What Is The Purpose Of Life?

This question has been debated by people throughout the ages, but here's a novel answer:

The purpose of life is to hydrogenate carbon dioxide.

Say what? The chemical equation is a little complex, but in short: The atmosphere of the primeval earth had a LOT of carbon dioxide in it. The interior of the planet had (and still has) a lot of free hydrogen in it. These two molecules would "prefer" to get together as hydrocarbons (such as methane) because they would be in a state of higher entropy if they did so. This is kind of like saying that two marbles put in a bowl would prefer to roll together at the bottom of the bowl...but there's a catch. In order for CO2 and H2 to combine, they actually need a little boost of energy first - imagine that there's a little lip on the bowl, and one of the marbles is stuck in the groove of it, so that the bowl needs a little jostle for the marble to hop over and roll to the bottom to join its companion.

CO2 and H2 can combine inorganically via a geochemical process called serpentinization (producing a kind of rock known as serpentine) - but biological processes are MUCH more efficient. Witness: all the hydrocarbons we've been pumping out of the earth's crust and burning were once living organic matter. And the carbon dioxide crisis we're creating by burning oil and coal is, essentially, running the evolution of our planet's atmosphere in reverse. Way back at the beginning of life on this planet, the air was great for trees but not so hot for animals to breathe. Yet another reason to pay attention to how we play around with the chemical balance of our environment.

Read more here: How Life Arose on Earth, and How a Singularity Might Bring It Down via scientificamerican.com