Earlier this year, the long-standing theory that the "building blocks of life" on Earth were seeded by meteorites got a big boost when NASA examined the ancient space rocks known as Monahan and Zag. Now, new research from the University of Hawaii suggests that phosphorus, another key chemical for life, could have formed in space and fallen to Earth with comets.
For life (at least human life) to form, we need DNA, and two of the chemicals essential to its formation are phosphates and diphosporic acid, which form the basis for chromosomes. What's interesting about phosphorus and its many forms is the transformation it goes through on the way to becoming an essential part of life: according to Andrew Turner, the lead author of the study, "On Earth, phosphine is lethal to living beings. But in the interstellar medium, an exotic phosphine chemistry can promote rare chemical reaction pathways to initiate the formation of biorelevant molecules such as oxoacids of phosphorus, which eventually might spark the molecular evolution of life as we know it."
To figure out how phosphorus oxoacids might form in space, Turner's team simulated material and conditions similar to those found on comets, including creating grains of ice and exposing them to ionizing radiation. The outcome of the experiment was the formation of the oxoacids the scientists were looking for, providing a strong case for the theory that comets hold essential elements for life within their icy bodies, and that they might be responsible for life on Earth.
According to Cornelia Meinert, from the University of Nice: "Since comets contain at least partially the remnants of the material of the protoplanetary disk that formed our solar system, these compounds might be traced back to the interstellar medium wherever sufficient phosphine in interstellar ices is available." In other words, our solar system may have been brewing these compounds for a while before they came to Earth, and there might be even more out there if they haven't already found their way onto a planet or moon."