Has life on Titan been discovered? No.

By Phil Plait | June 7, 2010 1:29 pm

saturn_titan_rings_smThere has been a bit of an uproar the past day or so that scientists have found evidence of life on Saturn’s giant moon Titan. As soon as I saw the press release I knew this was going to be a problem. So let’s be clear:

First, have we found life on Titan? No.

Have we found evidence that there might be life on Titan? Sorta. The results are preliminary and not yet confirmed; in fact, some of the evidence is from computer modeling and has not been directly observed.

Bear in mind as well that evidence is not proof. Evidence just means an observation was made that is consistent with life on the moon, but doesn’t say much else. There are non-biological explanations for the observations as well.

Of course, speculation is running rampant, so much so that Chris McKay, an exobiologist who studies Titan, has released an article clearing things up.

First, a little background. Titan is a monster, the second biggest moon in the solar system at 5150 km (3200 miles) in diameter. If it weren’t orbiting Saturn, it would probably be considered a planet in its own right: it’s bigger than Mercury and Pluto. It has a thick atmosphere, made up of nitrogen, methane, and other molecules. It’s very cold, but it’s known that lakes, probably of liquid methane, exist on the surface.

Five years ago, McKay and other scientists pointed out that if methane-based life existed on Titan, it might be detectable through a surface depletion of ethane, hydrogen, and acetylene. New observations show that this is the case; there are lower amounts of these substances than the chemistry of Titan would indicate.

As McKay points out, "This is a still a long way from ‘evidence of life’. However, it is extremely interesting."

Those are the basics. Go read McKay’s article for details. The point he makes is that the results are preliminary, may yet turn out to be wrong, if they’re right may have non-biological explanations, and we should not conclude biology is involved until we get a lot more evidence.

As far as the media goes, headlines get eyeballs and sell advertisements, of course. But in cases where the news is like this, news outlets should be particularly careful how they phrase things. They know how the public will react to certain phrases, and the phrase "evidence of life" is substantially less accurate and more likely to incite chatter than "evidence for possible life" — and the Telegraph’s technically accurate but seriously misleading "evidence ‘that alien life exists on Saturn’s moon’" is just asking for trouble.

The point is, when it comes to media outlets and big news like this, the phrase going through your head should be a variant of an old one, updated for this modern age:

"Don’t trust, and verify".

CATEGORIZED UNDER: Astronomy, Cool stuff

Comments (63)

  1. Huron

    Rather eerily similar to Stephan Baxter’s novel “Titan”


  2. Peachy

    I, for one, potentially welcome our potential Titanian potential Overlords.

  3. Points all taken, but still…why is it not accurate to say the depletion is possible evidence for life on Titan? We can hardly expect to convince people to stop and read our work with something like, “Extremely Interesting Finding on Titan.”

    So I guess my challenge is: If “possible evidence for life” is not the headline, and is inaccurate, what is the headline? Is there one?

    But I have to just quickly say….A headline is JUST a headline. It attracts attention — I mean, duh, that’s the whole idea — and then when you read the body of the story, it should be explain clearly and accurately. Criticisms of headlines miss the whole point of what science journalists do. We attract (with sexy headline) then pay up with the story.

    But if the lead paragraph, and the rest of the story mislead, yes, that’s wrong.

    Unfortunately, the ever-hungry online copy mouth is so hungry, people are covering anything that comes along. In the stone ages of journalism a decade or so ago, when we still behaved like gatekeepers, we simply didn’t cover a story if it didn’t meet the standard.

  4. ts

    If I recall my 100 level astronomy courses correctly, when we discussed the possibility methane-based life on Titan (and elsewhere) and there was one major problem. At the temperatures at which methane is liquid, chemical reactions are so slow that in the time since the birth of our solar system, it would be seemingly impossible for life to have arisen out of the random chemical interactions that need to happen to form the complex molecules necessary. Now, this says nothing of panspermia, but I recall it being a very convincing argument at least against the genesis of life on Titan.

    Can anyone enlighten me as to counter arguments? Is my memory simply poor?

  5. jjmcgaffey

    “Possible evidence for life on Titan found” would be an acceptable headline. What people are getting is “Evidence of life on Titan found”, which isn’t at all the same thing. And the BA’s “Evidence for possible life” isn’t going to happen….

    And again we’re running into the difference between standard language and scientific language (like ‘theory’) – in standard language, ‘evidence’ means proof (I have evidence that he’s guilty!), though not necessarily solid proof. In scientific language, it means much less than that – there are indicators which could be results of this…or not.

  6. gunslinger girl

    I came across the headline via Fark and I couldn’t click the link fast enough. As soon as I got past the headline my first thought was “How is this even news? Scientists kinda sorta think they have data which may or may not indicate life on Titan.” I don’t remember the exact phrasing but once I get hit with a bunch of speculative opinion, I tap out. The possibility of finding extra-terrestrial life in our solar system *is* exciting, but I’ll hold off on celebrating until irrefutable evidence is verified.

  7. Pieter Kok

    “Evidence just means an observation was made that is consistent with life on the moon, but doesn’t say much else.”

    I would say that evidence for something is stronger than this. Orbiting another body (e.g., Saturn) is consistent with the presence of life, but it is hardly “evidence for life”.

  8. ilostthegame

    Thanks for the clarification Phil. I’m with Peachy. Having other life forms in our solar system would be awesome!

  9. Worst teaser headline ever. ^^

  10. Richard L

    Time to read the original paper from 2005. This is gonna be fun! Astrobiology is so much fun and the original research papers are really easy to read since we haven’t found any life yet so you don’t have to learn a lot of strange new concepts as with mainstream biology or physics (which is fun to read once you’ve learned the concepts but that might take some years of training).

  11. @gunslinger girl
    I love your “How is this even news?” reaction. Spot on!

    Sometimes a story that really should be a longer feature (or even a news feature) gets done as a news item, and people can feel cheated that the headline promised what the body didn’t deliver. In features you can reconstruct the whole trail of investigation and show the relevance or importance of incremental findings like this — incremental, as opposed to definitive, as in “Scientists confirm double helix structure of DNA.”

    In part, science writers “follow the money.” If Chris McKay reports something, our radars go up because we know he does good work and we want to be there to report it. This episode would make a great case study in a j-school in “news judgment,” which is what to report, what not to report, and why.

  12. NAW

    I really wish that the news did not mess up stories like this. It means that the people doing the real work on finding out what is going on have to stop what they are doing to “fix” the damage that the news has done. But at least he did a good job at fixing it. But the cranks out there will still have to be convinced.

  13. Newfie

    *stomps foot*

    Methane-based, or any other based life would make for interesting bio/chem in the future.

  14. Utakata

    My money is on when they do find this to have another explanantion other than life (which is quite likely)…it will most likely be relegated to the back page of a few newspapers as something less than a footnote. /sigh

  15. No, it will be on the front page of “Exobiological Chemistry Today” but not in general circulation magazines and newspapers where non-scientist go to learn about interesting new findings. Operative word being “interesting.”

  16. Brian

    Thanks, Phil. I always like to have your perspective (and pointers to good sources) when these things hit the news.

  17. Billingham

    In any case, this keeps Titan on the list of the Most Interesting Places in the Solar System, along with Mars, Europa, Enceladus, and Amsterdam, right?

  18. Eric

    Well yes, this is hyped a bit. But it is still really, really, really interesting. Evidence for chemical disequilibrium on Titan is pretty cool. It may or may not be a false observation, it may or may not be life, but oh boy is this something important for follow-up.

    BTW: Perhaps we should invite them over to slurp up some tasty hydrocarbons more locally. We seem to have some in excess in the Gulf of Mexico as of late.

  19. Michael Swanson

    OH MY GOD! WE FOUND LIFE ON TITAN! THAT’S AMAZING! I NEED TO TELL EVERYONE I KNOW RIGHT AWAY! I … Oh. It looks like you have to read the whole headline.

    Damn it. Now I look like the internet.

  20. Torbjörn Larsson, OM

    If this bears up though, the fact that McKay’s model predicts three disequilibriums (at least two of which seems observed (ethane: observed, acetylene: observed at least with probe), makes it a likelier explanation. By this measure this is considerably more exciting than finding methane on Mars.

    At the temperatures at which methane is liquid, chemical reactions are so slow that in the time since the birth of our solar system, it would be seemingly impossible for life to have arisen out of the random chemical interactions that need to happen to form the complex molecules necessary.

    Three mistakes here:

    1. McKay’s article describes the research, and how “all the chemical methods suggested for life to derive energy from the environment on Titan involve consumption of hydrogen (McKay and Smith 2005; Schulze-Makuch and Grinspoon 2005). Acetylene, ethane, and solid organic material could all be consumed as well. Acetylene yields the most energy, but all give enough energy for microorganisms to live. [My bold.]”

    2. While evolution (change in populations over time) is independent of abiogenesis (biotic populations from probiotic chemistry), the reverse is not true. It is widely recognized that evolutionary processes of variation and selection is at play in probiotic chemistry (for example as organic macromolecule synthesis respectively photoselection).

    As in evolution selection makes it wrong to describe a locally adaptive change of traits in probiotic or protobiotic chemical populations as “random”.

    3. It is now known since several years that Titan’s methane is photo-catalyzed in the ionosphere to complex molecules at high rates, it is literary raining PAHs and fullerenes there. Some papers models amounts of atomic oxygen reactants trapped in those rained out fullerenes (from radiation trapping), bumping up the available energy even more.

    Therefore there are plenty of energy available and a massive rate of “chemical interactions that … form … complex molecules”.

  21. LSandman24

    “All these worlds are your except… [Titan]”?

    Dangnabbit, now I have to find something else to do with this big, black slab of rock in my back yard. It would be so much easier to move if it wasn’t so full of stars!

    /end nonsensical rant

  22. Chris A.

    How about this for a headline:
    “New evidence fails to rule out alien life on Saturnian moon”

    Okay, I kid. More seriously, what about:
    “Unusual chemistry hints at possibility of life on Saturn’s moon”

  23. Kevin F.

    They’ll have fun designing a rover to explore Titan and search for life. The thing would have to run cold – VERY COLD. Ice worms which live in glaciers here on earth can be burned to death with the touch of your finger – even moreso for Titan life, I’ll wager.

  24. Torbjörn Larsson, OM

    The easiest way to study life is to study dead specimens, you know. Think of them as “fast fossils with a side order of ice”. 😀

    Really, the sample methods used will be killers for most life.

  25. When I read about this yesterday, I was really hoping you’d post about it! And I am very glad you did.

  26. Brian Too

    Funny about language and expectations. The headline certainly didn’t say “Life found on Titan”, so it’s not blatantly inaccurate in that sense. Yet we know that “Evidence of life found on Titan” will be misunderstood as that phrase stands. The headline is misleading. Why? And what’s wrong with that?

    I’d posit that the problem is that it’s a deliberate tease. It suggests far more than the article will deliver. Yet as others have suggested, that’s at least part of the job of a headline.

    In a larger context, newspapers and news outlets that engage in this sort of thing, will find their reputations degraded. One good rule of business is to deliver more than you promise. This language, on a small scale, promises more than it can deliver. That sets the customers up for disappointment, however fleeting.

  27. Buzz Parsec

    Sheesh, so BA (Big Astro) is trying to cover this up already! Where is Hoagland when we need him? 😉

  28. How about this headline:
    Possible evidence for possible life possibly found on Titan, possibly.
    [rolls eyes]
    I agree that the headline writer’s job is to suck people in, but the scientist in me is aghast at that particular headline. Dirty pool, ya know?

  29. Chris Winter

    NBwaW wrote: “Worst teaser headline ever.”

    Forgive the nitpick, but I believe that’s true only for astronomy headlines.

    By way of example, allow me to cite some of the classics.

    * Prostitutes appeal to pope
    * Squad helps dog bite victim
    * City hacks man’s palm

  30. Tyler Durden

    This just in – an important announcement of extraterrestrial life will be made!

    …sometime. Somewhere. Maybe. They’re looking in to it…

  31. Brian

    I read an article on line yesterday about this and I was wondering how long it would take you to comment on it. The article implied that a methane/hydrogen breathing lifeform could exist and that evidence supporting this theory had been found. The author was not convinced, however, and indicated more research was needed. The website address is: http://paranormal.about.com/od/paranormalgeneralinfo/a/news_100605n_2.htm

  32. All the more reason to get another probe there ASAP! And not one that last just a couple hours!

  33. Hmf. I’ll believe it when I see it on a heavily-promoted multi-part series on Discovery Channel, preferably narrated by Mike Rowe. (And the CGI had better be GOOD, too.)

  34. csrster

    “Evidence isn’t proof.”

    Except, apparently, in Danish where they insist on using the same word for both. It gives rise to some very trying conversations.

  35. goofy redneck form kentucky

    do any of you speak a lick of english whats with the BIG WORDS by the way i think theres some kinda life out there do u really think were the only ones all that space and we’re the only lifeforms give me a break

  36. Messier Tidy Upper

    Nicely done BA & still very intriguing news far as I’m concerned. :-)

    @22. Chris A. Says:

    How about this for a headline: “New evidence fails to rule out alien life on Saturnian moon”Okay, I kid. More seriously, what about: “Unusual chemistry hints at possibility of life on Saturn’s moon”

    Or just “Hints of life on Titan?” for a possible best headline which is shorter and more accurate? IMHON. 😉

    @ 1. Huron Says:

    Rather eerily similar to Stephan Baxter’s novel “Titan” [link snipped.]

    Good book with some good astronomy & science generally in it, but OM FSM that was a bleak grim read.



    Aside from the final section which didn’t quite fit unless you go for the “dying dream” option. Note to the author in the highly unlikely event he reads this : Killing off the two most sympathetic and appealing characters, Siobhan Libet and Nicola Mott, was not a good move. :-( (In My Humble Opinion, Natch)


    However, I wonder how plausible Baxter’s plan for getting people to Titan using pretty much the technology we have now – the last of the shuttle gear plus a few extra bits – really is? Does anyone know if that plan could seriously work (as Baxter made it sound halfway plausible) or whether it was just a fictional “McGuffin” plot device?

    Have any studies at all been done into the feasibility of human exploration to Titan?

    I’d love to see humans go there. I’d happily volunteer myself provided there was plenty of reading material onboard for the long trip! (I can be happy anywhere if I’ve got a good book to read!) 😉

  37. The real question-will they ignite in an internal combustion engine?

  38. ts

    @Torbjörn Larsson Thanks for the explanation! I took the course I was referring to 10 years ago, and it seems we’ve learned quite a bit since then. Though the choice of the word ‘random’ was poor, I did, however, understand that those processes are not truly random. I was referring more to the unknowns in likelihood of biogenesis. Truthfully, I’m thankful I remember anything at all from a course that long ago.

  39. Torbjörn Larsson, OM

    ts, you are welcome!

    Yeah, I should have written “purely “random””. Contingencies, there are many: 4 or 6 legs – or more?

    “Evidence isn’t proof.” Except, apparently, in Danish where they insist on using the same word for both.

    Swedish too. “Bevis är inte [… is not …] bevis.”

    But you can get around that ambiguity, in the same way that cold weather and hot weather is still weather. Worse is that people’s thinking frame is influenced by (and influences, natch) language. So one has to make the point first.

    Very trying conversations, at times.

  40. Jeff

    The article I read didn’t say life had been found (although the headline implied it). It pretty much said the same thing as you – evidence of possible life has been found.

  41. JMW

    I seem to recall hearing about a story published many years ago in the Miami Herald, the paper with the 4th largest circulation in the US (at that time), when Cuban boat people landed on Jupiter Island off the coast of Florida.

    The headline read
    “Aliens Land on Jupiter”

  42. Gary Ansorge

    42. JMW

    “Aliens land on Jupiter” is a classic. How about the road sign that said “Eat and get gas”

    Gary 7

  43. steve oberski

    It’s obviously an interstellar refueling station.

  44. Theron

    So, would it be safer to send a probe to Titan than say Europa to hunt for life? I’m thinking about the possibility of Earth organisms contaminating the local biosphere. Though if you showed me an Earth-based micro-organism capable of thriving in a cold methane enviroment, I’d hardly be surprised.

  45. God bless the Titanian methanimals {proposed word sounding in my head like “me-thane-imals”, not “meth-animals”}, contingent both on the existence of God and of methane-based life forms on Titan. In the absence of God, I will bless them. In the absence of Titanian methanimals, God bless terran life {and any other life that may be Out There}. In the absence of both, I will bless all the Universe’s life.

  46. Pi-needles

    It is one of my life’s regrets that I never photographed a sign that said :

    “Petfood Pizza”

    in my neighbourhood while it was up for many years.

    (Products offered by two separate sho[ps but still .. 😉 )

  47. Jim

    Interesting definition of “evidence”. I prefer the one that Observation is Evidence – and thus is the only real proof. There IS something chemically interesting going on. As to what the mechanism for that might be, THAT is open to debate.

    Still, it is nice to have people thinking about it, including the basic question “just what evidence should we be expecting from methane-compatible life?”

  48. amphiox

    Really, the sample methods used will be killers for most life.

    Like how the old Viking experiments for detecting life would have slaughtered any hydrogen peroxide based organisms on Mars, if they had existed.

  49. vince charles

    Jim, observation is definitely NOT evidence- at least, not bulletproof evidence. Do some googling on “ontology” and “epistemology,” and find out why science has always been considered an “imperfect science” by philosophers and pure mathematicians. Hence, science has no “real proof” at all- in any form, at any time.

  50. TheInquisitor

    Rule of Acquisition 190: “Hear all, trust nothing”

  51. XPT

    I think what you pointed out in your post was pretty clear to anyone with a little knowledge in science. Although I’m still very hopeful about it. Finding microbes anywhere outside our Earth will be (yes I’m sure it will happen) one of the biggest events in human history.

  52. Blizzarrrg!!!

    I prefer the version used by Captain Dylan Hunt…something like “If your mother tells you she loves you, get verification.”

  53. Martin J Sallberg

    Before you start talking about life being the least likely explanation, you should doubt what you mean about a line of demarcation between life and non-life. Some form of hydrogen-consuming catalyst appears to be conclusively proven. Why is that catalyst so abundant? Since the catalyzed process produces energy, that energy can possibly create other chemical reactions nearby. If some of those reactions create new hydrogen catalysts, which is not unlikely, soon there would be plenty of that form of hydrogen catalyst. That is actually the MOST probable explanation for the apparent abundance of hydrogen catalysts. Is it life? That brings up the doubt about demarcation. Anything that can in some way evolve falls on a continuous “lifeness spectrum”, as shown by discoveries of viruses parasiting on other viruses, “giant” viruses (though smaller than true bacteria) with their own metabolism, and molecular exchanges normally associated with non-living complex organic chemistry in prokaryotes, which evolution have eliminated in eukaryotes. The latter is probably a holdover from the early chemical evolution. So even if the cold, methane instead of water environment on Titan may have slowed down evolution so that it is not as far-evolved on the “lifeness spectrum”, it is nonetheless on the biological continuum.


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