First Evidence of Water Vapor Revealed by Hubble in Jupiter’s Moon Ganymede

Water is Ganymede!

Wednesday, 28th July 2021

Astronomers have found evidence of water vapor in the atmosphere of Jupiter’s moon Ganymede, for the first time. The formation of this water vapor occurs when ice from the surface of the moon changes from solid to gaseous form, in other words, sublimates.

The discovery has been published in the journal Nature astronomy and scientists have been able to make it by using datasets both new and from the archives from NASA’s Hubble Space Telescope.

The observations from Hubble made in the past twenty years were reexamined by scientists who then came to the conclusion about the existence of water vapor.

Earlier discoveries have proven that the largest moon in the solar system, Ganymede ha more water than all the water there is in the Earth’s oceans. However, due to extremely low temperatures there, the water on the surface always remains frozen.

Also Read: Bringing Hubble Back to Life: How an Engineer Repaired an Aging Telescope with the Help of a 30-Year-Old Student.

It is however said that Ganymede’s ocean resides approximately 100 miles below the crust and thus it cannot account for the water vapor through evaporation from this ocean.

Hubble observations from 1998, that had taken the first UV images of Ganymede, had brought to light auroral bands which are colorful ribbons of electrified gas. This went on to corroborate the fact that Ganymede has a weak magnetic field.

The presence of molecular oxygen (O2) then went on to explain the similarities in these UV observations.

In the course of the Juno mission of 2018, Lorenz Roth of the KTH Royal Institute of Technology in Stockholm took upon himself to measure the amount of atomic oxygen with Hubble. Unlike earlier belief, it was found that there was next to no atomic oxygen in Ganymede's atmosphere. This went on to point that there could be an alternate answer to the observational differences in these UV aurora images.

Roth then explained, the moon’s surface temperature widely differs through the day, and around noon time near the equator, the temperature may get adequately warm for it to release tiny amounts of water molecules.

He said, “So far only molecular oxygen had been observed. This is produced when charged particles erode the ice surface. The water vapor that we measured now originates from ice sublimation caused by the thermal escape of water vapor from warm icy regions.”

The News Talkie Bureau

Source:

Indiatoday