Re: Study suggests Titan may hold keys for exotic brand of life


"Jason H." <exosearch@xxxxxxxx> wrote in message
news:1127268963.530634.111130@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
> Release - Study suggests Titan may hold keys for exotic
brand of life -
> Southwest Research Institute (SwRI) News (Sept. 8,'05)
>
> http://www.swri.org/9what/releases/2005/titan.htm
>
> "Saturn's moon Titan has long been a place of interest to
> astrobiologists, primarily because of its apparent
similarities to the
> early Earth at the time life first started. A thick
atmosphere composed
> primarily of nitrogen and abundant organic molecules (the
ingredients
> of life as we know it) are among the important
similarities between
> these two otherwise dissimilar planetary bodies.
>
> Scientists have considered it very unlikely that Titan
hosts life
> today, primarily because it is so cold (-289 degrees
Fahrenheit, or
> -178 Celsius) that the chemical reactions necessary for
life would
> proceed too slowly. Yet previously published data, along
with new
> discoveries about extreme organisms on Earth, raise the
prospect that
> some habitable locales may indeed exist on Titan.
>
> In a paper being presented at the Division for Planetary
Sciences 2005
> Meeting this week, a team of researchers from Southwest
Research
> Institute (SwRI) and Washington State University say that
several key
> requirements for life now appear to be present on Titan,
including
> liquid reservoirs, organic molecules and ample energy
sources.
>
> Methane clouds and surface characteristics strongly imply
the presence
> of an active global methane cycle analogous to Earth's
hydrological
> cycle. It is unknown whether life can exist in liquid
methane, although
> some such chemical schemes have been postulated. Further,
abundant
> hints of ice volcanism suggest that reservoirs of liquid
water mixed
> with ammonia may exist close to the surface.
>
> "One promising location for habitability may be hot
springs in contact
> with hydrocarbon reservoirs," says lead author Dr. David
H. Grinspoon,
> a staff scientist in the SwRI Space Science and
Engineering Division.
> "There is no shortage of energy sources [food] because
energy-rich
> hydrocarbons are constantly being manufactured in the
upper atmosphere,
> by the action of sunlight on methane, and falling to the
surface."
>
> In particular, the team suggests that acetylene, which is
abundant,
> could be used by organisms, in reaction with hydrogen gas,
to release
> vast amounts of energy that could be used to power
metabolism. Such a
> biosphere would be, at least indirectly, solar-powered.
>
> "The energy released could even be used by organisms to
heat their
> surroundings, helping them to create their own liquid
> microenvironments," says Grinspoon. "In environments that
are
> energy-rich but liquid-poor, like the near-surface of
Titan, natural
> selection may favor organisms that use their metabolic
heat to melt
> their own watering holes."
>
> The team says these ideas are quite speculative but useful
in that they
> force researchers to question the definition and universal
needs of
> life, and to consider the possibility that life might
evolve in very
> different environments.
>
> "Possible Niches for Extant Life on Titan in Light of
Cassini-Huygens
> Results" will be presented September 8 at the Division for
Planetary
> Sciences 2005 Meeting in Cambridge, United Kingdom.
Grinspoon, Dr. Mark
> A. Bullock, Dr. John R. Spencer (SwRI) and D.
Schulze-Makuch
> (Washington State University) performed the study with
funding from the
> NASA Exobiology Program using published results from the
> Cassini-Huygens mission. This project is not otherwise
affiliated with
> Cassini-Huygens.
>
> (I've left off the contact info, which can be found at the
above link.
> I originally saw this on Marsbugs Newletter.)
>
> Jason H.

Great stuff, Jason. These are the kind of thoughts I've been
having about Titan myself for a long time. Recent
confirmations, tentative or not, of the chemicals in the
local Titan environments are beginning to make such thoughts
more and more likely, all the time. My own thought as to an
appropriate liquid medium for life to begin and thrive is
that liquid ammonia alone would have been a potentially good
polar solvent on its own, even absent water--that both
compounds are present on Titan (along with so many other
compounds that have OOL potential also) is just (Titanic)
gravy! :)

Scientists like Grinspoon et al. will bring even more people
and related ideas to the table which is a good thing for OOL
studies in general. There are heady times ahead for
astrobiology I suspect. ...tonyC


.

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