A hidden world revealed: Titan

By Phil Plait | October 12, 2011 9:29 am

We’ve sent space probes to every planet in our solar system (and if you’re a die-hard Pluto fan, you only have to wait 4 more years). And yet there is still much to see, much to explore. Not every world gives up its secrets easily, and perhaps none has been so difficult to probe than Titan, Saturn’s largest moon. Bigger than Mercury, second only to Jupiter’s Ganymede, Titan has an atmosphere of nitrogen so thick it has twice the Earth’s air pressure at its surface.

That thick, hazy atmosphere is impenetrable by optical light… but infrared light can pierce that veil, and the Cassini space probe is well-equipped with detectors that can see in that part of that spectrum. And after 7 years, and 78 fly-by passes of the huge moon, there are enough images for scientists to make this amazing global map:

Pretty awesome. And making this animation was a huge effort. First, not all of the passes were at the same distance, so scientists had to resize the images to match the scale. Cassini passed at different times of day for the local regions, so the sunlight angle changed, making illumination and shadowing different. The atmosphere of Titan is dynamic, changing with time, so again compensations must be made. It’s painstaking work, but the results are truly incredible:

In this false-color map, what’s shown as blue is actually light at a wavelength of 1.27 microns — very roughly twice the wavelength the human eye can detect. Green is 2 microns, and red is 5 microns, well out into the infrared. When the final images are combined, what show up as brown regions near the equator are actually vast dune fields, grains of frozen hydrocarbons rolling across the plains in the relentless Titanian winds. White areas are elevated terrain. Near the north pole, only barely visible, are smudges on the map that have been shown to be lakes — literally, giant lakes of liquid methane!

So Titan has air, lakes, and weather. Sound familiar? It’s not exactly Earth-like, since the temperature there is roughly -180°C (-300°F), but the similarities are compelling. And Titan is loaded with organic compounds like methane, ethane, and more. A complex chemistry is certainly possible there, but complex enough to have formed life? No one knows. Just a few years ago I don’t think anyone would’ve taken the possibility seriously, but now… well, I wouldn’t rule it out.

Remember, these maps only show global features, and even though Cassini dropped the Huygens probe onto the surface, it saw a tiny fraction of what there is to see on this moon, which boasts over 80 million square kilometers of territory. That’s a lot of land. What else is there to find there?

[UPDATE: Just to be clear, this is the first global multicolor map of Titan; a map in single color was done in 2009.]

Credit: NASA/JPL/University of Arizona/CNRS/LPGNantes


Related posts:

- Lakes on Titan?
- A Titanic wink confirms otherwordly lakes
- Watch out, Titan! Vader’s onto you!
- Titanic slice

CATEGORIZED UNDER: Astronomy, Cool stuff, Pretty pictures

Comments (31)

  1. D Hunt

    What’s the radiation like on Titan? I seem to remember reading, though I can’t find where now, Jupiter’s magnetic field produces a great deal of ionizing radiation on its moons. Does Saturn do the same?
    Mostly I’m wondering if there’s radiation on Titan that might be a barrier to the formation of life there.

  2. D Hunt

    Woops, accidental double post.

  3. Theron

    More and more event for the X-Games 2112 — volcano surfing on Io, liquid methane jet ski-races on Titan….

  4. Chip

    What a difference from when I was a kid glimpsing Titan through a telescope, a faint dot that almost required averted vision to see and wondering what it was like on the surface!

  5. Mark

    This reminds me of those crude maps that early astronomers made of Mars; hand-drawn, imprecise, but lovingly crafted with years of patience and care. They might be replaced in ten or twenty years with something of the same quality that we have of Mars, but we’ll look back on this as a very proud first step.

    And musing about the image itself… I wonder if that band across the center has anything to do with it collecting dust from Saturn’s rings. It’s certainly an odd formation, like the ridge on Iapetus.

  6. Dragonchild

    Here’s an idea: Instead of a probe that gets dropped, let’s make one more designed for splashdown in a lake. It’d be very unlike any mission before, but we do have experience with splashdowns in water! It would target a lake on approach, detach from its transmitter (the Cassini to the probe’s Huygens) and then glide into the atmosphere. In the final stages, borrowing a book from pond-loving insects, it would hone in on (infrared) light polarized by the reflective surface and dive at it so it wouldn’t need to be controlled remotely. Then drop a camera UNDER the surface and see what’s there. Biggest challenge would be to design a probe that can both glide and dive, like a seagull. (Maybe we should call it Mehve?)

    The point here is that the lakes have only been confirmed indirectly. We’ve seen enough rocks; I think there’s a lot to be learned by diving into an extraterrestrial lake and seeing what’s under the surface.

    P.S. I am aware Huygens was designed to be capable of aquatic splashdown; the difference is that it was dropped like an unguided bomb whereas this probe would actively seek out a liquid surface to dive into.

  7. Jason

    I am not sure of the radiation levels on Saturn, I don’t think the magnetic field is as powerful as Jupiter, but if you are going to postulate life, why not life where the radiation, or perhaps movement through the magnetic field provides the necessary energy? Perhaps simple life could incorporate ferrous crystals that would generate an electrical potential to get chemical reactions going. That far from the sun and deep in an atmosphere something besides sunlight will be needed to provide energy for life.

  8. CR

    Regarding indirect evidence of lakes on Titan, we have direct evidence: a couple of years ago, Cassini caught a glimpse of reflected sunlight from one of the lakes… follow the “A Titanic wink…” link at the bottom of today’s entry.

    Mind you, that’s from orbit, and I for one would love to see a floater sent to get right into the thing. (Why did we only equip Cassini with a single drop probe? Aside from mass vs fuel costs and such, of course? That’s like sending a news crew to film a big breaking news story, but giving them a still camera with only one frame available to take any pictures…)

  9. CR

    By the way, I love how in the animation above, you can see not only mighty Saturn pass by, but a few of it moons as well.
    I’m guessing it (along with the background stars) was added for effect, but it is similar to all those pics of the various moons passing each other, whic Phil has posted about so many times.
    Still, I wonder how many uniformed readers out there might not actually read the text in the video and assume this is a ‘real’ video, or that Titan actually looks like those colors because they don’t know it’s a false-color map…

  10. I am very interested in the chemistry that is going on there. I wonder if we tell the congresscritters that there is a huge suply of petrolium products ready for their taking, if they would fund it? Hmm?

  11. Anyone else get Google ads for bankruptcy attorneys at the bottom of this video? Gotta wonder why Google thinks it’s related.

    Even stranger(?), the three ads are “Bankruptcy Atty”, “Sue Debt Collectors”, and “Online Project Mgmt. Cert”.

  12. GK4

    Is that an impact crater I see?

    In the image above, it’s in the upper left corner in the upper left image. In the 2009 map, it’s around latitude 15 north and longitude 15. There’s another, larger one at latitude 25 north and longitude 85, too.

    There might be another, but I think I might be suffering from crater pareidolia.

  13. rob

    that’s no moon, it’s a … oh, nevermind.

  14. Who else remembers the obviously patched-together pictures from the Sixties of, I guess, Mercury? I’m surprised that the edges in this globe weren’t smoothed like everything else nowadays.

  15. lqd

    @Dragonchild–

    The TiME (Titan Mare Explorer) mission has been proposed for the next low-cost Discovery Program mission. It would land and float in a Titanic sea.

    http://en.wikipedia.org/wiki/Titan_Mare_Explorer

  16. JB of Brisbane

    Eagerly awaiting Google Titan. ;-)

  17. Jason Perry

    @GK4: the one at latitude 15 north and longitude 15 is Sinlap, most definitely an impact crater. The other is Menrva, an impact basin. Good eyes.

    BTW, thanks to Phil for updating his post about our ISS map of Titan. We should have a version for 2011 up in the next few weeks.

  18. What’s the huge linear feature at 0.18 in the video, or in the upper-left image??? Black is basin and white is upland, IIRC, but why in a straight line for 40% of the circumference of the globe?

  19. @ ^ Jason Perry : Thanks & congrats! :-)

    Neat map – but by “elevated areas” do we mean actual hills and mountains and plateaux or something else? This has a bit of a jigsaw puzzle look about it too – but is still excellent & appreciated. :-)

    Is the black patch at the pole (north presumably) just an area that we don’t have any data on yet?

    Will there be more refined, higher resolution maps to come (please!) – & perhaps seasonal ones if it turns out Titans lakes grow and shrink and features change on a seasonal basis?

    (Wonders how it compares with the geography described in Baxter’s ‘Titan’ novel – click on my name for wiki-link – & whether we’ll ever land there and see for ourselves in person one day.)

  20. @11 Ken – Google adds are tailored to the viewers browsing, or try to be. I got auto parts, telescopes coatings and EMS training ads. Scary. Maybe they throw out bankruptsy ads when they don’t know you history so well, figuring with the current economy they might get a hit or sixty.

  21. Can we terraform it to be more temperate?

  22. The Lonely Sand Person

    That’s… amazing! Go Cassini go!

  23. Don

    Can’t we get the probe to slap up a big ass billboard and have Coke™ pay a trainload of cash for the advertising? :)

  24. Joseph G

    Titan is so fascinating. It’s like a Mr. Freeze version of Earth, with rain and rivers and lakes and even (they think) volcanism, but all with the operative fluids being those that are liquids at cryogenic temperatures. It’s even got a mostly nitrogen atmosphere, at the closest pressure to Earth’s of any body in the solar system (about 1.5 atmospheres).

    If we ever encounter intelligent life that’s methane/ammonia based, we’ll be able to make mucho moolah by selling them real estate on the balmy, scenic paradise that is Titan :D

  25. Joseph G

    This is so cool! I have to echo the sentiments of others who say this reminds them of the early maps of Mars.

  26. Joey

    And, what about possible bioengineering of Titan to where temperatures could be raised by mirrors on a satellite, and other technologies of the like. Could man with our more rapid science advancements put into better position more possibilities of life-like scenarios here??

  27. Grant

    Those dark areas are hydrocarbon-oceans, right? They look like oceans to me.

    Similar-quality image of Earth:

    http://www.flickr.com/photos/gsfc/4482476686/

  28. Matt B.

    Could we get the guy that did that amazing composite of Mercury to work on this? It’s so messy I can barely get anything out of it.

    We need to figure out different adjectives for Saturn’s moon Titan and Uranus’s moon Titania. Right now, they’re both “Titanian”, but once both worlds have been colonized, it’s only a matter of time before it’ll have to go to the GalCouRaNaConRes*.

    *Galactic Court for Race Name Conflict Resolution, from The Nitpicker’s Guide for Next Generation Trekkers.

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