Why is europa especially interesting

The arrows coming out of Europa in this illustration are called vectors. They represent the strength and direction of tug of Jupiter and the other moons on Europa. The strength of the gravitational pull changes as the distances and directions from Europa to the moons change. As gravitational pulls tug Europa this way and that, the friction from all this flexing creates internal heat.

This heat keeps the water under the surface liquid, and liquid water is necessary for life. This mission will travel to Europa and investigate whether the icy moon could harbor conditions suitable for life. It's believed that these cracks are caused by the flexing from Europa's tides. No one knows what the reddish material in the cracks might be. The Europa Clipper spacecraft will help us learn more about this material. Europa has lots of cracks on its surface, but not many craters. We know that on Earth there are few craters because the surface is constantly recycling.

Could that be what is happening on Europa? Warmer water might be rising and refreezing on the surface. The crust can also easily break apart and refreeze. Squyres, R. Reynolds, P. Pappalardo et al. For a review of current understanding of Europa and the other galilean satellites, see, for example, A.

Showman and R. Malhotra, "The Galilean Satellites," Science 77, Since its discovery in , Europa—one of Jupiter's four large moons—has been an object of interest to astronomers and planetary scientists. Much of this interest stems from observations made by NASA's Voyager and Galileo spacecraft and from Earth-based telescopes indicating that Europa's surface is quite young, with very little evidence of cratering, and made principally of water ice.

More recently, theoretical models of the jovian system and Europa have suggested that tidal heating may have resulted in the existence of liquid water, and perhaps an ocean, beneath Europa's surface.

NASA's ongoing Galileo mission has profoundly expanded our understanding of Europa and the dynamics of the jovian system, and may allow us to constrain theoretical models of Europa's subsurface structure. Meanwhile, since the time of the Voyagers, there has been a revolution in our understanding of the limits of life on Earth. Life has been detected thriving in environments previously thought to be untenable—around hydrothermal vent systems on the seafloor, deep underground in basaltic rocks, and within polar ice.

Elsewhere in the solar system, including on Europa, environments thought to be compatible with life as we know it on Earth are now considered possible, or even probable.

Spacecraft missions are being planned that may be capable of proving their existence. Against this background, the Space Studies Board charged its Committee on Planetary and Lunar Exploration COMPLEX to perform a comprehensive study to assess current knowledge about Europa, outline a strategy for future spacecraft missions to Europa, and identify opportunities for complementary Earth-based studies of Europa.

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Sign up for email notifications and we'll let you know about new publications in your areas of interest when they're released. Get This Book. Visit NAP. Looking for other ways to read this? No thanks. Suggested Citation: "1 Why Europa?. A Science Strategy for the Exploration of Europa. Page 8 Share Cite. Page 9 Share Cite. Page 10 Share Cite. Box 1. Page 11 Share Cite.

Page 12 Share Cite. Also, all planets revolved around the sun. Over time, moons around other planets were discovered — and additional moons found around Jupiter. Marius, the other "discoverer," first proposed that the four moons be given their current names, from Greek mythology.

But it wasn't until the 19th century that the moons were officially given the so-called Galilean names we know them by today. All of Jupiter's moons are named for the god's lovers or victims, depending on your point of view. In Greek mythology, Europa was abducted by Zeus the counterpart of the Roman god Jupiter , who had taken the form of a spotless white bull to seduce her.

She decorated the "bull" with flowers and rode on its back to Crete. Once in Crete, Zeus transformed back to his original form and seduced her. Europa was the queen of Crete and bore Zeus many children. A prominent feature of Europa is its high degree of reflectivity. Europa's icy crust gives it an albedo — light reflectivity — of 0. Scientists estimate that Europa's surface is about 20 million to million years old, which makes it fairly young. Pictures and data from the Galileo spacecraft suggest Europa is made of silicate rock, and has an iron core and rocky mantle, much like Earth does.

From fluctuations in Europa's magnetic field that suggests a conductor of some sort, scientists also think there is an ocean deep beneath the surface of the moon. This ocean could contain some form of life. This possibility of extraterrestrial life is one of the reasons interest in Europa remains high. In fact, recent studies have given new life to the theory that Europa can support life. The surface of Europa is covered with cracks. Many believe these cracks are the result of tidal forces on the ocean beneath the surface.

It's possible that, when Europa's orbit takes it close to Jupiter, the tide of the sea beneath the ice rises higher than normal. If this is so, the constant raising and lowering of the sea caused many of the cracks observed on the surface of the moon.

Obtaining samples of the ocean may not require drilling through the icy crust, should the repeated observations of possible plumes turn out to be actual jets of water. While researchers spotted evidence in , and , the true nature of the plumes — and why they appear sporadically — requires more observations.

In , scientists found that Europa may host a form of plate tectonics. Previously, Earth was the only known body in the solar system with a dynamic crust, which is considered helpful in the evolution of life on the planet.

The presence of water beneath the moon's frozen crust makes scientists rank it as one of the best spots in the solar system with the potential for life to evolve. The icy depths of the moons are thought to contain vents to the mantle much as oceans on Earth do.

These vents could provide the necessary thermal environment to help life evolve.