At the north pole of Saturn’s largest moon Titan lie the largest (and only known) bodies of surface liquid in the Solar System outside of Earth. But on Titan, where temperatures are regularly around negative 300ºF, the liquid isn’t water but rather methane and ethane: compounds which are found as gases here on Earth. Titan’s seas and lakes are exotic environments that scientists are only just starting to understand, and even with radar imaging by NASA’s Cassini spacecraft there’s a lot we just don’t know about them. But one thing some researchers have managed to figure out using simulated Titan environments in the lab is that these lakes may sometimes fizz with bubbles of nitrogen—potentially explaining some of the mysteries of Cassini’s observations.
“Thanks to this work on nitrogen’s solubility, we’re now confident that bubbles could indeed form in the seas, and in fact may be more abundant than we’d expected,” said Jason Hofgartner of JPL, who serves as a co-investigator on Cassini’s radar team and was a co-author of the study.
Read the news straight from NASA here: Experiments Show Titan Lakes May Fizz with Nitrogen
One of the biggest clues to finding evidence of life on Mars – past or present – has been the existence of methane, an organic compound that is the principal component of natural gas here on Earth. Methane can arise via both biological and non-biological processes, but in both cases it can be used as “food” for living organisms (known as methanotrophs.) Methane has been detected on Mars today by both orbiting spacecraft and rovers on the ground, and now researchers have identified methane within meteorites found on Earth that originated from the Red Planet.
While it’s not quite the “smoking gun” for evidence of life on Mars, the recent announcement of a detection of spiking methane levels by NASA’s Curiosity rover has certainly caught everyone’s attention – especially since the activity of microbes is one possible source for the presence of the compound, which has already been detected by spacecraft in orbit around Mars.
“This temporary increase in methane – sharply up and then back down – tells us there must be some relatively localized source,” said Sushil Atreya of the University of Michigan, a member of the Curiosity rover science team. “There are many possible sources, biological or non-biological, such as interaction of water and rock.”
Still, biological in origin or not, these findings are yet another milestone for the MSL mission.
“We have had a major discovery. We have found organics on Mars.”
– John Grotzinger, Curiosity lead scientist
By now you probably know about the lakes of liquid hydrocarbons on Titan. Thanks to Cassini, we know that Saturn’s largest moon is the one other place in the solar system where liquid can be found in stable amounts on the surface, except that it’s not water like we have here on Earth, but rather liquid methane. (Thank you for not smoking!) Now, radar measurements by Cassini show that Titan’s lakes are nearly all found in one 600 x 1100-mile region around its north pole — a true “land o’lakes!”
The animation above, made up of colorized radar data acquired over the past 9 years that the spacecraft has been in orbit around Saturn, takes us on a flyover tour of Titan’s northern lakes region. Fasten your seat belts!
Saturn’s largest moon Titan has often been likened to a primordial Earth, with its thick atmosphere, changing weather patterns, and — most intriguing of all — vast amounts of liquid on its surface in the form of lakes, streams, and rivers. One big difference though: nearly ten times farther from the Sun than we are, temperatures on Titan are a chilly 290 degrees below zero (F) and so the liquid isn’t water, it’s methane… what’s called natural gas on Earth.
Still, methane does a good job replacing water in Titan’s own version of a hydrologic cycle. Methane rain falls to fill streams, carving gullies and canyons through the frozen landscape (where water is harder than rock) and eventually filling methane lakes and seas — some as large as our Great Lakes! Cassini has found evidence of Titan’s lakes in both repeated radar scans as well as visible-light images… but what hasn’t been found yet, strangely enough, are waves on the surfaces of these lakes. If they are indeed liquid methane, and Titan has weather capable of creating rain and sculpting dunes, then why are these enormous lakes so incredibly flat?
As seasons slowly change, Cassini will find out the answer.
Although surface temperatures on Titan are cold enough that methane can exist as a liquid, filling lakes and flowing in streams, it may sometimes get so cold that even the liquid methane and ethane freezes, forming floes and icebergs of frozen hydrocarbons. This Titanic revelation was announced today during the 221st American Astronomical Society meeting in Long Beach, CA.