Backgrounds and the 2013 discovery

49:30the background neutrinos are a challenge. There's so many neutrinos that are coming in. So how do we filter out? Well, there's three ways that we can do this. One is direction. Just look for the ones that are coming up from the ground because they had to go through the earth. And so at least we know that those mostly aren't atmospheric. Another one is containment. We require most of the event to be inside the detector. It needs to start inside the detector and hopefully most of it is contained inside. And the third is energy. We can just filter out the low energy ones and be like these high energy ones are definitely not. Just because based on our power spectrum that we had earlier, these high energy ones definitely

50:11have to be outside. And so in 2013, IceCube reported two events with deposited energies of one petaelectron volt. That was huge for the world because this was the first time that we were having access to neutrino detections at that scale. That was the whole point of IceCube. And so it was really a big triumph. It was only two or three years after IceCube had gone online. And that kind of matches the one event per square kilometer per year. The math actually ended up being in practice. Yeah, it's like, oh, we detected the two events that we would have expected. And on the right hand side, you can actually match the distribution of like how many we were

50:56seeing at each of these different energies. The blue is our model for what the atmosphere and the smaller neutrinos background would look like. The red is how we're fitting the data for the extra galactic origin. And what we're seeing is the data is matching the sum of these two curves, right? The blue for the smaller energies and the red for the larger energies because the larger energies are what we actually care about. Modeling matters. Modeling matters, especially in particle physics. They do a lot of it. Yeah, and it's great when your tools map to see.

51:37This goes back to this not a black box thing we talk about often. So we now understand what the sort of end product of this Nobel Prize was given for, which is this neutrino observatory. It made these landmark detections within two years after coming online. Which is, it's better than what they were trying to do with Higgs boson, but that's a whole nother story. And I still think we come back to where we started, which is the whole purpose of this in the word observatory is to try to understand and map everything around us. And we landed on a limitation, which still leaves me with the question, where are they coming

52:20from? Because what we want to know is what is this object that's generating these energies, that's generating this amount of speed, such that when we detect it, it's in that peta volt, peta- Peta electron volt. Peta electron volt scale. Which we've seen like the two we just discussed. That's right, and that was the whole point, right? Yeah. Now with the 2013, the two that were detected there, right?