Europa

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    in Brief: Europa

    In Brief: Europa

    When Galileo Galilei discovered Jupiter’s four large moons — Io, Europa, Ganymede and Callisto — more than 400 years ago, he revolutionized humanity’s view of the universe. The discovery demonstrated that Earth was not the center of all motion in the cosmos. Now one of those moons might again challenge how we think about the universe and our place in it.

    Scientists are almost certain that hidden beneath the icy surface of Europa is a salty-water ocean thought to contain twice as much water as Earth’s oceans combined. It may be the most promising place in our solar system to find present-day environments suitable for some form of life beyond Earth.

    Slightly smaller than Earth's Moon, Europa’s water-ice surface is crisscrossed by long, linear fractures, cracks, ridges, and bands. The moon’s ice shell is probably 10 to 15 miles (15 to 25 kilometers) thick, beneath which the ocean is estimated to be 40 to 100 miles (60 to 150 kilometers) deep. Like Earth, Europa is thought to also contain a rocky mantle and iron core.

    Europa is named for a woman who, in Greek mythology, was abducted by the god Zeus — Jupiter in Roman mythology.

    10 Need-to-Know Things About Europa

    10 Need-to-Know Facts About Europa

    1

    Familiar Size

    Europa is slightly smaller than Earth’s Moon and barely one-quarter the diameter of Earth itself.

    2

    A Darker Realm

    Europa orbits Jupiter, the fifth planet from the Sun. Jupiter orbits the Sun at a distance of about 484 million miles (778 million kilometers).

    3

    Locked On

    Europa rotates once on its axis and completes one orbit of Jupiter every 3.5 Earth days, so the same side of Europa always faces Jupiter.

    Reddish Bands on Europa

    4

    Icy Moon

    Europa's surface is mostly solid water ice. It is crisscrossed by fractures.

    5

    Bring Your Spacesuit

    Europa has an extremely thin oxygen atmosphere — far too thin for humans to breathe.

    6

    Nothing in its Orbit

    Europa has no moons of its own.

    7

    Ringless

    Europa has no rings, but some moons in the solar system may have had rings in the past.

    8

    Popular Destination

    Europa has been visited by several spacecraft and more missions are planned.

    9

    All These Worlds

    Abundant liquid water, energy and the right chemical elements make Europa one of the best places in the solar system to seek present day life beyond Earth.

    10

    Don't Forget a Towel

    Europa's subsurface ocean might contain more than twice as much water as Earth

    Europa Rising

    Featured FAQ

    Featured FAQ: Could Europa Harbor Life?

    Europa is one of the few places in the solar system, aside from Earth, for which there is very strong evidence suggesting a liquid water ocean is present today and is in contact with rock.​ This is important because life as we know it requires three key basic "ingredients": liquid water, an energy source, and organic compounds to use as the building blocks for biological processes.

    Poster Showing Europa's Pwyll Crater
    This free Europa poster is part of the NASA Solar System and Beyond poster set.

    Europa could have all three of these ingredients, and its ocean may have existed for the whole age of the solar system, long enough for life to begin and evolve there.

    But while Europa may turn out to have the necessary ingredients for life, it may still be lifeless. After all, having all the ingredients to make a pie is not the same as having a pie.

    Pop Culture

    Pop Culture

    Europa has been featured in short stories, comics and novels, with perhaps the best-known being the Arthur C. Clarke novel “2010: Odyssey Two,” which was also adapted for film.

    More recently Europa was the setting for the 2013 film “Europa Report,” and it was featured in an episode of the animated television show “Futurama.”

    The moon has also been the setting or subject of several video games, including “Call of Duty: Infinite Warfare” and “Galaga: Destination Earth.”

    Additional Resources

    Additional Resources

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