Looking For Life on Titan

For my final life on other worlds themed entry, no really, I promise, I have saved my favorite object within our own solar system, for last. And if for some reason it strikes as odd that I might actually have a favorite such object, well then you've clearly underestimated just how much of a geek I truly am. The alien world to which I am referring in this case is Saturn's sixth moon, Titan. Which, if you're unfamiliar, is an amazing place.

Like most objects in the outer solar system, Titan is a frigid place, one where surface temperatures regularly dip down to a frosty -300 degrees F. But unlike any other known planetary satellite, Titan is veiled in a thick atmosphere, a soupy, haze of methane and nitrogen that allows for the formation of, amongst other things, weather patterns. Titan's atmosphere is so dense, in fact, that it effectively shielded the moon's surface from the view of probes until the arrival of the Cassini spacecraft and it's companion Hyugens lander, in 2004. The data and images Cassini collected, as well as the images hyugens managed to return during its brief life on Titan's surface, revealed what is without a doubt the most spectacular and Earth-like features of Titan- standing lakes, rivers, and even seas, of what is believed to be liquid methane and ethane, and a landscape which seemed to bear clear evidence of liquid erosion.

It goes without saying, that there are obviously major fundamental differences between our own world and Titan, but the more we learn about it, the clearer it becomes that this distant moon really is, in many ways, a mirror-image of Earth. Which is why some scientists have begun to speculate that if so many other processes could be mirrored using alternative chemistry -such as methane and ethane taking the place of water in it's weather cycle- why couldn't life do the same?

To be clear, there is as of yet no confirmed evidence of life of any form on this distant moon. But several papers analyzing data collected by the Cassini craft emerged last year, which described the seeming disappearance of hydrogen from the moon's atmosphere, as well as a lack of acetylene on it's surface. Theories have suggested that methane-based life, if it were to exist, would likely consume both hydrogen and acetylene as part of it's natural biological process. Such a methanogenic life form is, of course, entirely theoretical at this point, and some as of yet unidentified chemical process is much more likely to proven as the ultimate source of the missing materials. But, as always, there remains a chance that these apparent chemical anomalies could be the sign of an entirely new form of life, on a world some 890 million miles away from our own.

Though all suggestion of life on any world other than our own remains entirely speculative at this point, Titan, along with all the other worlds I have mentioned in this series of entries, are just a few of the known places, even within our own solar system, that could potentially serve as home for some basic form of life. And with the continued discovery of exoplanets orbiting in the habitable zones of distant stars and even the still fairly recent revelation that oxygen and water are far more abundant on other worlds than was previously believed, the notion that life too -basic life anyway, intelligent life is a whole other story- will eventually prove to be equally common place, seems a reasonable conclusion. For now of course, we'll all just have to wait and see.

-CAINE-

Image credit: NASA/JPL

Newly Identified Lake on Europa Could Increase The Odds it Harbors Life

Though I have concluded that I am not a huge fan of the whole theme-week thing, as I suspected I would not be. There were at least two other planets I had intended to get to during last week's little experiment. Both are places that I think are particularly exciting worlds to ponder because of the unique set of conditions on each. And since it is my blog...

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.

-CAINE-

Source: Wired Science
Image Credit: NASA/JPL