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We now offer the Cool It! card game in our Science Store. Cool It! is the new card game from UCS that teaches kids about the choices we have when it comes to climate change.

Exploratour - Does Europa have an Ocean?

This image shows the Earth and the moon, and the bulges produced on each side from the tides.
Click on image for full size

Reasons that planetary bodies are warm include

  • 1.) leftover heat from it's formation
  • 2.) radioactive material found in the body
  • 3.) outside forces on the body as a whole, such as those which cause tides
  • 4.) warming by the sun

Reason #3 applies to Europa. An example of what happens is shown in this drawing of the Earth and Moon. In this picture, the gravitational force of the Earth is pulling on the Moon, and the gravitational force of the Moon is pulling on the Earth. The Moon pulls more strongly on the side of the Earth facing the Moon than on the side facing away from the Moon. Because planets are not perfectly rigid, they change their shape when they are pulled this way.

In the case of Europa, the push-me, pull-me effect is caused by the pull of Jupiter on one side, and the other moons of Jupiter on the other side. (Europa is an inside moon). The volcanism of Jupiter's moon Io is caused by the very same effect.

If a body is very rigid or is not held together well, instead of getting pushed and pulled out of shape, the tidal forces can actually tear the body in half, as with comet Shoemaker-Levy 9.

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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