Like Dissolves Like Millions of Miles Away

One of the main reasons scientists study space is to find signs of life on other celestial bodies. This is also the basis for why Mars gets so much attention. Out of all the celestial bodies known to us, it is the one most likely to contain life. The reason why Mars has the possibility of containing life is that it has a strong possibility of having water on its surface. Water is considered the most essential part for life to exist for a few reasons. For one, every organism on Earth needs water to survive. Another reason is that all of the organic compounds that make of living things work well with water.

This makes sense because most of the organic compounds that are necessary for life are polar, such as glucose. Even some of the compounds that are not polar have high molar masses. Due to their high molar mass, these compounds have large London Dispersion Forces (LDF). Solubility of molecules depends on their intermolecular forces (IMF). Solvents with high IMFs dissolve solutes with high IMFs and vice versa; this is the “like dissolves like” rule. This why water, a polar molecule, can dissolve all of the organic compounds that organisms need to break down for food. What if organisms used compounds and solvents with lower IMFs?

New research about Titan, Saturn’s moon, proposes this same theory. Titan contains liquid and gaseous methane in its atmosphere and on parts of its surface. Scientist proposed a theory stating that there is a possibility that organisms on Titan could use methane as their organic solvent instead of water. Since methane is nonpolar and has a low LDF, compounds that are nonpolar and have low LDFs would be needed for the methane to be useful. Acetylene is a compound that scientist believe could be used in place on glucose if this theory were proven true. Since, this follows the “like dissolves like” rule, this concept is quite plausible.