You can’t carbon-date stone—but you can date when it was exposed. It’s called luminescence dating. When stone is shielded underground, it's not exposed to cosmic rays. But once it’s quarried and opened to sunlight and air, isotopes start forming. By measuring those isotopes, you can estimate when the stone was last exposed—like the walls around the Sphinx. And what we’re finding? It may rewrite everything we think we know about ancient history. | The Randall Carlson

Have you heard of the carbon cycle? Check out this animated infographic for a quick way to understand this process that is so important to all life on Earth. https://oceanservice.noaa.gov/facts/carbon-cycle.html #30DaysofOcean #OceanMonthNOAA #OceanMonth2021 | National Ocean Service