The Rise and Fall of the Dinosaurs: The Sunday Times Bestseller, The Untold Story of a Lost World

by Steve Brusatte

Beginning the moment a rock solidifies, its unstable potassium starts changing into argon. As this process continues, the accumulating argon gas becomes trapped inside the rock where it can be measured. We know from lab experiments the rate at which potassium-40 changes into argon-40. Knowing this rate, we can take a rock, measure the percentages of the two isotopes, and calculate how old the rock is.

I always wondered how they did this.

Most famous of these is surely Iguanodon, one of the very first fossils to be called a dinosaur, after it was discovered in the 1820s in England.

This kind of thing is all too common in China and in many other parts of the world (although it is often against the law). It is heartbreaking to think of the fossils that have been lost to the dark underworld of illegal dealing and organized crime.

I had no idea that this stuff happened!

how much force it required: 13,400 newtons, equivalent to about 3,000 pounds. That’s a staggering number—about the weight of an old-school pickup truck. By comparison, humans exert a maximum force of about 175 pounds with our rear teeth, and African lions bite at about 940 pounds.

This Jurassic hybrid was named Archaeopteryx, and it became a sensation. Darwin included it in later editions of the Origin of Species as evidence that birds had a deep history which could be explained only by evolution.