Jupiter’s moon Europa may host life
Jupiter’s icy moon Europa may host life in an ocean of liquid water hidden under its 10 kilometre-deep ice crust, scientists say. Researchers from the University of Sao Paulo (USP) in Brazil conducted a theoretical research to evaluate microbial habitability of Europa using data collected from similar environments on the Earth.
“We studied the possible effects of a biologically usable energy source on Europa based on information obtained from an analogous environment on Earth,” said Douglas Galante, a researcher at Brazil’s National Synchrotron Light Laboratory (LNLS). In the Mponeng gold mine near Johannesburg, South Africa, at a depth of 2.8 km, researchers not only found traces of major changes linked to history of life on Earth, but also a terrestrial context similar to Europa.
It was recently discovered that the bacterium Candidatus Desulforudis audaxviator survives inside the mine without sunlight by means of water radiolysis, the dissociation of water molecules by ionising radiation.
“This very deep subterranean mine has water leaking through cracks that contain radioactive uranium. The uranium breaks down the water molecules to produce free radicals,” Galante said.
According to the researchers, the environment colonised by bacteria in the Mponeng mine is an excellent analogue of the environment assumed to exist at the bottom of Europa’s ocean.
Jupiter’s powerful gravitational attraction causes the Europa’s orbit to be extremely elliptical, meaning the latter finds itself either to close or too far from the gas giant. This makes the icy moon suffer geometrical deformation as it moves at the mercy of Jupiter’s immense tidal force. The energy released by the alternating states of elongation and relaxation makes Europa’s subsurface capable of hosting an ocean of liquid water.