Jovian moon Europa is tipped to have an ocean of water flowing under its icy surface.
An underground ocean of water beneath the ice on Jupiter’s moon Europa appears to be capable of reaching the surface, according to Professor Mike Brown of the California Institute of Technology. The discovery suggests that it may be possible to detect any life in the ocean simply by sampling the residue on the surface.
Europa is well known for being the most likely place in the Solar System, other than Earth, to be home to life. This is because of the 100km (62-mile) deep ocean that it is believed the moon harbours. However, sending a probe to the moon to sample the ocean has always been problematic, given that the ocean is buried beneath kilometres of solid ice and would be nigh-on impossible to drill down into. However, judging by observations by Brown and his colleague,Kevin Hand of NASA’s Jet Propulsion Laboratory, that barrier may not be as impenetrable as previously thought.
Using an infrared spectrometer on the giant Keck II telescope in Hawaii, Brown and Hand were able to detect the signature of magnesium sulphate on the trailing hemisphere of the moon. They believe that the magnesium originates from the ocean deep underground, in the form of magnesium chloride. This then reacts with sulphur belched into space by the mighty volcanoes on Europa’s fellow moon Io and then falls onto Europa, to create magnesium sulphate. Because the sulphur does not come from the ocean, Europa’s ocean must be dominated by chlorides instead, such as potassium and sodium. In other words, this makes for a very salty ocean, just like on Earth.
The connection between the surface and the ocean means that there is an exchange of chemical energy between the two, which would be good for potential alien life. «Most importantly,» Brown says, «it means that if you want to know what is in the ocean of Europa, you just have to look at the surface and study the composition there.»