The venerable Hubble Space Telescope has given us another gorgeous picture of Jupiter and its moon Europa. The incredibly sharp image was captured on August 25th, and shows some of the stunning detail in Jupiter’s stormy atmosphere. Hidden in all that stormy activity is something new: a bright white storm plume travelling at about 560 km/h (350 mp/h).Continue reading “The Newest Picture of Jupiter and Europa Captured by Hubble”
Most massive planet in the solar system – twice that of all the other planets combined. This giant world formed from the same cloud of dust and gas that became our Sun and the rest of the planets. But Jupiter was the first-born of our planetary family. As the first planet, Jupiter’s massive gravitational field likely shaped the rest of the entire solar system. Jupiter could’ve played a role in where all the planets aligned in their orbits around the Sun…or didn’t as the asteroid belt is a vast region which could’ve been occupied by another planet were it not for Jupiter’s gravity. Gas giants like Jupiter can also hurl entire planets out of their solar systems, or themselves spiral into their stars. Saturn’s formation several million years later probably spared Jupiter this fate. Jupiter may also act as a “comet catcher.” Comets and asteroids which could otherwise fall toward the inner solar system and strike the rocky worlds like Earth are captured by Jupiter’s gravitational field instead and ultimately plunge into Jupiter’s clouds. But at other times in Earth’s history, Jupiter may have had the opposite effect, hurling asteroids in our direction – typically a bad thing but may have also resulted in water-rich rocks coming to Earth that led to the blue planet we know of today.Continue reading “Here’s Jupiter from Juno’s Latest Flyby”
It’s difficult to imagine the magnitude of storms on Jupiter. The gas giant’s most visible atmospheric feature, the Great Red Spot, may be getting smaller, but one hundred years ago, it was about 40,000 km (25,000 miles) in diameter, or three times Earth’s diameter.
Jupiter’s atmosphere also features thunderheads that are five times taller than Earth’s: a whopping 64 km (40 miles) from bottom to top. Its atmosphere is not entirely understood, though NASA’s Juno spacecraft is advancing our understanding. The planet may contain strange things like a layer of liquid metallic hydrogen.
Now a group of scientists are combining the power of the Hubble Space Telescope, the Gemini Observatory and the Juno spacecraft to probe Jupiter’s atmosphere, and the awe-inspiring storms that spawn there.Continue reading “Spacecraft and Ground Telescopes Work Together to Give us Stunning New Pictures of Jupiter”
For centuries, astronomers have been observing Jupiter swirling surface and been awed and mystified by its appearance. The mystery only deepened when, in 1995, the Galileo spacecraft reached Jupiter and began studying its atmosphere in depth. Since that time, astronomers have puzzled over its colored bands and wondered if they are just surface phenomenon, or something that goes deeper.
Thanks to the Juno spacecraft, which has been orbiting Jupiter since July of 2016, scientists are now much closer to answering that question. This past week, three new studies were published based on Juno data that presented new findings on Jupiter’s magnetic field, its interior rotation, and how deep its belts extend. All of these findings are revising what scientists think of Jupiter’s atmosphere and its inner layers.
The studies were titled “Measurement of Jupiter’s asymmetric gravity field“, “Jupiter’s atmospheric jet streams extend thousands of kilometres deep” and “A suppression of differential rotation in Jupiter’s deep interior“, all of which were published in Nature on March 7th, 2018. The studies were led by Prof. Luciano Iess of Sapienza University of Rome, the second by Prof. Yohai Kaspi and Dr. Eli Galanti of the Weizmann Institute of Science, and the third by Prof. Tristan Guillot of the Observatoire de la Cote d’Azur.
The research effort was led by Professo Kaspi and Dr. Galanti, who in addition to being the lead authors on the second study were co-authors on the other two. The pair have been preparing for this analysis even before Juno launched in 2011, during which time they built mathematical tools to analyze the gravitational field data and get a better grasp of Jupiter’s atmosphere and its dynamics.
All three studies were based on data gathered by Juno as it passed from one of Jupiter’s pole to the other every 53-days – a maneuver known as a “perijove”. With each pass, the probe used its advanced suite of instruments to peer beneath the surface layers of the atmosphere. In addition, radio waves emitted by the probe were measured to determine how they were shifted by the planet’s gravitational field with each orbit.
As astronomers have understood for some time, Jupiter’s jets flow in bands from east to west and west to east. In the process, they disrupt the even distribution of mass on the planet. By measuring changes in the planet’s gravity field (and thus this mass imbalance), Dr. Kaspi and Dr. Galanti’s analytical tools were able to calculate how deep the storms extend beneath the surface and what it’s interior dynamics are like.
Above all, the team expected to find anomalies because of the way the planet deviates from being a perfect sphere – which is due to how its rapid rotation squishes it slightly. However, they also looked for additional anomalies that could be explained due to the presence of powerful winds in the atmosphere.
In the first study, Dr. Iess and his colleagues used precise Doppler tracking of the Juno spacecraft to conduct measurements of Jupiter’s gravity harmonics – both even and odd. What they determined was Jupiter’s magnetic field has a north-south asymmetry, which is indicative of interior flows in the atmosphere.
Analysis of this asymmetry was followed-up on in the second study, where Dr. Kaspi, Dr. Galanti and their colleagues used the variations in the planet’s gravity field to calculate the depth of Jupiter’s east-west jet streams. By measuring how these jets cause an imbalance in Jupiter’s gravity field, and even disrupt the mass of the planet, they concluded that they extend to a depth of 3000 km (1864 mi).
From all this, Prof. Guillot and his colleagues conducted the third study, where they used the previous findings about the planet’s gravitational field and jet streams and compared the results to predictions of interior models. From this, they determined that the interior of the planet rotates almost like a rigid body and that differential rotation decreases farther down.
In addition, they found that the zones of atmospheric flow extended to between 2,000 km (1243 mi) and 3,500 km (2175 mi) deep, which was consistent with the constraints obtained from the odd gravitational harmonics. This depth also corresponds to the point where electric conductivity would become large enough that magnetic drag would suppress differential rotation.
Based on their findings, the team also calculated that Jupiter’s atmosphere constitutes 1% of its total mass. For comparison, Earth’s atmosphere is less than a millionth of its total mass. Still, as Dr. Kaspi explained in Weizzmann Institute press release, this was rather surprising:
“That is much more than anyone thought and more than what has been known from other planets in the Solar System. That is basically a mass equal to three Earths moving at speeds of tens of meters per second.”
All told, these studies have shed new light on the Jupiter’s atmospheric dynamics and interior structure. At present, the subject of what resides at Jupiter’s core remains unresolved. But the researchers hope to analyze further measurements made by Juno to see whether Jupiter has a solid core and (if so) to determine its mass. This in turn will help astronomers learn a great deal about the Solar System’s history and formation.
In addition, Kaspi and Galanti are looking to use some of the same methods they developed to characterize Jupiter’s jet streams to tackle its most iconic feature – Jupiter’s Great Red Spot. In addition to determining how deep this storm extends, they also hope to learn why this storm has persisted for so many centuries, and why it has been noticeably shrinking in recent years.
The Juno mission is expected to wrap up in July of 2018. Barring any extensions, the probe will conduct a controlled deorbit into Jupiter’s atmosphere after conducting perijove 14. However, even after the mission is over, scientists will be analyzing the data it has collected for years to come. What this reveals about the Solar System’s largest planet will also go a long way towards informing out understanding of the Solar System.
Since it established orbit around Jupiter in July of 2016, the Juno mission has been sending back vital information about the gas giant’s atmosphere, magnetic field and weather patterns. With every passing orbit – known as perijoves, which take place every 53 days – the probe has revealed more interesting things about Jupiter, which scientists will rely on to learn more about its formation and evolution.
During its latest pass, the probe managed to provide the most detailed look to date of the planet’s interior. In so doing, it learned that Jupiter’s powerful magnetic field is askew, with different patterns in it’s northern and southern hemispheres. These findings were shared on Wednesday. Oct. 18th, at the 48th Meeting of the American Astronomical Society’s Division of Planetary Sciencejs in Provo, Utah.
Ever since astronomers began observing Jupiter with powerful telescopes, they have been aware of its swirling, banded appearance. These colorful stripes of orange, brown and white are the result of Jupiter’s atmospheric composition, which is largely made up of hydrogen and helium but also contains ammonia crystals and compounds that change color when exposed to sunlight (aka. chromofores).
Until now, researchers have been unclear as to whether or not these bands are confined to a shallow layer of the atmosphere or reach deep into the interior of the planet. Answering this question is one of the main goals of the Juno mission, which has been studying Jupiter’s magnetic field to see how it’s interior atmosphere works. Based on the latest results, the Juno team has concluded that hydrogen-rich gas is flowing asymmetrically deep in the planet.
These findings were also presented in a study titled Comparing Jupiter interior structure models to Juno gravity measurements and the role of a dilute core, which appeared in the May 28th issue of Geophysical Research Letters. The study was led by Sean Wahl, a grad student from UC Berkeley, and included members from the Weizmann Institute of Science, the Southwest Research Institute (SwRI), NASA’s Goddard Space Flight Center and the Jet Propulsion Laboratory.
Another interesting find was that Jupiter’s gravity field varies with depth, which indicated that material is flowing as far down as 3,000 km (1,864 mi). Combined with information obtained during previous perijoves, this latest data suggests that Jupiter’s core is small and poorly defined. This flies in the face of previous models of Jupiter, which held that the outer layers are gaseous while the interior ones are made up of metallic hydrogen and a rocky core.
As Tristan Guillot – a planetary scientist at the Observatory of the Côte d’Azur in Nice, France, and a co-author on the study – indicated during the meeting, “This is something that was not expected. We were not sure at all whether we would be able to see that… It’s clear that giant planets have a lot of secrets.”
But of course, more passes and data are needed in order to pinpoint how strong the flow of gases are at various depths, which could resolve the question of how Jupiter’s interior is structured. In the meantime, the Juno scientists are pouring over the probe’s gravity data hoping to see what else it can teach them. For instance, they also want to know how far the Great Red Spot extends into the amotpshere.
This anticyclonic storm, which was first spotted in the 17th century, is Jupiter’s most famous feature. In addition to being large enough to swallow Earth whole – measuring some 16,000 kilometers (10,000 miles) in diameter – wind speeds can reach up to 120 meters per second (432 km/h; 286 mph) at its edges. Already the JunoCam has snapped some very impressive pictures of this storm, and other data has indicated that the storm could run deep.
In fact, on July 10th, 2017, the Juno probe passed withing 9,000 km (5,600 mi) of the Great Red Spot, which took place during its sixth orbit (perijove six) of Jupiter. With it’s suite of eight scientific instruments directed at the storm, the probe obtained readings that indicated that the Great Red Spot could also extend hundreds of kilometers into the interior, or possibly even deeper.
As David Stevenson, a planetary scientist at the California Institute of Technology and a co-author on the study, said during the meeting, “It’s not yet clear that it is so deep it will show up in gravity data. But we’re trying”.
Other big surprises which Juno has revealed since it entered orbit around Jupiter include the clusters of cyclones located at each pole. These were visible to the probe’s instruments in both the visible and infrared wavelengths as it made its first maneuver around the planet, passing from pole to pole. Since Juno is the first space probe in history to orbit the planet this way, these storms were previously unknown to scientists.
In total, Juno spotted eight cyclonic storms around the north pole and five around the south pole. Scientists were especially surprised to see these, since computer modelling suggests that such small storms would not be stable around the poles due to the planet’s swirling polar winds. The answer to this, as indicated during the presentation, may have to do with a concept known as vortex crystals.
As Fachreddin Tabataba-Vakili – a planetary scientist at NASA’s Jet Propulsion Laboratory and a co-author on the study – explained, such crystals are created when small vortices form and persist as the material in which they are embedded continues to flow. This phenomenon has been seen on Earth in the form of rotating superfluids, and Jupiter’s swirling poles may possess similar dynamics.
In the short time that Juno has been operating around Jupiter, it has revealed much about the planet’s atmosphere, interior, magnetic field and internal dynamics. Long after the mission is complete – which will take place in February of 2018 when the probe is crashed into Jupiter’s atmosphere – scientists are likely to be sifting through all the data it obtained, hoping to solve any remaining mysteries from the Solar System’s largest and most massive planet.
Further Reading: Nature
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.
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!)”
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.
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!
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.
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.
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
The Juno mission has made some remarkable finds since it reached Jupiter in July of 2016. During the many orbits it has made around Jupiter’s poles – which occur every 53 days – some stunning imagery has resulted. Not only have these pictures revealed things about Jupiter’s atmosphere, they have also been an opportunity for the public to participate in the exploration of this giant planet.
The latest feature that was publicly selected to be photographed is known as “STB Spectre“. This feature was photographed on March 27th, 2017, at 2:06 a.m. PDT (5:06 a.m. EDT), when Juno was 12,700 km from the planet. During this pass, the JunoCam captured a series of light and dark clouds coming together in Jupiter’s South Tropical Region (STR).
The left side of the photograph corresponds to the South Temperate Belt (STB), a prominent belt in Jupiter’s Southern Hemisphere which is typically darker. It is here that “the Spectre” – the wide bluish streaks on the upper right side of the photograph – can be seen, and which represent a long-lived storm that was taking place when the area was photographed.
On the right side of the image, we see the neighboring Southern Tropical Zone (STropZ), one of the most prominent zones on the planet. Here, we see another atmospheric condition colliding with the Spectre, one which is characterized by a series of anticyclonic storms (the small white ovals). Not surprisingly, it is within these two bands that part of the large anticyclonic storms known as the “Great Red Spot” and “Red Spot Junior” also exist.
Like all images snapped by the JunoCam since the probe began orbiting Jupiter, this image was made available to the public. In this case, the image was processed by Roman Tkachenko, an amateur astronomer, image processor, and 3D artist who’s body of work includes images and visualizations for the New Horizons mission. The description was produced by John Rogers, the citizen scientist who identified the point of interest.
As Tkachenko Universe Today via email, working with these missions pictures is all about bringing raw images to life:
“This image is based on a raw image. Working with raw data you can get a higher resolution than we can see in already constructed, and map-projected official versions. I worked with colors, sharpness and dynamic range to show more details and variety.”
This is something new for a space mission, where the public has a direct say in what features will be photographed for study, and can help process them as well. “The participation of amateur astronomers and citizen scientists in this mission is an opportunity to be involved in something gorgeous,” said Tkachenko. “They can also show their skills to the public and help the Juno team look at all these data from different angles.
The STB Spectre was one of five Points of Interest (POIs) that were selected by the public to be photographed during Perijove 5 – Juno’s fifth orbit of the planet, which began on March 27th, 2017. Before the next maneuver (Perijove 6) commences on May 19th, 2017, the public will once again be able to vote on what features they want to see photographed.
Things that have been captured during previous orbits include the stunning image of the “Jovian pearl“, a detailed view of Jupiter’s northern clouds, breathtaking images of the swirling clouds round Jupiter’s northern and southern poles. Many more are sure to follow between now and July 2018, as Juno conducts its seven remaining perijove maneuvers before being de-orbited and burning up in Jupiter’s atmosphere.
To learn more about the rules for voting, and to vote on what you’d like the JunoCam to capture, check out the Southwest Research Institute’s (SwRI) JunoCam voting page. And be sure to enjoy this mission video:
Further Reading: NASA
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.
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 scientists” were 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.
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.
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
Welcome to a new series here at Universe Today! In this segment, we will be taking a look at the weather on other planets. First up, we take a look at the “King of Planets” – Jupiter!
One of the most obvious facts about the gas giant Jupiter is its immense size. With a mean radius of 69,911 ± 6 km (43441 mi) and a mass of 1.8986 × 1027 kg, Jupiter is almost 11 times the size of Earth, and just under 318 times Earth’s massive. But this “go big or go home” attitude extends far beyond the planet’s size.
When it comes to weather patterns, Jupiter is also an exercise in extremes. The planet experiences storms that can grow to thousands of kilometers in diameter in the space of a few hours. The planet also experiences windstorms, lightning, and auroras in some areas. In fact, the weather on Jupiter is so extreme that it can be seen from space!
Jupiter is composed primarily of gaseous and liquid matter. It is the largest of the gas giants, and like them, is divided between a gaseous outer atmosphere and an interior that is made up of denser materials. It’s upper atmosphere is composed of about 88–92% hydrogen and 8–12% helium by percent volume of gas molecules, and approx. 75% hydrogen and 24% helium by mass, with the remaining one percent consisting of other elements.
The atmosphere contains trace amounts of methane, water vapor, ammonia, and silicon-based compounds as well as trace amounts of benzene and other hydrocarbons. There are also traces of carbon, ethane, hydrogen sulfide, neon, oxygen, phosphine, and sulfur. Crystals of frozen ammonia have also been observed in the outermost layer of the atmosphere.
Jupiter is perpetually covered with clouds that are composed of these ammonia crystals, and possibly ammonium hydrosulfide. These clouds are located in the tropopause and are arranged into bands of different latitudes, known as “tropical regions”. The cloud layer is only about 50 km (31 mi) deep, and consists of at least two decks of clouds: a thick lower deck and a thin clearer region.
These clouds are also what gives the planet is banded appearance, with clouds of yellow, brown and white circling the surface rapidly. These bands are produced by air flowing in different directions at various latitudes. Lighter-hued areas where the atmosphere rises are called zones. Darker regions where air falls are called belts. When these opposing flows interact, storms and turbulence appear (aka. “zonal jets”).
The Great Red Spot:
As noted already, Jupiter experiences violent storms, which often take the form of zonal jets. In these weather fronts, wind speeds of 100 m/s (360 km/h) are common. But wind storms on the mighty planet can reach as high as 620 kph (385 mph). These storms can form within hours and become thousands of kilometers in diameter overnight.
One storm, the Great Red Spot, has been raging since at least the late 1600s – when Italian astronomer Giovanni Cassini made the first recorded observation of it. The storm has been shrinking and expanding throughout its history; but in 2012, it was suggested that the Giant Red Spot might eventually disappear.
This storm is one of the best known features in the Solar System. It is located 22° south of the equator and reaching sizes of up to 40,000 km across, it is larger in diameter than Earth. The storm rotates in a counter-clockwise motion, making it an anti-cyclonic storm.
It rotates differently than the rest of the atmosphere: sometimes faster and sometimes slower. During its recorded history it has traveled several times around the planet relative to any fixed position below it.
Jupiter also experience weather phenomena that are similar to those of Earth. These lightning storms, which have been detected in Jupiter’s atmosphere. Scientists believe that these may be due to a thin layer of water clouds underlying the ammonia layer.
The presence of this water layer (and it’s polarity) would create the charge separation needed for lightning to occur. Observations of these electrical discharges indicate that they can be up to a thousand times as powerful as those observed here on the Earth.
Like Earth, Jupiter also experiences auroras near its northern and southern poles. But on Jupiter, the auroral activity is much more intense and rarely ever stops. The intense radiation, Jupiter’s powerful magnetic field, and the abundance of material from Io’s volcanoes that react with Jupiter’s ionosphere, create a light show that is truly spectacular.
What it comes down to is that Jupiter experiences weather that is similar to what we experience here on Earth. This includes wind storms, lightning, and auroras in both the northern and southern polar regions. The only difference is, in Jupiter’s case, the size and scale of the weather is much, much larger!
On Jupiter, as with everything else on the “King of Planets”, the weather is the result of titanic forces that produce some seriously powerful results. If any of these were to happen here on Earth, the results would be disasterous!
We have written many interesting articles about Jupiter here at Universe Today. Here’s Ten Interesting Facts About Jupiter, How Long Does it take to get to Jupiter?, How Much Bigger is Jupiter than Earth?, How Strong is Jupiter’s Gravity?, and Jupiter Compared to Earth.