Dinosaurs loom large in our imaginations not just because they were in fact enormous, but also they are so ridiculously old. There has always been a big, impenetrable curtain separating us from prehistoric life. Sure, we have some ancient bones, but those had long since turned to stone. Any actual tissue, the stuff of flesh-and-blood creatures, is irrevocably lost, lasting only a few tens of thousands of years in most cases. Maybe a few stray organic molecules could persist for a few million if, say, they were frozen deep within primeval ice.
So, needless to say, it came as something of a shock when Mary Schweitzer discovered that she had some 68-million-year-old dinosaur tissue on her hands.
The find was and is controversial.