Life in the Solar System - Europa

Since life in the habitable zone did not yet reveal itself, the search has moved further in the solar system to reach the Jovian planets. While life on the gas giants seems unlikely, the Galileo mission to Jupiter has disclosed that its moons are a whole different topic, and Europa holds the gold medal as far as life is concerned, mainly because liquid water seems to be abundant on this tiny moon. Europa presents itself to be a fascinating world. If there is complex life anywhere else in the solar system, it would be here. The moon is covered by an icy, young crust, almost crater-free, denoting that Europa’s surface is active, and craters must have flattened out by the warmth beneath. [1] The moon has no magnetic field, hence no melted inner core. But there is definitely tidal heat, and therefore geological activity, and interaction with Jupiter’s magnetosphere, revealing that the layer under the thick icy crust might as well be a liquid water sea with warm thermal vents at the bottom of the ocean. [2] On Earth life already thrives in warm thermal vents on the ocean floor. Images of Europa taken by Galileo have also revealed volcanic activity that would generate the chemicals necessary for life.

Europa is the main candidate for complex life forms. As Neil deGrasse Tyson points out enthusiastically, “I want to go ice-fishing on Europa, cut a hole, put a submersible, look around, see if anything swims up to the camera lens and looks at the camera”. [3] But a mission capable of digging through the thick icy crust seems ambitious at the moment. A hydrobot is being built in Austin, Texas - the Deep Phreatic Thermal Explorer (DepthX). [4] If DepthX proves itself successful in exploring Earth’s oceans, it may become a viable solution for a mission to Europa. For now, the Europa Jupiter System Mission seems more realistic, as it would search the surface for evidence of fossilized organisms that have been carried up through the cracks and deposited on the surface. Such a mission would be sufficient to reveal life on this moon. Europa Jupiter System Mission is at the moment only a concept planned to launch around 2020 with an orbiter on board. [5]

Notes

[1] Pappalardo, Robert T., James W. Head, and Ronald Greeley. "The Hidden Ocean of EUROPA." Scientific American Special Edition 13, no. 3 (September 2, 2003): 64-73. Academic Search Premier, EBSCOhost (accessed October 11, 2011), 56.

2 Seeds, Michael. The Solar System. Boston: Brooks/Cole, Cengage Learning, 2011, 594.

3 The Universe: Jupiter, directed by Andrew Nock (2007; The History Channel). DVD.

4 Deep Phreatic Thermal Explorer Project. About the DepthX Project. http://www.frc.ri.cmu.edu/depthx/about.html (Accessed October 11, 2011).

5 Lawler, Andrew. "Is This the Best Place to Find Life in the Solar System?." Discover 30, no. 8 (September 2009): 42-47. Academic Search Premier, EBSCOhost (accessed October 11, 2011), 2.