Life On Earth May Have Begun In Comet Craters

A team of geochemists from Trinity College Dublin’s School of Natural Sciences have published a paper outlining their evidence for a possible new theory about the origins of life on Earth. According to the team’s paper, published in the journal Geochimica et Cosmochimica Acta, chemical evidence left in the basin of comet impact craters may hold the keys to determining where and how life began. The study centers around a study of the composition of the crater wall of Canada’s Sudbury Basin, thought to be the oldest and second-largest impact crater on Earth.  

This theory proposes that shortly after a comet struck the Earth’s surface and formed the Sudbury crater, sea water rushed into the crater where it met with superheated rock melted by the comet's impact. This combination of molten minerals and saline water is capable of producing many different organic compounds, some of which can potentially create life-forming molecules. Balz Kamber, Chair of Geology and Mineralogy at Trinity College Dublin, told Science News Journal that his team’s findings suggest that the interaction between salt water and molten minerals in impact craters such as the Sudbury Basin might be the source of the building blocks of life:

On the modern earth, this is the one place where fresh volcanic rock and shallow bodies of magma are commonly emplaced in seawater. The new study suggests that sub-aqueous impact structures could also provide suitable environments and that rock-water interaction at such sites needs to be studied in the context of synthesis of complex molecules.

These findings are important because they shed light on how organic molecules can form through natural processes such as comet impacts or hydrothermal eruptions. Sites like the Sudbury Basin are perfect for these types of studies because they represent what are known as microhabitats -small, isolated areas that have developed their own ecosystems.

This study is the first to look solely at impact craters as being a source of life, as opposed to deep sea hydrothermal vents. While this study might lean towards the theory of panspermia, which argues that life on Earth has extraterrestrial origins, the authors acknowledge that it is still uncertain whether life developed on its own in these craters or if it was brought in by surrounding sea water.