Helium-3 and how scientists measured recovery speed

38:13isotope helium 3. This is an incredibly rare isotope. So, already, this piqued my interest because helium 3 is incredibly rare. It's the It's one of the most expensive substances on Earth because helium 3 is used for very specific industrial applications. For example, if you have a something called a dilution refrigerator, which is what you use to cool down things like quantum computers, you require a lot of helium 3 in order to do that. Helium 3 is two protons, one neutron, instead of normal helium 4, which is two protons, two neutrons. That's the more stable isotope. Here, you've got helium 3. That's an isotope, right? And if you look at the dynamics of helium 3, helium

38:543 actually accumulates in the ocean sediments at a steady rate. Uh-huh. So, when the sediment builds up slowly, you're going to have higher concentrations. >> Mhm. But, if it's being deposited really fast, you're going to have lower concentrations in that layer of sediment that whatever core that you drilled, >> Mhm. right? So, by looking at the relative abundance of helium 3 versus helium 2 or like whatever not helium 2, obviously, but like, you know, other elements that it could decay into, we can figure out what was the rate at which the sediment was being depen- deposited. Because the helium 3's abundance level is correlated with the rate of sediment sediment accumulation.

39:34>> Exactly, yeah. The faster it gets accumulated, the lower the density, right? Because it doesn't have enough time to really pile up. And so, from that, they got the KP boundary location, you know, that layer of um meteorite like layer, >> Mhm. they got they got samples from that layer of sediment all the way from Europe, North Africa, and the Gulf of Mexico. >> Oh, interesting. So, all over the planet. >> Yep. And they looked at this helium 3 data Yes. to figure out what was the sedimentation rate. >> Yes. And from that, they actually figured out that the normal plankton species that we usually think about, it's called P.

40:15Ujubina. I hope I'm saying that right. I don't really know how plankton um is pronounced honestly. >> think it's pronounced Chum Bucket. I'm not Yeah, yeah, exactly. Yeah, but this normal plankton species that we normally look for um showed up about 3.5 to 11,000 years after the Chicxulub Chicxulub impact. >> Mhm. So, that's already pretty fast. >> Yes. There were certain species there were that there were certain species that appeared fewer than 2,000 years after the asteroid strike. Mhm. And that's pretty ridiculous. >> Yeah, no, that's very ridiculous. >> Right?