The gargantuan number comes from crunching data on photosynthesis, other means of converting carbon dioxide into organic matter
17 Oct 2023
From bacteria to blue whales, the number of cells in living things exceeds the estimated number of sand grains on Earth by a factor of a trillion. It’s 1 million times larger than all the stars in the universe. And the number of cells that have ever lived is 10 orders of magnitude larger still, according to new estimates researchers reported last week in Current Biology. These calculations aren’t just an exercise in superlatives. They could also help scientists better understand our planet’s fecundity and predict how lifeforms may use carbon in the future.
“These efforts are absolutely indispensable,” says Rob Phillips, a biophysicist at the California Institute of Technology who was not involved with this work but has collaborated with some of the authors. Quantifying such baselines is crucial to scientists’ ability to ask meaningful questions. “Simply counting and measuring things [is] the difference between being able to do science versus not.”
Peter Crockford, a geologist at Carleton University, and his colleagues began their inventory by combining existing estimates of the number of microbes currently in the ocean, soil, and Earth’s subsurface with the number of cells in larger organisms. The result was the number of cells alive today. That number—an eye-popping 10^30 cells, the majority of them cyanobacteria—was the starting point for calculating the total number of cells that have ever lived.
https://www.science.org/content/article ... yaZ6UQ-_9g
These microbes, called cyanobacteria, helped jump-start life on Earth—and their cells outnumber those of all other organisms. FRANK FOX/Science Source
