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With Explore the Planets, investigate the planets, their moons, and understand the processes that shape them. By G. Jeffrey Taylor, Ph.D. See our DVD collection.

Exploratour - Does Europa have an Ocean?

This is an image of Europa.
Click on image for full size

7.) From what geologists have been able to tell so far, the heights of features such as domes and ridges seem low. Remember we said that scientists are using close up pictures of features, such as the one shown here, to help determine the heights of different features which can be seen in other pictures. Since there is no wind or other means of erosion, the low heights of these features suggest that somehow domes are prevented from rising very high into the sky.

Mountain ranges on Earth are buried in the mantle of the Earth. They are able to rise our of the crust because the "root" of the mountain receives support under the surface by the rocky (Earths crust is made of rock, not water) but pliable (it is also warm and flexible) mantle beneath the surface. The process is somewhat like that of an ice cube floating in water in which the tip of the ice cube (or iceberg in the open sea) which rises above the surface is much smaller than the portion which is below the surface. The portion below the surface we can call a "root". If the material in which the root is floating is strong enough, it can allow more of the tip to rise above the surface.

This phenomenon of low heights of mountanous features on Europa suggests that there might be a process at work whereby the strength of the underlying material is not sufficient to raise mountains up to large heights. Notice that if true, such a process would require the presence of a weak subterranean layer or ocean.

You may leave the tour and read more about the process of erosion, the process of mountain building, or the qualities of the Earth's mantle by using the links found at the bottom of this page.

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Windows to the Universe, a project of the National Earth Science Teachers Association, is sponsored in part is sponsored in part through grants from federal agencies (NASA and NOAA), and partnerships with affiliated organizations, including the American Geophysical Union, the Howard Hughes Medical Institute, the Earth System Information Partnership, the American Meteorological Society, the National Center for Science Education, and TERC. The American Geophysical Union and the American Geosciences Institute are Windows to the Universe Founding Partners. NESTA welcomes new Institutional Affiliates in support of our ongoing programs, as well as collaborations on new projects. Contact NESTA for more information. NASA ESIP NCSE HHMI AGU AGI AMS NOAA