Water has been detected in the atmosphere of Jupiter’s moon Europa for the first time, providing evidence of the possibility of an ocean several miles below the surface of the Europa Ice, U.S. researchers report Wednesday in the British journal Nature Astronomy.
Ganymede, also known as Europa, is similar in size to the moon, covered with a thick layer of ice, which may have a huge ocean under it. It is described by NASA as a “high priority investigative target” for the search for life beyond Earth in the solar system.
On 17 nights between 2016 and 2017, NASA planetary scientist Lucas Paganini’s team used a spectrometer at the Keck Observatory in Hawaii to detect water vapor signals on Ganymede, which detects the absorption or radiation of infrared light by chemical components in the planet’s atmosphere.
Scientists had speculated that liquid water beneath The Ice would erupt in geysers, but because of the limited detection capacity of existing detectors and the interference of ground-based telescopes by water molecules in the Earth’s atmosphere, it has been difficult to find water in Ganymede’s atmosphere. To minimize this interference, Paganini’s team built a complex set of mathematical and computer models to simulate the Earth’s atmospheric conditions, removing water molecules from Europa’s observations.
The study provides evidence of the possible existence of oceans miles below the surface of Ganymede’s ice. Another possible source of these water molecules, the researchers believe, is the melting ice reservoir beneath Ganymede’s shallow surface.
NASA plans to launch the Europa Express probe around 2025 to uncover the mysteries of Ganymede at close range.