Titan has a hydrologic cycle... with Methane instead of water.

[msbae]

http://blogs.discovermagazine.com/badastronomy/2009/08/27/titanic-fog/

Well, at least now we know Earth isn't the only world in the universe with a climate cycle that affects some kind of liquid...

 

[SilentP]

Hmmm, even though for now they're not considering that this fact means there's life on the moon, but is it...'feasible' that there could lifeforms existing on a methane rather than water base? I'm not expert in biology or chemistry so I don't know if you could supplant water for methane in biological reactions, but then again it could be a whole different ball game with the conditions* on Titan over Earth.

*By they way, anyone knows what the word equivalent of 'planetary' for a moon? If there is one, that is.

 

[msbae]

Not a clue.
​

 

[Asbo Zaprudder]

By they way, anyone knows what the word equivalent of 'planetary' for a moon? If there is one, that is.

The word "satellite" can be used as a noun or an adjective.

http://dictionary.reference.com/browse/satellite

 

[SilentP]

By they way, anyone knows what the word equivalent of 'planetary' for a moon? If there is one, that is.

The word "satellite" can be used as a noun or an adjective.

http://dictionary.reference.com/browse/satellite

So for example instead of saying 'planetary conditions' we say 'satellite conditions'?

 

[Asbo Zaprudder]

So for example instead of saying 'planetary conditions' we say 'satellite conditions'?

Yes. I admit it's hard to parse if you're not used to "satellite" being used as an adjective.

 

[Zachary Smith]

The big problem with the idea of methane instead of water-based life (as I see it) is the issue of hydrogen bonding. Hydrogen bonding is necessary for proteins and complex organic molecules and is a process that may not even be chemically possible to happen when methane is substituted for water.

The Role of Hydrogen Bonding in Proteins, DNA and Nucleotides:

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

Hydrogen bonding also plays an important role in determining the three-dimensional structures adopted by proteins and nucleic bases. In these macromolecules, bonding between parts of the same macromolecule cause it to fold into a specific shape, which helps determine the molecule's physiological or biochemical role. The double helical structure of DNA, for example, is due largely to hydrogen bonding between the base pairs, which link one complementary strand to the other and enable replication.
In the secondary structure of proteins, hydrogen bonds form between the backbone oxygens and amide hydrogens. When the spacing of the amino acid residues participating in a hydrogen bond occurs regularly between positions i and i + 4, an alpha helix is formed. When the spacing is less, between positions i and i + 3, then a 3subscript 10 helix is formed. When two strands are joined by hydrogen bonds involving alternating residues on each participating strand, a beta sheet is formed. Hydrogen bonds also play a part in forming the tertiary structure of protein through interaction of R-groups.

When you try to substitute methane for water, hydrogen bonding becomes problematic for the following reasons:

http://www.wiley.com/legacy/college/boyer/0470003790/reviews/pH/ph_water.htm

WATER

METHANE

All the vertices on the methane that form the points of a pyramid are occupied by a hydrogen. However, only two vertices in water are occupied with hydrogens. The other two vertices are each occupied by a lone pair of electrons. This fact causes the water molecule to have a bent molecular shape. Oxygen is highly electrophilic (electron loving). This means that even though the oxygen in water is bound to each of the hydrogens by a covalent bond (sharing a pair of electrons), the oxygen "pulls" the shared electrons closer to itself. This unequal sharing of the electrons in the O-H bond in water causes the hydrogens to have a partial positive charge (positive dipole), and the oxygen has a partial negative charge (negative dipole). Water is called a polar molecule because it has a positive side and a negative side, called a dipole moment. In contrast, the carbon in methane shares electrons equally with the 4 hydrogens. Methane's does not have a dipole moment, and in contrast with water is non-polar.

Water molecules, then, have both a partial positive and a partial negative charge. Since opposites attract, this means that water molecules are attracted to each other, like the positive and negative ends of a magnet. Because of these attractive forces, water molecules are in close proximity to one another, making water very dense. Methane molecules do not have a dipole attraction for one another, and therefore and are spaced farther apart.

As such, it may not even be possible for methane to form the proper bonds that allow the formation of complex proteins and organic molecules, even though it ACTS like water in a chemical sense on Titan. The charges are (probably) wrong for it to FUNCTION like water in any biological fashion.

 

[FrankR]

The big problem with the idea of methane instead of water-based life (as I see it) is the issue of hydrogen bonding. Hydrogen bonding is necessary for proteins and complex organic molecules and is a process that may not even be chemically possible to happen when methane is substituted for water.

Sorry I have to say it.

It's life Jim, but not as we know it.


-frank

 

[Zachary Smith]

The big problem with the idea of methane instead of water-based life (as I see it) is the issue of hydrogen bonding. Hydrogen bonding is necessary for proteins and complex organic molecules and is a process that may not even be chemically possible to happen when methane is substituted for water.

Sorry I have to say it.

It's life Jim, but not as we know it.


-frank

But does it register on a tricorder?