Tag: Jupiter

Cool movie time! Using images produced by Juno in orbit around Jupiter, citizen scientist Kevin Gill has produced a very nice movie of the spacecraft’s 27th fly-by on June 2, 2020.

During the closest approach of this pass, the Juno spacecraft came within approximately 2,100 miles (3,400 kilometers) of Jupiter’s cloud tops. At that point, Jupiter’s powerful gravity accelerated the spacecraft to tremendous speed — about 130,000 mph (209,000 kilometers per hour) relative to the planet.

I have embedded the movie below the fold. The choice of a piece of music by Vangellis might seem hokey, but I think in this case it works very nicely. I also was impressed with the addition of some 3D depth near the movie’s beginning.
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Cool movie time! Below is a short movie created by citizen scientist Gerald Eichstädt from images taken by Juno as it swung past Jupiter on its 28th close pass since arriving in orbit in 2016.

In natural colors, Jupiter looks pretty pale. Therefore, the still images are approximately illumination-adusted, i.e. almost flattened, and consecutively gamma-stretched to the 4th power of radiometric values, in order to enhance contrast and color.

Like for all its previous flybys, Juno approached Jupiter roughly from north, and left Jupiter looking towards the soutern hemisphere. Closest approach to Jupiter was 3,500 km above the nominal IAU 1-bar level, and near 25.3 degrees north (planetocentric), according to long-term planning of November 2017.

Play video: YouTube video

Click for full illustration.

Using data from Juno, scientists now theorize that Jupiter produces what they dub “shallow lightning” as well as ammonia-water hailstones dubbed “mushballs.”

The image to the right, cropped and reduced to post here, is only an artist’s illustration of the lightning. Sadly Juno’s camera doesn’t have the resolution to capture such flashes.

An unexpected form of electrical discharge, shallow lightning originates from clouds containing an ammonia-water solution, whereas lightning on Earth originates from water clouds.

Other new findings suggest the violent thunderstorms for which the gas giant is known may form slushy ammonia-rich hailstones Juno’s science team calls “mushballs”; they theorize that mushballs essentially kidnap ammonia and water in the upper atmosphere and carry them into the depths of Jupiter’s atmosphere.

As with the InSight results below, there is much uncertainty with these results, especially the hypothesis of mushballs. These features fit their present data from Juno, but we must remember that the data is still somewhat superficial.

Click for full image.

Cool image time! The photo to the right, rotated and reduced to post here, was taken by Juno during its 28th close orbital fly-by of Jupiter, and then processed by citizen scientist Hemant Dara.

While not the first Juno image of the poles of Jupiter, this photo illustrates very well the evolution of the gas giant’s deep atmosphere as you move from the equator to the pole. From the equator to the high mid-latitudes the planet’s rotation, producing a day only 10 hours long, organizes that atmosphere into jet streams that form the bands that astronomers have spied from Earth since the first telescopes.

At the pole the influence of that rotation seems to wane, or at least influence the atmosphere differently, so that the storms seem to form randomly and incoherently.

The image also shows that there appear to be several types of storms at the south pole. Some appear as tight spirals, similar to hurricanes. Others appear chaotic, with no consistent shape, almost like clouds on Earth.

The processes that would explain all this are not yet understood, in the slightest, and won’t be until we get orbiters at Jupiter able to watch the atmosphere continuously, as we do here on Earth. Then it will be possible to assemble movies of the formation and dissipation of these storms, and begin (only begin) to decipher what causes them.

Click for full image.

Cool image time! The photograph on the right, reduced to post here, was color enhanced by citizen scientist Emma Walimaki from the original Juno image in order to bring out the features and storms visible in the upper storm layers of Jupiter.

The photo was taken during Juno’s 25th close fly-by of the gas giant, and thus we are only seeing a small portion of Jupiter’s sphere.

In comparing this image with the original, it appears that Walimaki simply made the colors that were already there brighter and more distinctive. Thus, these colors represent real data. Jupiter’s cloud tops are really blue, orange, tan, and brown, unlike Earth’s consistently and boringly white water clouds.

The uncertainty of science: Scientists today released their first measurements from Juno of the amount of water found in Jupiter’s atmosphere.

The Juno science team used data collected during Juno’s first eight science flybys of Jupiter to generate the findings. They initially concentrated on the equatorial region because the atmosphere there appears more well-mixed, even at depth, than in other regions. From its orbital perch, the radiometer was able to collect data from a far greater depth into Jupiter’s atmosphere than the Galileo probe – 93 miles (150 kilometers), where the pressure reaches about 480 psi (33 bar).

“We found the water in the equator to be greater than what the Galileo probe measured,” said Cheng Li, a Juno scientist at the University of California, Berkeley. “Because the equatorial region is very unique at Jupiter, we need to compare these results with how much water is in other regions.”

These results remain very preliminary, especially because they have not yet gathered data at higher latitudes. Regardless the amount so far detected, 0.25% of all molecules in Jupiter’s atmosphere. seems remarkably small, suggesting that Jupiter has relatively little hydrogen or oxygen in its atmosphere.

Citizen scientist Brian Swift has created a new movie from images taken by Juno during its December 25th close pass of Jupiter, the 24th such flyby of the spacecraft’s mission.

I have embedded the movie below. While it isn’t as spectacular as previous movies (see here, here, here, and especially here and here), as it appears that either Juno did not get quite as close, or Swift did not shape it to give that impression, it is still most breathtaking.

Play video: YouTube video

Cool image time! Citizen scientist Gerald Eichstädt has used images taken by Juno of Jupiter’s south polar storms to produce an animation that shows the evolution of those storms over a short time period.

The movie is more a computer model than an assemblage of images.

A fluid dynamical 2D model rotating with Jupiter’s System III rotation rate is started with a map of PJ19 (Juno’s 19th close approach) vorticity measurements of the south polar region between 75 and 90 degrees south (azimuthal, equidistant, planetocentric) as initial condition. The vorticity map is based on a sequence of PJ19 JunoCam images.

Relative vorticities are encoded in color, blue for cyclonic, orange for anticyclonic relative vorticity. The animated gif covers 48 hours, with one frame per real-time hour. Played with 25 fps, the result is a 90,000-fold time-lapsed animation.

I have embedded the animation below the fold. It is quite impressive.
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Click for full image.

New images from Juno have revealed the formation of a new Texas-sized cyclone joining the circle of storms around Jupiter’s south pole.

In the infrared Juno image to the right, the new storm is the small bright cyclone in the lower right.

[D]uring Juno’s 22nd science pass [on November 3], a new, smaller cyclone churned to life and joined the fray. “Data from Juno’s Jovian Infrared Auroral Mapper [JIRAM] instrument indicates we went from a pentagon of cyclones surrounding one at the center to a hexagonal arrangement,” said Alessandro Mura, a Juno co-investigator at the National Institute for Astrophysics in Rome. “This new addition is smaller in stature than its six more established cyclonic brothers: It’s about the size of Texas. Maybe JIRAM data from future flybys will show the cyclone growing to the same size as its neighbors.”

Probing the weather layer down to 30 to 45 miles (50 to 70 kilometers) below Jupiter’s cloud tops, JIRAM captures infrared light emerging from deep inside Jupiter. Its data indicate wind speeds of the new cyclone average 225 mph (362 kph) – comparable to the velocity found in its six more established polar colleagues.

Because of Juno’s orbit we do not get continuous views of the gas giant’s cloud-tops, so we can’t see the moment-by-moment evolution of these storms, which makes it impossible to obtain a full understanding of their formation or disappearance. Even then it will likely take centuries of observations to even begin to get a fuller understanding of the meteorology of Jupiter.

Click for full image.

Cool image time! The photo to the right, taken by Juno on November 3, was enhanced by citizen scientist Björn Jónsson to bring out the colors. It shows a band of repeating large storms, with tiny white thunderheads popping up within them.

The dark areas at the edges of the swirls are likely not an aspect of the clouds but shadows created because the white swirls sit higher than the surrounding gases.

Sadly the press release does not give us a scale. The image was taken from a distance of 3,200 miles. I suspect each cloud swirl would likely cover much of the Earth.

Click for full image.

Using raw Juno images, citizen scientist Gerald Eichstädt has created the processed and color enhanced image to the right, cropped to post here. From the Juno press release:

This view from NASA’s Juno spacecraft captures colorful, intricate patterns in a jet stream region of Jupiter’s northern hemisphere known as “Jet N3.”

Jupiter’s cloud tops do not form a simple, flat surface. Data from Juno helped scientists discover that the swirling bands in the atmosphere extend deep into the planet, to a depth of about 1,900 miles (3,000 kilometers). At center right, a patch of bright, high-altitude “pop-up” clouds rises above the surrounding atmosphere.

Some of the darker areas are darker mostly because they are lower and therefore in shadow.

The raw image was taken on May 29, 2019 when Juno was about 6,000 miles away. Unfortunately, they do not provide a scale, but I suspect that the image is probably close to the size of the entire Earth.

In order to avoid a twelve-hour plunge through Jupiter’s shadow that would have likely sucked all power from Juno’s solar powered systems and killed the spacecraft, mission engineers have successfully used its attitude thrusters to complete a 10.5 long engine burn.

Juno began the maneuver yesterday, on Sept. 30, at 7:46 p.m. EDT (4:46 p.m. PDT) and completed it early on Oct. 1. Using the spacecraft’s reaction-control thrusters, the propulsive maneuver lasted five times longer than any previous use of that system. It changed Juno’s orbital velocity by 126 mph (203 kph) and consumed about 160 pounds (73 kilograms) of fuel. Without this maneuver, Juno would have spent 12 hours in transit across Jupiter’s shadow – more than enough time to drain the spacecraft’s batteries. Without power, and with spacecraft temperatures plummeting, Juno would likely succumb to the cold and be unable to awaken upon exit.

“With the success of this burn, we are on track to jump the shadow on Nov. 3,” said Scott Bolton, Juno principal investigator at the Southwest Research Institute in San Antonio.

This burn did not use the spacecraft’s main engine, which they fear has a problem that would produce a catastrophic failure if fired. Instead, they used Juno’s small attitude thrusters, which explains the length of the maneuver. In fact, this 10.5 hour burn might actually be the longest chemical engine burn in space ever. While ion engines routinely fire for this long or longer, as far as I can remember no chemical engine in space has ever fired even close to this length of time.

As he has done previously, citizen scientist Gerald Eichstädt has created a movie using Juno images of the spacecraft’s twenty-second fly-by of Jupiter.

I have embedded the movie below the fold. This fly-by included the images of Io’s shadow posted by other citizen scientists earlier. Because the movie shows this shadow in the context of the fly-by (near its lowest altitude), it illustrates why the shadow appears far larger than it is, relative to the entire planet.

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