“Our current scientiﬁc understanding is that, qualitatively, Europa is likely habitable today and likely has been habitable for much of the history of the solar system.”
-Pappalardo et al, Astrobiology, 13 (8): 2013
In the late 1800’s we were able to resolve the surface of Mars for the first time. The astronomers of the day were awestruck when they saw rivers, mountains, and polar activity. Quite a few reports quickly emerged from around the world that signals were coming from intelligent Martians. In 1938, a radio adaptation of War of the Worlds, a novel about a Martian invasion, caused some Americans to panic.
Since then books, movies, and news reports have fantasized about UFOs and aliens either observing Earth or possibly invading us. Extraterrestrial life has joined Bigfoot and Doomsday predictions as typical History Channel programming. Although absence of evidence isn’t evidence of absence, most of these stories lack credibility, and this makes any serious discussion about extraterrestrial life difficult.
Gradually, astrobiologists have found new favorite places to hunt for life. Jupiter’s moon Europa is now what excites the scientific community. Recently, a panel of experts came together to assess the habitability of the icy moon, and the results were somewhat shocking, even for skeptics.
Magnetic readings of Europa suggest a deep subsurface, global ocean that is warmed by tidal heating. A big question that remains is whether or not this ocean has access to enough energy not only to support life, but to support the origins of life—an important distinction.
Particularly striking is the report’s discussion of the chemistry of Europa: “Both modeling and empirical constraints suggest that temperature, pressure, pH, and salinity within the ocean likely fall within the limits known to be tolerated by extant terrestrial life.”
In other words, Europa appears to be currently habitable to various life forms on Earth. Some of our fellow earthlings may be capable of surviving there.
That’s why scientists are so excited to explore Europa. But, a mission to the Jovian moon presents logistical problems. We probably would not be able to go straight into the ocean because of how thick the icy shell is. But, Pappalardo et al. describe a few other intriguing hypothetical missions.
For instance, we could analyze dust that litters the surface of Europa, which blew in from other bodies in the Jovian system. Such a mission could tell us how molecules can escape from atmospheres of other moons like Io and travel to Europa.
But, to answer the million-dollar habitability question would require much greater effort. We would need to puncture about a meter into the surface. This would reveal an almost pristine portion of the icy shell, and it may answer questions about the organic and inorganic chemistry of the moon. The scientists in the report say that these analyses alone would be revolutionary to science.
And while we’re there, we should conduct a seismic experiment to precisely determine the thickness of the icy shell. After all, we will want to come back and dig a little deeper.
Who knows what we’ll find?
Source: R.T. Pappalardo et al. Astrobiology. (Ahead of print.) doi:10.1089/ast.2013.1003.