Nile-like River of Liquid Hydrocarbons On The Surface On Titan

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

Titan's Atmosphere Could Be Producing the Basic Ingredients For Life

There are many theories about how exactly life began on our planet. The most commonly held belief of course, is that life began in the oceans. But a recent experiment using radio waves to simulate the effects of ultraviolet radiation from the sun striking the top of Saturn's largest moon Titan's thick atmosphere, has shown that life may actually have begun in the sky.

The experiment showed that when the ultraviolet radiation strikes Titan's atmosphere it can break apart molecules in the air, like molecular nitrogen and methane, leading to the production of amino acids and the nucleotide bases which make up DNA and RNA, without the need for liquid water.

More than merely having the potential to redefine how life began on earth, as if that weren't enough, if researchers could confirm the presence of nucleotide bases and amino acids in Titan's atmosphere, it would be one more piece of evidence pointing to the possible existence of life on Titan itself. Which is already seen by many as a potential home for some, perhaps alternative, form of life.

According to planetary scientist Jonathan Lunine, Cassini has already detected heavy ions in Titan's atmosphere which could potentially be the Nucleotide bases and amino acids found in the study, but the particles were too large for Cassini's instruments to identify. Lunine says that confirming these particles are actually being produced in Titan’s atmosphere will require an orbiter that can carry instruments 100 to 200 kilometers deeper than Cassini does into Titan’s haze layer.

-CAINE-

Source:Wired Science

For more about the potential for life on Titan read: Methanogenic Life on Titan?

More On Titan

While doing some Googling for my next entry I stumbled upon this Flash presentation on Titan from NASA's Planet Quest page and I thought I would share. The presentation begins with video and narration covering most of the facts about Titan I discussed in my own entry on the moon. After this overview is complete, or even before it's complete if you're the impatient type, you can then move on to a 3d global view where specific features have been highlighted and can be clicked for additional images and information. There is also a quick fact tab for general statistics such as it's radius and mass as well as a latest images tab and additional links to other sites relating to Titan at the bottom of the page.
-CAINE-

Methanogenic Life on Titan?

Saturn's moon Titan is one of my absolute favorite objects in our solar system. The above image, taken by the Casini spacecraft using infrared imaging to cut through Titans thick atmosphere, reveals the sun glinting off the surface of what are believed to be standing lakes or even an ocean of methane near Titans north pole. The largest of Saturn's moons, Titan is the only natural satellite known to have a dense atmosphere,1.19 times as massive as Earth's, and is the only object other than Earth for which clear evidence of stable bodies of surface liquid exists.

Titan's dense hazy atmosphere made it impossible for the first probes to pass near enough to image the moon to penetrate through to the surface, until The Cassini–Huygens spacecraft reached Saturn on July 1, 2004 and began the process of mapping it's surface by radar. On January 14, 2005,The Huygens Probe touched down on the surface of Titan after a three hour descent through the moons thick atmosphere, revealing that many of the moon's surface features seemed to have been formed by flowing liquid. Now, new evidence has arisen seeming to suggest there may be life on Titan, or so the headlines would have you believe. But as with the recent hype surrounding the creation of so called synthetic life, the evidence for life on Titan has been greatly exaggerated for the sake of a story.

The first thing you need to understand is that Titan is extremely cold, around minus 290 degrees Fahrenheit or minus 179 degrees Celsius, so water cannot exist on the surface of Titan in liquid form. That means any organism that did live on Titan would have evolved to use a substance which would remain liquid at those temperatures, methane being the most likely candidate. While there are liquid-water-based microbes on Earth that thrive on methane or produce it as a waste product, methane based life remains speculative.

All of this speculation is the result of two recently released papers based on the analysis of chemical data returned by the Casini spacecraft. The first paper by Darrell Strobel suggests that hydrogen molecules flowing down through Titan's atmosphere are disappearing on the surface. The second paper by Roger Clark maps hydrocarbons on Titan's surface and finds a surprising lack of acetylene. Both substances would be essential to methanogenic life which would use hydrogen as we do oxygen and could potentially consume acetylene as food, thus accounting for the seeming lack of each substance in Casini's data. Could all this be evidence that methane based life exists on Titan? Absolutely. But as always Occam's razor applies and it's far more likely that further analysis will reveal a less spectacular reason for the seeming anomalies.

Here on earth, the existence of creatures living hundreds of feet below the ice in the arctic, thriving in poisonous lakes in under ground caves or living in sulfur vents in the deep ocean make it clear that life can adapt to most anything, and I personally believe we will find life outside of Earth. Weather that life will be as simple as some alien cave slime or microbe or as exotic as silicone based lifeforms thriving in oceans of methane I certainly don't know. But as tantalizing as it may be, it's too soon to say that Casini's most recent findings represent proof of such life on Titan.
-CAINE-


First, check out the Space.com and Universe Today articles on this story, which were my primary sources for today's entry then, this video from the ESA which condenses the hours of data the Huygens probe collected down to 4 mins and 40 seconds.(The sounds added to this video get annoying you might want to consider muting it.)

Video posted by Youtube user:nequest
Image Credit:NASA