Re: Subject: Astrobiology: Living breathing planet w/o H2O?

Hi Kevin,
I've seen Alien Planet! Its a very fun show and the website is great as 
well!  As much research went into this show we must always be careful to 
draw the line between science and science fiction.  It's true that I too 
have not seen much water on this fictious planet and I'm not sure if the 
shows intention is to have life witout "water" as we know it 
hydrogen2oxygen or H2O.

In fact when looking for "life" on other plantes one of the criteria is 
the presence of water. Whether it be the geographical signature of dried 
up river beds and streams or iced capped mountains. No one believes that 
life cannot exist without this crucial liquid.  Comets have been found to 
not only have water, but also some basic essential components of life 
(the factors that make up proteins, amino acids).

In fact, there has never been a chemical compound found on a planet or in 
a comet or meteorite (that I know of or have heard of) that is new to the 
periodic chart of elements. From 1 proton to 109 protons (the last dozen 
or so being made synthetically in laboratories and lasting only fractions 
of a second!)  Otherwise every element of life, their characteristics 
(melting points, boiling points, crystal structure, electron maps etc) 
are all well characterized.  This along with the fundamental laws of 
thermodynamics and the biological laws of evolution pretty much tell us 
what is and what isn't possible in "life" as we know it.  Therefore, I'm 
pretty safe to say that life without water is extremely impossible.

Now, what is carbon-based life? Simply put, the element carbon is 
the base or foundation of life on this planet.  If you look at all the 
molecules (chemicals with more than two atoms) that create life, all have 
carbon assiocated with them.
The major biological molecules are:
1) lipids
2) amino acids
3) nucleic acids
4) steriods
5) sugars

All of these conatin carbon as their backbone structure.  A quick look in 
any biology text book will detail this.

Lipids make up not only nutritional fats, and soaps, but are also the 
foundation of our cellular membranes.

Steriods and sugars compose many structures in the cell and body and help 
the all organism in a variety of ways.

Amino acids make up all proteins which function a multitude of tasks in 
the body

Nucleic acids are the basis of DNA; the genetic factor in all living 
organisms.

All these essential components are made up of Carbon (C) with Hydrogen 
(H), Nitrogen (N), Oxygen (O) and sometimes Phosphorus (P) coming off of 
the carbon atoms.

These elements are some of the must essential elements that make up life, 
but its carbon that serves as the backbone for all these chemicals to be 
made.

That is what it means to be a carbon based lifeform.

I hope that helps and if you still have questions feel free to ask again 
or explore any biology textbook and the internet!

Matt