantially less than our 10 km uncertainty. The low volume fraction, small size and shallow depth of the scatterers indicate that the fracture interfaces observed at Europa’s surface are alone unlikely to be capable of carrying nutrients between the surface and the ocean. [emphasi mine]

The highlighted sentence is the important one. If this new estimate is right, than the unidentified reddish material that appears to leak out of the long ridgelike cracks on Europa’s surface, clearly visible in the picture to the right, are not coming from any underground ocean. The distances are too large.

Other estimates have suggested that ice crust could be as thin as 2 miles, but like this research the uncertainties are very large.

Meanwhile, the Juno mission is still alive, though essentially winding down operations. The mission was expected to officially end at the end of September 2025, when its budget ran out, but the just passed budget included enough money to keep it going, albeit at a relatively low level. According to the orbiter’s webpage, it will continue to orbit Jupiter, its orbit degrading naturally until it falls into Jupiter to burn up. As it does so data will continue to be collected, though at a much lower rate.

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Computer simulations suggest Jupiter and Saturn have fundamentally different interiors

9:57 am

The different polar vortexes of Jupiter and Saturn

The uncertainty of science: In attempting to explain why the polar vortexes of Jupiter and Saturn are so different, scientists running large computer simulations have found that the difference could be because Jupiter’s interior is “softer” than Saturn’s.

The two images to the right illustrate the different polar vortexes of both planets. Jupiter’s (top) is made up of multiple chaotic small storms that form a hexagon-like ring around the pole. Saturn’s (bottom) is a single very coherent hexagon-shaped storm.

Over multiple different simulations, they observed that some scenarios evolved to form a single large polar vortex, like Saturn, whereas others formed multiple smaller vortices, like Jupiter. After analyzing the combinations of parameters and variables in each scenario and how they related to the final outcome, they landed on a single mechanism to explain whether a single or multiple vortices evolve: As random fluid motions start to coalesce into individual vortices, the size to which a vortex can grow is limited by how soft the bottom of the vortex is. The softer, or lighter the gas is that is rotating at the bottom of a vortex, the smaller the vortex is in the end, allowing for multiple smaller-scale vortices to coexist at a planet’s pole, similar to those on Jupiter.

Conversely, the harder or denser a vortex bottom is, the larger the system can grow, to a size where eventually it can follow the planet’s curvature as a single, planetary-scale vortex, like the one on Saturn.

If this mechanism is indeed what is at play on both gas giants, it would suggest that Jupiter could be made of softer, lighter material, while Saturn may harbor heavier stuff in its interior.

This conclusion however runs completely counter to what we should expect. Jupiter has a much great mass, and one would assume from this that its interior would therefore be denser and thus harder.

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Webb tracks volcanic eruptions on Io

9:59 am

Different Webb infrared detections of Io over time
Click for original image.

Using the Webb Space Telescope, scientists have tracked two different volcanic eruptions on Io that too place from 2022 to 2023, detecting sulfur monoxide both from those eruptions as well as sulfur from the magnetic plasma torus produced as the planet travels through Jupiter’s strong magnetic field. From the paper’s abstract:

Volcanic thermal emission was detected from Loki Patera and Kanehekili Fluctus [two volcanic vents]. The main changes in the shape of the thermal emission spectra since [Webb] observed Io in November 2022 were consistent with the continued cooling of emplaced lava flows in the Kanehekili Fluctus region, and the crust that had formed on the surface of the lava lake in Loki Patera. Images of Io in the SO 1.707 μm emission band [sulfur monoxide] show a concentration above Kanehekili Fluctus and in two regions in the northern hemisphere. The emissions are sourced from SO molecules ejected from volcanic vents. We further detected, for the first time, sulfur line emissions at 1.08 and 1.13 μm. These emissions are distributed homogeneously across a band in Io’s northern hemisphere. They are mainly produced through excitation by electrons from the plasma torus, penetrating Io’s atmosphere.

The top image to the right shows the heat signature above the two volcanoes, one to the southwest and the second to the northeast. The middle image shows the sulfur monoxide emissions detected by Webb above those volcanoes from their on-going eruptions. The bottom image shows the more diffuse sulfur emissions, mostly in the northern hemisphere, believed produce by interactions with the plasma torus.

This research also relied on data obtained by both the Keck telescopes in Hawaii and the Hubble Space Telescope.

There are of course uncertainties with these results. For example, the conclusion that the more diffuse sulfur is produced by interactions with the plasma torus is not as certain. First, those sulfur emissions still appear closely linked to the volcanoes, which suggests this still could be a source.

Second, the observations also cover only two data points in time, in 2022 and 2023. To get a more precise map of the activity on Io we really need an orbiter there observing the planet on a continuous basis, something that is at this time impossible, not only because no mission is planned but because the hostile radiation environment this close to Jupiter makes the engineering quite challenging. It is this reason why Europa Clipper is not going into orbit around Europa when it arrives there in 2031. Better to orbit Jupiter and only periodically dip into that harsh radiation environment.

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Juice successfully completes Venus fly-by

9:41 am

The European orbiter Juice, on its way to Jupiter, successfully completed its fly-by of Venus on August 31, 2025, zipping 6,923 miles above the planet’s surface to get some of the velocity needed to get to Jupiter in 2031.

It still has to do two more fly-bys of Earth before it has enough speed to reach Jupiter.

There were no science observations during the Venus fly-by, as the spacecraft had to be oriented so that its large high gain antenna would protect its instruments from the Sun’s heat. It appears however that the science team has confirmed the spacecraft is in fine shape using its medium-gain antenna.

Once in orbit around Jupiter the spacecraft’s prime mission will be to do numerous fly-bys of the large icy Galilean moons, Europa, Ganymede, and Callisto. Its data will also reinforce what Europa Clipper will learn while it does the same, beginning in 2030.

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Juno enters and then recovers from safe mode

9:03 am

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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The Europa Clipper team prepares for Mars fly-by

8:52 am

Europa Clipper's route to Jupiter
Click for original image.

As planned, Europa Clipper is set to do a very close fly-by of Mars on March 1, 2025, zipping past the red planet at a speed of 15.2 miles per second only 550 miles above its surface. The graphic to the right shows the spacecraft’s planned route to Jupiter, including an additional fly-by of Earth in 2026.

During this first fly-by the science team will test two of Europa Clipper’s instruments.

About a day prior to the closest approach, the mission will calibrate the thermal imager, resulting in a multicolored image of Mars in the months following as the data is returned and scientists process the data. And near closest approach, they’ll have the radar instrument perform a test of its operations — the first time all its components will be tested together. The radar antennas are so massive, and the wavelengths they produce so long that it wasn’t possible for engineers to test them on Earth before launch.

The spacecraft launched with transistors not properly hardened for the hostile environment around Jupiter. Engineers claimed these would “heal” themselves once in Jupiter orbit. No word on whether there has been any issue from these components since launch.

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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

10:57 am

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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JPL unveils website for viewing all high resolution imagery so far taken of Europa

9:29 am

In anticipation of the eventual arrival of Europa Clipper in orbit around Jupiter to begin its close investigation of that planet’s moon Europa, JPL yesterday unveiled a website that allows a view to quickly find and review all the high resolution imagery so far taken of Europa by the Jupiter orbiters, Voyager, Galileo, and Juno.

You can visit the Europa Trek portal website here.

The announcement touts the webpage’s ability to take viewers on “fly-overs” of the terrain, but that’s just a bell and whistle claim of little importance. More significant is the easy access this webpage provides to all that imagery, organized in context with a global map of the planet. Not only can anyone quick find interesting features, you can do so within the global context of the whole planet. In addition, the page provides detailed commentary about each image.

When Europa Clipper arrives this portal will be invaluable in deciphering the significance of every new image and datapoint.

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SpaceX’s Falcon Heavy launches NASA’s Europa Clipper mission

9:50 am

Europa's approximate orbit around Jupiter
Click for original image.

SpaceX’s Falcon Heavy rocket this morning successfully launched NASA’s Europa Clipper mission on its way to Jupiter, the rocket lifting off from the Kennedy Space Center in Florida.

In order to get the energy to reach Jupiter, none of the Falcon Heavy’s first stage boosters were recovered today. The two side boosters completed their sixth and final flights with this mission, while the core booster completed its first launch. The only parts of the rocket that will be recovered and reused were the two fairing halves.

To get to Jupiter, the spacecraft will make first a fly-by of Mars in February 2025, and then a fly-by of Earth in December 2026. It will arrive in Jupiter orbit in April 2030, where its orbit will be adjusted to fly close past Europa many times in order to study it closely, as shown by the graphic on the right. It will not going into orbit around the planet because that would place it permanently inside the high radiation environment around Jupiter. This is especially important because the spacecraft has installed transistors that were not properly hardened for that environment.

The leaders in the 2024 launch race:

98 SpaceX
45 China
11 Russia
11 Rocket Lab

American private enterprise now leads the rest of the world combined in successful launches 115 to 68, while SpaceX by itself now leads the entire world, including American companies, 98 to 85.

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Jupiter’s Great Red Spot appears to jiggle like Jello on a 90-day cycle

9:07 am

Jupiter as seen by Hubble over time
Click for original image.

Using the Hubble Space Telescope to photograph Jupiter’s Great Red Spot repeatedly over a four month period from December 2023 to March 2024 scientists have detected a 90-day cycle in which the spot oscillated in shape, shaking like Jello.

“While we knew its motion varies slightly in its longitude, we didn’t expect to see the size oscillate. As far as we know, it’s not been identified before,” said Amy Simon of NASA’s Goddard Space Flight Center in Greenbelt, Maryland, lead author of the science paper published in The Planetary Science Journal. “This is really the first time we’ve had the proper imaging cadence of the GRS. With Hubble’s high resolution we can say that the GRS is definitively squeezing in and out at the same time as it moves faster and slower. That was very unexpected, and at present there are no hydrodynamic explanations.”

The four images to the right are some of those observations. For a full movie showing the changes over ninety days, go here.

The scientists also predict that though the spot has been shrinking for decades, they expect that shrinkage to stop once the spot size no longer extends beyond the jet stream band within which it sits. At that point the different jet streams in the upper and lower bands will hold the spot in place and its size will stabilize.

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

1:12 pm

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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In approving Europa Clipper’s launch, NASA and JPL claim its non-spec transistors will “heal” themselves in Jupiter orbit

9:12 am

Europa in true color
Europa in true color, taken by Juno September 2022.
Click for full image.

In making the decision to allow Europa Clipper to be launched on a Falcon Heavy on October 10, 2024, NASA and JPL officials explained that after several months of testing, they believe the improperly hardened transistors installed throughout the orbiter will “heal” themselves while in the low radiation portions of its orbit around Jupiter.

[The testing] showed the transistors in question will, in effect, heal themselves during the 20 days between the high radiation doses the probe will receive during each of 49 close flybys of Europa, all of them deep in Jupiter’s powerful magnetic field and radiation environment.

In addition, onboard heaters can be used as needed to raise the temperature of affected transistors, improving the recovery process. “After extensive testing and analysis of the transistors, the Europa Clipper project and I personally have high confidence we can complete the original mission for exploring Europa as planned,” said Jordan Evans, Europa Clipper project manager at NASA’s Jet Propulsion Laboratory.

I hope this analysis is right, though I fear there is a lot of wishful-thinking involved. It could be however that this testing, in combination with what engineers have learned during Juno’s so-far 64 orbits around Jupiter, might have reassured them.

We however will not know for sure until Europa Clipper is on its way and reaches Jupiter in 2030.

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NASA confirms Europa Clipper launch on October 10, 2024 with questionable transistors

9:21 am

NASA yesterday confirmed that it has decided to go ahead with the October 10, 2024 launch of its $5+ billion Europa Clipper mission to Jupiter, despite the installation of transistors on the spacecraft that the agency knows are not properly hardened for that harsh environment.

Those transistors were built by a German company as part of equipment used by the spacecraft’s electrical system. Apparently that company hired a subcontractor to furnish the transistors, which failed to make them to the right specifications. Subsequent testing found that it is quite likely that at least some of the transistors will fail when Europa Clipper reaches Jupiter orbit.

It appears that NASA decided that the issue risk was small enough for the mission to achieve its minimal expected results, and decided the cost of delay and bad publicity replacing the transistors before launch would be worse than the limited science payoff and bad publicity that would take place years hence, when those transistors fail.

Remember this story in in 2030 when Europa Clipper enters Jupiter orbit and begins to experience problems.

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NASA leans toward launching Europa Clipper as scheduled, despite transistor issue

9:26 am

Though the final decision will be made in early September, NASA revealed today in a short post that management is leaning towards launching the multi-billion Europa Clipper mission as scheduled on October 10, 2024, despite a very recently discovered transistor issue where the transistors were not properly hardened in construction for the harsh radiation environment surrounding Jupiter.

The next major milestone for Clipper is Key Decision Point E on Monday, Sept. 9, in which the agency will decide whether the project is ready to proceed to launch and mission operations. NASA will provide more information at a mission overview and media briefing targeted for that same week.

The Europa Clipper mission team recently conducted extensive testing and analysis of transistors that help control the flow of electricity on the spacecraft. Analysis of the results suggests the transistors can support the baseline mission. [emphasis mine]

The highlighted sentence suggests NASA officials have weighed the option between launching on time with a limited ability to do science once at Jupiter versus delaying the launch years to fix the transistors, and are now favoring the former option. The cost of delay would be high and long, and NASA officials might believe the bad press for that option would be much greater than a mission that only achieves its bare minimum results. For example, to admit publicly that NASA installed transistors that were not space-hardened when that necessity has been known about since the 1960s would be as embarrassing to the agency as it was for Boeing when it discovered it had installed flammable tape in its Starliner capsule. NASA management might be leaning to letting a flawed multi-billion dollar project launch, knowing its capabilities are quite limited, in order to avoid that embarrassment.

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Juice completes fly-by of Moon

9:58 am

Juice's view of the Moon
Click for original image.

Europe’s Juice probe to Jupiter yesterday successfully completed its close fly-by of the Moon, shifting its path as it prepares for a close fly-by of the Earth today.

The picture to the right, cropped, reduced, and sharpened to post here, was taken during yesterday’s flyby. At its closest approach Juice was only 435 miles above the lunar surface. It will pass the Earth today at a distance of 4,230 miles.

If the Earth fly-by today is successful, Juice will then do flybys of Venus in August 2025, Earth in September 2026, and Earth again in January 2029, arriving in Jupiter orbit in July 2031, where it is designed to study the large icy moons (Europa, Gandymede, and Calisto) of that gas giant.

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ESA’s Juice probe to Jupiter prepares for first Earth+Moon slingshot fly-by

10:35 am

Graphic showing Juice's upcoming duel fly-by
Graphic showing Juice’s upcoming duel fly-by.
Click for original image.

The European Space Agency’s (ESA) first mission to Jupiter, dubbed Juice (Jupiter Icy Moons Explorer) is about to do the first ever back-to-back fly-bys of the Moon and then the Earth immediately afterward in order to slingshot it forward on its long journey to the gas giant.

The graphic to the right, cropped and reduced to post here, shows the plan. Juice will first fly past the Moon, shifting its path slightly, and then zip past the Earth one day later, its trajectory then under-going a much larger change.

The lunar-Earth flyby will see Juice pass just 700 km [435 miles] from the Moon’s surface at 23:16 CEST on 19 August and 6807 km [4230 miles] from Earth’s surface almost exactly 24 hours later at 23:57 CEST on 20 August.

Using the gravity of the Moon to slightly bend Juice’s trajectory first will improve the effectiveness of the much larger gravity assist at Earth. However, the dual flyby requires extraordinarily precise navigation and timing, as even minor deviations could send Juice in the wrong direction.

The engineering teams have already been doing simulations to make sure they get this complex maneuver right. If all goes right, the spacecraft will then do flybys of Venus in August 2025, Earth in September 2026, and Earth again in January 2029, arriving in Jupiter orbit in July 2031.

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Scientists surprised by new Webb data of the upper layers of Jupiter’s Great Red Spot

9:33 am

Jupiter's Great Red Spot, as seen in infrared
Click for original image.

The uncertainty of science: Using the Webb Space Telescope, scientists have obtained infrared data of the upper layers of Jupiter’s Great Red Spot, revealing that it is far more complicated that predicted by researchers.

The upper atmosphere of Jupiter is the interface between the planet’s magnetic field and the underlying atmosphere. Here, the bright and vibrant displays of northern and southern lights can be seen, which are fuelled by the volcanic material ejected from Jupiter’s moon Io. However, closer to the equator, the structure of the planet’s upper atmosphere is influenced by incoming sunlight. Because Jupiter receives only 4% of the sunlight that is received on Earth, astronomers predicted this region to be homogeneous in nature.

The Great Red Spot of Jupiter was observed by Webb’s Near-InfraRed Spectrograph (NIRSpec) in July 2022, using the instrument’s Integral Field Unit capabilities. The team’s Early Release Science observations sought to investigate if this region was in fact dull, and the region above the iconic Great Red Spot was targeted for Webb’s observations. The team was surprised to discover that the upper atmosphere hosts a variety of intricate structures, including dark arcs and bright spots, across the entire field of view.

You can read the published research paper here. The image to the right is figure 4 from that paper, with each panel showing different infrared wavelengths indicated by the different colors, and thus the complex structures and physical properties.

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Juno looks down at Jupiter

9:50 am

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

2:01 pm

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

10:18 am

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

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Jupiter, as seen by Hubble in 2020
A 2020 Hubble picture of Jupiter.
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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.

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Hubble snaps an ultra-violet view of Jupiter

9:59 am

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.

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