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Groundwater could have naturally occurring chemical elements, such as arsenic, that come from bedrock.

They are theorised to have burnt brilliant but brief lives, forging in their nuclear cores the heavier chemical elements known in nature today.

Next, they used a special technique involving heavier versions of chemical elements that occur in nature as tracers to track the microbial processes.

At this time, the universe was made mostly of hydrogen and helium and very low abundances of other chemical elements, such as strontium and barium.

Catching planets in the act of forming is important because astronomers can glean information not only about the formation process, but how chemical elements get distributed throughout a planetary system.