Ancient World
How Fossils Are Dated: Rock Layers, Ash Beds and Isotopes
A dinosaur bone carries no date stamp. Geologists read the layers around it and the slow ticking of uranium and potassium in volcanic ash to work out its age.
Tag: fossils
Ancient World
How Big Was Megalodon? New Size Estimates and Why They Changed
The biggest shark that ever lived is known mostly from teeth the size of a hand. Here is how scientists estimate its size, why the numbers keep changing, when it died out, and why it is not hiding in the deep sea.