Many of these features coincide with long, curving streaks that are dark and reddish in color — some stretching across the surface in great arcs over miles kilometers long. Elsewhere, domes, pits and chaotic jumbles of icy blocks hint that warm ice may be rising from deep below. Models suggest that Europa's icy shell is relatively thin.
The icy moon gets stretched and released by the tug of Jupiter's gravity, in an endless cycle, as Europa orbits the giant planet. This squeezing in and out is a process called tidal flexing, which may be creating heat inside Europa; the warmed ice from this heat may be pushing the surface upward to create the ridges. The tidal flexing also may be creating enough heat inside Europa to maintain a liquid ocean beneath the moon's icy surface.
Most of the heat would be focused at the boundary between the ocean and the icy crust. For Europa to be potentially habitable, it would need to have the essential chemical ingredients for the chemistry of life. These include carbon, hydrogen, nitrogen, oxygen, phosphorus and sulfur, which are common elements, and scientists think it's likely they were present on Europa as it formed.
Later on, asteroids and comets impacted the moon and would have deposited even more organic, or carbon containing, materials. The chemical elements for life might be found within Europa's icy shell, as well as its ocean. Tidal heating could be powering a system that cycles water and nutrients between the moon's rocky interior, ice shell and ocean, creating a watery environment rich with chemistry conducive to life.
This is why studying Europa's chemistry — on the surface and within the suspected ocean — is important for understanding its habitability, because living things extract energy from their environments by chemical reactions. All lifeforms need energy to survive. Where would life on an icy world far from the Sun get energy?
The type of life that might inhabit Europa likely would not be powered by photosynthesis — but by chemical reactions. Europa's surface is blasted by radiation from Jupiter. That's a bad thing for life on the surface — it couldn't survive. But the radiation may create fuel for life in an ocean below the surface.
The radiation splits apart water molecules H2O, made of oxygen and hydrogen in Europa's extremely tenuous atmosphere. The hydrogen floats away and the oxygen stays behind. Along with helping maintain liquid water, we think that tidal energy may also allow that ocean to interact with rocks on Europa's sea floor, and it may even give rise to things like hydrothermal vents, which could help provide, not just the building blocks for life, but also the energy for life.
The question of whether or not life exists beyond Earth, the question of whether or not biology works beyond our home planet, is one of humanity's oldest and yet unanswered questions. And for the first time in the history of humanity we have the tools and technology and capability to potentially answer this question.
And, we know where to go to find it. Jupiter's ocean world Europa. This animation showing a flyover of ridged plains on Europa was created using stereo imaging data obtained by NASA's Galileo spacecraft. Androgeos Linea Flyover. Jupiter's moon Europa may have an ocean more than twice the size of Earth's oceans combined. Why do scientists think so? Find out in 60 seconds. In this movie Europa is seen in a cutaway view through two cycles of its 3.
Europa Tide Movie. This animation showing a flyover of the region named Agenor Linea on Europa was created using stereo imaging data obtained by NASA's Galileo spacecraft. Agenor Linea Flyover. Could a liquid water ocean beneath the surface of Jupiter's moon Europa have the ingredients to support life?
Reanalysis of old data data suggests that the Galileo spacecraft, on its closest flyby of Europa, flew through a plume. This animation showing a flyover of Europa was created using stereo imaging data obtained by NASA's Galileo spacecraft. There also were tantalizing hints that perhaps Europa had a warm interior at some time in the past, and perhaps still does.
Studies of how tidal heating should affect Europa suggested that a global subsurface ocean might exist within the icy moon today. These intriguing findings led to a strong sense of anticipation for the Galileo mission, which launched in and entered orbit around Jupiter in Galileo's primary mission included observations of each the four Galilean satellites during repeated flybys.
The information about Europa that Galileo sent was so intriguing that the mission was extended to make a total of 12 close flybys of the icy moon. Data from the mission included images of Europa at a range of scales, revealing new details about the surface and providing context for how those details related to the moon as a whole.
One of the most important measurements made by the Galileo mission showed how Jupiter's magnetic field was disrupted in the space around Europa. This measurement strongly implied that a special type of magnetic field is being created induced within Europa by a deep layer of some electrically conductive fluid beneath the surface. Based on Europa's icy composition, scientists think the most likely material to create this magnetic signature is a global ocean of salty water.
Europa Clipper will seek to confirm the presence of its ocean.
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