WEBVTT - Astronomy On Ice 0:00:04.320 --> 0:00:07.600 Get in test with technology with text stuff from stuff 0:00:08.039 --> 0:00:15.600 coming either everyone, and welcome to tech stuff. I'm Jonathan 0:00:15.640 --> 0:00:20.200 Strickland and today's topic comes to us courtesy of a listener. 0:00:20.239 --> 0:00:23.599 Actually I had blogged about this topic. It's the ice 0:00:23.680 --> 0:00:28.639 cube neutrino telescope, and I wrote a little Twitter message about, Hey, 0:00:28.720 --> 0:00:30.800 I got to write about this telescope that's buried a 0:00:30.840 --> 0:00:34.800 mile beneath the ice, And immediately Nick on Twitter said 0:00:35.400 --> 0:00:37.760 you should do a podcast about that, And I thought 0:00:38.159 --> 0:00:41.120 I should do a podcast about that because I've already 0:00:41.120 --> 0:00:43.839 done the research for that thing. That's why you got 0:00:43.840 --> 0:00:48.240 this research out so quickly. Well, you know, repurposing. No, No, 0:00:48.400 --> 0:00:51.840 it's actually here's the thing. Well one, it's buried under 0:00:51.880 --> 0:00:55.800 the ice, so already it's super cool. But I'm sorry 0:00:56.400 --> 0:01:01.880 it's already started. But I genuinely find this absolutely fascinating. 0:01:01.880 --> 0:01:05.920 I mean, it's it's the world's largest neutrino detector, it's 0:01:06.040 --> 0:01:11.039 buried a mile under the ice. It's this is something 0:01:11.080 --> 0:01:13.080 that if you had told me was in a science 0:01:13.080 --> 0:01:16.280 fiction story, I would have said, that's just silly, that's 0:01:16.319 --> 0:01:19.680 a that's a lame bond villain's layer. Yeah, there's no 0:01:19.800 --> 0:01:23.839 way that would really exist, and it totally exists. So 0:01:24.240 --> 0:01:28.240 what is it looking for. It's looking for evidence of neutrinos, 0:01:28.400 --> 0:01:33.600 which are these massless or nearly massless particles with no 0:01:33.840 --> 0:01:36.640 electrical charge. And we'll talk more about them a little 0:01:36.640 --> 0:01:40.160 bit later. Yeah, because specifically it's looking for for interactions 0:01:40.200 --> 0:01:44.039 of neutrinos with stuff. But but well, yes, yeah, because 0:01:44.160 --> 0:01:47.200 as it turns out, neutrinos are a little tricky. But 0:01:47.319 --> 0:01:50.280 they It is at the South Pole, or really it's 0:01:50.440 --> 0:01:56.160 underneath it. It's in Antarctica, and specifically, like I said, 0:01:56.200 --> 0:01:59.640 it's about a mile beneath the surface of the ice, 0:02:00.040 --> 0:02:04.240 between between one and two thousand meters or one to 0:02:04.280 --> 0:02:08.280 one point five miles. Yeah, it's pretty incredible. That's and 0:02:08.320 --> 0:02:12.040 it takes up about a cubic kilometer of ice, which 0:02:12.040 --> 0:02:13.840 is about two thirds of a mile on each side. 0:02:14.280 --> 0:02:18.000 So just imagine an area underneath the surface of the 0:02:18.000 --> 0:02:21.680 ice and Antarctica that is this kilometer by a kilometer 0:02:21.680 --> 0:02:25.760 by a kilometer in in in proportions, and that is 0:02:25.800 --> 0:02:30.120 a telescope. And the reason why it's there is because well, 0:02:30.160 --> 0:02:32.160 there's a couple of reasons. One is that the ice 0:02:32.240 --> 0:02:36.720 provides a medium through which the neutrinos travel, and an 0:02:36.720 --> 0:02:39.960 exceptionally clear medium at that the pressure of the ice 0:02:40.040 --> 0:02:43.160 that deep has has pushed all the air bubbles out, right, 0:02:43.200 --> 0:02:45.920 so it's incredibly clear. And also when you get to 0:02:46.000 --> 0:02:49.680 be about a mile down below the surface, things get 0:02:49.680 --> 0:02:53.000 a little dark, especially when sunlight isn't hitting you for 0:02:53.120 --> 0:02:55.799 what seven or eight months out of the year, right, Right, 0:02:55.880 --> 0:02:59.000 So it's already in a part of the world where, yeah, 0:02:59.000 --> 0:03:00.959 for eight months of the or you have no sun 0:03:01.720 --> 0:03:05.360 and it's a mile down and so it's really really dark. 0:03:05.520 --> 0:03:07.360 The medium it's in is really clear. And both of 0:03:07.400 --> 0:03:12.239 those things are incredibly important. So when was this thing 0:03:12.760 --> 0:03:16.800 actually built? Well, it was proposed in yeah, but um, 0:03:17.200 --> 0:03:20.360 it wasn't actually approved as a project until May first, 0:03:20.480 --> 0:03:24.760 two thousand four. Right, They began building it in December 0:03:24.760 --> 0:03:27.360 two thousand four. They started melting the holes they would 0:03:27.360 --> 0:03:30.680 need to drill down to put the various censors that 0:03:30.720 --> 0:03:33.440 are part of this telescope. Uh, they started drilling those 0:03:33.480 --> 0:03:37.440 on on December one, two thousand four. The very last 0:03:37.440 --> 0:03:42.960 censor was placed in a December, Yes, so six years 0:03:43.000 --> 0:03:45.920 to do a complete telescope. Now they had already started 0:03:45.960 --> 0:03:50.160 to gather information from the censors they had placed up 0:03:50.160 --> 0:03:52.560 to that point, but it wasn't until they did that 0:03:52.680 --> 0:03:55.200 last row in two thousand ten for it to be 0:03:55.280 --> 0:04:00.480 a completed project. So pretty cool. And um, we cost 0:04:00.720 --> 0:04:04.360 you know, a couple of bucks, right, easily two seventy 0:04:04.440 --> 0:04:06.520 one million, as we would say in the old days 0:04:06.520 --> 0:04:10.440 of tech stuff, a princely some most of that money 0:04:10.680 --> 0:04:14.120 was provided by the National Science Foundation. They footed the 0:04:14.160 --> 0:04:17.359 bill for a tune of two forty two million, and 0:04:17.400 --> 0:04:20.560 the rest came from funders from all well, all around 0:04:20.560 --> 0:04:25.640 the world. Really, so it's truly an international effort. It's 0:04:25.640 --> 0:04:30.720 not something that is controlled by one entity. Uh. There's 0:04:30.760 --> 0:04:34.440 a kind of a consortium called the ice Cube Collaboration 0:04:34.520 --> 0:04:38.520 that sort of represents all the different parties involved. Right. 0:04:38.600 --> 0:04:40.760 It has a total staff of about two hundred and 0:04:40.760 --> 0:04:45.400 fifty people from forty one institutions in twelve countries overall. Um, 0:04:45.400 --> 0:04:48.680 it's all led out of the University of Wisconsin Madison, right, 0:04:48.800 --> 0:04:51.039 and some of the institutions that are part of this 0:04:51.080 --> 0:04:53.920 include the University of Delaware. Uh. They designed some of 0:04:53.920 --> 0:04:57.279 the key elements for the project, the Lawrence Berkeley National Lab, 0:04:57.640 --> 0:05:00.839 Clark Atlanta University. Shout out to a low cool school. Hey, 0:05:00.880 --> 0:05:06.320 how about my rival college, Georgia Tech. Uh I of 0:05:06.360 --> 0:05:08.400 course went to the University of Georgia. Georgia Tech are 0:05:08.440 --> 0:05:10.599 are hated enemies. They were part of this as well. 0:05:10.960 --> 0:05:13.200 So we could actually we could literally go down the 0:05:13.200 --> 0:05:16.480 street and probably find someone who works work on the project, 0:05:16.640 --> 0:05:19.080 works on this project, which is kind of exciting. The 0:05:19.160 --> 0:05:22.440 Neils Bore Institute. You might have heard of us talking 0:05:22.440 --> 0:05:25.839 about that when we did our Heisenberg episode. There's also 0:05:25.920 --> 0:05:32.080 Ohio State University, Pennsylvania State University, Stockholm University, University of Alberta, Edmonton, 0:05:32.760 --> 0:05:37.520 University of Canterbury in New Zealand, and Oxford, so among 0:05:37.600 --> 0:05:40.400 lots of others. So, I mean, it's a it's it's 0:05:40.400 --> 0:05:42.240 a really big project and it's something that a lot 0:05:42.279 --> 0:05:46.279 of people, you know, physicists and engineers and computer science 0:05:46.360 --> 0:05:48.960 kids have been really excited to get in on exactly 0:05:49.080 --> 0:05:52.720 and when you start looking into what this telescope does 0:05:52.880 --> 0:05:57.080 and the hesitated used the word, but the scope of 0:05:57.120 --> 0:06:00.400 the project, it's it's you know, it's understandable why people 0:06:00.440 --> 0:06:02.400 are so eager to be part of it. Lauren is 0:06:02.600 --> 0:06:06.599 judging me and grinning and shaking your head. Uh So, 0:06:07.160 --> 0:06:09.360 let's talk about what it is they're looking for. Let's 0:06:09.400 --> 0:06:15.560 talk about these neutrinos, these nearly massless particles. So there's 0:06:15.600 --> 0:06:19.120 sub atomic particles, meaning that they're smaller than actual atoms. 0:06:19.960 --> 0:06:22.440 And what's really interesting about them is is that they're 0:06:22.480 --> 0:06:26.120 they're electrically neutral, yeah, which means that they aren't affected 0:06:26.120 --> 0:06:31.240 by electro magnetic fields or forces exactly. They they So 0:06:31.279 --> 0:06:34.719 if you were to have, say, a positively charged particle 0:06:34.800 --> 0:06:38.880 and ion flying through space, and it happened to come 0:06:38.920 --> 0:06:42.640 either close to another positively charged body, it would be 0:06:42.960 --> 0:06:45.560 repulsed by that and its direction would change, or if 0:06:45.600 --> 0:06:48.240 it came close to a negatively charged body, would be 0:06:48.279 --> 0:06:51.279 attracted to that, and again its course would change, meaning 0:06:51.320 --> 0:06:54.039 that there'd be no way for you to tell where 0:06:54.080 --> 0:06:57.720 that particle originated from because they bounce around. Yeah, they 0:06:57.720 --> 0:07:00.280 could have been moving all over the place. It would 0:07:00.279 --> 0:07:04.040 look kind of like the old Family Circus cartoons where 0:07:04.080 --> 0:07:07.680 Billy's pathway does the little dotted line over the entire neighborhood. 0:07:07.680 --> 0:07:10.840 You just don't know where it came from. But neutrinos 0:07:10.920 --> 0:07:14.160 don't have that charge, so they're not affected by positive 0:07:14.200 --> 0:07:17.360 or negative charges. That won't change the pathway. So to 0:07:17.640 --> 0:07:20.080 you know that they're traveling in a straight line, and 0:07:20.160 --> 0:07:23.960 they're traveling extremely fast. Because they are massless or near massless, 0:07:24.000 --> 0:07:26.840 they can travel right up nosing up to the to 0:07:26.920 --> 0:07:29.160 the speed of light right now. Obviously, if they were 0:07:29.200 --> 0:07:30.920 to travel to the speed of light, that would be 0:07:30.960 --> 0:07:33.440 a problem. According to the theory of relativity, anything with 0:07:33.560 --> 0:07:37.160 mass would require infinite energy to get to the speed 0:07:37.160 --> 0:07:39.559 of light. So it's close but not quite the speed 0:07:39.560 --> 0:07:42.760 of light. And uh, depending upon the medium, it can 0:07:42.760 --> 0:07:46.840 actually travel faster than light within that media, not within 0:07:46.840 --> 0:07:49.840 the vacuum of space, but within the medium of say, 0:07:49.880 --> 0:07:53.000 I don't know ice. This will be important later on. Um. 0:07:53.040 --> 0:07:55.120 But but back to the basics here. Okay, So, so 0:07:55.200 --> 0:07:57.480 we think that they're the second most common particle in 0:07:57.520 --> 0:08:00.560 the entire universe, the first being photons. Right, So the 0:08:00.960 --> 0:08:04.520 fundamental unit of light is more there's more of that 0:08:04.600 --> 0:08:07.080 than neutrinos. But that's the only thing out there besides 0:08:07.480 --> 0:08:11.240 the stuff we can't identify, like dark matter, but we'll 0:08:11.280 --> 0:08:14.080 get into that too, yes, um. And and there's there's 0:08:14.080 --> 0:08:17.600 three basic types of neutrinos or um or flavors as 0:08:17.640 --> 0:08:20.920 they are legitimately called in physics, right, which makes me 0:08:21.000 --> 0:08:24.680 just so excited. So it's vanilla chocolate and rocky road. 0:08:25.000 --> 0:08:29.920 Is that it U close electron, muon, and taw neutrinos alright, 0:08:29.960 --> 0:08:35.040 So electrons, muans and taw are all negatively charged particles. 0:08:35.240 --> 0:08:39.560 Electrons are subatomic particles, thank you. Uh they are the 0:08:39.559 --> 0:08:42.000 electrons I would say are the most familiar to people. 0:08:42.120 --> 0:08:45.360 Everyone who has taken basic science knows the electrons the 0:08:45.360 --> 0:08:48.520 negatively charged particle that you find in atoms. They have 0:08:49.120 --> 0:08:53.480 uh energy shells that they stay in and orbit around 0:08:53.520 --> 0:08:57.040 a eight an atomic nucleus um. So you know those 0:08:57.080 --> 0:09:01.160 were familiar with. Muans and taw are a little more exotic. 0:09:01.320 --> 0:09:04.640 They are actually heavier than electrons, but they also have 0:09:04.679 --> 0:09:07.600 a negative charge. Right, Mulons have about twice the mass 0:09:07.600 --> 0:09:11.360 of electrons, and how have almost four times the massive electrons. 0:09:11.520 --> 0:09:15.160 And now most of what we know about neutrinos really 0:09:15.160 --> 0:09:17.560 only comes from research done in the past couple of decades. 0:09:17.720 --> 0:09:20.520 But we will get to that. Yeah, well you've got 0:09:20.520 --> 0:09:23.760 a whole timeline that was actually really fascinating to me too. 0:09:24.520 --> 0:09:27.320 Once again, it's one of those examples how people way 0:09:27.360 --> 0:09:29.920 smarter than I am are able to figure out things 0:09:30.040 --> 0:09:33.080 about the universe without ever actually seeing any proof of it, 0:09:33.559 --> 0:09:36.480 which is phenomenal with with answers to questions that we 0:09:36.520 --> 0:09:38.400 have not even thought of. Yeah, I would just think 0:09:38.720 --> 0:09:42.120 my equations must be wrong because things aren't equaling out. 0:09:42.200 --> 0:09:44.439 These are people are saying, my equations can't be wrong. 0:09:44.480 --> 0:09:46.400 So something's going on that I don't know about. I 0:09:46.400 --> 0:09:48.880 need to invent a new particle to explain it exactly. 0:09:48.960 --> 0:09:51.400 And it turned out it works. So where do they 0:09:51.400 --> 0:09:54.800 come from? Well, from from a bunch of different places. 0:09:54.920 --> 0:09:58.520 They can come from lots of cosmological events like um 0:09:58.640 --> 0:10:02.280 like like supernova more or even the Sun. Okay, so 0:10:02.280 --> 0:10:05.640 so you know weak stuff, right, this little low power 0:10:06.000 --> 0:10:10.640 now obviously black holes, no big yeah, exactly, little stuff, 0:10:10.679 --> 0:10:14.640 you know, just the things that can rip a galaxy apart. Yeah. 0:10:15.000 --> 0:10:17.640 It turns out that neutrinos can be generated lots of 0:10:17.640 --> 0:10:21.000 different ways. But the ones that we are particularly interested 0:10:21.040 --> 0:10:25.400 in are these high energy neutrinos that would be so 0:10:25.520 --> 0:10:28.640 high energy as to be it would be impossible for 0:10:28.640 --> 0:10:31.520 them to have originated in our solar system, right, because 0:10:31.559 --> 0:10:35.960 we can detect the neutrinos that come to us courtesy 0:10:36.000 --> 0:10:38.040 of the Sun or the ones that are formed within 0:10:38.080 --> 0:10:42.520 the Earth's atmosphere, but the more elusive ones are neutrinos 0:10:42.559 --> 0:10:46.719 that might come from a cosmological event that happened on 0:10:46.760 --> 0:10:49.680 the other side of the galaxy millions of years ago. 0:10:49.920 --> 0:10:54.440 Well and and those those larger events create vastly more 0:10:54.480 --> 0:10:56.920 neutrinos than say, the Sun would create on any given day. 0:10:56.960 --> 0:10:58.560 But since the Sun is so much closer to us, 0:10:58.679 --> 0:11:02.040 we're basically in and did with with neutrinos from the Sun, 0:11:02.120 --> 0:11:06.400 Electron neutrinos specifically um as a byproduct of the nuclear 0:11:06.440 --> 0:11:10.080 fusion that goes on in in the sun where uh 0:11:10.160 --> 0:11:11.600 you know, if you if you hold up your hand 0:11:11.600 --> 0:11:14.280 to sunlight, billions of neutrinos passed through it in a 0:11:14.320 --> 0:11:17.240 single second. Yeah. Now, remember, because these are sub atomic 0:11:17.280 --> 0:11:20.320 particles and they have no mass, these things, they're so 0:11:20.400 --> 0:11:23.320 small and they're moving so quickly, they can pass right 0:11:23.880 --> 0:11:27.360 through what would appear to be completely solid matter. Because 0:11:27.400 --> 0:11:29.319 I don't know if you know this or not, solid 0:11:29.320 --> 0:11:31.720 matter still has gaps in it at the atomic level, 0:11:32.280 --> 0:11:34.760 and so a neutrino can pass right through that, right 0:11:34.760 --> 0:11:38.079 through the Earth, and in fact, billions do every single day. 0:11:38.120 --> 0:11:42.120 So being able to detect these these neutrinos that came 0:11:42.120 --> 0:11:46.120 from cosmological events would tell us more about our universe, 0:11:46.120 --> 0:11:49.160 which is why we're so interested in them. All Right, 0:11:49.200 --> 0:11:52.319 So we've already talked a little bit about how neutrinos 0:11:52.400 --> 0:11:55.079 behave They aren't affected by electrical charge, they move nearly 0:11:55.120 --> 0:11:57.800 at the speed of light. And the nice thing is 0:11:57.800 --> 0:12:00.200 is that if we detect a neutrino and we're able 0:12:00.280 --> 0:12:03.440 to observe the effects that the neutrino has had on 0:12:03.559 --> 0:12:08.360 other atomic particles, then we can draw some information about 0:12:08.400 --> 0:12:11.400 that neutrino, for example, where it may have come from 0:12:11.440 --> 0:12:15.520 and how powerful it was. And so that is why 0:12:15.720 --> 0:12:19.120 we're looking at the cosmological ones versus the ones that 0:12:19.160 --> 0:12:23.960 we would say are emanating from our son um because 0:12:24.040 --> 0:12:28.880 they are so they're they're nearly massless. They're also barely 0:12:28.920 --> 0:12:32.319 affected by gravity, so because that's one thing that things 0:12:32.320 --> 0:12:35.000 with mass do get affected by his gravity. But gravity, 0:12:35.000 --> 0:12:37.680 out of the four fundamental forces of the universe, is 0:12:37.679 --> 0:12:41.240 the weakest, right, So the only real force that tends 0:12:41.280 --> 0:12:44.280 to affect neutrinos is the weak atomic force, but that 0:12:45.000 --> 0:12:49.000 only takes effect at incredibly short distances. We're talking on 0:12:49.040 --> 0:12:51.760 the atomic scale. So this is the kind of stuff 0:12:51.800 --> 0:12:55.520 that holds atoms together. And so unless you're unless you're 0:12:55.600 --> 0:12:58.040 is close to and I forget the exact distances that 0:12:58.080 --> 0:13:01.800 we're that we're talking about here, but it's it's it's like, yeah, 0:13:01.880 --> 0:13:04.080 as close as you can possibly get without being the 0:13:04.120 --> 0:13:09.679 same thing pretty much plunk is what we're talking about here. Uh, 0:13:09.800 --> 0:13:13.400 incredibly short distances. So you know, otherwise they just like 0:13:13.440 --> 0:13:17.160 I said, our fly through uh uninhibited. They just go 0:13:17.320 --> 0:13:20.240 straight in a straight line. So by seeing the direction 0:13:20.280 --> 0:13:22.960 that they traveled in through the evidence they leave, which 0:13:23.000 --> 0:13:25.720 we'll talk about in a second, then we can determine 0:13:25.800 --> 0:13:28.520 where they came from. And and if we are able 0:13:28.559 --> 0:13:31.400 to measure how much energy there was in that neutrino, 0:13:32.000 --> 0:13:34.920 then that can give us an idea of what might 0:13:35.040 --> 0:13:37.400 have eventually spawned it. For example, if we are able 0:13:37.440 --> 0:13:39.080 to see what direction it came from and we figure 0:13:39.120 --> 0:13:42.280 it was pretty powerful and we end up kind of 0:13:42.320 --> 0:13:45.560 tracing back that pathway and we see that that pathway 0:13:45.640 --> 0:13:48.079 takes it through to what used to be a supernova, 0:13:48.520 --> 0:13:53.959 you could potentially say, hey, this neutrino was uh, it 0:13:54.080 --> 0:13:57.280 came to us from that supernova. That's pretty phenomenal stuff. 0:13:57.280 --> 0:14:01.040 That means we can learn more about a thing that 0:14:01.080 --> 0:14:03.520 happens in our universe that otherwise we would never be 0:14:03.559 --> 0:14:07.120 close enough to observe. Pretty mysterious. Yeah, you know, Unfortunately, 0:14:07.240 --> 0:14:11.080 since they don't interact with matter all that much. You know, 0:14:11.160 --> 0:14:13.960 you know, there's for for about every hundred billion neutrinos 0:14:14.000 --> 0:14:17.040 that paths of the Earth, only one or so is 0:14:17.080 --> 0:14:20.240 going to interact with anything. And since it's really the 0:14:20.320 --> 0:14:24.080 interactions with stuff that we're looking for, not the neutrinos themselves, 0:14:24.600 --> 0:14:26.360 that that is part of why they are a so 0:14:26.520 --> 0:14:30.360 elusive and be so attractive as a field of scientific study. 0:14:30.400 --> 0:14:33.480 And exactly, and that's also an explanation of why the 0:14:33.520 --> 0:14:36.920 ice cube telescope is so enormous. If you were to 0:14:36.960 --> 0:14:40.680 create a human sized neutrino detector, it would take you 0:14:40.720 --> 0:14:44.720 a century before you would be likely to detect a neutrino, 0:14:44.760 --> 0:14:48.400 Whereas if you make it a cubic kilometer, you have 0:14:48.520 --> 0:14:51.840 increased your odds of that happening, uh like, quite a bit, 0:14:51.880 --> 0:14:54.160 as it turns out, yea, by more than two. So 0:14:54.440 --> 0:14:57.120 when did we first figure out that there were these things, 0:14:57.160 --> 0:15:00.360 or at least suspect that they existed that That first 0:15:00.360 --> 0:15:05.560 suspicion was in nineteen one. Um. That was theorist Wolfgang Polly. Yeah, 0:15:06.000 --> 0:15:10.880 he was looking at some radioactive decay equations and saw 0:15:10.920 --> 0:15:13.520 that there was some missing energy and energy k be 0:15:13.560 --> 0:15:16.760 created or destroyed. Right, So he figured there has to 0:15:16.800 --> 0:15:20.720 be something responsible for this, and and therefore there there 0:15:20.720 --> 0:15:25.440 has to be a particle that's being given off. There's 0:15:25.480 --> 0:15:28.440 some undetectable particle that is making off with some of 0:15:28.480 --> 0:15:34.480 this energy. It must be an electrically neutral right and yeah, 0:15:34.560 --> 0:15:37.400 so he figured out the basics of what must have 0:15:37.440 --> 0:15:41.360 been there, but had no way of detecting it. And uh, 0:15:41.440 --> 0:15:44.120 you know, this is again something that sounds phenomenal to me. 0:15:44.160 --> 0:15:47.200 I can't imagine coming up with this conclusion. But if 0:15:47.200 --> 0:15:49.280 you look at particle physics, this is a story that 0:15:49.320 --> 0:15:52.120 we see happen over and over again, where people see something, 0:15:52.560 --> 0:15:57.000 they theorize or hypothesize what must be happening, and then 0:15:57.560 --> 0:16:01.520 future experiments end up bearing that out right. Um. Now, 0:16:01.640 --> 0:16:05.360 the term neutrino wasn't coined until ninety four by by 0:16:05.480 --> 0:16:09.400 Enrico Fermi. Oh for me, we've talked about for me before. Yeah, 0:16:09.560 --> 0:16:13.280 so neutrino is an Italian word, and I think it 0:16:13.360 --> 0:16:18.120 means enormous pasta dish, little neutral one, I think is 0:16:18.160 --> 0:16:22.000 the more common translation. Well, I was using poetic license. 0:16:22.600 --> 0:16:26.280 Uh yeah, so it's you know, it was it still 0:16:26.320 --> 0:16:30.200 had not been actually seen or observed, right right, Um, 0:16:30.240 --> 0:16:33.320 but this this was just a kind of formal equation 0:16:33.440 --> 0:16:37.480 that he was using that incorporated Polly's ideas. Right, So 0:16:37.920 --> 0:16:40.040 you have to skip from nineteen thirty four all the 0:16:40.080 --> 0:16:42.640 way to nineteen fifty nine before you get to some 0:16:42.800 --> 0:16:46.240 scientists who observed a new trino, and that would be 0:16:46.280 --> 0:16:50.360 Clyde Cowen and Fred Rens, who discovered a particle that 0:16:50.480 --> 0:16:54.280 fit all the expected characteristics of what was being called 0:16:54.640 --> 0:16:57.800 the new trino. So now it was no longer hypothetical. 0:16:57.880 --> 0:16:59.920 Now they actually had a particle they could point to 0:17:00.040 --> 0:17:02.560 and say, that's it. This thing that we found in 0:17:02.560 --> 0:17:05.960 the lab, that thing is probably a neutrino UM. And 0:17:06.000 --> 0:17:08.920 specifically what they found was an electron neutrino, which is UM. 0:17:09.400 --> 0:17:12.120 And I think that we forgot to explain this part earlier. 0:17:12.119 --> 0:17:14.720 But the three different kinds of neutrinos pair with three 0:17:14.720 --> 0:17:17.880 different kinds of particles, so it's the electron neutrinos pair 0:17:17.880 --> 0:17:21.280 with electrons, right, and muon neutrinos pair with muan, so 0:17:21.320 --> 0:17:23.879 they're heavier, they have more mass. You guys tell us 0:17:24.320 --> 0:17:26.800 the tal neutrinos are a little heavier than the muans. 0:17:26.960 --> 0:17:30.280 So yeah, each new trino has a mass that is equivalent, 0:17:30.640 --> 0:17:34.719 well not not equivalent. It matches in a sense the 0:17:34.840 --> 0:17:38.239 size of the other subatomic particle, because actually a an 0:17:38.240 --> 0:17:41.680 electron new trino has less mass than an electronic way 0:17:41.760 --> 0:17:45.760 less mass, but but they scale up as the negatively 0:17:45.840 --> 0:17:48.960 charged subatomic particles scale up as well. So I don't 0:17:48.960 --> 0:17:51.480 mean to suggest that an electron and electron new trino 0:17:51.600 --> 0:17:54.479 are equivalent in the sense of mass. They are not. 0:17:55.119 --> 0:17:58.160 But now we get up to nineteen sixty two when 0:17:58.480 --> 0:18:03.040 another UH organization we're familiar with CERN along with the 0:18:03.119 --> 0:18:07.440 Brookhaven National Laboratory. Yet they independently conducted experiments and discovered 0:18:07.440 --> 0:18:10.720 a second type of neutrino, which was the muon neutrino, 0:18:11.200 --> 0:18:13.800 and it behaved differently from the electron neutrino. That's what 0:18:13.960 --> 0:18:16.480 first gave them a little bit of confusion, in fact, 0:18:16.480 --> 0:18:19.520 to a point where they would expect to observe a 0:18:19.520 --> 0:18:23.160 certain number of neutrinos coming from the Sun on any 0:18:23.240 --> 0:18:25.840 given day, and they had a certain number that they 0:18:25.840 --> 0:18:29.119 expected for electron neutrinos and a certain number for muon neutrinos, 0:18:29.440 --> 0:18:31.720 and for some reason that wasn't working out, and they 0:18:31.720 --> 0:18:34.600 could not figure out why that was, and they couldn't 0:18:34.600 --> 0:18:37.200 figure out why that was for a long time, very 0:18:37.280 --> 0:18:42.600 long time. So you have the Stanford Linear Accelerator Center, 0:18:42.920 --> 0:18:46.720 and they discovered the twel subatomic particle, which was the 0:18:46.840 --> 0:18:50.480 negatively charged sub atomic particle that's heavier than electron or muan, 0:18:51.200 --> 0:18:53.760 and that led the scientist to hypothesize that perhaps there 0:18:53.840 --> 0:18:57.000 was in fact a third type of neutrino, because there 0:18:57.040 --> 0:19:00.119 already were neutrino counterparts for the other two negative lee 0:19:00.200 --> 0:19:03.320 charged particles. So now they had the new the tow 0:19:03.520 --> 0:19:06.879 new trino um, but they could not directly observe it. 0:19:07.760 --> 0:19:10.280 And at that point they were still kind of wondering 0:19:10.400 --> 0:19:13.159 why there seems to be this new trino shortage, you know, 0:19:13.200 --> 0:19:16.240 based upon their calculations, there should be more than what 0:19:16.320 --> 0:19:19.960 they were detecting. Yeah, like like twice again as much, right, 0:19:20.520 --> 0:19:24.320 And then we get up to in nine seven, an 0:19:24.520 --> 0:19:29.080 enormous newtrino detector is built, the Cameo conde, and I'm 0:19:29.200 --> 0:19:32.520 sure I'm mispronouncing that newtrino detector. It was a large 0:19:32.520 --> 0:19:35.240 water detector, not meaning that I don't mean that it 0:19:35.280 --> 0:19:37.679 was detecting large amounts of water. I meant that it 0:19:37.760 --> 0:19:39.920 had a large amount of water and that used as 0:19:39.960 --> 0:19:45.399 the detector. Now, this water was incredibly pure and incredibly clear, 0:19:46.160 --> 0:19:50.000 so clear that sunlight could pass through it without slowing 0:19:50.080 --> 0:19:54.840 down for something like seventy meters, which is far longer 0:19:54.880 --> 0:19:56.560 than it could if it were passing through the water 0:19:56.640 --> 0:20:01.840 of say, your typical swimming pool. Yeah, in in your 0:20:01.880 --> 0:20:04.199 typical swimming pool, you might get a couple of meters 0:20:04.200 --> 0:20:07.800 if you're lucky, right, So it was very very clear, 0:20:07.840 --> 0:20:11.120 and that was important to detect these tiny little reactions 0:20:11.119 --> 0:20:14.000 that the neutrino would cause if it collided with another 0:20:14.040 --> 0:20:16.880 sub atomic particle. And it also had more than eleven 0:20:16.920 --> 0:20:21.359 thousand light collectors that were called photo multiplier tubes in 0:20:21.440 --> 0:20:24.040 the water itself, and those were what we're looking for, 0:20:24.080 --> 0:20:26.359 these these reactions that we're going to talk about in 0:20:26.359 --> 0:20:30.040 the second So that was a huge advance. It was 0:20:30.080 --> 0:20:33.760 an enormous neutrino detector, one of the largest until the 0:20:33.800 --> 0:20:38.800 ice cube one comes along. Certain starts to experiment and 0:20:38.840 --> 0:20:41.680 determine that no other types of neutrinos beyond the three 0:20:41.800 --> 0:20:45.080 types that already been identified could exist based upon what 0:20:45.160 --> 0:20:48.240 we know. So maybe one day we'll find out we're 0:20:48.240 --> 0:20:51.080 wrong about that, but based upon everything we know right now, 0:20:51.119 --> 0:20:54.680 it appears that only those three types of neutrinos, the electron, muan, 0:20:54.800 --> 0:20:58.080 and tao, are the ones that exist. UM now in 0:20:58.119 --> 0:21:01.439 two thousand one was that was when we finally solved 0:21:01.480 --> 0:21:04.439 that solar neutrino problem that we were talking about earlier. 0:21:04.600 --> 0:21:08.320 UM experiments that were conducted at the Canadian Solar Neutrino 0:21:08.400 --> 0:21:13.200 Observatory or snow UM showed because it's in Canada, there's 0:21:13.640 --> 0:21:16.440 anyway showed that it could be solved with the explanation 0:21:16.520 --> 0:21:19.600 that okay, So so even though the Sun releases only 0:21:19.680 --> 0:21:24.000 electron neutrinos, they oscillate sometimes while they travel through space 0:21:24.040 --> 0:21:26.840 to become a pretty even mix of muan, tao, and 0:21:27.040 --> 0:21:31.680 electron neutrinos, So that that explains like if they're oscillating 0:21:31.760 --> 0:21:34.040 and some of them are town neutrinos, which we have 0:21:34.160 --> 0:21:36.720 not been able to observe directly, that would that would 0:21:36.720 --> 0:21:41.800 explain the apparent shortage of neutrinos right, previous experiments. Most 0:21:41.840 --> 0:21:45.760 previous experiments were really only looking for electron neutrinos, especially 0:21:45.760 --> 0:21:49.400 coming from the Sun, and the instruments were not calibrated 0:21:49.440 --> 0:21:53.200 to be detecting Muon and tao. So, and that's because 0:21:53.280 --> 0:21:55.919 if it's if it's oscillating, it has to have mass. 0:21:55.960 --> 0:22:00.719 It's one of those things fundamental nature. Yeah, so you know, 0:22:01.960 --> 0:22:05.320 they're still really tiny. An electron neutrino would be about 0:22:05.400 --> 0:22:08.720 one one million the mass of an electron. Yeah, that's 0:22:08.760 --> 0:22:13.359 that's incredibly that's inconceivably tiny, at least in my mind. 0:22:13.600 --> 0:22:17.639 But but something so inconceivably tiny is very important on 0:22:17.680 --> 0:22:22.199 a universal level because this could possibly explain why, uh, 0:22:23.040 --> 0:22:26.240 why the universe contains more matter than antimatter. Why we 0:22:26.280 --> 0:22:29.879 think that this could explain dark matter basically exactly. It 0:22:29.880 --> 0:22:32.760 could well, when you get to why more matter than 0:22:32.800 --> 0:22:35.840 antimatter that explained. That would explain why the universe is 0:22:35.880 --> 0:22:37.439 the way it is, because if there had been an 0:22:37.440 --> 0:22:39.560 equal amount of matter and antimatter, it would have all 0:22:39.560 --> 0:22:42.440 annihilated itself and we wouldn't have a universe, which would 0:22:42.480 --> 0:22:45.399 be terrible because that's where I keep all my stuff. Now, 0:22:45.720 --> 0:22:49.159 how do we actually create neutrinos ourselves. Well, it's mostly 0:22:49.200 --> 0:22:52.280 through particle accelerators. You know, you moved some subatomic particles 0:22:52.320 --> 0:22:54.840 fast enough and smash them to see what happens. And 0:22:54.880 --> 0:22:56.879 some of the stuff that gets spun off tends to 0:22:56.960 --> 0:23:01.600 be these other subatomic particles and energy that we would 0:23:01.640 --> 0:23:05.080 otherwise not have been able to observe, and neutrinos are 0:23:05.080 --> 0:23:08.399 one of those. Although again we don't directly observe the neutrinos, 0:23:08.480 --> 0:23:12.320 we observe the reactions that they have with other stuff, right, 0:23:12.400 --> 0:23:14.520 And these neutrinos that we can create here on Earth 0:23:14.560 --> 0:23:16.600