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A wonderful new world: the Juno spacecraft reveals Jupiter as we have never known it

The initial information collected by the Juno spacecraft, which entered orbit around Jupiter last year, was very different from what the researchers expected. Among other things, he points out that Jupiter has a huge core in its center, but it is "fuzzy" and there is no clear separation between it and the layer of hydrogen above it; A mysterious emanation of ammonia was discovered, rising from the depths of the atmosphere in the equatorial region; Jupiter's powerful magnetic field likely formed closer to Jupiter than expected; And the poles of the planet show a chaotic and inexplicable display of huge cyclones.

The south pole of Jupiter, from a distance of 52,000 km. The image consists of photographs from three different planes, to create a uniform image of the entire pole, while the original photographs could only photograph the illuminated half of the pole. Source: NASA/JPL-Caltech/SwRI/MSSS /Betsy Asher Hall/Gervasio Robles.
The south pole of Jupiter, from a distance of 52,000 km. The image consists of photographs from three different planes, and this is to create a uniform image of the entire pole, while the original photographs could only photograph the illuminated half of the pole. source: NASA/JPL-Caltech/SwRI/MSSS/Betsy Asher Hall/Gervasio Robles.

The Juno spacecraft entered orbit around Jupiter last year, and yesterday NASA researchers published the first findings collected by the spacecraft, during its initial orbits around the planet. While researchers had hoped the data would teach them more about the atmosphere, internal structure and magnetic field of the largest planet in the solar system, the information from Juno appears to only add to their questions, chipping away at their existing models of Jupiter's nature.

"There are so many things happening here that we didn't expect, that we had to take a step back and think about this as a whole new justice," said John Bolton, principal investigator of the Juno mission, from the Southwest Research Center in San Antonio, Texas.

The findings were published in a large number of separate articles, 2 in the journal Science and a collection of 44 articles in the journal Geophysical Research Letters.

Juno was launched into space in 2011, and after a five-year journey, it arrived at Jupiter on July 4, 2016. Since then, it has managed to make only six orbits around it, and this is due to the unique nature of its orbit around it. The spacecraft orbits Jupiter in a very elongated polar orbit of 53 days. The farthest point in the orbit reaches a distance of millions of km from Jupiter, while the closest point in the orbit reaches a distance of only about 3,500 km above the clouds of Jupiter.

The chaotic poles of Jupiter

Image taken by Juno on May 18, 2017, showing Jupiter's south pole as well as more equilateral latitudes in Jupiter's southern hemisphere. It can be seen that in the polar region the bands of clouds disappear, and instead a medley of bluer-hued storms is revealed. Source: NASA / SwRI / MSSS / Gerald Eichstädt / Seán Doran.
Image taken by Juno on May 19, 2017, showing Jupiter's south pole as well as more equilateral latitudes in Jupiter's southern hemisphere. It can be seen that in the polar region the bands of clouds disappear, and instead a medley of bluer-hued storms is revealed. source: NASA / SwRI / MSSS / Gerald Eichstädt / Seán Doran.

It is possible that if we were shown the beautiful pictures that Juno took of Jupiter's poles, without knowing that Juno was the one who took them, we would not recognize that it was Jupiter at all. This is because in the polar region the familiar cloud bands of Jupiter disappear, and in their place a dance of dozens of enormous cyclones, some the size of the entire Earth, as well as other storms with a completely chaotic shape, is revealed.

Bolton noted that the researchers are not sure if what they are seeing at the poles is a stable state: "We are debating how they [the storms] form, how stable this configuration is, and why Jupiter's north pole doesn't look like the south pole," he said. "We are looking into whether this is a dynamic system, and whether we only see one phase, and over the course of the next year we will see it disappear, or is it a stable configuration, and these storms rotate next to each other?"

Jupiter's atmosphere is not as uniform as researchers expected

A cross-sectional diagram of the inner layers of Jupiter's atmosphere, down to a depth of 350 km. The diagram depicts Juno's microwave instrument data. Orange color signifies a greater amount of ammonia, and blue a lesser amount. You can see the deep ammonia layer which reaches a depth of up to 350 km, as well as the "column" of ammonia that rises above the surface in the equatorial region. Source: NASA/JPL-Caltech/SwRI.
Cross-sectional diagram of the inner layers of Jupiter's atmosphere, up to a depth of 350 km. The chart depicts Juno's Micro Radiometer instrument data. Orange color signifies a greater amount of ammonia, and blue a lesser amount. You can see the deep ammonia layer that reaches a depth of up to 350 km, as well as the "pillar" of ammonia, which rises up in the area of ​​the equator. source: NASA/JPL-Caltech/SwRI.

One of the researchers' estimates was that, due to being made of gas, Jupiter would be uniform in the deeper layers of its atmosphere - but the initial data from Juno refutes this assumption, and indicates that even in the deeper layers of the atmosphere there is great complexity and diversity. "The idea that once you step under the sunlight everything will be uniform and boring was completely wrong. It actually changes a lot depending on where you look at it," said Bolton, according to BBC report.

To penetrate through the outer cloud cover, Juno measures the microwave radiation emitted by Jupiter, which allows it to "look" down to a depth of about 350 km.

Using this method, Juno revealed a deep layer of ammonia, which extends to the edge of the spacecraft's field of view, and possibly far beyond. What's more, from the mysterious ammonia layer, a "pillar" of ammonia rises up into the atmosphere in the equatorial region, and the researchers don't really have a good explanation for this.

Bolton compared the equatorial band of ammonia to a somewhat similar phenomenon on Earth, known as "The bucket compartment", and in which air in the equatorial region rises up, falls back to the ground or sea and rises again. However, Bolton stressed, Jupiter has neither solid land nor sea, so the explanation for the ammonia mystery must be different.

Jupiter's "rough" magnetic field

The map of Jupiter's magnetic field - most of which is still based on models and not on the information measured by Juno. Juno's orbit around Jupiter is depicted in the black line, and the rough areas are those that Juno measured and added to the magnetic field map. It can be seen that the magnetic field that Juno measured is different from what the models predicted, and more varied. Source: NASA/JPL-Caltech/SwRI/GSFC/Harvard.
The map of Jupiter's magnetic field - most of which is still based on models and not on the information measured by Juno. Juno's orbit around Jupiter is outlined in the black line, and its measurements have been inserted on the map as small patches. It can be seen that the magnetic field that Juno measured is different from what the models predicted, and more varied. source: NASA/JPL-Caltech/SwRI/GSFC/Harvard.

Jupiter has the strongest magnetic field in the solar system. The environment of its influence (the magnetosphere), extends over millions of kilometers, and reaches the orbit of the planet Saturn.

The prevailing model among researchers is that Jupiter's magnetic field is created as a result of the movement of metallic hydrogen in the inner layers of the planet (dynamo process). The metallic hydrogen was created due to the enormous pressure in the depths of Jupiter, which causes it to behave like an electrically conductive liquid.

Juno can map the magnetic field in great detail, thanks to the close proximity that its orbit brings to Jupiter. The information collected by the spacecraft shows that the magnetic field is "rough", according to the researchers They call this. In some areas, where they expected the field to be stronger, it was twice as strong, while in areas where they expected it to be weak, it was weaker than expected.

According to the researchers, these findings indicate that the source of the magnetic field is closer to the surface - and it is even possible that it was formed above the metallic hydrogen layer. This of course would require correcting the existing models of how the magnetic field is formed in the depths of Jupiter.

Does Jupiter have a core at its center? Juno just complicates the question

A model showing a cross-section of the interior composition of Jupiter - the upper layers of the outer atmosphere are enlarged on the right. The middle, blue layer is that of metallic hydrogen, and below it, the supposed rocky core, according to one of the models for Jupiter's internal composition. Source: NASA/JPL-Caltech/SwRI.
A model showing a cross-section of the interior composition of Jupiter - the upper layers of the outer atmosphere are enlarged on the right. The middle, blue layer is that of metallic hydrogen, and below that, the supposed core, according to one of the models for Jupiter's internal composition. source: NASA/JPL-Caltech/SwRI.

Jupiter researchers debated for years between two main models regarding the internal structure of Jupiter - one of them hypothesized the existence of a core in the center of Jupiter, which melted several Earths, while the other model hypothesized that Jupiter would not have a core at all.

The debate about the existence of the core, or its absence, was at the center of a deeper issue - the way of the formation of justice. The first model hypothesizes that Jupiter was formed by the crystallization of ice and rock particles into a primordial body, which absorbed the hydrogen and helium gas in the preplanetary disk, from which the solar system was formed about 4.5 billion years ago. The second model, on the other hand, claims that Jupiter formed like the Sun, from the collapse of the gas of the preplanetary disk in on itself.

Even in this case, it seems that the two models are not so compatible with the findings.

From the data of the gravitational field of Jupiter, which the spacecraft mapped by measuring slight changes in its orbit near Jupiter, the researchers estimate that the planet does have a central core, but it is very different from the one they predicted. Its size may reach up to half the diameter of Jupiter, and its nature is not really clear - "Fuzzy", that's what the researchers call it. The core, according to the new hypothesis, is not clearly separated from the hydrogen layer that surrounds it, and is diluted by it.

Jupiter's polar lights behave the opposite of Earth's polar lights

Jupiter's southern polar aurora. Juno is the first spacecraft capable of photographing Jupiter's auroras in full, due to its polar orbit around Jupiter. Red color indicates emission from deeper layers in the atmosphere, while green and white from higher layers. It is interesting to note that the outer orbit with the left bulge is an imprint left by the moon Io on the polar lights, this is due to the large amount of material it ejects into space during its volcanic activity, which is captured by Jupiter's magnetic field and joins the energetic particles that create Jupiter's aurora. The image was taken by Juno on its fifth flyby of Jupiter on February 2, 2017. Source: NASA/JPL-Caltech/SWRI.
Jupiter's southern polar aurora. Juno is the first spacecraft capable of photographing Jupiter's auroras in full, due to its polar orbit around Jupiter. Red color indicates emission from deeper layers in the atmosphere, while green and white - from higher layers. It is interesting to note that the outer orbit with the left bulge is a mark that the Moon leaves on the polar lights, this is due to the large amount of material it emits into space in its volcanic activity, which is captured by Jupiter's magnetic field and joins the energetic particles that create the aurora borealis. Photo taken by Juno on February 2, 2017. Source: NASA/JPL-Caltech/SWRI.

Juno, whose orbit takes it from the north pole to the south pole of Jupiter, has an excellent ability to study its polar lights as well. These lights are very similar to the polar lights of the Earth, but they dwarf them in terms of size and intensity.

The phenomenon is caused by energetic particles that are driven by the magnetic field, collide with molecules in the atmosphere and cause them to glow.

Juno discovered that some of Jupiter's aurora lights are created by electrons moving outward - from the atmosphere into space, while on Earth the movement is completely the opposite - from space into the atmosphere.

"It's a 180-degree change," said Jack Connerney, principal investigator of the Juno mission's magnetic research field, in a telephonic press conference held by NASA yesterday.

Rings of justice face

The shot of Juno in the space between Jupiter and its small rings. This is the first time that Saturn's rings have been photographed from the inside, rather than the outside. Stars that can be seen both from Jupiter and from Earth were also highlighted in the photo - the star Beetlejuice and the stars of Orion's belt. Source: NASA/JPL-Caltech/SwRI.
Jupiter's rings in a photo of Juno, from the gap between the planet and its rings. The image has marked stars that can be seen both from Jupiter and from Earth - the star Beetlejuice and the stars of Orion's belt. source: NASA/JPL-Caltech/SwRI.

The largest and best known planetary rings are of course those of the planet Saturn, but the other gas giants, including Jupiter, also have rings.

Juno, which passes inside the central ring of Jupiter in its orbit around it, was able to photograph the ring from the inside for the first time, when until now other spacecraft that studied Jupiter had photographed it from the outside.

Juno's special photo was taken by her star mapper, which allows her to orientate herself in space. In the photo you can see that Jupiter's sky is no different from that on Earth - at the top of the photo you can see the star Beetlejuice, and at the bottom on the right you can see Orion's belt.

High ice clouds are made of ammonia and water 

An image taken by Juno on May 19, 2017, showing tiny white dots, which are actually clouds about 50 km in size, that are high above the rest of the clouds and cast a shadow over them. These high clouds are likely made of ammonia ice and water, and may which are also a source of lightning. For the full image. Source: NASA/SWRI/MSSS/Gerald Eichstädt/Seán Doran.
An image taken by Juno on May 19, 2017, showing tiny white dots, which are actually clouds about 50 km in size, that are high above the other clouds and cast a shadow over them. These high clouds are probably made of ammonia ice and water, and may also be a source of lightning. for the full picture. Source: NASA/SWRI/MSSS/Gerald Eichstädt/Seán Doran.

In some Juno images, like the one above, you can see relatively small clouds, which look more like tiny white dots, whose size is estimated at about 50 km. These clouds are high in the atmosphere, and can be determined because they cast a shadow on their surroundings. The clouds are made mainly of ammonia ice particles and some water ice, and may be a source of lightning.

Juno still has a lot of work ahead of her

Image taken by Juno on May 19, 2017. Also in it you can see tiny white dots, which are actually clouds about 50 km in size, that are high above the rest of the other clouds and cast a shadow on them. These high clouds are probably made of ammonia ice and water , and may also be a source of lightning. For the full image. Source: NASA/SWRI/MSSS/Gerald Eichstädt/Seán Doran.
Photo taken by Juno on May 19, 2017. Also in it you can see tiny white dots, which are actually clouds about 50 km in size, which are high above the rest of the other clouds and cast a shadow over them. These high clouds are probably made of ammonia ice and water. for the full picture. Source: NASA/SWRI/MSSS/Gerald Eichstädt/Seán Doran.

All 46 papers published by the researchers were largely based on Juno's first few flybys around Jupiter, and the spacecraft has many more orbits it is expected to complete before the end of its mission.

On its next flyby near Jupiter, on July 11, the spacecraft will fly over for the first time The big red spot - Jupiter's most famous and huge storm, which has been raging for over 300 years. The spacecraft will be able to explore the deep roots of the storm, and try to understand how it works and how it survived for so long.

Juno is not the only spacecraft investigating a gas giant these days: the Cassini spacecraft is now In the last phase of its research mission around Saturn. At this stage, the spacecraft entered an orbit very reminiscent of Juno's - an elliptical and elongated orbit that brings it very close to the planet. This method will also allow her to study the internal composition of Saturn and its poles.

The researchers hope in the future to compare the findings of Cassini and Juno, and to better understand the reasons for the differences and similarities between the giant planets. One of the most obvious differences that can be seen between Saturn and Jupiter is their poles: Saturn has a huge hexagon at its north pole, at the center of which is a single giant cyclone. Not rightly so, and the researchers have not yet found a clear reason for this.

Comparison between the pole of Saturn (right), and the pole of Jupiter. Source: NASA / Preston Dyches.
Comparison between the pole of Saturn (right), and the pole of Jupiter. source: NASA / Preston Dyches.

See more on the subject on the science website:

5 תגובות

  1. I wanted to know if someone could explain to me, if the universe is constantly expanding and we are actually looking at the past - come on, is there such a thing as looking back? Where are we in the middle? At first? at the end? I understand that the whole space expands like a bubble in every direction so that every direction we look is actually forward or backward in time, which means we are the center? Or is there a reason that the universe in it expanded further away from us or less far away from us?

  2. Fascinating article, written in a fluent and interesting manner. The pictures are stunning.
    Looking forward to the next article on the subject 🙂
    Thank you very much!

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