If they are finding life & microbes etc. deep deep underground, has anybody done any work regarding the possibility that life first evolved underground and came to the surface via volcanism or other similar mechanism.

Seems to me that the heat underground would provide the energy necessary, rather than needing the sun necessarily.



Last edited by Graeme Lloyd (16th Mar 2008 16:12:05)


Last edited by Graeme Lloyd (16th Mar 2008 16:12:20)

People certainly are interested in where life may have started. Understanding the environment of origin would greatly constrain the mechanism by which such a momentous event could occur.

However, I seriously doubt even the hardiest of the 'extremophiles' you hint at could have survived at the temperatures and pressures present in the depths from which volcanic rocks originate.

Most evidence points to an oceanic origin for life. But how do we arrive at such conclusions?

Life in a basic sense is just a collection of complex chemical reactions that work in tandem to perpetuate itself; something chemists call autocatalysis. Because such reactions only work under precise conditions of pressure and temperature we can use family trees to estimate what kinds of reactions would have occurred in a primitive ancestor and then infer the temperature and pressure this ancestor probably lived in.

One recent paper (http://www.nature.com/nature/journal/v4 … 0.html#abs) suggested a temperature of a little over 70-degrees Celsius near the origin of life, a value that closely fits geologists estimates of ocean temperatures at the time, but is way to low for volcanism.

However, you are certainly right to point out that the Sun was unlikely to have been important here. By all accounts photosynthesis came later.

Last edited by Graeme Lloyd (16th Mar 2008 16:12:30)