Re: Other Life Forms - what to expect?

[Dan Fiscus <***>]

John,

So water may be specific rather than general. I am not
sure of the details but will look at the article. Water is
pretty darn special in terms of its properties - heat
capacity (specific heat), latent heat of fusion, latent heat
of evaporation, density (with maximum at 4 deg. C),
surface tension, dielectric constant, dipole moment,
viscosity, transparency (these from a class I took on
Enviro. Geochem., one that almost killed me by the way
so I am no expert). Many of these properties help and
even co-conspire to help with environment in terms of
Henderson's Fitness of the Environment for life. I'd be
curious to see how other solvents, media, thermal
masses might compare.

But, even if water is optional, variable, non-generic...
what properties, qualities, relations, associations of life
might be more generic? My top nominee is coupled
complementary process. I think life anywhere - even if
hydrocarbon based instead of water - would have pairs
of interdependent, impredicative (causal loopy with no
primacy, like chicken and egg) processes/functions
analogous to these:

1. autotroph with heterotroph - composer with
decomposer

2. male-female

3. dual hemispheres of brain - rational with emotional

4. binocular parallax - to see that third dimension

5. bilateral symmetry - with ears, nostrils, limbs,
organs, etc.

Some ideas...partly borrowed from Bateson among
others.

Dan


John M wrote:
>  believe we have to prepare for serious re-thinking on "life" unless we 
> restrict ourselves to the wet Earth.
> Nature's recent article (excerpts only):
>
>
>     Titanic life may bloom without water
>
> Philip Ball
>  
> *Hydrocarbon seas on Saturn's moon could be a solvent for biological 
> molecules.*
> ...does life depend on water? Or could it be that Earth life has evolved 
> to suit its watery home? Anything we might recognize as life probably 
> needs a liquid solvent to transport molecules and bring them together. 
> But who says the solvent must be water?
> ...Benner and his colleagues argue (Organisms should be comfortable in a 
> hydrocarbon ocean) in /Current Opinion in Chemical Biology/ that 
> water-free environments on other worlds might fulfil the conditions for 
> life^1 <http://www.nature.com/news/2005/050131/full/050131-2.html#B1> 
> . (Benner S. A., Ricardo A. & Carrigan M. A. /Curr. Opin. Chem. Biol./, 
> *8*. 672 - 689 (2004). 
> ...Titan looks like the best candidate for non-aqueous life. It seems to 
> have rivers and oceans (of hydro-carbons), and its sticky surface is 
> apparently made partly from organic molecules. (reactive nitrils).
> ...So it's not obvious that water is special, apart from the fact that 
> it exists in large quantities on Earth.
> *
> Nasa restricted its plans to bodies with water for life.
> Our ways of thinking about biology seem to need a rather fundamental 
> refurbishing.
>  
> John M
>