Subscribe free to our newsletters via your
. 24/7 Space News .

Subscribe free to our newsletters via your

Methane World Is Truely Titanic

Titan continues to puzzle scientists who speculate about whether the darker regions are oily lakes. Credit: NASA/JPL.
by Astrobioogy Magazine
Moffet Field CA (SPX) Jan 20, 2005
University of Hawaii astronomer Toby Owens spoke with Astrobiology Magazine shortly after the successful Huygens mission had completed. In this second part of the interview, Owens talks about the significance of methane in Titan's atmosphere.

Astrobiology Magazine (AM): You said that one thing that was particularly intriguing about Titan was its thick nitrogen-methane atmosphere. Do you think that the data that Huygens has collected going through that atmosphere is going to enable the science community to figure out how and why Titan got its atmosphere, and why other bodies didn't?

Toby Owens (TO): I hope it will. That was one of our major goals. But it's not going to be easy. In other words, it's going to be one of those studies where you don't get a single data point that suddenly illuminates the landscape for you. You have to put together all the different results that you get. And we're just in the early stages of doing that.

For example, one of the clues to the history of any small-body atmosphere, including the Earth, is the amount of noble gases in the atmosphere - argon, krypton, xenon - and their relative abundances.

Because they're very heavy, so they don't escape easily, and they're inert, so they don't combine chemically with what's in the rocks. Once you get them in the atmosphere they stay there. So they give you a kind of record of what sort of volatiles have come out of the ground or have been brought to the planet.

We're very eager to see what that record is on Titan.

AM: Will the data from the Huygens GCMS (Gas Chromatograph/Mass Spectrometer) be able to tell you that?

TO: That's one of the main goals of the GCMS, yes. Another goal is to look at the isotopes: nitrogen, carbon, and oxygen. We have some indications already from the so-called INMS, the ion neutral mass spectrometer on the Cassini spacecraft, which went through the upper atmosphere [of Titan], and we'll get more data because [Huygens went] down inside where the densities are higher.

So we already know that there's been quite a lot of escape. Some gases have escaped; others have not.

The difference suggests that methane, for example, must be continually resupplied to the atmosphere - which we were pretty sure was the case already, because you can calculate that it's disappearing as a result of photochemical reactions. The lifetime of what's there, the amount of methane there, is only 10 or 20 million years.

It might be that we just happened to come along just before it disappears, but nobody liked that idea very much. Now that we have the isotopes, it shows us that the carbon isotopes are completely normal, whereas the oxygen and the nitrogen show the escape. So, again, the methane couldn't have been there a long time. It must have been resupplied relatively recently.

AM: Methane seems to be a key to Titan. But it's been somewhat puzzling that methane clouds appear to be concentrated at the south pole of Titan, which is not what most researchers expected.

TO: That whole issue came up from ground-based observations just in the last five years. When people began to see these clouds over the south pole, and only over the south pole. And that was very strange, because nobody could understand why that should be.

We still don't. Now we're seeing clouds in other places as well. But still there's this tendency for more clouds at the south pole. It is odd.

AM: Now that you have these images from the landing site and the initial methane data from the descent, to what extent is the picture fitting together, and to what extent is it still a little odd?

TO: Well, initially, as I guess you're aware, there was some talk that the whole surface of Titan might be covered by a global ocean. Then we came to realize that was not the case. Ground-based observations showed that there was a big bright area on one hemisphere that didn't exist on the other, so it could only be half-covered by oceans.

Then we got better ground-based data that showed that there are dark and light areas, and the best you could hope for was some seas. And now we're getting down to lakes, maybe.

It's getting tough. But what we're seeing so far is that in these images we don't have a clear indication of open bodies of liquid hydrocarbons - yet. We see some intriguing possibilities, things that look like lakes or seas.

But we don't know that they're liquid. They're just very dark and very smooth. So we don't yet have the evidence we want. But assuming that they are, or even without that, we do see these river channels, which indicate that liquids have been flowing over the surface. And those liquids must be the hydrocarbons.

AM: The channels couldn't be formed by ice? It couldn't be glaciation?

TO: No. It's much too cold for that. It won't make these little channels. You could get a massive movement of ice, but at these temperatures I don't think you'd even get that. You have to warm it up somehow to do that. And there seem to be places where that has happened. The equivalent of hot springs or something like that.

It's not a passive world. There is some internal energy that's being dissipated and causing these geological formations. It's not rivers of water running around. But it's rivers. And it looks like it's liquid hydrocarbons, which is what we expected.

AM: I know it's a little early in the process, and I know it's difficult to interpret things right off the bat, but when you see the panoramic mosaic of the Huygens landing site, what do you see?

TO: Well, I'm from Hawaii, and what I see is surf. It really looks to me as if there is a shoreline, with waves along it. But that's just a visual impression, and my impression is no better than yours.

AM: That's what I saw, too, actually. But then it got described as ground fog, so I thought, Okay, maybe it isn't surf. Will it be possible to distinguish between those two by studying the data?

TO: Yes. Eventually it will. But I think it could well be a combination of the two. That's what we have on Earth, frequently.

AM: So this would be a hydrocarbon fog?

TO: Yeah. You just have to get used to the idea of methane and ethane being liquids - which, of course, we do on the Earth all the time. I was just reading about how people are now shipping gas as a liquid.

They cool it down to condense it, and they put it in these big refrigerated tankers - my god! - and they ship it across the ocean. So Titan does it for us. All we have to do is get a hose out there.

Related Links
Search SpaceDaily
Subscribe To SpaceDaily Express

Targeting Titan
Moffett Field CA (SPX) Jan 19, 2005
University of Hawaii astronomer Toby Owens is one of the original planners of the Cassini-Huygens mission to Saturn and its moon Titan. Astrobiology Magazine's editor Henry Bortman spoke with Owens shortly after the successful Huygens mission had completed. In this part of the interview, Owens talks about the history of the mission and the reasons scientists were interested in exploring Titan.

Thanks for being here;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.

SpaceDaily Contributor
$5 Billed Once

credit card or paypal
SpaceDaily Monthly Supporter
$5 Billed Monthly

paypal only

Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News

The content herein, unless otherwise known to be public domain, are Copyright 1995-2016 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement All images and articles appearing on Space Media Network have been edited or digitally altered in some way. Any requests to remove copyright material will be acted upon in a timely and appropriate manner. Any attempt to extort money from Space Media Network will be ignored and reported to Australian Law Enforcement Agencies as a potential case of financial fraud involving the use of a telephonic carriage device or postal service.