Ganymede, Jupiter’s moon, was recently discovered to have water vapor in its atmosphere.
Ganymede is the largest moon in Jupiter’s solar system. This moon is completely covered with a layer of ice. And scientists believe that Ganymede may have an ocean of water 100 miles (161km) below its plains surface. The ocean is predicted to contain liquid that is almost similar to water, which indicates it can support the life of certain entities.
Recently, NASA announced that by looking at Hubble Space Telescope data over the past two decades, astronomers from the KTH Royal Institute of Technology have found evidence of water vapor in Ganymede’s atmosphere. But the findings suggest that this water vapor did not originate in the ocean of water beneath the surface of the Ganymede plain. On the other hand, it is possible that the water vapor comes from a layer of ice that evaporates on the surface of the moon.
Previous research has shown that the ice on Ganymede’s surface can change from a solid to a gas. So, the ice does not go through the process of melting to become water vapor that forms part of the atmospheric layer on Ganymede. But in the explanation regarding the change of ice into water vapor, there are still some shortcomings.
In 1998, Hubble managed to capture Ganymede’s first ultraviolet signal, including its auroral signal. Ultraviolet signals detected in this aurora have indicated the presence of oxygen molecules or water vapor. Astronomers at that time were still interpreting that water vapor was made of two oxygen atoms that eroded Ganymede’s icy surface. However, some of the results from these ultraviolet signals do not indicate if the atmosphere contains pure oxygen molecules. And previous research explained that the difference in results was due to the presence of fully concentrated oxygen atoms.
As part of an observation program to support NASA’s Juno mission to Jupiter in 2018, astronomers attempted to measure the number of oxygen atoms in Ganymede’s atmosphere using Hubble. Unexpectedly, they found that there were almost no oxygen atoms there. This finding is the basis for the latest research this time, to explain the findings of previous ultraviolet signals related to the process of forming water vapor.
Reported NASA (28/7), the latest research found answers related to the cause of the emergence of water vapor in Ganymade’s atmosphere. These oxygen molecules or water vapor are not formed from concentrated oxygen atoms, but because there is sublimation of the ice that occurs on Ganymede. The sublimation was encouraged because there was a very extreme hot temperature of 193 degrees Celsius. This allows the permafrost on Ganymede to turn directly into water vapor.
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