While scientists like to bandy origin of life theories around, they seldom make the connection to astrobiological research. These theories, however, have a lot to suggest about how life may have developed on other worlds. According to recent studies, low-density vesicular volcanic rock material like pumice might have acted as something like a natural laboratory for chemical reactants that produced the so-called primordial soup. Early geological records show that pumice clasts were abundant in the approximate 3,460 Ma era period.
Samples collected from the Pilbara region in Western Australia exhibit signs of carbon. Traces of titanium oxide and iron sulfide were also found in the samples. Both of these are catalysts for certain reactions that suggest basic life processes. Other researchers have pointed to aluminosilicate minerals in the geological samples, which might be some sort of remains left by prokaryote life forms. Early prokaryotes might have colonized the clasts before they were buried, and therefore what scientists are currently examining are modified forms of what would have otherwise been regular rocks.
In any case, these are some of the earliest examples of life forms currently known to researchers. By examining these samples, it’s somewhat same to assume that a profile can be put together of what substances to look for when searching for remnants of life in astronomical materials. Asteroids are probably what have been covered the most in these studies, but they aren’t the only places to search. If a meteorite were to strike Earth that resembles these clasts, it would pretty exciting nevertheless.
When taking soil samples from other planets, researchers haven’t always been sure what they’re looking for. The Viking probes on Mars attempted to incubate microbes, and this proved relatively fruitless. However, future missions could instead try to locate geological samples that resemble those collected from the Pilbara region. There are plenty of samples in laboratory storage facilities anyway, and these could be examined without any real problems if permission could be granted to scientists.
That’s assuming that evolution takes an identical path on every planet. While some people might suggest this is a shortsighted way to look at the problem, it does have the benefit of making the fewest assumptions. Either way, there’s no reason not to take a look at existing rock samples to see if they match any of these chemical configurations. There’s little risk, and the benefit for a pretty impressive reward if successful.
Martin D. Brasiera, Richard Matthewmana, Sean McMahonb, Matt R. Kilburnc, & David Wacey (2013). Pumice from the ∼3460 Ma Apex Basalt, Western Australia: A natural laboratory for the early biosphere Precambrian Research, 224, 1-10 : 10.1016/j.precamres.2012.09.008