The most well-known spacecraft that collected data on Jupiter and its moons was Juno. Back in 2016, it brought some valuable findings on the gas giant and its moons. However, this wasn’t the only spacecraft that studied the planet and its surroundings. Twenty years after its mission, researchers managed to put together some interesting discoveries collected by NASA’s Galileo on Jupiter’s moon Ganymede.
Jupiter’s biggest moon has some truly interesting properties
Ganymede has always been an interesting object of study due to its properties. The cosmic body is about twice the size of our own moon, and also bigger than some planets in the Solar System. This makes it the largest natural satellite in the system, so all astronomers wanted to find more about it.
Initially, they thought Ganymede was hiding an ocean beneath its surface which might have hosted more saltwater than you can find on our planet. However, the most remarkable property of the moon is its magnetosphere, which make it unique among the other natural satellites.
The Galileo spacecraft was the one that discovered the presence of the magnetosphere. During the four years of the mission, it flew by Ganymede six times, and could study the plasma near the satellite. Twenty years later, researchers found some interesting data that never went public, so they decided to revisit it.
Galileo spotted plasma rain and magnetic phenomena around Ganymede
They noticed how the satellite had some plasma rain falling over it. This disturbed the particles present on its icy surface and affected the magnetic field between the satellite and its home planet. In fact, the interaction between the two magnetic fields caused plasma rains, and also a strange shape of Ganymede’s magnetosphere.
The presence of this magnetic field allowed the formation of auroras in the satellite’s atmosphere. Apart from these beautiful events, Galileo also highlighted the presence of another interesting phenomenon. It is called magnetic reconnection, where all individual lines in the field get entangled. It is these tangles that lead to plasma rains and the particle exchange between Jupiter and Ganymede. This contributes to the brightness of its auroras.
The study was published in the journal Geophysical Research Letters.
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