A window into Titan

By Phil Plait | October 14, 2011 10:35 am

I know I just posted a global color map of Saturn’s moon Titan, but sometimes it’s cool just to take a step back and look at a picture that gives a little context… and it doesn’t hurt that it’s a moody grayscale shot, too:

[Click to encronosenate.]

This shot of Titan was taken by the Cassini spacecraft back in August, and shows the moon superposed on Saturn’s rings, seen here almost — but not quite — edge-on.

The fact that you can see surface detail on Titan is a dead giveaway this shot was taken in the infrared: optical light, the kind we see, can’t penetrate the thick, hazy, nitrogen/methane atmosphere blanketing this moon. Infrared light gets through, though, so surface features can be seen. In fact, this image was taken using a filter that lets through light at 938 nanometers (the reddest light the human eye can see is about 750 nm). Methane is pretty good at absorbing light at a bunch of different wavelengths, but at 938 nm it’s transparent, so this is a particularly good place in the spectrum to look at Titan — astronomers call it the "methane window". Not only that, but this image also employed a polarizing filter, which blocks a lot of light from the atmospheric haze, making the surface easier to see (it also makes rainbows appear and disappear, too).

Not that the atmosphere is completely invisible in this picture: look around the moon’s edge and you can just see some of the upper atmospheric layers, and at the top you can easily spot the north polar hood, which may have water ice crystals in it.

And that dark region on Titan’s surface? It may have once been the bed of a methane sea, but now it’s a dry, vast area of wind-blown dunes, hydrocarbon grains collected by the Titanian winds. It’s called Shangri-La, and that makes me smile. I’m not sure anything at -180°C could be called a human paradise, but for astronomers, it’s certainly a scientific one.


Related posts:

Polarized rainbow, what does this mean???
In astronomy, a polarizing view is good
Watch out, Titan! Vader’s onto you!
A hidden world revealed: Titan

CATEGORIZED UNDER: Astronomy, Pretty pictures

Comments (18)

  1. James

    So since optical light cannot penetrate the atmosphere we would have a hard time walking around the surface wouldn’t we? Besides the other problems like cold…

  2. Paulo Matos

    Ahahah, you’ll love this as you’re into Pareidolia.
    I can see the face of Billy ( http://en.wikipedia.org/wiki/Billy_(Saw) ) on Titan. Looking down direction south-west. :)

    What about you?

  3. Bill Davidson

    Do you know what the temperature is at Titan’s surface ? I know in the past that it was assumed that the ammonia/water layer might be fluid, which would suggest roughly -98 Celsius at a minimum. Does the thick atmosphere help provide enough heat to keep the material fluid? Also, is Titan close enough to Saturn for the tidal forces to cause internal heat?

  4. Mike

    Paradise is a relative term when we’re talking about off-Earth environments. Mars is probably the happiest place for us to settle down, and the Moon gets all kinds of bonus points for being so close (and, of course, for actually hosting humans.)

    But after those two, I’d say Titan is probably the third most hospitable place. The cold is a bigtime problem, of course, but I think we can tackle it more easily than we could tackle the extreme heat of Venus, plus it’s got an atmosphere as close to one bar as we get out there.

  5. Joseph G

    @2 Bill Davidson: Well, Phil GAVE the number in his fancee science-speak “Celsius”. I’ve heard -300 degrees Fahrenheit, what us Real Amurcans use!
    Seriously, I know “teh Wiki” isn’t exactly the sort of thing you cite in a doctoral thesis, but its article on Titan is fantastic, and I believe it contains the answers to your questions. If I remember correctly, the water/ammonia layer is buried and under pressure, which is what allows it to remain liquid.

    EDIT: Apologies if I sounded snarky or sarcastic. “Tone” doesn’t always get conveyed well on the intertoobs. I was going for “silly, with a lot of caffiene in the system”. As I am now :)

  6. Joseph G

    @#3 Mike: I find the idea of colonizing Titan just fascinating. Think of all the chemistry we can do with all those hydrocarbons laying around. The heck with “mooncrete,” we can manufacture plastics till the cows come home.
    I wonder if heat pollution would be an issue? If your habitat is built on “sands” made of chemicals that are liquid (or even gaseous) at Earth temperatures, I’d think that insulation becomes a really important matter, and not just for saving energy! Of course, you need to dump heat to generate power. Might hydrocarbon “bogs” form downwind of large human habitats?

  7. Mike

    @5:

    That is interesting, and I haven’t thought about it before. On earth, it’s roughly the equivalent of keeping all buildings at volcanic temperatures – any heat gets out into the bedrock, and it melts and the whole thing collapses. We do seem to do a fairly good job of containing our ultra-high heat endeavours – we have all kinds of space to vent heat around here. I suppose you still have a lot of space on Titan to soak up the heat.

    I did read one brief description in a novel about life forms that live in cryogenic environments, who basically believed that humans drink lava. After all, water on their planet is a rock-hard mineral.

  8. Pete Jackson

    I presume that these dark areas are unrelated to the dark areas near the poles and considered as liquid or at lease oozy because they don’t return radar images well. Does the infrared detector also see these if it flies over Titan’s pole?

  9. Jason

    I would think that the way around that would be to anchor to something that isn’t going to melt away if it gets close to temps we consider warm. Surely there is some rock on Titan, hopefully near or at the surface that could be used.

  10. Gray, hazy, polluted and cold? It’s a dead ringer for London in the ’50s!

  11. Das Boese

    Nah, you want your structures well insulated anyway, and that thick atmosphere should be fairly effective at removing any excess heat you want to get rid of.

    Put it on stilts like the newest generation of research stations in Antarctica and you should be fine. Power generation could be a problem because that far from the Sun under a thick haze, you’re pretty much restricted to nuclear.

    @Mike: I believe that description is from Stephen Baxter’s “Titan”, which sadly sucks otherwise.

  12. John F

    “The cold is a bigtime problem, of course, but I think we can tackle it more easily than we could tackle the extreme heat of Venus, plus it’s got an atmosphere as close to one bar as we get out there.” I tend to agree- keeping OUT Titan’s atmosphere (which if I’m not mistaken is not “toxic” per se, just thick and lacking oxygen) is not much different than what our submarines and other submersibles do. In space or other near vacuums even a tiny pin prick of a leak can be catastrophic- I think one module in the ISS was completely depressurized in less than an hour as the result of a hole that turned out to be barely visible- Titan’s atmosphere is what 145%? We can equalize to that easily.

    The temperature? I almost hate to say it, but bringing along a naval vessel type nuclear reactor would solve that pretty handily.

  13. Messier Tidy Upper

    Good youclip on Titan here :

    http://www.youtube.com/watch?v=SOKONNaNHkM

    by AggMan UK. :-)

    @11. Das Boese : “@Mike: I believe that description is from Stephen Baxter’s “Titan”, which sadly sucks otherwise.”

    Well, I’m not so sure. Baxter’s Titan novel :

    http://en.wikipedia.org/wiki/Titan_(Stephen_Baxter_novel)

    [WARNING : CONTAINS SPOILERS]

    is one I enjoyed reading and thought had sections that were wonderfully well written and evocative and yet also found incredibly bleak and depressing. It’s a work I have mixed feelings about but I wouldn’t say it “sucked” exactly.

  14. Messier Tidy Upper

    Looks like some grey fruit with dark blotches that’s been impaled on a spit for roasting – that spit being Saturn’s rings! (Yeah, I know, who roasts fruit? But A-n-y-h-o-w.)

    Nice image of an amazing moon. :-)

    One of the most oddly earth-like yet ever so uneathly strange places in our solar system.

  15. Messier Tidy Upper

    @12. John F :

    The temperature? I almost hate to say it, but bringing along a naval vessel type nuclear reactor would solve that pretty handily.

    Unfortunately, you can just imagine the stink the crazed anti-nuclear Luddites would make if that idea went ahead. :-(

    Remember the “controversy” when Cassini was launched with its necessary, tiny supply of Plutonium powering its RTG’s but which sent the anti-nuke hysterics ballistic? :

    http://www.sonoma.edu/users/w/wallsd/pdf/Cassini.pdf

    But you’re quite right though.

    @7. Mike :

    I did read one brief description in a novel about life forms that live in cryogenic environments, who basically believed that humans drink lava. After all, water on their planet is a rock-hard mineral.

    Well, speculation about possible life – albeit likely only microbial – on Titan isn’t limited to SF novels as this link :

    http://blogs.discovermagazine.com/sciencenotfiction/2010/08/25/life-on-titan/

    plus this link :

    http://blogs.discovermagazine.com/80beats/2009/11/23/new-take-on-titan-hints-at-more-fuel-for-potential-life/

    demonstrates.

    Of course, the only way we’ll ever find out for sure whether or not there’s life on Titan (as opposed to, say, just weird chemistry) will be to go there and see for ourselves. Hopefully, we’ll do that one day, would just love to see it happen in my lifetime although that’s looking ever less likely as time goes on.

  16. Das Boese

    12. John F Says:
    “I think one module in the ISS was completely depressurized in less than an hour as the result of a hole that turned out to be barely visible-”

    it was a module of MIR, after being hit with a 7-tonne Progress supply craft. The ISS is fine ;)

  17. Joseph G

    Actually, with that chilly atmosphere to dump heat into, you’re going to be able to build fantastically efficient power plants (nuclear, I assume). Heat dissipation is a big deal in space – look at the size of the radiators just on the ISS.
    @15 MTU: Ugh, don’t remind me. I think Hoagland and his ilk also had some theory about using the RTGs to ignite Jupiter and turn it into another sun. Cripes.

  18. Matt B.

    The large “islands” of white seem to form an elongated skull facing the upper right.

NEW ON DISCOVER
OPEN
CITIZEN SCIENCE
ADVERTISEMENT

Discover's Newsletter

Sign up to get the latest science news delivered weekly right to your inbox!

ADVERTISEMENT

See More

ADVERTISEMENT
Collapse bottom bar
+

Login to your Account

X
E-mail address:
Password:
Remember me
Forgot your password?
No problem. Click here to have it e-mailed to you.

Not Registered Yet?

Register now for FREE. Registration only takes a few minutes to complete. Register now »