Strontium-90 is not good news. It emits ionizing radiation, which means you want to keep it out of our body. Unfortunately, your body has other ideas. The body’s own mechanisms welcome this isotope in, and store it away.
Every sixty million years, the biodiversity of our planet's oceans mysteriously crashes. This strange boom and bust cycle goes back 500 million years, and we now might know why: rising continents make the oceans too shallow for species to survive.
Your teeth can reveal a lot about you - including where you grew up. They're also the part of you that's most likely to endure long after you've died. Now some ancient teeth are revealing dating habits that date back a million years.