The impact layer as a geological time bookmark

36:54>> cool, right? >> Yeah, yeah. It actually took um Luis Alvarez, who um he's mentioned in the Oppenheimer movie. We're going to do a special on all the scientists of the Oppenheimer movie and we're going to rank them. You're going to see where he falls, but Luis Alvarez, um he's one of Lawrence's PhD students. Mhm. And he actually later on in his life, he started doing lots of random stuff. Like he did this Chicxulub crater thing. He also mapped the pyramids. Like once he won his Nobel Prize in physics, he was just doing side quests. And each side quest was like, "Wow." You know? That's awesome. So, anyways, um so so that's what we normally do, right? Now, that's built on an assumption. This this

37:36whole sediment thing, right? You take the zero and then you you like figure out where the fossil is and where the sediment how much sediment is. From that, it's it's built on the assumption that um the rate at which sediment is deposited is the same before and after. Okay. Now, that's not entirely true, right? Because if there's a giant mass extinction, >> Right. all your trees are dead, all your plants are dead, there's going to be more erosion, so there's going to be faster sediment being deposited. So, you might have an over or an underestimate on when actually these plankton got where they are. That makes sense. So, how do you resolve this discrepancy? Yes. What they did was they used the radioactive