# Are the darker blue/black areas in this picture what the atmosphere of Jupiter looks like without clouds?

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This is a picture (mosaic?) of Jupiter's south pole taken by Juno (also shown below). It has gotten a lot of press, but I haven't seen anything, even in the scientific paper that accompanied its release, that answers the first question that came to mind when I saw it : is this a view into the inside of Jupiter? I seem to recall seeing IR images of Jupiter where the poles appear quite hot, which would be consistent with a "clear sky" providing a view of deeper, hotter layers. But how deep can see in this picture?

Edit: I am aware that this is a visible light image, and that visible light does not penetrate the cloud layer of Jupiter.

My question is whether part of the south pole of Jupiter is cloud-free, at least to a depth where atmospheric extinction limits our ability to see the clouds. This interpretation of the picture would assume that blue light penetrates deeper than red light into the atmosphere (clouds not included) of Jupiter, and that this is the reason that some of the clouds, presumed to be deeper, look blue, while some areas between them are essentially black.

Here is an example of a picture of Jupiter in IR, which shows the poles as being relatively hot. The troposphere of Jupiter (or any planet) is generally hotter the deeper you go, so the poles appearing hotter is consistent with less cloud cover at the poles. [

I'm aware that perhaps no-one, including the Juno team, knows the answer to my question. Some useful partial answers would include an estimate of the depth to which visible light could penetrate Jupiter's atmosphere in the absence of clouds, and whether blue light would penetrate deeper than red.

userLTK's comment is correct, you cannot see very deep at all.

First off, there are three imagers on the Juno spacecraft: JunoCam, UVS, and JIRCAM. You can see a full list of instruments here. JunoCam is described as a:

visible-light camera/telescope of the Juno Jupiter orbiter, a NASA space probe launched to the planet Jupiter on 5 August 2011. It was built by Malin Space Science Systems. The telescope/camera has a field of view of 58 degrees with four filters (3 for visible light).

The image you're seeing was taken by JunoCam and is a visible image. In fact, this image is combined by images taken over multiple days and from multiple orbits to get different vantage points and show all areas lit up. It isn't however a mosaic $-$ the 58 degree field of view allows JunoCam to image the entirety of Jupiter in one image. Instead, this image is simply the carefully crafted combination of many different images of the south pole.

FWIW, UVS is an imager in the ultraviolet and JIRAM is an imager in the infrared.

### How deep are you seeing into Jupiter?

Not very deep at all. Because the image is in the visible spectrum, the depth into Jupiter before it becomes too opaque is going to be very, very short. You may not even be seeing down to Jupiter's "surface" where the atmospheric pressure equals 1 bar.

Incidentally, JIRCAM can see down to about 5-7 bars if its lucky, enough to penetrate the very upper layers of the atmosphere.

### Infrared images of the poles

Obviously I can't be certain what you saw before concerning infrared images of Jupiter's poles, but my guess is they may have been something like the image below. This image was taken by JIRAM

## Red, White, and Blue in Space Photography

T he image above might look like something many Americans will see at a 4th of July fireworks display. They depict a single galaxy, named the Southern Pinwheel Galaxy, or Messier 83, processed in red, white, and blue. What is the significance of these colors?

In the case of the American flag, the colors were originally not assigned any meaning at all and perhaps were chosen simply to mimic the colors of the British flag. It was only later, when the country adopted an official U.S. seal, that the colors were assigned meaning. “White signifies purity and innocence. Red, hardiness and valour, and Blue&hellip signifies vigilance, perseverance & justice,&rdquo declared Charles Thomson, Secretary of the Continental Congress in 1782.

Those who process astronomical images, which are almost always black and white in their raw form, also face the decision of assigning meaning to colors. Sometimes, images are processed with an eye for artistry and aesthetic appeal, as in many of the beautiful, rainbow-tinged images from the Hubble Space Telescope.

More often, color is used to reveal a particular feature of an astronomical object, as the Hubble Telescope’s site explains. Depending on the instruments used to capture the images, an image might be composed of visible light, as human eyes can see, or any variety of the wavelengths of light which are invisible to us, such as infrared or x-rays. Standard practice is to assign colors based on &ldquochromatic order,” meaning that the lowest wavelength captured should be given a blue hue, the middle wavelength a green hue and the highest wavelength a red hue.

There is an enormous variety of astronomical images out there, from the grainiest black and white images, to the most spectacular, dramatic, showstoppers. Each of them has something different it can tell us about the universe.

## Astronomers Capture Stunning New Images of Jupiter

Three images of Jupiter from the 8-m Frederick C. Gillett Gemini North telescope at the Gemini Observatory and the NASA/ESA Hubble Space Telescope show the gas giant at three different types of light (infrared, visible, and ultraviolet) and reveal a multitude of atmospheric features such as the Great Red Spot, superstorms, and cyclones stretching across the planet’s disk.

This visible-light image of Jupiter was created from data captured on January 11, 2017 using Hubble’s Wide Field Camera 3. Near the top, a long brown feature called a ‘brown barge’ extends 72,000 km (nearly 45,000 miles) in the east-west direction. The Great Red Spot stands out prominently in the lower left, while the smaller feature nicknamed Red Spot Jr. (known to Jovian scientists as Oval BA) appears to its lower right. Image credit: NASA / ESA / NOIRLab / NSF / AURA / Wong et al. / de Pater et al. / M. Zamani.

The new images of Jupiter highlight the key advantage of multiwavelength astronomy: viewing planets and other astronomical objects at different wavelengths of light allows scientists to glean otherwise unavailable insights.

Jupiter’s Great Red Spot is a prominent feature of the visible and ultraviolet (UV) images, but it is almost invisible at infrared (IR) wavelengths. The planet’s counter-rotating bands of clouds, on the contrary, are clearly visible in all three views.

Observing the Great Red Spot at multiple wavelengths yields other surprises — the dark region in the IR image is larger than the corresponding red oval in the visible image.

This discrepancy arises because different structures are revealed by different wavelengths the IR observations show areas covered with thick clouds, while the visible and UV observations show the locations of chromophores — the particles that give the Great Red Spot its distinctive hue by absorbing blue and UV light.

This infrared view of Jupiter was created from data captured on January 11, 2017 with the Near-InfraRed Imager on the Gemini North telescope. In the image warmer areas appear bright, including four large hot spots that appear in a row just north of the equator. South of the equator, the oval-shaped and cloud-covered Great Red Spot appears dark. Image credit: Gemini Observatory / NOIRLab / NSF / AURA / Wong et al. / de Pater et al. / M. Zamani.

The Red Spot Jr. — also known as Oval BA — appears in both the visible and UV observations.

This storm — to the bottom right of its larger counterpart — formed from the merger of three similar-sized storms in 2000.

In the visible-wavelength image, it has a clearly defined red outer rim with a white center. In the IR, however, Red Spot Jr. is invisible, lost in the larger band of cooler clouds, which appear dark in the IR view.

Like the Great Red Spot, this storm is colored by chromophores that absorb solar radiation at both UV and blue wavelengths, giving it a red color in visible observations and a dark appearance at UV wavelengths.

This ultraviolet image of Jupiter was created from data captured on January 11, 2017 using Hubble’s Wide Field Camera 3. The Great Red Spot and Red Spot Jr. absorb ultraviolet radiation from the Sun and therefore appear dark in this view. Image credit: NASA / ESA / NOIRLab / NSF / AURA / Wong et al. / de Pater et al. / M. Zamani.

Just above Red Spot Jr. in the visible observations, a Jovian superstorm appears as a diagonal white streak extending toward the right side of Jupiter’s disk.

One atmospheric phenomenon that does feature prominently at IR wavelengths is a bright streak in the northern hemisphere of Jupiter.

This feature — a cyclonic vortex or perhaps a series of vortices — extends 72,000 km (nearly 45,000 miles) in the east-west direction.

At visible wavelengths the cyclone appears dark brown, leading to these types of features being called ‘brown barges’ in images from NASA’s Voyager spacecraft.

At UV wavelengths, however, the feature is barely visible underneath a layer of stratospheric haze, which becomes increasingly dark toward the north pole.

Similarly, lined up below the brown barge, four large ‘hot spots’ appear bright in the IR image but dark in both the visible and UV views.

Astronomers discovered such features when they observed Jupiter in IR wavelengths for the first time in the 1960s.

## Telescopes and Spacecraft Look Deep into Jupiter’s Atmosphere

S torms on Jupiter are among the most powerful squalls seen anywhere in the Solar System. Now, a new study brings together the Gemini Observatory in Hawaii, the Hubble Space Telescope, and the Juno spacecraft in an effort to understand these behemoth tempests.

Thunderheads on Jupiter can reach 65 kilometers (40 miles) tall, five times as large as their cousins on Earth. Lightning from these storms erupt with three times as much power as the most massive superbolts seen on our own world. Like familiar lightning here at home, lightning on Jupiter produces both visible light and radio waves.

Once every 53 days, the Juno spacecraft orbiting Jupiter dips down low above the planet. At these altitudes, the orbiting observatory witnesses sferics and whistlers, types of radio signals produced by lightning on Jupiter. The name sferic is short for atmospheric, and whistlers are named after the distinct sound they make on radio receivers. Even on the day side of Jupiter, or deep within its mighty cloud tops, these signals allow astronomers to detect lightning, even when it cannot be seen.

As Juno swoops down low, the Gemini Observatory on Earth and the Hubble Space Telescope in orbit each train their sights on the region. While Juno probes deep into the atmosphere, examining the events in microwaves and high-energy radio waves, Gemini looks at the region in infrared light, and Hubble views the same area in visible light.

“Juno’s microwave radiometer probes deep into the planet’s atmosphere by detecting high-frequency radio waves that can penetrate through the thick cloud layers. The data from Hubble and Gemini can tell us how thick the clouds are and how deep we are seeing into the clouds,” Amy Simon of NASA’s Goddard Space Flight Center explained.

Two’s Company, Three’s a Cloud

Together, observations from the three observatories suggest that outbreaks of lightning on Jupiter result from interactions between three types of clouds. The first of these a deep clouds composed of water. The second are mammoth thunderhead columns that form from upswelling of air. The third formation are clear regions outside the columns, where drier air falls back down into the depths of the atmosphere.

“The largest concentration of lightning seen by Juno came from a swirling storm called a “filamentary cyclone.” Imaging from Gemini and Hubble shows details in the cyclone, revealing it to be a twisted collection of tall convective clouds with deep gaps offering glimpses to the water clouds far below,” NOIRLab reports.

The convective towers, featuring thick clouds, are apparent in images from Hubble. The Gemini telescope spied into the clear regions, glimpsing deep water clouds in their depths. As Juno orbits the planet, Hubble and Gemini are both studying the world more often, hoping to unravel the secrets of the largest planet in our Solar System.

The Gemini team used a technique they call Lucky Imaging to produce their contribution to the three-mission study. This technique is similar to the way a portrait photographer might take hundreds of shots of a model, attempting to get a few great poses. The Gemini North telescope in Hawaii was used to take a large number of photographs of Jupiter. The most detailed of these — recorded when atmospheric conditions were best — were selected. This resulted in images nearly as clear and detailed as those taken by space-based observatories, researchers state.

That’s One Big Jack-o-Lantern

Lightning may be common in folded filamentary regions, where whirlpools of gas release energy from one region of the planet to another.

Studying deep water clouds like these could help astronomers learn more about how Jupiter — as well as our entire solar system — formed. Astronomers hope to learn how much water is found in the atmosphere of Jupiter, and how heat is transferred around the gas giant.

“Whom Jupiter would destroy he first drives mad.” — Sophocles

The magnificent colors of Jupiter — including the Great Red Spot — are a hallmark of what makes the planet so beautiful. But, why they are there remains a mystery, despite study by several generations of spacecraft.

“The era of high-resolution Jupiter imaging at visible wavelengths began in space, with the Pioneer and Voyager spacecraft flybys. These missions gave the first looks at discrete features like convective plumes and the first accurate measurements of the zonal winds,” researchers report in The Astrophysical Journal.

Previous missions to Jupiter showed dark spots within the Great Red Spot, which appear, change shape, and disappear over time. One of the questions astronomers sought to answer was whether these markings were dark features within (or on top of) the storm, or if these regions were “holes” in the mighty storm, allowing us to see into the vortex.

By combining data from the trio of observatories, it is now possible to answer that question. The dark markings are, in fact, holes in the massive storm system.

Regions which look dark in visible light are quite bright in infrared images, showing they extend into the storm. Where clouds are scarce, heat from the interior of Jupiter is free to escape to space, in the form of infrared light. This radiation — seen in data from Gemini— is blocked by clouds.

“It’s kind of like a jack-o-lantern. You see bright infrared light coming from cloud-free areas, but where there are clouds, it’s really dark in the infrared,” Wong said.

As Juno orbits Jupiter, astronomers will learn more about how the atmosphere and weather behaves on that giant planet. In some ways, the combination of observatories acts in much the same way as utilizing both satellite and surface data in predicting terrestrial weather.

“Because we now routinely have these high-resolution views from a couple of different observatories and wavelengths, we are learning so much more about Jupiter’s weather. This is our equivalent of a weather satellite. We can finally start looking at weather cycles,” Simon says.

Using multiple instruments, each with its own capabilities, allows astronomers to see targets using multiple instruments at the same time. This multi-messenger astronomy shows events in several wavelengths of light at the same time. Looking at objects over several frequencies of the electromagnetic spectrum can also remove barriers, like clouds of gas and dust, that can obscure some observations.

James Maynard is the founder and publisher of The Cosmic Companion. He is a New England native turned desert rat in Tucson, where he lives with his lovely wife, Nicole, and Max the Cat.

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The infrared observations show areas covered with thick clouds, while the visible and ultraviolet observations show the locations of chromophores.

These are the particles that give the Great Red Spot its distinctive hue by absorbing blue and ultraviolet light.

The Great Red Spot isn’t the only storm system visible in these images though, as the smaller storm system known as Red Spot Jr appears in visible and UV.

This storm — to the bottom right of its larger counterpart — formed from the merger of three similar-sized storms in 2000 and has a defined red outer rim in visible light.

This infrared view of Jupiter was created from data captured on 11 January 2017 with the Near-InfraRed Imager (NIRI) instrument at Gemini North. It is actually a mosaic of individual frames that were combined to produce a global portrait of the planet

In the infrared, however, Red Spot Jr is invisible, lost in the larger band of cooler clouds, which appear dark in the infrared view.

Like the Great Red Spot, Red Spot Jr is coloured by chromophores that absorb solar radiation at both ultraviolet and blue wavelengths, giving it a red colour in visible observations and a dark appearance at ultraviolet wavelengths.

Just above Red Spot Jr in the visible observations, a Jovian superstorm appears as a diagonal white streak extending toward the right side of Jupiter’s disk.

One atmospheric phenomenon that does feature prominently at infrared wavelengths is a bright streak in the northern hemisphere of Jupiter.

This feature - a cyclonic vortex or perhaps a series of vortices - extends nearly 45,000 miles in the east-west direction.

This ultraviolet image of Jupiter was created from data captured on 11 January 2017 using the Wide Field Camera 3 on the Hubble Space Telescope. The Great Red Spot and Red Spot Jr absorb ultraviolet radiation from the Sun and therefore appear dark in this view

At visible wavelengths the cyclone appears dark brown, leading to these types of features being called ‘brown barges’ in images from NASA’s Voyager spacecraft.

At ultraviolet wavelengths, however, the feature is barely visible underneath a layer of stratospheric haze, which becomes increasingly dark toward the north pole.

Similarly, lined up below the brown barge, four large ‘hot spots’ appear bright in the infrared image but dark in both the visible and ultraviolet views.

Astronomers discovered such features when they observed Jupiter in infrared wavelengths for the first time in the 1960s.

As well as providing a beautiful scenic tour of Jupiter, these observations provide insights about the planet’s atmosphere, with each wavelength probing different layers of cloud and haze particles.

### WHAT CAUSES JUPITER'S CHARACTERISTIC BANDS?

Experts have studied recent evidence gathered from Nasa's Juno spacecraft to reveal the reason why gases form bands on Jupiter.

Clouds of ammonia at Jupiter's outer atmosphere are carried along by jet streams to form Jupiter's regimented coloured bands.

Jupiter's jet streams reach as deep as 1,800 miles (3,000 km) below Jupiter's clouds, which are shades of white, red, orange, brown and yellow.

The gas in the interior of Jupiter is magnetised, which researchers believe explains why the jet streams go as deep as they do but don't go any deeper.

There are also no continents and mountains below Jupiter's atmosphere to obstruct the path of the jet stream.

This makes the jet streams on Jupiter simpler than those on Earth and cause less turbulence in it's upper atmosphere.

## Amazing Look at Jupiter’s Incredible Storms Using Ground and Space Observations

This image showing the entire disk of Jupiter in infrared light was compiled from a mosaic of nine separate pointings observed by the international Gemini Observatory, a program of NSF’s NOIRLab on May 29, 2019. From a “lucky imaging” set of 38 exposures taken at each pointing, the research team selected the sharpest 10%, combining them to image one ninth of Jupiter’s disk. Stacks of exposures at the nine pointings were then combined to make one clear, global view of the planet. Even though it only takes a few seconds for Gemini to create each image in a lucky imaging set, completing all 38 exposures in a set can take minutes — long enough for features to rotate noticeably across the disk. In order to compare and combine the images, they are first mapped to their actual latitude and longitude on Jupiter, using the limb, or edge of the disk, as a reference. Once the mosaics are compiled into a full disk, the final images are some of the highest-resolution infrared views of Jupiter ever taken from the ground. Credit: International Gemini Observatory/NOIRLab/NSF/AURA, M.H. Wong (UC Berkeley) and team Acknowledgments: Mahdi Zamani

### Hubble and Gemini Watch From Afar, Capturing High-Resolution Global Views of Jupiter That Are Key to Interpreting Juno’s Close-Up Observations of the Planet.

With thunderheads that tower forty miles high and stretch half the width of a continent, hurricane-force winds in enormous storms that rage for centuries, and lightning three times as powerful as Earth’s strongest superbolts, Jupiter—king of the planets—has proven itself a more-than-worthy namesake to the supreme Roman god of sky and thunder.

In spite of more than 400 years of scientific observations, many details of the gas giant’s turbulent and ever-changing atmosphere have remained elusive. Now, thanks to the teamwork of the Hubble Space Telescope, the Gemini Observatory, and the Juno spacecraft, scientists are able to probe deep into storm systems, investigating sources of lightning outbursts, mapping cyclonic vortices, and unravelling the nature of enigmatic features within the Great Red Spot.

This unique collaboration is allowing researchers to monitor Jupiter’s weather and estimate the amount of water in the atmosphere, providing insight into how Jupiter operates today as well as how it and the other planets in our solar system formed more than four-and-a-half billion years ago.

NASA’s Hubble Space Telescope and the ground-based Gemini Observatory in Hawaii have teamed up with the Juno spacecraft to probe the mightiest storms in the solar system, taking place more than 500 million miles away on the giant planet Jupiter.

A team of researchers led by Michael Wong at the University of California, Berkeley, and including Amy Simon of NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and Imke de Pater also of UC Berkeley, are combining multiwavelength observations from Hubble and Gemini with close-up views from Juno’s orbit about the monster planet, gaining new insights into turbulent weather on this distant world.

“We want to know how Jupiter’s atmosphere works,” said Wong. This is where the teamwork of Juno, Hubble and Gemini comes into play.

Jupiter’s constant storms are gigantic compared to those on Earth, with thunderheads reaching 40 miles from base to top — five times taller than typical thunderheads on Earth — and powerful lightning flashes up to three times more energetic than Earth’s largest “superbolts.”

Like lightning on Earth, Jupiter’s lightning bolts act like radio transmitters, sending out radio waves as well as visible light when they flash across the sky.

Every 53 days, Juno races low over the storm systems detecting radio signals known as “sferics” and “whistlers,” which can then be used to map lightning even on the day side of the planet or from deep clouds where flashes are not otherwise visible.

This graphic shows observations and interpretations of cloud structures and atmospheric circulation on Jupiter from the Juno spacecraft, the Hubble Space Telescope and the Gemini Observatory. By combining the Juno, Hubble and Gemini data, researchers are able to see that lightning flashes are clustered in turbulent regions where there are deep water clouds and where moist air is rising to form tall convective towers similar to cumulonimbus clouds (thunderheads) on Earth. The bottom illustration of lightning, convective towers, deep water clouds and clearings in Jupiter’s atmosphere is based on data from Juno, Hubble and Gemini, and corresponds to the transect (angled white line) indicated on the Hubble and Gemini map details. The combination of observations can be used to map the cloud structure in three dimensions and infer details of atmospheric circulation. Thick, towering clouds form where moist air is rising (upwelling and active convection). Clearings form where drier air sinks (downwelling). The clouds shown rise five times higher than similar convective towers in the relatively shallow atmosphere of Earth. The region illustrated covers a horizontal span one-third greater than that of the continental United States. Credit: NASA, ESA, M.H. Wong (UC Berkeley), A. James and M.W. Carruthers (STScI), and S. Brown (JPL)

Coinciding with each pass, Hubble and Gemini watch from afar, capturing high-resolution global views of the planet that are key to interpreting Juno’s close-up observations. “Juno’s microwave radiometer probes deep into the planet’s atmosphere by detecting high-frequency radio waves that can penetrate through the thick cloud layers. The data from Hubble and Gemini can tell us how thick the clouds are and how deep we are seeing into the clouds,” Simon explained.

By mapping lightning flashes detected by Juno onto optical images captured of the planet by Hubble and thermal infrared images captured at the same time by Gemini, the research team has been able to show that lightning outbreaks are associated with a three-way combination of cloud structures: deep clouds made of water, large convective towers caused by upwelling of moist air — essentially Jovian thunderheads — and clear regions presumably caused by downwelling of drier air outside the convective towers.

The Hubble data show the height of the thick clouds in the convective towers, as well as the depth of deep water clouds. The Gemini data clearly reveal the clearings in the high-level clouds where it is possible to get a glimpse down to the deep water clouds.

Wong thinks that lightning is common in a type of turbulent area known as folded filamentary regions, which suggests that moist convection is occurring in them. “These cyclonic vortices could be internal energy smokestacks, helping release internal energy through convection,” he said. “It doesn’t happen everywhere, but something about these cyclones seems to facilitate convection.”

The ability to correlate lightning with deep water clouds also gives researchers another tool for estimating the amount of water in Jupiter’s atmosphere, which is important for understanding how Jupiter and the other gas and ice giants formed, and therefore how the solar system as a whole formed.

While much has been gleaned about Jupiter from previous space missions, many of the details — including how much water is in the deep atmosphere, exactly how heat flows from the interior and what causes certain colors and patterns in the clouds — remain a mystery. The combined result provides insight into the dynamics and three-dimensional structure of the atmosphere.

### Seeing a ‘Jack-O-Lantern’ Red Spot

With Hubble and Gemini observing Jupiter more frequently during the Juno mission, scientists are also able to study short-term changes and short-lived features like those in the Great Red Spot.

Images from Juno as well as previous missions to Jupiter revealed dark features within the Great Red Spot that appear, disappear and change shape over time. It was not clear from individual images whether these are caused by some mysterious dark-colored material within the high cloud layer, or if they are instead holes in the high clouds — windows into a deeper, darker layer below.

Now, with the ability to compare visible-light images from Hubble with thermal infrared images from Gemini captured within hours of each other, it is possible to answer the question. Regions that are dark in visible light are very bright in infrared, indicating that they are, in fact, holes in the cloud layer. In cloud-free regions, heat from Jupiter’s interior that is emitted in the form of infrared light — otherwise blocked by high-level clouds — is free to escape into space and therefore appears bright in Gemini images.

“It’s kind of like a jack-o-lantern,” said Wong. “You see bright infrared light coming from cloud-free areas, but where there are clouds, it’s really dark in the infrared.”

Credit: NASA, ESA, and M.H. Wong (UC Berkeley) and team

The above images of Jupiter’s Great Red Spot were made using data collected by the Hubble Space Telescope and the Gemini Observatory on April 1, 2018. By combining observations captured at almost the same time from the two different observatories, astronomers were able to determine that dark features on the Great Red Spot are holes in the clouds rather than masses of dark material.

Upper left (wide view) and lower left (detail): The Hubble image of sunlight (visible wavelengths) reflecting off clouds in Jupiter’s atmosphere shows dark features within the Great Red Spot.

Upper right: A thermal infrared image of the same area from Gemini shows heat emitted as infrared energy. Cool overlying clouds appear as dark regions, but clearings in the clouds allow bright infrared emission to escape from warmer layers below.

Lower middle: An ultraviolet image from Hubble shows sunlight scattered back from the hazes over the Great Red Spot. The Great Red Spot appears red in visible light because these hazes absorb blue wavelengths. The Hubble data show that the hazes continue to absorb even at shorter ultraviolet wavelengths.

Lower right: A multiwavelength composite of Hubble and Gemini data shows visible light in blue and thermal infrared in red. The combined observations show that areas that are bright in infrared are clearings or places where there is less cloud cover blocking heat from the interior.

The Hubble and Gemini observations were made to provide a wide-view context for Juno’s 12th pass (Perijove 12).

### Hubble and Gemini as Jovian Weather Trackers

The regular imaging of Jupiter by Hubble and Gemini in support of the Juno mission is proving valuable in studies of many other weather phenomena as well, including changes in wind patterns, characteristics of atmospheric waves and the circulation of various gases in the atmosphere.

Hubble and Gemini can monitor the planet as a whole, providing real-time base maps in multiple wavelengths for reference for Juno’s measurements in the same way that Earth-observing weather satellites provide context for NOAA’s high-flying Hurricane Hunters.

“Because we now routinely have these high-resolution views from a couple of different observatories and wavelengths, we are learning so much more about Jupiter’s weather,” explained Simon. “This is our equivalent of a weather satellite. We can finally start looking at weather cycles.”

Because the Hubble and Gemini observations are so important for interpreting Juno data, Wong and his colleagues Simon and de Pater are making all of the processed data easily accessible to other researchers through the Mikulski Archives for Space Telescopes (MAST) at the Space Telescope Science Institute in Baltimore, Maryland.

“What’s important is that we’ve managed to collect this huge data set that supports the Juno mission. There are so many applications of the data set that we may not even anticipate. So, we’re going to enable other people to do science without that barrier of having to figure out on their own how to process the data,” Wong said.

The results were published in April 2020 in The Astrophysical Journal Supplement Series.

Reference: “High-resolution UV/Optical/IR Imaging of Jupiter in 2016–2019” by Michael H. Wong, Amy A. Simon, Joshua W. Tollefson, Imke de Pater, Megan N. Barnett, Andrew I. Hsu, Andrew W. Stephens, Glenn S. Orton, Scott W. Fleming, Charles Goullaud, William Januszewski, Anthony Roman, Gordon L. Bjoraker, Sushil K. Atreya, Alberto Adriani and Leigh N. Fletcher, 1 April 2020, The Astrophysical Journal Supplement Series.
DOI: 10.3847/1538-4365/ab775f

## Stunning new images of Jupiter reveal atmosphere details in different light (video)

Watch Jupiter's famous superstorm disappear in infrared images from NOIRLab.

Newly processed images captured by the Hubble Space Telescope and the Gemini North observatory in Hawaii reveal details of the turbulent atmosphere of Jupiter in different wavelengths, helping scientists to figure out what drives the formation of the gas giant's massive storms.

Scientists have processed the images — captured in infrared, visible and ultraviolet wavelengths — to allow interactive side-by-side comparison of the different views of the clouds above the gas giant.

The changing appearance of the planet in different wavelengths allows astronomers to gain new insights into the behavior of Jupiter's atmosphere. Strangely, the Great Red Spot, the giant superstorm that persists south of Jupiter's equator, is very obvious in the visible and ultraviolet light wavelengths but almost blends into the background the infrared.

#### Jupiter in infrared light

The comparison between the three types of wavelengths also reveals that the dark region representing the Great Red Spot in the infrared image is larger than the corresponding red oval in the visible image. The discrepancy is caused by the fact that each of the imaging techniques captures different properties of the planet's atmosphere, according to a statement by the U.S. National Optical-Infrared Astronomy Research Laboratory (NOIRLab), which released the images on Tuesday (May 11).

While the infrared observations show areas covered with thick clouds, the visible and ultraviolet images highlight locations of the so-called chromophores, which are molecules that absorb blue and ultraviolet light, thus giving the spot its characteristic red color.

On the other hand, Jupiter's counter-rotating bands of clouds are clearly visible in all three views.

The images were captured simultaneously on Jan. 11, 2017. The ultraviolet and visible views were taken by the Wide Field Camera 3 on the Hubble Space Telescope, while the infrared photo was captured by the Near-Infrared Imager (NIRI) instrument at Gemini North in Hawaii.

In addition to the Great Red Spot, the Hubble images also reveal the smaller Red Spot Jr, which formed in 2000 when three similar-sized storms merged southwest of the larger superstorm. Just like the Great Red Spot, the "Junior" is barely visible in the infrared wavelength, disappearing into the larger band of cooler clouds.

Unlike the red spots, a cyclonic vortex can be seen prominently in the infrared image, spreading from east to west. This nearly 45,000-miles-long (72,000 kilometers) series of vortices, appears like a bright streak in the northern hemisphere of the planet.

At visible wavelengths the cyclone appears dark brown, leading to these types of features being called brown barges in images from NASA's Voyager spacecraft, which flew past the gas giant in 1979. At ultraviolet wavelengths, however, the feature is barely visible underneath a layer of stratospheric haze, which becomes increasingly dark toward the north pole.

Scientist Mike Wong, of the University of California, has further compared the images with radio signals detected by NASA's Juno spacecraft currently studying the planet. Those radio signals denote lightning in Jupiter's atmosphere. By combining the three types of images with the lightning data, Wong and his team were able to probe various layers of the cloud structure to gain a better understanding of the formation processes behind Jupiter's massive storms.

## Hubble captures blistering pitch-black planet

This artist’s impression shows the exoplanet WASP-12b — an alien world as black as fresh asphalt, orbiting a star like our Sun. Scientists were able to measure its albedo: the amount of light the planet reflects. The results showed that the planet is extremely dark at optical wavelengths. Credit: NASA, ESA, and G. Bacon (STScI)

Astronomers have discovered that the well-studied exoplanet WASP-12b reflects almost no light, making it appear essentially pitch black. This discovery sheds new light on the atmospheric composition of the planet and also refutes previous hypotheses about WASP-12b's atmosphere. The results are also in stark contrast to observations of another similarly sized exoplanet.

Using the Space Telescope Imaging Spectrograph (STIS) on the NASA/ESA Hubble Space Telescope, an international team led by astronomers at McGill University, Canada, and the University of Exeter, UK, have measured how much light the exoplanet WASP-12b reflects—its albedo—in order to learn more about the composition of its atmosphere.

The results were surprising, explains lead author Taylor Bell, a Master's student in astronomy at McGill University who is affiliated with the Institute for Research on Exoplanets: "The measured albedo of WASP-12b is 0.064 at most. This is an extremely low value, making the planet darker than fresh asphalt!" This makes WASP-12b two times less reflective than our Moon which has an albedo of 0.12. Bell adds: "The low albedo shows we still have a lot to learn about WASP-12b and other similar exoplanets."

WASP-12b orbits the Sun-like star WASP-12A, about 1400 light-years away, and since its discovery in 2008 it has become one of the best studied exoplanets. With a radius almost twice that of Jupiter and a year of just over one Earth day, WASP-12b is categorised as a hot Jupiter. Because it is so close to its parent star, the gravitational pull of the star has stretched WASP-12b into an egg shape and raised the surface temperature of its daylight side to 2600 degrees Celsius.

The high temperature is also the most likely explanation for WASP-12b's low albedo. "There are other hot Jupiters that have been found to be remarkably black, but they are much cooler than WASP-12b. For those planets, it is suggested that things like clouds and alkali metals are the reason for the absorption of light, but those don't work for WASP-12b because it is so incredibly hot," explains Bell.

The daylight side of WASP-12b is so hot that clouds cannot form and alkali metals are ionised. It is even hot enough to break up hydrogen molecules into atomic hydrogen which causes the atmosphere to act more like the atmosphere of a low-mass star than like a planetary atmosphere. This leads to the low albedo of the exoplanet.

To measure the albedo of WASP-12b the scientists observed the exoplanet in October 2016 during an eclipse, when the planet was near full phase and passed behind its host star for a time. This is the best method to determine the albedo of an exoplanet, as it involves directly measuring the amount of light being reflected. However, this technique requires a precision ten times greater than traditional transit observations. Using Hubble's Space Telescope Imaging Spectrograph the scientists were able to measure the albedo of WASP-12b at several different wavelengths.

"After we measured the albedo we compared it to spectral models of previously suggested atmospheric models of WASP-12b", explains Nikolay Nikolov (University of Exeter, UK), co-author of the study. "We found that the data match neither of the two currently proposed models.". The new data indicate that the WASP-12b atmosphere is composed of atomic hydrogen and helium.

WASP-12b is only the second planet to have spectrally resolved albedo measurements, the first being HD 189733b, another hot Jupiter. The data gathered by Bell and his team allowed them to determine whether the planet reflects more light towards the blue or the red end of the spectrum. While the results for HD 189733b suggest that the exoplanet has a deep blue colour, WASP-12b, on the other hand, is not reflecting light at any wavelength. WASP-12b does, however, emit light because of its high temperature, giving it a red hue similar to a hot glowing metal.

"The fact that the first two exoplanets with measured spectral albedo exhibit significant differences demonstrates the importance of these types of spectral observations and highlights the great diversity among hot Jupiters," concludes Bell.

The results will appear online Sept. 14 in The Astrophysical Journal Letters.

## Scientists Share One Of The Highest-Resolution Photos Of Jupiter Taken From Earth

Giedrė Vaičiulaitytė
Community member

With the COVID-19 pandemic and its many scares, life on Earth can be overwhelming to many of us. That&rsquos why it can be refreshing to look somewhere else and the Gemini Observatory recently released something truly exciting to look at&mdasha fascinating picture of Jupiter that is one of the highest-resolution images of the planet taken on Earth.

The scientists behind the Gemini North telescope released the stunning image in their blog post on May 7, 2020. They used a technique called &ldquolucky imaging&rdquo and collected thousands of snapshots of Jupiter through the years that they finally merged into a single composite. The sharp details of the planet&rsquos surface are the result of a tedious work process that involved sifting through thousands of photos to find the sharpest ones.

### The image shows the entire disk of Jupiter in infrared light

The scientists of the observatory provided some additional (and pretty interesting) details on the process:

&ldquoResearchers using a technique known as &lsquolucky imaging&rsquo with the Gemini North telescope on Hawaii&rsquos Mauna Kea have collected some of the highest-resolution images of Jupiter ever obtained from the ground. These images are part of a multi-year joint observing program with the Hubble Space Telescope in support of NASA&rsquos Juno mission. The Gemini images, when combined with the Hubble and Juno observations, reveal that lightning strikes, and some of the largest storm systems that create them, are formed in and around large convective cells over deep clouds of water ice and liquid. The new observations also confirm that dark spots in the famous Great Red Spot are actually gaps in the cloud cover and not due to cloud color variations.&rdquo

So not only did their hard work result in such a stunning photo, it also revealed some interesting information about Jupiter and its clouds.

### You can compare Gemini&rsquos image of Jupiter with the NASA Hubble Space Telescope&rsquos

The above photo is what most of us imagine when someone mentions Jupiter and we have this image thanks to the Hubble Space Telescope. Pretty colorful, right? So, you might be asking why the Gemini photo looks like a lava pancake? Well, the Gemini Jupiter photo is in infrared light!

&ldquoFrom a lucky imaging set of 38 exposures taken at each pointing, the research team selected the sharpest 10%, combining them to image one ninth of Jupiter&rsquos disk. Stacks of exposures at the nine pointings were then combined to make one clear, global view of the planet. Even though it only takes a few seconds for Gemini to create each image in a lucky imaging set, completing all 38 exposures in a set can take minutes&mdashlong enough for features to rotate noticeably across the disk. In order to compare and combine the images, they are first mapped to their actual latitude and longitude on Jupiter, using the limb, or edge of the disk, as a reference. Once the mosaics are compiled into a full disk, the final images are some of the highest-resolution infrared views of Jupiter ever taken from the ground.&rdquo

### The comparison of sharp and unsharp pictures from the lucky imaging process

&ldquoBecause the telescope must observe through the Earth&rsquos atmosphere, any disturbances in the air such as wind or temperature changes will distort and blur the image (left). This greatly limits the resolution the telescope can achieve on a target when only one image is taken. However, during a single night of lucky imaging observations, the telescope takes hundreds of exposures of the target. Some will be blurred, but many exposures will be taken when the view to space is still and clear of disturbances (right). In these lucky images, much smaller, more complex details on Jupiter are revealed. The research team finds the sharpest of these exposures, and compiles them into a mosaic of the whole disk.&rdquo

### These images of Jupiter&rsquos Great Red Spot were made using data collected by the Hubble Space Telescope and the international Gemini Observatory

&ldquoBy combining observations captured at almost the same time from the two different observatories, astronomers were able to determine that dark features on the Great Red Spot are holes in the clouds rather than masses of dark material. Upper left (wide view) and lower left (detail): The Hubble image of sunlight (visible wavelengths) reflecting off clouds in Jupiter&rsquos atmosphere shows dark features within the Great Red Spot. Upper right: A thermal infrared image of the same area from Gemini shows heat energy emitted as infrared light. Cool overlying clouds appear as dark regions, but clearings in the clouds allow bright infrared emission to escape from warmer layers below. Lower middle: An ultraviolet image from Hubble shows sunlight scattered back from the haze over the Great Red Spot. The Great Red Spot appears red in visible light because the haze absorbs blue wavelengths. The Hubble data show that the haze continues to absorb even at shorter ultraviolet wavelengths. Lower right: A multiwavelength composite of Hubble and Gemini data shows visible light in blue and thermal infrared in red. The combined observations show that areas that are bright in infrared are clearings or places where there is less cloud cover blocking heat from the interior.&rdquo

### This illustration shows Jupiter&rsquos cloud structure and what data is collected

&ldquoThis illustration of lightning, convective towers (thunderheads), deep water clouds, and clearings in Jupiter&rsquos atmosphere is based on data collected by the Juno spacecraft, the Hubble Space Telescope, and the international Gemini Observatory, a program of NSF&rsquos NOIRLab. Juno detects radio signals generated by lightning discharges. Because radio waves can pass through all of Jupiter&rsquos cloud layers, Juno is able to detect lightning in deep clouds as well as lightning on the day side of the planet. Hubble detects sunlight that has reflected off clouds in Jupiter&rsquos atmosphere. Different wavelengths penetrate to different depths in the clouds, giving researchers the ability to determine the relative heights of cloud tops. Gemini maps the thickness of cool clouds that block thermal infrared light from warmer atmospheric layers below the clouds. Thick clouds appear dark in the infrared maps, while clearings appear bright. The combination of observations can be used to map the cloud structure in three dimensions and infer details of atmospheric circulation. Thick, towering clouds form where moist air rises (upwelling and active convection). Clearings form where drier air sinks (downwelling). The clouds shown rise five times higher than similar convective towers in Earth&rsquos relatively shallow atmosphere. The region illustrated covers a horizontal span one third greater than that of the continental United States.&rdquo

## Acknowledgments

Levin, Orton, Sinclair, and Tabataba-Vakili were supported by funds from NASA distributed to the Jet Propulsion Laboratory, California Institute of Technology. Bolton and Hansen were supported by funds from NASA to the Southwest Research Institute and to the Planetary Science Institute, respectively. Brueshaber was supported by Western Michigan University's Dissertation Completion Fellowship. Ravine and Caplinger were supported by funds from NASA to Malin Space Science Systems. Fletcher is a Juno Participating Scientist supported by a Royal Society Research Fellowship and European Research Council Consolidator Grant (under the European Union's Horizon 2020 research and innovation program, grant agreement No. 723890) at the University of Leicester. Wong was supported by NASA's Juno Participating Scientist program a part of his contribution was based on observations from program GO-14661, made with the NASA/ESA Hubble Space Telescope, obtained at STScI, which is operated by AURA under NASA contract NAS5-26555. Nicholson was supported by NASA funds to the Jet Propulsion Laboratory as a participant in Caltech's Summer Undergraduate Research Fellowship (SURF) program at JPL. Thepenier and Anthony were participants in JPL's Student Independent Research Internship (SIRI) program. We thank Agustin Sánchez-Lavega and an anonymous reviewer for valuable comments that improved this article. All the images used in this study are available for direct download from the Planetary Data System at https://pds-imaging.jpl.nasa.gov/volumes/juno.html, in the data sets JNOJNC_0001 through JNOJNC_0011. The wind-field data shown in Figure 6 can be accessed via Wong ( 2020 ), which also provides a reference to the global map shown in this figure. The map can also be referenced directly via Wong ( 2017 ). The values of the measurements shown in Figures 16 and 17 are displayed in a table in Section SI2 of the supporting information, and they can be accessed via Orton ( 2020 ). We note that preliminary results, including a version of Figure 11, were included in a NASA press release: https://www.jpl.nasa.gov/news/news.php?feature=7264.

Supporting Information S1

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