There is an ocean on Ganymede
Just a day later, as we learned about hydrothermal activity at the bottom of the subsurface ocean of Saturn’s satellite, NASA confirmed the long-standing theory of the existence of the ocean on Ganymede, the satellite of Jupiter and the largest satellite in the solar system. Ganymede is almost as big as Mars and it is the only moon in the solar system with its own magnetic field. This field is created by a molten iron core, just as it happens on Earth. And the thin atmosphere of the moon is rich in oxygen.
The Voyagers data in the 1970s became the basis of the hypothesis of the existence of the ocean on Ganymede. Then the Galileo spacecraft, which had studied the Jupiter system since 1995, discovered the magnetic field of Ganymede, confirmed the theory of the presence of an ocean of liquid water beneath the surface of Europe, but could not reliably confirm the presence of liquid water in the depths of Ganymede - there was ambiguity in the data.
It was only now possible to confirm the theory of the presence of an ocean of liquid water under the surface of Ganymede with the help of the Hubble Space Telescope. Ganymede was observed for several hours, most of this time was spent studying the aurora observed in the subtlest atmosphere of the moon of Jupiter. In the absence of an ocean, the aurora should shift by approximately ± 6 degrees around the circumference of Ganymede as it moves in orbit around Jupiter. In the presence of a salty electrically conductive ocean, the aurora should be stable - the offset should be about 2 degrees.
Observations on the Hubble finally proved the existence of the ocean. The ocean is most likely located at a depth of about 100 kilometers below the surface and it is unlikely that it will be available for study by automatic stations.
So far, there is no reason to believe that there is hydrothermal activity at the bottom of the subsurface ocean of Ganymede. And that means that the likelihood of life on Ganymede is small. Previously, scientists assumed that the water under the surface of Ganymede is present in the form of a mixture of ice and salt water.
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However, the European Agency is planning to launch the JUICE spacecraft in 2022, which in 2030 will reach the Jupiter system and for at least three years will conduct studies of Jupiter and its largest satellites Ganymede, Callisto and Europe.
The Voyagers data in the 1970s became the basis of the hypothesis of the existence of the ocean on Ganymede. Then the Galileo spacecraft, which had studied the Jupiter system since 1995, discovered the magnetic field of Ganymede, confirmed the theory of the presence of an ocean of liquid water beneath the surface of Europe, but could not reliably confirm the presence of liquid water in the depths of Ganymede - there was ambiguity in the data.
It was only now possible to confirm the theory of the presence of an ocean of liquid water under the surface of Ganymede with the help of the Hubble Space Telescope. Ganymede was observed for several hours, most of this time was spent studying the aurora observed in the subtlest atmosphere of the moon of Jupiter. In the absence of an ocean, the aurora should shift by approximately ± 6 degrees around the circumference of Ganymede as it moves in orbit around Jupiter. In the presence of a salty electrically conductive ocean, the aurora should be stable - the offset should be about 2 degrees.
Observations on the Hubble finally proved the existence of the ocean. The ocean is most likely located at a depth of about 100 kilometers below the surface and it is unlikely that it will be available for study by automatic stations.
So far, there is no reason to believe that there is hydrothermal activity at the bottom of the subsurface ocean of Ganymede. And that means that the likelihood of life on Ganymede is small. Previously, scientists assumed that the water under the surface of Ganymede is present in the form of a mixture of ice and salt water.
')
However, the European Agency is planning to launch the JUICE spacecraft in 2022, which in 2030 will reach the Jupiter system and for at least three years will conduct studies of Jupiter and its largest satellites Ganymede, Callisto and Europe.
Source: https://habr.com/ru/post/374751/
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