Europa

Europa is one of the moons of Jupiter. Europa has an icy surface. Europa is special to scientists as they beleive there is an ocean under the ice. Life may live in the ocean.

Facts about Europa

• Europa may have an ocean under its icy surface
• Some scientists think that extraterrestrial life may live in Europa's oceans

How Big is Europa?

Europa is 3,121.6km (.246 earths) across. It would take 125 Europa's to equal the weight of one Earth, and almost 67 Europa's could be fit into the volume that Earth occupies.

What is the Surface of Europa Like?

The Europan surface is extremely smooth; few features more than a few hundred meters high have been seen. There are very few craters on Europa, and only three are more than 5 km wide. This would seem to indicate a young and active surface; based on estimates of the frequency of cometary bombardment Europa probably endures, the surface must be no more than 30 million years old. The smoothness and visible markings strongly resemble that of sea ice on Earth, and it is thought that under the surface there is a layer of liquid water kept warm by tidally generated heat. The temperature on the surface of Europa is far below freezing, even at the equator, so water ice is as hard as rock. The largest craters appear to be filled with flat, fresh ice; based on this and on the calculated amount of heat generated by Europan tides it is predicted that the outer crust of solid ice is approximately 10-30 kilometers thick, which could mean that the liquid ocean underneath may be as deep as 90 kilometers.

Europa's most striking surface feature is a series of dark streaks crisscrossing the entire globe. These streaks strongly resemble the cracks that form in sea ice on Earth, and close examination shows that the edges of Europa's crust on either side of the cracks have moved relative to each other. The larger bands are roughly 20 km across with a central band of lighter material that is thought to have been produced by a series of volcanic water eruptions or geysers as the Europan crust spread open to expose warmer layers beneath. The effect is similar to that seen in the Earth's oceanic ridges. These various fractures are thought to have been caused in large part by the tidal stresses exerted by Jupiter; Europa's surface is thought to rise and fall up to 30 meters between high and low tides. Since Europa is tidally locked to Jupiter- the same side always faces towards Jupiter - the stress patterns should form a distinctive and predictable pattern. However, only the youngest of Europa's fractures conform to the predicted pattern; other fractures appear to have occurred at increasingly different orientations the older they are. This can be explained if Europa's surface rotates slightly faster than its interior, which is possible due to the subsurface ocean seperating the moon's surface from its rocky mantle.

It has been suggested that life may exist in this under-ice ocean. Scientists who suggest this point out that life can thrive in similarly harsh conditions on Earth: around deep-ocean hydrothermal vents or in the Antarctic Lake Vostok, which is also under a thick sheet of ice. There is currently no supporting evidence that life exists on Europa, but efforts have nevertheless been made to avoid any possibility of contamination. The Galileo mission was concluded by crashing the spacecraft into Jupiter—if simply abandoned, the unsterilized craft might have eventually crashed into Europa and contaminated it with microorganisms from Earth. This would have made it impossible to determine if Europa ever had its own native life, and could even destroy native organisms if they exist.

How Long Is a Day on Europa?

Europa rotates just as fast as it goes around Jupiter so that the surface of Europa always faces the same way towards Jupiter. This means that there is no day and night on Europa, but rather a light and dark side, just like with the Moon

How Long Is an Europa's Orbit Around Jupiter?

Europa takes a little more than three and a half days to go around Jupiter.

Who is Europa Named After?

Europa is nammed after one of Zeus' love interests.

How was Europa discovered?

Europa was discovered by two people: Simon Marius and Galileo Galilei. Galileo discovered it on Janurary 7, 1610. Marius also observed it around the same time.