Water’s origin story, science and sci-fi and more reader feedback
Water from space
A barrage of icy asteroids might have brought water to Earth. In “Water, water everywhere” (SN: 5/16/15, p. 18), Christopher Crockett described how planetary scientists are piecing together the origin story for Earth’s abundant H2O.
To figure out where Earth’s water came from, researchers looked at the ratio of hydrogen to a heavy form of hydrogen called deuterium in water samples from asteroids and comets. But reader Daryl Dubas noted that lots of chemical processes, like photosynthesis and respiration, can create and break down water molecules. “Is it not possible that these processes have some sort of predisposition towards using or creating certain variants of the water molecule that changes the deuterium-to-hydrogen ratio over time?” he asked.