Europa, Jupiter’s sixth-largest moon, is thought to host an underground ocean filled with saltwater beneath its icy surface, in contact with an exposed rock seafloor. Scientists speculate that Europa might even possess life.
Water is essential to life as it dissolves nutrients and transports chemicals between living cells. Scientists will use this research to understand if there’s an environment on Europa that could support life.
Water
Europa may possess all three essential ingredients for life to survive: an energy source, organic molecules, and liquid water.
Scientists speculate that Europa harbors a vast ocean of liquid water beneath its icy shell, heated by Jupiter’s tides to maintain liquidity. Tidal effects from Jupiter likely keep this ocean liquid and make it one of the best spots in our solar system to search for life beyond Earth; possibly holding double what exists here on our own planet’s oceans combined.
Europa’s rocky interior could provide life-sustaining organic molecules, yet also demand massive amounts of energy to move chemical compounds around. If sunlight was unavailable as a source of this energy, tidal flexing would likely be the ideal source. Similar to repeatedly bending a paperclip generates heat, tidal flexing drives tectonic movements on Europa that might produce hydrothermal vents or volcanoes which provide heat and chemicals into its oceans.
Scientists on the JUICE mission will conduct a detailed survey of Europa, its surface, deep interior and thin atmosphere in search of signs of activity or lack thereof as well as chemical compounds that might indicate living organisms or evidence against their existence. Furthermore, specific regions will be probed in order to see how essential elements for life get there.
Organic Molecules
Water is essential for life as it dissolves nutrients that living things need for sustenance, transports chemicals between cells, and helps dispose of waste. But life also depends on organic molecules: carbon-based compounds formed when other elements combine with carbon molecules to form DNA, proteins, and fats – essential building blocks of matter and structure that support life itself. Organic molecules may either attract water easily by being hydrophilic (attracting it easily) or repel water (hydrophobicity).
Hydrogen, nitrogen, oxygen and phosphorus – elements which make up organic molecules – are found throughout the universe, such as meteoroids and comets. Scientists hypothesize that some of these elements were likely included in Europa as it formed and that collisions between asteroids and comets may have further added more.
NASA’s Europa Clipper mission will fly by Europa several times between 2023-2025, using cameras to take high-resolution pictures and radiation-tolerant instruments to study its surface composition and subsurface ocean. They’ll also search for signs of plumes as possible pathways through which material could travel between its icy shell and ocean depths; radar will search for hidden lakes; while magnetometers would help confirm whether there truly exists an undersurface ocean.
Energy
Europa, an icy moon belonging to Jupiter and one of four Galilean satellites known as Galilean Satellites in Greek mythology, has long captured scientists’ imaginations. Scientists believe Europa holds one of its six Galilean Satellites’ oceans under its icy shell – possibly twice as much liquid water than Earth has. Water plays a critical role in life as it provides nutrition to living organisms while transporting essential chemicals between cells as well as helping eliminate wastes produced within them.
Scientists theorize that tidal flexing may have played an essential part in cycling water and nutrients between Europa’s rocky interior, its icy shell and the ocean, creating an environment rich in organic molecules which could have served as the building blocks for life on Europa.
ALMA in Northern Chile has revealed that some regions of Europa’s icy shell show evidence of heat. This may be caused by sunlight interacting with its molecules and producing chemical energy; or perhaps water molecules are being released as it melts off and breaks apart, providing energy sources for microorganisms living below in its ocean depths. Scientists using instruments aboard NASA spacecraft Clipper are actively searching for evidence of plumes on Europa.
Environment
Scientists suspect that Europa’s icy surface conceals a salty ocean beneath, with the possibility that its rocky ocean floor may even be active. For life to exist in Europa’s environment, three things would be needed: energy from light or chemicals, liquid water and organic compounds derived from sunlight; radiation from Jupiter could break apart molecules while keeping any fragments within Europa itself – something radiation cannot accomplish easily enough without spilling over into the surrounding water body below.
Liquid water is essential to microbial life as it provides organisms with food sources they need, transports vital chemicals in living cells and helps them dispose of waste products. Europa may contain twice as much liquid water than Earth and support hydrothermal activity by releasing heat and materials from its interior.
Europa shows evidence of its subsurface ocean in its chaotic terrain. A mixture of pits, ridges and craters suggest shifting ice sheets; plumes may even erupt above its surface to eject material upwards.
Researchers studying Europa’s environment rely on data gleaned from various telescopes orbiting Jupiter, including ALMA observatory. This provides maps that display Europa’s thermal properties – for instance how quickly temperatures even out across its surface or its emissivity (how it absorbs and radiates sunlight). As some spots on the map appeared too hot or cold to explain simply by sunlight alone, researchers began investigating other possible sources of heat or light that may exist within its atmosphere.
