Juno Mission Makes Mysterious Finds about Auroras on Jupiter

Even after decades of study, Jupiter’s atmosphere continues to be something of a mystery to scientists. Consistent with the planet’s size, its atmosphere is the largest in the Solar System, spanning over 5,000 km (3,000 mi) in altitude and boasting extremes in temperature and pressure. On top of that, the planet’s atmosphere experiences the most powerful auroras in the Solar System.

Studying this phenomena has been one of the main goals of the Juno probe, which reached Jupiter on July 5th, 2016. However, after analyzing data collected by the probe’s instruments, scientists at Johns Hopkins University Applied Physics Laboratory (JHUAPL) were surprised to find that Jupiter’s powerful magnetic storms do not have the same source as they do on Earth.

The study which details these findings, “Discrete and Broadband Electron Acceleration in Jupiter’s Powerful Aurora“, recently appeared in the scientific journal Nature. Led by Barry Mauk, a scientist with the JHUAPL, the team analyzed data collected by Juno’s Ultraviolet Spectrograph (UVS) and Jovian Energetic Particle Detector Instrument (JEDI) to study Jupiter’s polar regions.

Ultraviolet auroral images of Jupiter from the Juno Ultraviolet Spectrograph instrument. Credit: NASA/SwRI/Randy Gladstone

As with Earth, on Jupiter, auroras are the result of intense radiation and Jupiter’s magnetic field. When this magnetosphere aligns with charged particles, it has the effect of accelerating electrons towards the atmosphere at high energy levels. In the course of examining Juno’s data, the JHUAPL team observed signatures of electrons being accelerated toward the Jovian atmosphere at energy levels of up to 400,000 electron volts.

This is roughly 10 to 30 times higher than what is experienced here on Earth, where only several thousand volts are typically needed to generate the most intense aurora. Given that Jupiter has the most powerful auroras in the Solar System, the team was not surprised to see such powerful forces at work within the planet’s atmosphere. What was surprising, however, was that this was not the source of the most intense auroras.

As Dr. Mauk, who leads the investigation team for the APL-built JEDI instrument and was the lead author on the study , explained in a JHUAPL press release:

“At Jupiter, the brightest auroras are caused by some kind of turbulent acceleration process that we do not understand very well. There are hints in our latest data indicating that as the power density of the auroral generation becomes stronger and stronger, the process becomes unstable and a new acceleration process takes over. But we’ll have to keep looking at the data.”

Image compiled using data from Juno’s Ultraviolet Spectrograph, which marks the path of Juno’s readings of Jupiter’s auroras. Credit: NASA/SwRI/Randy Gladstone

These findings could have significant implications for the study of Jupiter, who’s composition and atmospheric dynamics continue to be a source of mystery. It also has implications or the study of extra-solar gas giants and planetary systems. In recent decades, the study of these systems has revealed hundreds of gas giants that have ranged in size from being Neptune-like to many times the size of Jupiter (aka. “Super-Jupiters”).

These gas giants have also shown significant variations in orbit, ranging from being very close to their respective suns to very far (i.e. “Hot Jupiters” to “Cold Gas Giants”). By studying Jupiter’s ability to accelerate charged particles, astronomers will be able to make more educated guesses about space weather, radiation environments, and the risks they pose to space missions.

This will come in handy when it comes time to mount future missions to Jupiter, as well as deep-space and maybe even interstellar space. As Mauk explained:

“The highest energies that we are observing within Jupiter’s auroral regions are formidable. These energetic particles that create the auroras are part of the story in understanding Jupiter’s radiation belts, which pose such a challenge to Juno and to upcoming spacecraft missions to Jupiter under development. Engineering around the debilitating effects of radiation has always been a challenge to spacecraft engineers for missions at Earth and elsewhere in the solar system. What we learn here, and from spacecraft like NASA’s Van Allen Probes and MMS that are exploring Earth’s magnetosphere, will teach us a lot about space weather and protecting spacecraft and astronauts in harsh space environments. Comparing the processes at Jupiter and Earth is incredibly valuable in testing our ideas of how planetary physics works.”

Before the Juno mission is scheduled to wrap up (in February of 2018), the probe is likely to reveal a great many things about the planet’s composition, gravity field, magnetic field and polar magnetosphere. In so doing, it will address long-standing mysteries about how the planet formed and evolved, which will also shed light on the history of the Solar System and extra-solar systems.

Further Reading: JHUAPL, Nature

Here They are! New Juno Pictures of the Great Red Spot

Earlier this week, on Monday, July 10th, the Juno mission accomplished an historic feet as it passed directly over Jupiter’s most famous feature – the Great Red Spot. This massive anticyclonic storm has been raging for centuries, and Juno’s scheduled flyby was the closest any mission has ever come to it. It all took place at 7:06 p.m. PDT (11:06 p.m. EDT), just days after the probe celebrated its first year of orbiting the planet.

And today – Wednesday, July 12th, a few days ahead of schedule – NASA began releasing the pics that Juno snapped with its imager – the JunoCam – to the public. As part of the missions’ seventh orbit around the planet (perijove 7) these images are the closest and most detailed look of Jupiter’s Great Red Spot to date. And as you can clearly see by going to the JunoCam website, the pictures are a sight to behold!

And as always, citizen scientists and amateur astronomers are already busy processing the images. This level of public involvement in a NASA mission is something quite new. Prior to every perijove, NASA has asked for public input on what features they would like to see imaged. These Points of Interest (POIs), as they are called, are then photographed, and the public has had the option of helping to process them for public consumption.

“Great Red Spot from P7 Flyover”. Credit: NASA/SwRI/MSSS/Jason Major © public domain

As Scott Bolton – the associate VP at the Southwest Research Institute (SwRI) and the Principle Investigator (PI) of the Juno mission – said in a NASA press release, “For generations people from all over the world and all walks of life have marveled over the Great Red Spot. Now we are finally going to see what this storm looks like up close and personal.” And in just the past two days, several processed images have already come in.

Consider the images that were processed by Jason Major – an amateur astronomer and graphic designer who created the astronomy website Lights in the Dark. In the image above (his own work), we see a cropped version of the original JunoCam image in order to put Jupiter’s Great Red Spot center-frame. It was then color-adjusted and enhanced to mark the boundaries of the storm’s “eye” and the swirling clouds that surround it more clearly.

On his website, Major described the method he used to bring this image to life:

“[T]he image above is my first rendering made from a map-projected PNG file which centers and fully-frames the giant storm in contrast- and color-enhanced detail… The resolution is low but this is what my “high-speed” workflow is set up for—higher resolution images will take more time and I’m anticipating some incredible versions to be created and posted later today and certainly by tomorrow and Friday by some of the processing superstars in the imaging community (Kevin, Seán, Björn, Gerald, I’m looking at you!)”

Wide-frame shot of the Great Red Spot, processed to show contrast between the storm and Jupiter’s clouds. Credit: NASA/SwRI/MSSS/Jason Major © public domain

Above is another one of Major’s processed images, which was released shortly after the first one. This image shows the GRS in a larger context, using the full JunoCam image, and similarly processed to show contrasts. The same image was processed and submitted to the Juno website by amateur astronomers Amadeo Bellotti and Oliver Jenkins – though their submissions are admittedly less clear and colorful than Major’s work.

Other images include “Juno Eye“, a close up of Jupiter’s northern hemisphere that was processed by our good friend, Kevin M. Gill. Shown below, this image is a slight departure from the others (which focused intently on Jupiter’s Great Red Spot) to capture a close-up of the swirls in Jupiter’s northern polar atmosphere. Much like the GRS, these swirls are eddies that are created by Jupiter’s extremely high winds.

The Juno mission reached perijove – i.e. the point in its orbit where it is closest to Jupiter’s center – on July 10th at 6:55 p.m. PDT (9:55 p.m. EDT). At this time, it was about 3,500 km (2,200 mi) above Jupiter’s cloud tops. Eleven minutes and 33 seconds later, it was passing directly over the anticyclonic storm at a distance of about 9,000 km (5,600 mi); at which time, all eight of its instruments were trained on the feature.

In addition to the stunning array of images Juno has sent back, its suite of scientific instruments have gathered volumes of data on this gas giant. In fact, the early science results from the mission have shown just how turbulent and violent Jupiter’s atmosphere is, and revealed things about its complex interior structure, polar aurorae, its gravity and its magnetic field.

“Juno Eye”. Credit : NASA/JPL-Caltech/MSSS/SwRI/©Kevin M. Gill

The Juno mission reached Jupiter on July 5th, 2016, becoming the second probe in history to establish orbit around the planet. By the time the mission is scheduled to end in 2018 (barring any mission extensions), scientist hope to have learned a great deal about the planet’s structure and history of formation.

Given that this knowledge is likely to reveal things about the early history and formation of the Solar System, the payoffs from this mission are sure to be felt for many years to come after it is decommissioned.

In the meantime, you can check out all the processed images by going to the JunoCam sight, which is being regularly updated with new photos from Perijove 7!

Further Reading: NASA, JunoCam, Lights in the Dark

We’re About to Get Our Closest Look at Jupiter’s Great Red Spot

When the Juno mission reached Jupiter on July 5th, 2016, it became the second mission in history to establish orbit around the Solar System’s largest planet. And in the course of it conducting its many orbits, it has revealed some interesting things about Jupiter. This has included information about its atmosphere, meteorological phenomena, gravity, and its powerful magnetic fields.

And just yesterday – on Monday, July 10th at 7:06 p.m. PDT (11:06 p.m. EDT) – just days after the probe celebrated its first year of orbiting the planet, the Juno mission passed directly over Jupiter’s most famous feature – the Great Red Spot. This massive anticyclonic storm has been a focal point for centuries, and Juno’s scheduled flyby was the closest any mission has ever come to it.

Jupiter’s Great Red Spot was first observed during the late 17th century, either by Robert Hooke or Giovanni Cassini. By 1830, astronomers began monitoring this anticyclonic storm, and have noted periodic expansions and regressions in its size ever since. Today, it is 16,000 kilometers (10,000 miles) in diameter and reaches wind speeds of 120 meters per second (432 km/h; 286 mph) at the edges.

The Juno spacecraft isn’t the first one to visit Jupiter. Galileo went there in the mid 90’s, and Voyager 1 snapped a nice picture of the clouds on its mission. Credit: NASA

As part of its sixth orbit of Jupiter’s turbulent cloud tops,  Juno passed close to Jupiter’s center (aka. perijove), which took place at 6:55 p.m. PDT (9:55 p.m. EDT). Eleven minutes later – at 7:06 p.m. PDT (10:06 p.m. EDT) – the probe flew over the Great Red Spot. In the process, Juno was at a distance of just 9,000 km (5,600 miles) from the anticyclonic storm, which is the closest any spacecraft has ever flown to it.

During the flyby, Juno had all eight of its scientific instruments (as well its imager, the JunoCam) trained directly on the storm. With such an array aimed at this feature, NASA expects to learn more about what has been powering this storm for at least the past three and a half centuries. As Scott Bolton, the principal investigator of Juno at the Southwest Research Institute (SwRI), said prior to the event in a NASA press release:

“Jupiter’s mysterious Great Red Spot is probably the best-known feature of Jupiter. This monumental storm has raged on the Solar System’s biggest planet for centuries. Now, Juno and her cloud-penetrating science instruments will dive in to see how deep the roots of this storm go, and help us understand how this giant storm works and what makes it so special.”

This perijove and flyby of the Giant Red Spot also comes just days after Juno celebrated its first anniversary around Jupiter. This took place on July 4th at 7:30 p.m. PDT (10:30 p.m. EDT), at which point, Juno had been in orbit around the Jovian planet for exactly one year. By this time, the spacecraft had covered a distance of 114.5 million km (71 million mi) while orbiting around the planet.

This artist's illustration shows Juno's Microwave Radiometer observing deep into Jupiter's atmosphere. The image shows real data from the 6 MWR channels, arranged by wavelength. Credit: NASA/SwRI/JPL
This artist’s illustration shows Juno’s Microwave Radiometer observing deep into Jupiter’s atmosphere. The image shows real data from the 6 MWR channels, arranged by wavelength. Credit: NASA/SwRI/JPL

The information that Juno has collected in that time with its advanced suite of instruments has already provided fresh insights into Jupiter’s interior and the history of its formation. And this information, it is hoped, will help astronomers to learn more about the Solar System’s own history of formation. And in the course of making its orbits, the probe has been put through its paces, absorbing radiation from Jupiter’s powerful magnetic field.

As Rick Nybakken, the project manager for Juno at NASA’s Jet Propulsion Laboratory, put it:

“The success of science collection at Jupiter is a testament to the dedication, creativity and technical abilities of the NASA-Juno team. Each new orbit brings us closer to the heart of Jupiter’s radiation belt, but so far the spacecraft has weathered the storm of electrons surrounding Jupiter better than we could have ever imagined.”

The Juno mission is set to conclude this coming February, after completing 6 more orbits of Jupiter. At this point, and barring any mission extensions, the probe will be de-orbited to burn up in Jupiter’s outer atmosphere. As with the Galileo spacecraft, this is meant to avoid any possibility of impact and biological contamination with one of Jupiter’s moons.

Further Reading: NASA

Best Jupiter Images From Juno … So Far

The original plans for the Juno mission to Jupiter didn’t include a color camera. You don’t need color images when the mission’s main goals are to map Jupiter’s magnetic and gravity fields, determine the planet’s internal composition, and explore the magnetosphere.

But a camera was added to the manifest, and the incredible images from the JunoCam have been grabbing the spotlight.

As an instrument where students and the public can choose the targets, JunoCam is a “public outreach” camera, meant to educate and captivate everyday people.

“The whole endeavor of JunoCam was to get the public to participate in a meaningful way,” said Candy Hansen, Juno co-investigator at the Planetary Science Institute in Tucson, Arizona, speaking at a press conference last week to showcase Juno’s science and images.

And participate they have. Hundreds of ‘amateur’ image processing enthusiasts have been processing raw data from the JunoCam, turning them into stunning images, many reminiscent of a swirling Van Gogh ‘starry night’ or a cloudscape by Monet.

The swirling cloudtops of Jupiter, as seen by Juno during Perijove 5 on March 27, 2017. Credit: NASA/JPL-Caltech/SwRI/MSSS/Sophia Nasr.

“The contributions of the amateurs are essential,” Hansen said. “I cannot overstate how important the contributions are. We don’t have a way to plan our data without the contributions of the amateur astronomers. We don’t have a big image processing team, so we are completely relying on the help of our citizen scientists.”

Jupiter as seen by Juno during Perijove 6 in May, 2017. Credit: NASA/SwRI/MSSS/Gerald Eichstädt / Seán Doran.

Click on this image to have access to a 125 Megapixel upscaled print portrait.

Featured here are images processed by Seán Doran, Sophia Nasr, Kevin Gill and Jason Major. Like hundreds of others around the world, they anxiously await for data to arrive to Earth, where it is uploaded to the public Juno website. Then they set to work to turn the data into images.

“What I find the most phenomenal of all is that this takes real work,” Hansen said. “When you download a JunoCam image and process it, it’s not something you do in five minutes. The pictures that we get that people upload back onto our site, they’ve invested hours and hours of their own time, and then generously returned that to us.”

This video shows Juno’s trajectory from Perijove 6, and is based on work by Gerald Eichstädt, compiled and edited by Seán Doran. “This is real imagery projected along orbit trajectory,” Doran explained on Twitter.

Many of the images are shared on social media, but you can see the entire gallery of processed JunoCam images here. The Planetary Society also has a wonderful gallery of images processed by people around the world.

Intricate swirls on Jupiter Jupiter, from Juno’s Perijove 6 pass on May 19, 2017. Credit:
NASA/JPL-Caltech/SwRI /MSSS/Kevin M. Gill.
Details of Jupiter’s swirling gas clouds, as seen by Juno during the Perijove 6 pass in May, 2017. Credit:
NASA / SwRI / MSSS / Gerald Eichstädt / Seán Doran.

JunoCam was built by Malin Space Science Systems, which has cameras on previous missions like the Curiosity Mars Rover, the Mars Global Surveyor and the Mars Color Imager on the Mars Reconnaissance Orbiter. To withstand the harsh radiation environment at Jupiter, the camera required special protection and a reinforced lens.

Whenever new images arrive, many of us feel exactly like editing enthusiast Björn Jónsson:

Even the science team has expressed their amazement at these images.

“Jupiter looks different than what we expected,” said Scott Bolton, Juno’s principal investigator at the Southwest Research Institute. “Jupiter from the poles doesn’t look anything like it does from the equator. And the fact the north and south pole don’t look like each other, makes us wonder if the storms are stable, if they going to stay that way for years and years like the the Great Red Spot. Only time will tell us what is true.”

Read our article about the science findings from Juno.

A sequence of images of Jupiter from Juno’s Perijove 6 pass during May, 2017. Credit:
NASA / SwRI / MSSS / Gerald Eichstädt / Seán Doran.

Part of what makes these images so stunning is that Juno is closer to Jupiter than any previous spacecraft.

“Juno has an elliptical orbit that brings it between the inner edges of Jupiter’s radiation belt and the planet, passing only 5,000 km above the cloud tops,” Juno Project Manager Rick Nybakken told me in my book ‘Incredible Stories From Space: A Behind-the-Scenes Look at the Missions Changing Our View of the Cosmos.’ “This close proximity to Jupiter is unprecedented, as no other mission has conducted their science mission this close to the planet. We’re right on top of Jupiter, so to speak.”

Juno engineers designed the mission to enable the use of solar panels, which prior to Juno, have never been used on a spacecraft going so far from the Sun. Juno orbits Jupiter in a way that the solar panels are always pointed towards the Sun and the spacecraft never goes behind the planet. Juno’s orbital design not only enabled an historic solar-powered mission, it also established Juno’s unique science orbit.

White oval on Jupiter during Juno’s Perijove 4 pass on February 2, 2017. Processed from raw data. Credit: NASA/JPL-Caltech/SwRI/MSSS/Kevin M. Gill.
Uncalibrated, processed raw image from Juno’s Perijove 6 pass of Jupiter on May 19, 2017. Credit: NASA/SwRI/MSSS/Jason Major.

Juno spacecraft launched from Cape Canaveral on August 5, 2011. After traveling five years and 1.7 billion miles Juno arrived in orbit at Jupiter on July 4, 2016. The mission will last until at least February 2018, making 11 science orbits around Jupiter, instead of the 32 laps originally planned. Last year, engineers detected a problem with check valves in the propulsion system, and NASA decided to forego an engine burn to move Juno into a tighter 14-day orbit around Jupiter. The current 53.4 day orbit will be maintained, but depending on how the spacecraft responds, NASA could extend the mission another three years to give Juno more flybys near Jupiter.

The next science flyby will occur on July 11, when Juno will get some close-up views of the famous Great Red Spot.

Thanks to everyone who works on these images.

Animation of six images acquired by NASA’s Juno spacecraft on March 27, 2017. Credit: NASA/JPL-Caltech/SwRI/MSSS/Jason Major.
This enhanced color view of Jupiter’s south pole was created by citizen scientist Gabriel Fiset using data from the JunoCam instrument on NASA’s Juno spacecraft. Oval storms dot the cloudscape. Approaching the pole, the organized turbulence of Jupiter’s belts and zones transitions into clusters of unorganized filamentary structures, streams of air that resemble giant tangled strings. The image was taken on Dec. 11, 2016 at 9:44 a.m. PST (12:44 p.m. EST), from an altitude of about 32,400 miles (52,200 kilometers) above the planet’s beautiful cloud tops. Credits: NASA/JPL-Caltech/SwRI/MSSS/Gabriel Fiset

Juno is Ready to Tell Us What it Found at Jupiter

The tightly clustered storms that crowd Jupiter's polar regions are another of the gas giant's mysteries. In this image, cyclones the size of Earth bump up against each other at the south pole. Image: NASA/JPL-Caltech/SwRI/MSSS/Betsy Asher Hall/Gervasio Robles

Even a casual observer can see how complex Jupiter might be. Its Great Red Spot is one of the most iconic objects in our Solar System. The Great Red Spot, which is a continuous storm 2 or 3 times as large as Earth, along with Jupiter’s easily-seen storm cloud belts, are visual clues that Jupiter is a complex place.

We’ve been observing the Great Red Spot for almost 200 years, so we’ve known for a long time that something special is happening at Jupiter. Now that the Juno probe is there, we’re finding that Jupiter might be a more surprising place than we thought.

“There is so much going on here that we didn’t expect that we have had to take a step back and begin to rethink of this as a whole new Jupiter.” – Scott Bolton, Juno’s Principal Investigator at the Southwest Research Institute.

So far, the stunning images delivered to us by the JunoCam have stolen the show. But Juno is a science mission, and the fantastic images we’re feasting on might stir the imagination, but it’s the science that’s at the heart of the mission.

Just one of the many beautiful images of Jupiter we're accustomed to seeing. NASA has invited interested citizens to process JunoCam images and has made them available for anyone to use. NASA / SwRI / MSSS / Gerald Eichstädt / Seán Doran © public domain
Just one of the many beautiful images of Jupiter we’re accustomed to seeing. NASA has invited interested citizens to process JunoCam images and has made them available for anyone to use. NASA / SwRI / MSSS / Gerald Eichstädt / Seán Doran © public domain

The Juno probe arrived at Jupiter in July 2016, and completed its first data-pass on August 27th, 2016. That pass took it to within 4,200 km of Jupiter’s cloud tops. Results from that first pass are being published in the journal Science and in Geophysical Research Letters.

Taken together, the results confirm what we might have guessed by just looking at Jupiter from afar: it is a stormy, complex, turbulent world.

“It was a long trip to get to Jupiter, but these first results already demonstrate it was well worth the journey.” – Diane Brown, Juno Program Executive.

“We are excited to share these early discoveries, which help us better understand what makes Jupiter so fascinating,” said Diane Brown, Juno program executive at NASA Headquarters in Washington. “It was a long trip to get to Jupiter, but these first results already demonstrate it was well worth the journey.”

Jupiter’s Magnetic Field

We’ve known for a long time that Jupiter has the most powerful magnetic field in the Solar System. In fact, the magnetic field is what shaped the design of the Juno probe, and the profile of the mission itself. Juno’s Magnetometer Investigation (MAG) has measured the gas giant’s magnetosphere up close, and these measurements tell us that the magnetic field is even stronger than anticipated, and its shape is more irregular as well. At 7.66 Gauss, the field is about 10 times more powerful than Earth.

The irregularities in the magnetic field are an indication that the field is generated closer to the surface than thought. Earth generates its magnetic field from it its rotating core, but because Jupiter’s is “lumpy”, or stronger in some regions than in others, the gas giant’s magnetic field might be generated above its metallic hydrogen layer.

Results from Juno's first data-pass suggest that Jupiter's powerful magnetic field is generated closer to the surface than previously thought. It may be generated above the core of metallic hydrogen. Image: By Kelvinsong - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=31764016
Results from Juno’s first data-pass suggest that Jupiter’s powerful magnetic field is generated closer to the surface than previously thought. It may be generated above the core of metallic hydrogen. Image: By Kelvinsong – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=31764016

“Juno is giving us a view of the magnetic field close to Jupiter that we’ve never had before,” – Jack Connerney, Juno Deputy Principal Investigator

“Juno is giving us a view of the magnetic field close to Jupiter that we’ve never had before,” said Jack Connerney, Juno deputy principal investigator and the lead for the mission’s magnetic field investigation at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “Already we see that the magnetic field looks lumpy: it is stronger in some places and weaker in others. This uneven distribution suggests that the field might be generated by dynamo action closer to the surface, above the layer of metallic hydrogen. Every flyby we execute gets us closer to determining where and how Jupiter’s dynamo works.”

Jupiter’s Atmosphere

Juno’s Microwave Radiometer (MWR) is designed to probe Jupiter’s thick atmosphere. It can detect the thermal microwave radiation in the atmosphere, both at the surface, and much deeper. Data from the MWR shows us that the storm belts are mysteries themselves.

This artist's illustration shows Juno's Microwave Radiometer observing deep into Jupiter's atmosphere. The image shows real data from the 6 MWR channels, arranged by wavelength. Credit: NASA/SwRI/JPL
This artist’s illustration shows Juno’s Microwave Radiometer observing deep into Jupiter’s atmosphere. The image shows real data from the 6 MWR channels, arranged by wavelength. Credit: NASA/SwRI/JPL

The belts near Jupiter’s equator extend deep into the atmosphere, while other belts seem to evolve and transform into other structures. The MWR can probe a few hundred kilometers into the atmosphere, where it has found variable and increasing amounts of ammonia to that depth.

Polar Regions and Auroras

Jupiter is home to intense aurora activity at both poles. One of Juno’s mission goals is to study those auroras and the powerful polar magnetic fields that create them. Initial observations from Juno suggest that they are formed differently than Earthly auroras.

Juno is in a unique position to study the magnetosphere and the auroras. Its elongated polar orbit allows it to span the entire magnetosphere all the way from the bow shock to the planet itself.

The tilt of Juno's orbit relative to Jupiter changes over the course of the mission, sending the spacecraft increasingly deeper into the planet's intense radiation belts. This also gives Juno the ability to study the structure of the magnetosphere. Credit: NASA/JPL-Caltech
The tilt of Juno’s orbit relative to Jupiter changes over the course of the mission, sending the spacecraft increasingly deeper into the planet’s intense radiation belts. This also gives Juno the ability to study the structure of the magnetosphere. Credit: NASA/JPL-Caltech

According to the paper detailing the initial data on Jupiter’s magnetosphere an auroras, many of the observations have “terrestrial analogs.” But other aspects are very Jovian, and have no counterpart on Earth.

“…a radically different conceptual model of Jupiter’s interaction with its space environment.” – from J. E. P. Connerney et. al., 2017

As the authors say in their summary, “We observed plasmas upwelling from the ionosphere, providing a mechanism whereby Jupiter helps populate its magnetosphere. The weakness of the magnetic field-aligned electric currents associated with the main aurora and the broadly distributed nature of electron beaming in the polar caps suggest a radically different conceptual model of Jupiter’s interaction with its space environment.”

Polar Storms

JunoCam has also found some puzzling features in Jupiter’s atmosphere. The poles themselves are populated by densely clustered, swirling storms the size of Earth. Since they’ve only been observed briefly, there are a host of unanswered questions about them.

“We’re puzzled as to how they could be formed, how stable the configuration is, and why Jupiter’s north pole doesn’t look like the south pole.” – Scott Bolton, Juno’s Principal Investigator at the Southwest Research Institute

“We’re puzzled as to how they could be formed, how stable the configuration is, and why Jupiter’s north pole doesn’t look like the south pole,” said Bolton. “We’re questioning whether this is a dynamic system, and are we seeing just one stage, and over the next year, we’re going to watch it disappear, or is this a stable configuration and these storms are circulating around one another?”

The tightly clustered storms that crowd Jupiter's polar regions are another of the gas giant's mysteries. In this image, cyclones the size of Earth bump up against each other at the south pole. Image:  NASA/JPL-Caltech/SwRI/MSSS/Betsy Asher Hall/Gervasio Robles
The tightly clustered storms that crowd Jupiter’s polar regions are another of the gas giant’s mysteries. In this image, cyclones the size of Earth bump up against each other at the south pole. Image: NASA/JPL-Caltech/SwRI/MSSS/Betsy Asher Hall/Gervasio Robles

The Great Red Spot: Juno’s Next Target

Juno’s purposeful orbit takes it extremely close to the cloud tops, where it can perform powerful science. But the orbit also takes it a long way from Jupiter. Every 53 days it takes another plunge at Jupiter, where it gathers its next set of observations.

“Every 53 days, we go screaming by Jupiter, get doused by a fire hose of Jovian science, and there is always something new.” – Scott Bolton, Juno’s Principal Investigator at the Southwest Research Institute.

“Every 53 days, we go screaming by Jupiter, get doused by a fire hose of Jovian science, and there is always something new,” said Bolton. “On our next flyby on July 11, we will fly directly over one of the most iconic features in the entire solar system — one that every school kid knows — Jupiter’s Great Red Spot. If anybody is going to get to the bottom of what is going on below those mammoth swirling crimson cloud tops, it’s Juno and her cloud-piercing science instruments.”

The JunoCam's next target: Jupiter's iconic Great Red Spot. Image:  NASA/JPL-Caltech/SwRI/MSSS/Roman Tkachenko
Juno’s next target: Jupiter’s iconic Great Red Spot. Image: NASA/JPL-Caltech/SwRI/MSSS/Roman Tkachenko

During each pass, Juno collects about 6 megabytes of data, which it sends back to Earth via the Deep Space Network. After that, the data is analyzed and published.

Juno has many more fly-bys of Jupiter before it’s sent to its end in the atmosphere of Jupiter. We can expect many more surprises, and hopefully some answers, between now and then.

Juno’s Monday Jupiter Flyby Promises New Batch of Images & Science

Juno is only part way through its mission to Jupiter, and already we’ve seen some absolutely breathtaking images of the gas giant. On Monday, the Juno spacecraft will flyby Jupiter again. This will be the craft’s 5th flyby of the gas giant, and it’ll provide us with our latest dose of Jupiter science and images. The first 4 flybys have already exceeded our expectations.

Juno will approach to within 4,400 km of Jupiter’s cloud tops, and will travel at a speed of 207,600 km/h. During this time of closest approach, called a perijove, all of Juno’s eight science instruments will be active, along with the JunoCam.

The JunoCam is not exactly part of the science payload. It was included in the missions to help engage the public with the mission, and it appears to be doing that job well. The Junocam’s targets have been partly chosen by the public, and NASA has invited anyone who cares to to download and process raw Junocam images. You can see those results throughout this article.

This image of Jupiter’s dancing cloud tops was captured during perijove 3. Image: NASA / JPL-Caltech / SwRI / MSSS / Kootenay Nature Photos © cc nc sa

This is Juno’s 5th flyby, but only its 4th science pass. During Juno’s first encounter with Jupiter, the science instruments weren’t active. Even so, after only 3 science passes, we have learned some things about Jupiter.

“We are excited to see what new discoveries Juno will reveal.” – Scott Bolton, NASA’s Principal Investigator for the Juno Mission

“This will be our fourth science pass — the fifth close flyby of Jupiter of the mission — and we are excited to see what new discoveries Juno will reveal,” said Scott Bolton, principal investigator of Juno from the Southwest Research Institute in San Antonio. “Every time we get near Jupiter’s cloud tops, we learn new insights that help us understand this amazing giant planet.”

We’ve already learned that Jupiter’s intense magnetic fields are much more complicated than we thought. We’ve learned that the belts and zones in Jupiter’s atmosphere, which are responsible for the dazzling patterns on the cloud tops, extend much deeper into the atmosphere than we thought. And we’ve discovered that charged material expelled from Io’s volcanoes helps cause Jupiter’s auroras.

The South Pole of Jupiter, taken during perijove 3. Image: NASA / JPL-Caltech / SwRI / MSSS / Luca Fornaciari © cc nc sa

Juno has the unprecedented ability to get extremely close to Jupiter. This next flyby will bring it to within 4,400 km of the cloud tops. But to do so, Juno has to pay a price. Though the sensitive equipment on the spacecraft is protected inside a titanium vault, Jupiter’s powerful radiation belts will still take a toll on the electronics. But that’s the price Juno will pay to perform its mission.

Jupiter’s dazzle as revealed by JunoCam and Shane Drever. Image: NASA / JPL-Caltech / SwRI / MSSS / Shane Drever © cc nc sa

Other missions, like Cassini, have been measured in years, while Juno’s will be measured in orbits. And once it’s completed its final orbit, it will be sent to its destruction in Jupiter’s atmosphere.

But before that happens, there’s a lot of science to be done, and a lot of stunning images to be captured.

Here’s an interview with the man leading the Juno Mission: Understanding Juno’s Orbit: An Interview with NASA’s Scott Bolton.

Here is the page for the JunoCam: https://www.missionjuno.swri.edu/junocam

Juno Will Get No Closer To Jupiter Due To Engine Troubles

On July 4th, 2016, the Juno mission established orbit around Jupiter, becoming the second spacecraft in history to do so (after the Galileo probe). Since then, the probe has been in a regular 53.4-day orbit (known as perijove), moving between the poles to avoid the worst of its radiation belts. Originally, Juno’s mission scientists had been hoping to reduce its orbit to a 14-day cycle so the probe could make more passes to gather more data.

To do this, Juno was scheduled for an engine burn on Oct. 19th, 2016, during its second perijovian maneuver. Unfortunately, a technical error prevented this  from happening. Ever since, the mission team has been pouring over mission data to determine what went wrong and if they could conduct an engine burn at a later date. However, the mission team has now concluded that this won’t be possible.

The technical glitch which prevented the firing took place weeks before the engine burn was scheduled to take place, and was traced to two of the engines helium check valves. After the propulsion system was pressurized, the valves took several minutes to open – whereas they took only seconds during previous engine burns. Because of this, the mission leaders chose to postpone the firing until they could get a better understanding of why the glitch happened.

This amateur-processed image was taken on Dec. 11th, 2016, at 9:27 a.m. PST (12:27 p.m. EST), as NASA’s Juno spacecraft performed its third close flyby of Jupiter. Credits: NASA/JPL-Caltech/SwRI/MSSS/Eric Jorgensen

And after pouring over mission data from the past few months and performing calculations on possible maneuvers, Juno’s science team came to the conclusion that an engine burn might be counter-productive at this point. As Rick Nybakken, the Juno project manager at NASA’s Jet Propulsion Laboratory (JPL), explained in a recent NASA press release:

“During a thorough review, we looked at multiple scenarios that would place Juno in a shorter-period orbit, but there was concern that another main engine burn could result in a less-than-desirable orbit. The bottom line is a burn represented a risk to completion of Juno’s science objectives.”

However, this is not exactly bad news for the mission. It’s current perijove orbit takes it from one pole to the other, allowing it to pass over the cloud tops at a distance of around 4,100 km (2,600 mi) at its closest. At its farthest, the spacecraft reaches a distance of 8.1 million km (5.0 million mi) from the gas giant, which places it far beyond the orbit of Callisto.

During each pass, the probe is able to peak beneath the thick clouds to learn more about the planet’s atmosphere, internal structure, magnetosphere, and formation. And while a 14-day orbital period would allow for it to conduct 37 orbits before its mission is scheduled to wrap up, its current 53.4-day period will allow for more information to be collected on each pass.

And as Thomas Zurbuchen, the associate administrator for NASA’s Science Mission Directorate in Washington, declared:

“Juno is healthy, its science instruments are fully operational, and the data and images we’ve received are nothing short of amazing. The decision to forego the burn is the right thing to do – preserving a valuable asset so that Juno can continue its exciting journey of discovery.”

In the meantime, the Juno science team is still analyzing the returns from Juno’s four previous flybys – which took place on August 27th, October 19th, December 11th, and February 2nd, 2017, respectively. With each pass, more information is revealed about the planet’s magnetic fields, aurorae, and banded appearance. The next perijovian maneuver will take place on March 27th, 2017, and will result in more images and data being collected.

Before the mission concludes, the Juno spacecraft will also explore Jupiter’s far magnetotail, its southern magnetosphere, and its magnetopause. The mission is also conducting an outreach program with its JunoCam, which is being guided with assistance of the public. Not only can people vote on which features they want imaged with every flyby, but these images are accessible to “citizen scientists” and amateur astronomers.

Under its current budget plan, Juno will continue to operate through to July 2018, conducting a total of 12 science orbits. At this point, barring a mission extension, the probe will be de-orbited and burn up in Jupiter’s outer atmosphere. As with the Galileo spacecraft, this will be as to avoid any possibility of impact and biological contamination with one of Jupiter’s moons.

Further Reading: NASA

Juno Buzzes Jupiter a mere 4,300 Km’s above the Cloud Tops

On July 4th, 2016, NASA’s Juno spacecraft made history when it became the second mission to establish orbit around Jupiter – the previous being the Galileo spacecraft, which orbited the planet from 1995 to 2003. Since that time, it has circled the massive gas giant three times, collecting data on the gas giant’s composition, interior and gravity field.

This past Thursday, February 1st, the mission conducted its fourth orbit of the planet. In the process, the spacecraft collected more vital data on the gas giant and snapped several dozen pictures. And in what is has been a first for a space mission, NASA will once again be asking the public what features they would like to see photographed during Juno’s next pass.

Juno made its closest pass (what is known as perijove) to Jupiter at precisely 1257 GMT (7:57 a.m. EST), passing the cloud tops at a distance of 4,300 km (2,670 mi) and traveling at a velocity of about 208,000 km/h (129,300 mph) relative to the gas giant. Using its suite of instruments, it scanned Jupiter’s atmosphere, gathered data on its radiation and plasma, and began returning this information to Earth.

Processed image taken on Dec. 11, 2016, at 9:27 a.m. PST (12:27 p.m. EST) by the NASA Juno spacecraft, as it performed its third close flyby of Jupiter. Credits: NASA/JPL-Caltech/SwRI/MSSS/Eric Jorgensen

And during this latest pass, the JunoCam snapped several dozen more pictures. During two of its three previous perijove maneuvers, this instruments captured some of the most breathtaking photographs of Jupiter’s clouds to date (like the one seen above). Once they were transmitted back to Earth and made available to the public, “citizen scientistswere able to download and process them at their leisure.

And with this latest pass complete, the public is once again being encouraged to vote on what features they want to see photographed during the next pass. As Candy Hansen, the Juno mission’s co-investigator from the Planetary Science Institute, stated shortly before Juno made its fourth perijovian maneuver:

“The pictures JunoCam can take depict a narrow swath of territory the spacecraft flies over, so the points of interest imaged can provide a great amount of detail. They play a vital role in helping the Juno science team establish what is going on in Jupiter’s atmosphere at any moment. We are looking forward to seeing what people from outside the science team think is important.”

This has all been part of a first-ever effort on behalf of NASA to get the public involved in what kinds of images are to be taken. According to NASA, this is to become a regular feature of the Juno mission, with a  new voting page being created for each upcoming flyby. The next perijovian maneuver will take place on March 27th, 2017, coinciding with the Juno spacecraft’s 53.4-day orbital period.

False color view of Jupiter’s polar haze, created by citizen scientist Gerald Eichstädt using data from the JunoCam instrument. Credit: NASA/JPL-Caltech/SwRI/MSSS/Eric Jorgensen

Originally, the mission planners had hoped to narrow Juno’s orbital period down to 14 days, which would have been accomplished by having the craft fire its main engine while at perijove. However, two weeks before the engine burn was scheduled to take place (Oct. 19th, 2016), ground controllers noticed a problem with two of the engine’s check valves – which are part of the spacecraft’s fuel pressurization system.

As Juno project manager Rick Nybakken said at the time:

“Telemetry indicates that two helium check valves that play an important role in the firing of the spacecraft’s main engine did not operate as expected during a command sequence that was initiated yesterday. The valves should have opened in a few seconds, but it took several minutes. We need to better understand this issue before moving forward with a burn of the main engine.”

Because of this technical issue, the mission leaders chose to postpone the engine burn so they could check the craft’s instruments to get a better understanding of why it happened. The Juno team was hoping to use the third orbit of the spacecraft to study the problem, but this was interrupted when a software performance monitor induced a reboot of the spacecraft’s onboard computer.

To accomplish its science objectives, Juno is orbiting Jupiter’s poles and passing very close to the planet, avoiding the most powerful (and hazardous) radiation belts in the process. Credit: NASA/JPL-Caltech

Because of this, the spacecraft went into safe mode during its third flyby, which prevented them from gathering data on the engine valve problem. On Oct. 24th, the mission controllers managed to get the craft to exit safe mode and performed a trim maneuver in preparation for its next flyby. But the mystery of why the engine valves failed to open remains, and the mission team is still unable to resolve the problem.

Thus, the decision to fire the main engine (thereby shortening its orbital period) has been postponed until they get it back online. But as Scott Bolton – the Associate Director of R&D at the Southwest Research Institute (SwRI) and Juno’s Principal Investigator – has emphasized in the past:

“It is important to note that the orbital period does not affect the quality of the science that takes place during one of Juno’s close flybys of Jupiter. The mission is very flexible that way. The data we collected during our first flyby on August 27th was a revelation, and I fully anticipate a similar result from Juno’s October 19th flyby.”

In the meantime, the Juno science team is still analyzing data from all previous Jupiter flybys. During each pass, the spacecraft and its instruments peer beneath Jupiter’s dense cloud cover to study its auroras, its magnetic field, and to learn more about the planet’s structure, composition, and formation. And with the public’s help, it is also providing some of the clearest and most detailed imagery of the gas giant to date.

Further Reading: NASA

 

A Proposal For Juno To Observe The Volcanoes Of Io

To accomplish its science objectives, NASA’s Juno spacecraft orbits over Jupiter’s poles and passes repeatedly through hazardous radiation belts. Two Boston University researchers propose using Juno to probe the ever-changing flux of volcanic gases-turned-ions spewed by Io’s volcanoes. Credit: NASA/JPL-Caltech

Jupiter may be the largest planet in the Solar System with a diameter 11 times that of Earth, but it pales in comparison to its own magnetosphere. The planet’s magnetic domain extends sunward at least 3 million miles (5 million km) and on the back side all the way to Saturn for a total of 407 million miles or more than 400 times the size of the Sun.

Jupiter’s large magnetic field interacts with the solar wind to form an invisible magnetosphere. If we were able to see it, it would span at least several degrees of sky. It would show its greatest extent when viewing Jupiter from the side at quadrature, when the planet stands due south at sunrise or sunset.In the artist’s depiction, the planet would be located between the two “purple eyes” — too small to see at this scale. Credit: NASA.

If we had eyes adapted to see the Jovian magnetosphere at night, its teardrop-like shape would easily extend across several degrees of sky! No surprise then that Jove’s magnetic aura has been called one of the largest structures in the Solar System.

A 5-frame sequence taken by the New Horizons spacecraft in May 2007 shows a cloud of volcanic debris from Io’s Tvashtar volcano. The plume extends some 200 miles (330 km) above the moon’s surface. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute

Io, Jupiter’s innermost of the planet’s four large moons, orbits deep within this giant bubble. Despite its small size — about 200 miles smaller than our own Moon — it doesn’t lack in superlatives. With an estimated 400 volcanoes, many of them still active, Io is the most volcanically active body in the Solar System. In the moon’s low gravity, volcanoes spew sulfur, sulfur dioxide gas and fragments of basaltic rock up to 310 miles (500 km) into space in beautiful, umbrella-shaped plumes.

This schematic of Jupiter’s magnetic environments shows the planets looping magnetic field lines (similar to those generated by a simple bar magnet), Io and its plasma torus and flux tube. Credit: John Spencer / Wikipedia CC-BY-SA3.0 with labels by the author

Once aloft, electrons whipped around by Jupiter’s powerful magnetic field strike the neutral gases and ionize them (strips off their electrons). Ionized atoms and molecules (ions) are no longer neutral but possess a positive or negative electric charge. Astronomers refer to swarms of ionized atoms as plasma.

Jupiter rotates rapidly, spinning once every 9.8 hours, dragging the whole magnetosphere with it. As it spins past Io, those volcanic ions get caught up and dragged along for the ride, rotating around the planet in a ring called the Io plasma torus. You can picture it as a giant donut with Jupiter in the “hole” and the tasty, ~8,000-mile-thick ring centered on Io’s orbit.

That’s not all. Jupiter’s magnetic field also couples Io’s atmosphere to the planet’s polar regions, pumping Ionian ions through two “pipelines” to the magnetic poles and generating a powerful electric current known as the Io flux tube. Like firefighters on fire poles, the ions follow the planet’s magnetic field lines into the upper atmosphere, where they strike and excite atoms, spawning an ultraviolet-bright patch of aurora within the planet’s overall aurora. Astronomers call it Io’s magnetic footprint. The process works in reverse, too, spawning auroras in Io’s tenuous atmosphere.

The tilt of Juno’s orbit relative to Jupiter changes over the course of the mission, sending the spacecraft increasingly deeper into the planet’s intense radiation belts. Orbits are numbered from early in the mission to late. Credit: NASA/JPL-Caltech

Io is the main supplier of particles to Jupiter’s magnetosphere. Some of the same electrons stripped from sulfur and oxygen atoms during an earlier eruption return to strike atoms shot out by later blasts. Round and round they go in a great cycle of microscopic bombardment! The constant flow of high-speed, charged particles in Io’s vicinity make the region a lethal environment not only for humans but also for spacecraft electronics, the reason NASA’s Juno probe gets the heck outta there after each perijove or closest approach to Jupiter.

Io’s flux tube directs ions down Jupiter’s magnetic field lines to create magnetic footprints of enhanced aurora in Jupiter’s polar regions. An electric current of 5 million amps flows along Io’s flux tube.Credit: NASA/J.Clarke/HST

But there’s much to glean from those plasma streams.  Astronomy PhD student Phillip Phipps and assistant professor of astronomy Paul Withers of Boston University have hatched a plan to use the Juno spacecraft to probe Io’s plasma torus to indirectly study the timing and flow of material from Io’s volcanoes into Jupiter’s magnetosphere. In a paper published on Jan. 25, they propose using changes in the radio signal sent by Juno as it passes through different regions of the torus to measure how much stuff is there and how its density changes over time.

The technique is called a radio occultation. Radio waves are a form of light just like white light. And like white light, they get bent or refracted when passing through a medium like air (or plasma in the case of Io). Blue light is slowed more and experiences the most bending; red light is slowed less and refracted least, the reason red fringes a rainbow’s outer edge and blue its inner. In radio occultations, refraction results in changes in frequency caused by variations in the density of plasma in Io’s torus.

The best spacecraft for the attempt is one with a polar orbit around Jupiter, where it cuts a clean cross-section through different parts of the torus during each orbit. Guess what? With its polar orbit, Juno’s the probe for the job! Its main mission is to map Jupiter’s gravitational and magnetic fields, so an occultation experiment jives well with mission goals. Previous missions have netted just two radio occultations of the torus, but Juno could potentially slam dunk 24.

New Horizons took this photo of Io in infrared light. The Tvastar volcano is bright spot at top. At least 10 other volcanic hot spots dot the moon’s night side. Credit: NASA/JHUPL/SRI

Because the paper was intended to show that the method is a feasible one, it remains to be seen whether NASA will consider adding a little extra credit work to Juno’s homework. It seems a worthy and practical goal, one that will further enlighten our understanding of how volcanoes create aurorae in the bizarre electric and magnetic environment of the largest planet.

Juno Just Took One Of The Best Images Of Jupiter Ever

Wow! If you’ve ever wanted to know what it would be like to hang above Jupiter’s clouds, here you go. This absolutely stunning view of Jupiter’s northern latitudes shows incredible detail of gas giant’s swirling cloudtops. And it features, in the lower left in the image below, the storm on the gas planet known as NN-LRS-1, or more colloquially, the Little Red Spot.

The JunoCam imager on NASA’s Juno spacecraft snapped this shot of Jupiter’s northern latitudes on Dec. 11, 2016. Credit: NASA/JPL-Caltech/SwRI/MSSS/Gerald Eichstaedt/John Rogers.

Juno’s JunoCam, a visible light camera, is able to get never-before-seen images like this because it is doing something that no other mission to Jupiter has done.

“The spacecraft’s proximity to Jupiter is very unusual,” Rick Nybakken told me during an interview at JPL last year. Nybakken is Juno’s project manager. “Juno has an elliptical orbit that brings it just 3,107 miles (5,000 km) above the cloud tops. No other mission has been this close, and we’re right on top of Jupiter so to speak.”

Special instruments are studying Jupiter’s radiation belt and magnetosphere, its interior structure, and the turbulent atmosphere, as well as providing views of the planet with spectacular, close-up images.

And another great thing about this image is that it was processed by citizen scientists. Gerald Eichstaedt and John Rogers processed the image and drafted the caption, and this will be the norm for many of the JunoCam images, because it’s “the public’s camera.”

“I’m excited though for what we’re doing with the visible light camera,” said Juno Project Scientist Steve Levin, who I also interviewed at JPL. “We’re making JunoCam as much as much as we possibly can an instrument that belongs to the public. We’ll solicit the aid of the public in picking which images to take, and releasing the data in its rawest form, and allow people to go and make the images.”

Scientist Candy Hansen is leading this citizen science effort, and she uses the phrase, “science in a fishbowl,” meaning the JunoCam team is showing people what it is like to do science by allowing anyone to participate and see the data as it arrives from Juno.

Damian Peach reprocessed one of the latest images taken by Juno’s JunoCam during its 3rd close flyby of the planet on Dec. 11. The photo highlights two large ‘pearls’ or storms in Jupiter’s atmosphere. Credit: NASA/JPL-Caltech/SwRI/MSSS

You can find the raw images here, so go ahead and test out your image processing skills.

JunoCam is designed to capture remarkable pictures of Jupiter’s poles and cloud tops. Although its images will be helpful to the science team to help provide context for the spacecraft’s other instruments, it is not considered one of the mission’s science instruments. JunoCam was included on the spacecraft specifically for purposes of engaging and including the public.

The Little Red Spot is the third largest anticyclonic oval on the planet, which Earth-based observers have tracked for the last 23 years. An anticyclone is a weather phenomenon with large-scale circulation of winds around a central region of high atmospheric pressure. They rotate clockwise in the northern hemisphere, and counterclockwise in the southern hemisphere. The Little Red Spot shows very little color these days, just a pale brown smudge in the center. Back in 2006, the storm was stronger and the color changed darker and more red. Now, with the storm not quite as active, the color is very similar to the surroundings, making it difficult to see.

If you’d like to download a larger version of this processed image (need a new wallpaper?) you can find it on NASA’s website.