Evidence of water vapour in the atmosphere of Jupiter’s moon, Ganymede, has been proven for the first time. The discovery was made when NASA noticed a strange phenomenon in the images captured from the two decades of data from the Hubble Space Telescope.
Back in 1998, when the first bright-coloured ribbons of electrified gas known as auroral bands were captured, astronomers associated the images with the presence of oxygen in the atmosphere. However, the gathered data did not match the expected emissions of a body that had an atmosphere of pure oxygen. There is also the fact that there is hardly any atomic oxygen in the Jovian’s moon atmosphere.
Lorenz Roth of the KTH Royal Institute of Technology in Sweden made this discovery together with his team. They used data from archival images from the Space Telescope Imaging Spectrograph (STIS) from 1998 and 2010 and data from Hubble’s Cosmic Origins Spectrograph from 2018.
Roth stated, “So far only the molecular oxygen had been observed. This is produced when charged particles erode the ice surface. The water vapour that we measured now originates from ice sublimation caused by the thermal escape of water vapour from warm icy regions.”
With the European Space Agency’s Juice mission ( the JUpiter ICy moons Explorer) planning to launch in 2022 and arrive at Jupiter in 2029, this new information will allow the ESA to refine their observation plans.
