Carbon is the foundation for all life on Earth, so finding it on other planets always excites scientists. The Curiosity Rover on Mars recently discovered an unusual mix of the chemical element, which may theoretically indicate to the presence of alien life. That isn’t a given, but it is a possibility. It’s one of three possible explanations for the carbon found in sediment in the Gale crater throughout a nine-year period from August 2012 to July 2021, according to researchers. Curiosity burned 24 powder samples to separate individual molecules, revealing a wide range of carbon 12 and carbon 13 isotope mixes: the two stable carbon isotopes that potentially indicate how the carbon cycle works.
What’s remarkable about these variances – some samples loaded with carbon 13 and others severely depleted – is that they point to mechanisms that aren’t like those formed by the carbon cycle in the present age. “The quantities of carbon 12 and carbon 13 in our Solar System are the same as they were when the Solar System was formed,” says Pennsylvania State University geoscientist Christopher House. Both exist in everything, but because carbon 12 reacts faster than carbon 13, the carbon cycle may be deduced by comparing the relative levels of both in samples.
That leaves the third hypothesis, which is that methane produced by biological activities was once converted by ultraviolet light or bacteria, and that we’re looking at carbon created as a byproduct of life. We’ll need more proof to know for sure, just like the other two alternatives, but there are some parallels on Earth. Of course, Curiosity mission continues. The discovery of microbial mats, large methane plumes, or signs of long-lost glaciers in the future would aid scientists in determining which of these three theories is most likely.