The Juno probe sent back images of Ganymede's North Pole, where plasma rain is heard all year round
Juno, the science spacecraft, has been orbiting and observing Jupiter and its moons non-stop for 4 years, but it still has many surprises to share with us. Juno was the first successful photographer of the North Pole of ganymede, one of the strangest objects in the solar system.
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Ganymede – Genimedes' Arctic Source: nasa/jpl-caltech/swri/asi/inaf/jiram
The images show that at Europa's north pole, a constant rain of plasma from Jupiter's magnetosphere dramatically alters the moon's surface ice. In fact, Genimede is an unusual moon, the largest and largest satellite in the entire solar system, with a diameter of 5268 km (3272 mi). On a scale, Genimede could single-handedly single out all the stars of the entire dwarf planet category, and its size even exceeded that of Mercury. (Mercury, however, is denser, and it's like a "fruitcake" planet.) ）
The innermost layer of Genimede is a liquid iron core, surrounded by a liquid ocean on the outside, and a frozen shell on the surface, a planet made of water ice and silicate rocks. It is thought that it was this liquid iron core that set Genimede apart — the only moon in the solar system with its own magnetosphere, which is generated by convection in its iron nucleus.
Because Genimede orbited Jupiter's planetary magnetic field, his own magnetosphere was therefore in Jupiter's magnetic field. Extremely strong plasma waves are produced when plasma particles, mainly electrons, accelerate along complex magnetic field lines. In addition, the accelerated movement of particles along the magnetic field lines also brings about an effect - the aurora. On Earth, these particles are channeled to the poles, where they interact with atoms in the atmosphere and put on a stunning light show for us.
By contrast, Genimede's atmosphere is almost negligible, so a large number of plasma particles are ejected directly onto the satellite's surface. The latest infrared images from Jupiter's Aurora Infrared Imager (JIRAM), carried by Juno, show that the continuous plasma rainfall has had a significant impact on the satellite's surface. Alessandro Mulla, a co-researcher for the Juno project at the Italian National Institute of Astrophysics, said: "Jiram's data show that the ice that covers and surrounds The Guinimide Arctic has been altered by plasma deposition. Since we were finally able to observe the full picture of the Genimedean Arctic, this is the first time we learned about this phenomenon through Juno. ”
The ice of the Gemimed pole has a distinctly different infrared feature than the ice at the moon's equator. The analysis showed that this was because the plasma rain changed the structure of the ice crystals. On Earth, and in much of The Genimedean surface, the structure of the vast majority of ice molecules is very orderly, hexagonal. But under certain conditions, this neatly arranged structure will fall into a disordered chaotic structure, and this disordered form is called amorphous ice. Although amorphous ice is rare on Earth, it is common in space, for example in the dust, comets or ice bodies of interstellar clouds.
Among Jupiter's many moons, Europa, Ganymede, Ganymede, and Callisto are covered in ice and snow. Interestingly, their ice features vary: Calisto's ice is crystalline, Europa's is amorphous, and Genimede's is a strange mixture.
Previous studies have found that this phenomenon may be related to the distance between the moon and Jupiter. Europa is the closest to Jupiter and is therefore most affected by the radiation bands generated by Jupiter's magnetosphere; in contrast, Calisto is the farthest away from Jupiter and receives less radiation. Genimede is somewhere in between, and scientists have previously proposed that its own magnetic field directs radiation to its poles, making the amorphous ice there more concentrated. Now that Juno's data confirms this, the Jiram team believes it is difficult for the ice there to form crystal structures because its poles continue to be "bombarded" with charged particles.
The next observations will also reveal more about this fascinating phenomenon, and while Juno's primary task is to observe Jupiter, many "side missions" are also being planned. The European Space Agency (ESA) is planning to launch an orbiter called the Jupiter Ice Satellite Explorer (juice) in 2022 specifically for observing Genimede, Europa and Calisto. These comparative observations will shed more mysteries about The Genimede ice and the effects of Jupiter's radiation belts than they would have observed Himmede alone.
by: michelle starr
fy: Small North Mouth
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