Europa, Jupiter's smallest moon, has been imaged by Galileo spacecraft for some years. It's surface, seen as a frozen layer of water, was thought in the past to be tens of kilometers thick, denying the oceans below any exposure which can indicate to life. But more recent findings show that there is liquid water underneath the ice.

Jupiter is the largest planet in the solar system, and its tidal stresses on Europa create enough heat to keep the water on Europa in a liquid state. This opened the door to speculation about life on this planet. Because where there is water there may be life. But more than just water is needed to support life. Tides also play a role in providing for life. The mixing of substances needed to support life is driven by tides. The combination of tidal processes, warm waters and periodic surface exposure may contain life and also encourage evolution.

It is still not known yet whether there is life on this planet, but if there is, life on Europa could resemble that of simple sea-dwelling organisms of Earth. Many of Earth's organisms live at 32 degrees (Fahrenheit) or below," Microbes, in the Antarctic, can hibernate for up to a million years in the ice. European organisms, trapped in the ice, could emerge when the next warm tide flows through.