Jupiter's moon Europa is one of the more intriguing candidates for extraterrestrial life in our solar system. New models suggest that its ice-covered waters are turbulent near the lower latitudes, giving rise to its chaotic equatorial landscapes. Intriguingly, these warm waters may make it easier for life to make it to the surface.
Europa is covered in a miles-thick layer of ice, but a liquid ocean lies beneath. This icy shell is relatively young, featuring an extensive array of cracks and streaks. Craters are all but nonexistent. Exogeologists hypothesize that heat generated by tidal forces are causing the ocean to remain in liquid form.
But Europa's surface features aren't consistent. The landscape is marked by features of disrupted ice known as chaos terrains — extensive regions which cover up to 40% of the moon's surface, and most commonly occurring within 40° of the equator. These geological features are characterized by huge chunks of ice that have broken away and then re-froze into chaotic patterns.
New computer simulations by University of Texas geophysicist Krista Soderlund and colleagues now show that turbulent global ocean currents move Europa's internal heat to the surface most efficiently in regions closest to the moon's equator. This is likely causing the melting and upwelling at the surface, and why regions further north and south appear to be smoother.
And in fact, given Europa's spin, heat flow, and other factors, it likely percolates upward at about 1m per second or so — which is remarkably fast. This would explain why the equatorial regions appear to be so fragmented. But it also means that these areas are also relatively fragile and soft.
Excitingly, the upward currents could bring nutrients and even living organisms to the surface. Any potential search for signs of life on this moon now appear to be considerably easier. If we're going to send a probe to Europa, the equator would be the best place to send it.
Read the entire study at Nature Geoscience: "Ocean-driven heating of Europa's icy shell at low latitudes".
Images: MODEL IMAGE: J. WICHT; EUROPA: UNIV. OF ARIZONA, JPL/NASA.