Sunday, January 15, 2012
At first glance, Jupiter's sixth closest moon would seem to be a near featureless, dead ball of ice, hardly the kind of place most would think of as being hospitable to life. But there's an ever growing body of evidence which clearly suggests that beneath it's icy surface, there is a deep sea of liquid water with an estimated volume of two to three times that of all the oceans on Earth, covering Europa's rocky interior. Most recently, researches analyzing data collected by NASA’s Galileo spacecraft in 1995-2003, identified what they believe to be signs of a body of water about the size of the great lakes sitting just a few miles beneath the planet's surface.
Then there are the dark lines which form the moon's most prominent features, which are actually deep cracks in the ice shell which covers it. Those cracks are believed to be formed by the gravitational pull of Jupiter essentially stretching and squeezing the planet like a rubber ball, causing the ice to crack and in turn, allowing warm salty water to flow up from beneath and fill them. Some theorize that process alone could generate enough heat to sustain a liquid ocean beneath Europa's ice sheets. But even if not, other processes like thermal venting from within the planet's core could also be contributing heat, as well as various minerals into the watery subsurface, minerals which could potentially aid in the development of life. There isn't yet any way of knowing for sure weather or not any of this is true of course. The idea that life might exist on Europa if it is, is a particularly speculative one. But it does make for an undeniably interesting thought experiment; trying to visualize how life might have developed on a world where ice becomes the atmosphere that shields you from the radiation of the sun, the vacuum of space, and serves to hold in the heat needed to sustain your existence. A world devoid of light, where there is no such thing as open air, and no way to leave the water into which you were born.
If there is life on Europa, it's a safe bet that it isn't advanced enough to ponder it's existence. But it's also within the realm of possibility to think that if there is life on the frozen moon, it might have managed to develop into something more complex than the types of microbial life we're most likely to find Mars. The odds are admittedly against such a thing on either account. But it's still cool to think about.
Source: Wired Science
Image Credit: NASA/JPL