WEBVTT - What is the Space Roar? 0:00:08.240 --> 0:00:10.280 Hey, Daniel, do you ever think we should explore the 0:00:10.360 --> 0:00:14.360 universe with all five senses? Well, I'm definitely a fan 0:00:14.520 --> 0:00:17.800 of looking out into space. Yeah, but we have other senses. 0:00:17.840 --> 0:00:21.640 Have you thought about what space smells like? Well, astronauts 0:00:21.680 --> 0:00:24.680 report that space smells a little bit like a barbecue. 0:00:25.680 --> 0:00:28.639 Really does it taste like barbecue? Also, I don't know, 0:00:28.720 --> 0:00:31.640 maybe frozen barbecue, I guess. Well, I hope it doesn't 0:00:31.680 --> 0:00:35.200 feel like barbecue. Space is not that saucy it turns 0:00:35.200 --> 0:00:37.839 out or sound like barbecue. That would just be the 0:00:37.880 --> 0:00:41.239 sound of aliens preparing their barbecue grills. Well, I just 0:00:41.280 --> 0:00:46.000 hope we're not on the menu. Talk about first contact first, 0:00:46.000 --> 0:01:04.399 of course, of course I am more handmade cartoonists and 0:01:04.400 --> 0:01:07.360 the creator of PhD comics. Hi, I'm Daniel. I'm a 0:01:07.360 --> 0:01:10.160 particle physicist, and I do love me a barbecue. So 0:01:10.160 --> 0:01:13.039 it really smells like barbecue space? It does. Actually, we 0:01:13.080 --> 0:01:16.520 had to listener question recently about what space smells like. 0:01:16.959 --> 0:01:19.920 And they're a bunch of really interesting organic molecules out 0:01:19.920 --> 0:01:22.640 there in space that like cling to space suits and 0:01:22.680 --> 0:01:25.000 then release themselves when you come back inside, And they 0:01:25.000 --> 0:01:28.840 smell like sometimes like sulfur, sometimes like barbecue. What does 0:01:28.840 --> 0:01:31.120 it mean? Like the astronauts would go out into space 0:01:31.440 --> 0:01:33.200 on a spacewalk and then when they come in they 0:01:33.200 --> 0:01:36.160 smell like barbecue. Yeah, exactly, when they open up their 0:01:36.200 --> 0:01:38.600 helmets again after they've come back in, the stuff that's 0:01:38.600 --> 0:01:41.039 stuck to their space suit now goes up their nostrils 0:01:41.080 --> 0:01:44.080 and it smells a little bit like barbecue. Guess technically 0:01:44.080 --> 0:01:47.440 barbecues are part of the universe. So yeah, the universe 0:01:47.480 --> 0:01:50.280 does smell like barbecue, as it does smell like other things. 0:01:50.440 --> 0:01:54.200 Our barbecue universe. Welcome to our podcast Daniel and Jorge 0:01:54.240 --> 0:01:56.960 Explain the Universe, a perlection of I Heart Radio in 0:01:57.000 --> 0:02:00.240 which we use all sorts of absurd food analogy used 0:02:00.280 --> 0:02:03.360 to explain to you what the universe is like. Is 0:02:03.360 --> 0:02:06.640 it goopy and saucy? Is it chewy and stringy? Can 0:02:06.680 --> 0:02:08.960 you bite right through it? But really, we want to 0:02:08.960 --> 0:02:11.880 make sure that you understand the nature of the universe, 0:02:12.040 --> 0:02:14.960 the things that scientists are thinking about, the things that 0:02:15.000 --> 0:02:17.600 we are mentally chewing on, and the things we have 0:02:17.760 --> 0:02:20.840 not yet been able to digest. That's right because even 0:02:20.960 --> 0:02:24.000 analogies are part of the universe, and so it's a 0:02:24.000 --> 0:02:27.120 broad topic that we are discussing here Daniel and Jorge 0:02:27.200 --> 0:02:32.400 explain bad analogies with other worse analogies. Yeah, it feels 0:02:32.440 --> 0:02:35.480 like we just be compounding the problem there. But it 0:02:35.639 --> 0:02:38.920 is a pretty interesting universe out there, and there's a 0:02:38.919 --> 0:02:41.040 lot going on. Like if you just sit there in 0:02:41.080 --> 0:02:43.200 space and you float, you can smell things, you can 0:02:43.400 --> 0:02:45.960 feel things, I'm sure radiation hitting you, and you can 0:02:45.960 --> 0:02:49.000 see definitely a lot out there in the universe. Absolutely, 0:02:49.080 --> 0:02:52.480 and we are continuing to invent new ways to interrict 0:02:52.520 --> 0:02:56.320 with our universe. And basically every time we do, we 0:02:56.400 --> 0:03:00.080 find something shocking, we discover something else out there the 0:03:00.160 --> 0:03:03.240 universe we didn't even know existed. Yeah, I mean, we're 0:03:03.280 --> 0:03:05.280 just sitting here in one corner of the Milky Way, 0:03:05.320 --> 0:03:08.079 which is sitting in one corner of the observable universe, 0:03:08.160 --> 0:03:11.320 and we're getting a lot of signals from everywhere. Basically, 0:03:11.400 --> 0:03:13.600 anything that gives up light, we get that light, and 0:03:13.600 --> 0:03:17.120 we detected with our telescopes and our antennants. Exactly we 0:03:17.240 --> 0:03:20.800 are drowning and information from the universe, much of which 0:03:20.800 --> 0:03:24.560 we didn't even know existed until recently. For example, most 0:03:24.560 --> 0:03:27.760 of astronomy has been done using visible light. Light that 0:03:27.840 --> 0:03:30.400 you can see with your eyes and even maybe enhanced 0:03:30.400 --> 0:03:33.560 with telescopes, but there are really interesting signals in X 0:03:33.680 --> 0:03:36.080 rays and on the other side of the spectrum down 0:03:36.120 --> 0:03:38.360 to radio waves, you can also look at all the 0:03:38.480 --> 0:03:42.240 particles that are washing over us, neutrinos and other crazy 0:03:42.280 --> 0:03:45.560 sources of information about what's going out there in the universe. 0:03:45.760 --> 0:03:50.000 And recently we added gravitational waves to our toolkit for 0:03:50.240 --> 0:03:53.080 listening to the universe. And each of these tells us 0:03:53.160 --> 0:03:55.760 something different about the nature of the universe because different 0:03:55.760 --> 0:03:58.680 stuff out there emits in different ways. Some of it 0:03:58.720 --> 0:04:02.760 gives off light, some radio waves, some gravitational waves. Each 0:04:02.800 --> 0:04:05.080 one can tell us something different about what's out there 0:04:05.080 --> 0:04:07.440 in the universe. What sense would you use, Daniel to 0:04:07.480 --> 0:04:11.280 describe detecting gravitational waves, Like, what what sense do you 0:04:11.280 --> 0:04:14.400 need to detect gravity? Do you feel it? Do we 0:04:14.480 --> 0:04:16.680 hear it, do we see it? You would feel it 0:04:16.720 --> 0:04:19.400 technically because it's a space quake, right, It's like a 0:04:19.600 --> 0:04:24.480 shaking of space itself. Space contracts, it expands into wiggles, 0:04:24.520 --> 0:04:27.240 So that's really what's happening. And a lot of science 0:04:27.279 --> 0:04:31.040 communication about gravitational waves, though they talk about listening to 0:04:31.200 --> 0:04:35.159 the universe they talk about like the chirp of black holes. 0:04:35.400 --> 0:04:38.080 I think that's a tiny bit confusing because we're not 0:04:38.200 --> 0:04:41.159 using our ears to hear these things. We're not getting 0:04:41.279 --> 0:04:45.159 sound waves from gravitational waves. What they've done is taken 0:04:45.279 --> 0:04:48.760 the frequency of those waves, transform them into sound waves, 0:04:48.800 --> 0:04:52.560 and then listen to them. We're feeling the gravitational waves. Yeah. 0:04:52.640 --> 0:04:56.000 I like thinking about gravitational waves as the shaking of space. 0:04:56.600 --> 0:04:58.480 All right, Well, there are a lot of things out 0:04:58.520 --> 0:05:01.760 there giving of a light and signals and gravity, and 0:05:01.839 --> 0:05:03.960 for the most part we sort of know where it's 0:05:04.080 --> 0:05:07.120 coming from over or what's making these signals. But sometimes 0:05:07.120 --> 0:05:10.760 there are surprises. There are almost always surprises, and a 0:05:10.760 --> 0:05:13.359 lot of times these things are picked up by accident. 0:05:13.720 --> 0:05:16.400 Somebody develops a new kind of antenna or a new 0:05:16.480 --> 0:05:18.560 kind of telescope and looks out of the universe the 0:05:18.560 --> 0:05:21.760 first time, maybe looking for one thing and finding something 0:05:21.839 --> 0:05:24.839 totally different, and then puzzling over and wondering like, huh, 0:05:24.880 --> 0:05:28.159 what's making all that light or emitting all that radiation? 0:05:28.320 --> 0:05:31.000 And those are fascinating clues that tell us about something 0:05:31.120 --> 0:05:33.360 new out there in the universe, or something we knew 0:05:33.400 --> 0:05:36.240 about that's doing something we didn't know about. Yeah, and 0:05:36.279 --> 0:05:39.960 there is one particular signal out there that is basically 0:05:40.000 --> 0:05:42.600 all around us. You can hear it in every direction, 0:05:42.800 --> 0:05:44.839 but we don't know what's making it. It's sort of 0:05:44.960 --> 0:05:49.440 this weird, unexplained phenomenon exactly, and it's also got a 0:05:49.640 --> 0:05:53.680 hilarious name to it. Oh does it in physics? How surprising? 0:05:54.640 --> 0:06:00.000 I'm shocked, hilarious and some ways misleading? Well do they? 0:06:00.000 --> 0:06:07.240 On the podcast will be tackling the question what is 0:06:07.440 --> 0:06:10.880 the space roar now, Daniel? Is it like a roar 0:06:10.960 --> 0:06:13.080 like a lines war or is it more like a 0:06:13.200 --> 0:06:17.960 cat's meo like rare like is the universe caddie or 0:06:18.040 --> 0:06:20.520 is it you know, not had its morning coffee yet? 0:06:20.560 --> 0:06:24.120 What is the universe's attitude exactly? Does the universe need 0:06:24.200 --> 0:06:26.840 to go to therapy? Like, dude, chill out, somebody give 0:06:26.839 --> 0:06:30.800 the universe some valium? What's definitely cool and chill We've 0:06:30.839 --> 0:06:33.760 I think we've established that. Does it got kind of 0:06:33.760 --> 0:06:37.760 hot sometimes? Yeah? Exactly. Roar is a pretty funny name. Really. 0:06:37.800 --> 0:06:40.560 I would have called this the space hiss, the space 0:06:40.680 --> 0:06:44.080 his his yeah, exactly, like the space buzzes. Yeah, the 0:06:44.120 --> 0:06:46.320 space buzz That would have been a great name for it, 0:06:46.440 --> 0:06:51.800 the space hum um. That makes it sound like alien music, 0:06:51.880 --> 0:06:55.640 you know, like Gregorian alien chance, the space whistle while 0:06:55.640 --> 0:06:58.839 you work. Yeah, exactly. I think all of those would 0:06:58.839 --> 0:07:03.480 have been more accurate name than the space raw. Now 0:07:03.520 --> 0:07:05.960 I see now you're calling it. I would spell that 0:07:06.000 --> 0:07:08.600 differently than r O A r oh. Yeah, that's more 0:07:08.680 --> 0:07:12.040 like the space meal. Yeah. But anyways, it is a thing, 0:07:12.240 --> 0:07:15.440 the space roar, and it's kind of a big mystery 0:07:15.480 --> 0:07:17.520 in physics, and we were wondering how many people out 0:07:17.600 --> 0:07:20.360 there knew what it was or had heard of it 0:07:20.800 --> 0:07:24.000 or been I don't know the subject of its attitude. 0:07:24.720 --> 0:07:27.640 So thanks to everybody who's willing to guess at the 0:07:27.720 --> 0:07:31.440 true nature of something poorly named by astronomers. If you 0:07:31.480 --> 0:07:34.480 were willing to participate for a future episode, please write 0:07:34.520 --> 0:07:37.440 to me. Two questions at Daniel and Jorge dot com. 0:07:37.680 --> 0:07:40.640 I like how you just totally through astronomers under the 0:07:40.680 --> 0:07:44.120 bus there. You could have said physicists. You definitely specifically 0:07:44.160 --> 0:07:46.600 said astronomers there. Yeah. Well, I feel like they are 0:07:46.680 --> 0:07:49.480 the target of your criticism more often than other kind 0:07:49.520 --> 0:07:55.600 of physics. Mr particle man, are you serious? Yeah? We 0:07:55.680 --> 0:07:59.040 got strange names. We got charming names. But you know, 0:07:59.360 --> 0:08:02.800 astronomer is there. Maybe let's call them more creative with 0:08:02.880 --> 0:08:06.880 their names. Remember that whole episode about space centaurs. Let's 0:08:06.920 --> 0:08:10.120 not hear me raw about this topic any longer. Alright, 0:08:10.160 --> 0:08:12.120 let's not hiss about it all right? Well, as usual, 0:08:12.200 --> 0:08:14.440 Daniel went out there and ask people what they thought 0:08:14.560 --> 0:08:17.160 the space roar was. To think about it for a second. 0:08:17.200 --> 0:08:20.120 If someone ask you, what would you say? How would 0:08:20.120 --> 0:08:23.120 you answer? Here's what people had to say, saying, as 0:08:23.160 --> 0:08:26.239 it's called aurora, I imagine Scott to do with sound waves, 0:08:26.480 --> 0:08:30.280 and I think they might come from all directions in space. 0:08:30.920 --> 0:08:34.400 The space roar sort of reminds me of a tiger 0:08:34.600 --> 0:08:38.240 or Allian. But in our universe, I think that the 0:08:38.280 --> 0:08:42.200 space roar could be like an explosion. Maybe it could 0:08:42.240 --> 0:08:45.480 be compared to the Big Bang, and maybe this explosion 0:08:45.720 --> 0:08:48.680 was the beginning of something. I don't know if it 0:08:48.720 --> 0:08:52.720 could have been the beginning of a galaxy. The spice role, 0:08:52.880 --> 0:08:58.040 I'm fairly certain is aliens. Probably it can only be 0:08:58.840 --> 0:09:03.040 radio waves since nobody can scream with us, who wouldn't 0:09:03.240 --> 0:09:07.200 hear it? Because you avoids, the sound cannot travel, So 0:09:07.760 --> 0:09:11.400 the space road can be in radio We always talk 0:09:11.480 --> 0:09:15.880 about light and energy being transmitted through space, but a 0:09:15.880 --> 0:09:18.599 lot of what happens in the universe also produces or 0:09:18.679 --> 0:09:22.560 could produce sound if there was something to convey that sound. 0:09:22.640 --> 0:09:25.400 So is this some sort of accumulation of that? I 0:09:25.440 --> 0:09:28.000 have no idea, all right, I like this idea of 0:09:28.000 --> 0:09:33.960 a space tiger or a space lion when alien space tiger? Yeah, 0:09:34.000 --> 0:09:36.760 that was basically your answer. Yeah, and some people assume 0:09:36.840 --> 0:09:39.720 it has something to do with radio waves or at 0:09:39.800 --> 0:09:42.520 least some sort of waves that we're getting out there 0:09:42.559 --> 0:09:45.840 from the universe. Yeah, totally solid response there. Yeah, but 0:09:45.880 --> 0:09:48.280 technically can you get sound from space? I know in 0:09:48.360 --> 0:09:50.600 space no one can hear you scream. But is that 0:09:50.640 --> 0:09:54.199 because you're wearing a helmet or because you can't transmit sound? Right, 0:09:54.320 --> 0:09:57.800 Anything where you describe something we get from space in 0:09:58.000 --> 0:10:01.360 terms of a sound is usually playing the same trick 0:10:01.440 --> 0:10:04.000 we talked about with respect to gravitational waves, where you're 0:10:04.000 --> 0:10:06.800 getting some other kind of wave and all waves have 0:10:06.840 --> 0:10:10.120 a frequency, and then you transform that wave into a 0:10:10.160 --> 0:10:12.520 sound wave so you can listen to it. This is 0:10:12.520 --> 0:10:16.720 no different than like taking radio waves or X rays 0:10:16.760 --> 0:10:19.640 from space which you can't see visually, and then just 0:10:19.840 --> 0:10:22.200 shifting them in the spectrum so that you can see 0:10:22.200 --> 0:10:24.880 them like a false color image. So no, you can't 0:10:24.920 --> 0:10:30.040 actually hear any sounds from space because sounds are mechanical waves. 0:10:30.040 --> 0:10:33.920 They require like air shifting or something banging into something else. 0:10:34.360 --> 0:10:38.000 So we can't hear anything technically from space, right. But 0:10:38.040 --> 0:10:41.760 space isn't completely empty, is right. It's not a perfect vacuum. 0:10:41.800 --> 0:10:45.600 There's a little bit of gas and hydrogen everywhere, isn't there? No, exactly, 0:10:45.720 --> 0:10:47.920 there are some particles out there, and so you can 0:10:48.000 --> 0:10:51.320 imagine there are some like waves in the solar wind, 0:10:51.400 --> 0:10:54.800 for example, oscillations that happened, like the sun has a 0:10:54.840 --> 0:10:57.920 period of eleven years, where like there's lots of ups 0:10:57.920 --> 0:11:00.440 and downs in the radiation it emits. So you can 0:11:00.480 --> 0:11:04.000 imagine waves propagating in that medium, and perhaps you can 0:11:04.040 --> 0:11:07.160 imagine actually listening to them. So yeah, there are ways 0:11:07.160 --> 0:11:10.920 you're right for sound to propagate through not totally empty space. 0:11:11.080 --> 0:11:13.760 But space is also not empty in another way. We 0:11:13.840 --> 0:11:17.000 always talk about space being filled with quantum fields, and 0:11:17.040 --> 0:11:20.600 those fields can propagate waves, and for example, that's what 0:11:20.640 --> 0:11:23.720 a photon is. It's a wave in the electromagnetic field 0:11:23.760 --> 0:11:28.000 in otherwise empty space m sounds good, so they can 0:11:28.080 --> 0:11:32.559 hear you scream in space from radiation burning. Probably if 0:11:32.600 --> 0:11:35.280 you scream in light, then yes, people can hear you scream. 0:11:35.480 --> 0:11:38.040 All right, So there's this big mystery in physics called 0:11:38.120 --> 0:11:41.360 the space roar. Now, Daniel step us through this. What 0:11:41.559 --> 0:11:45.400 is the space war? The space roar is a totally weird, 0:11:45.720 --> 0:11:50.560 unexplained source of radio from space, And that's why they 0:11:50.640 --> 0:11:52.840 call it the space roar because it comes in the 0:11:53.000 --> 0:11:56.600 radio spectrum, which is a spectrum where we often listen to. Right, 0:11:56.720 --> 0:11:59.400 you might even be hearing this podcast on the radio, 0:11:59.440 --> 0:12:03.240 which means it's and transmitted using radio waves. So because 0:12:03.240 --> 0:12:07.160 we associate radio waves with sound often, I think that's 0:12:07.200 --> 0:12:10.000 why I got this name, the space roar. But basically 0:12:10.080 --> 0:12:13.800 it's unexplained source of radio waves from space, I guess, 0:12:13.840 --> 0:12:16.080 meaning that if you turn on your radio, you would 0:12:16.120 --> 0:12:19.280 technically be able to listen to this roar, right, yeah, exactly, 0:12:19.679 --> 0:12:22.360 it is coming in through the radio waves. You need 0:12:22.400 --> 0:12:26.080 a radio antenna. And remember that radio waves are just 0:12:26.240 --> 0:12:30.800 another part of the electromagnetic spectrum. All of these are photons. 0:12:30.920 --> 0:12:32.640 You could call all of it light if you want, 0:12:32.920 --> 0:12:35.000 but they're all just part of the same wiggling of 0:12:35.040 --> 0:12:38.760 electromagnetic fields. In the center of the spectrum, there's visible light. 0:12:38.960 --> 0:12:42.240 Above that there's UV light, and then X rays. Below it, 0:12:42.320 --> 0:12:45.559 there's infrared light, and below that are radio waves. So 0:12:45.800 --> 0:12:49.280 radio waves are just photons with a very very long wavelength. 0:12:49.360 --> 0:12:51.760 And you know, as we were saying earlier, for centuries, 0:12:51.800 --> 0:12:54.839 people were doing astronomy only by looking at visible light, 0:12:55.080 --> 0:12:57.000 the light you could see with your eyes, and of 0:12:57.000 --> 0:12:59.839 course there's a lot of fascinating information about stars and 0:12:59.880 --> 0:13:01.840 the universe you can see you just with your eyes 0:13:01.960 --> 0:13:05.320 or gathering more of those visible moutons into a telescope. 0:13:05.320 --> 0:13:08.360 But in the ninet thirties it was this amazing discovery 0:13:08.400 --> 0:13:11.360 that you could actually listen to the sky using radio 0:13:11.400 --> 0:13:14.240 waves also, and that there was a huge source of 0:13:14.360 --> 0:13:17.679 radio waves coming to us from space. How did we 0:13:17.760 --> 0:13:20.920 discover that it wasn't through like actual radios. No, it 0:13:20.960 --> 0:13:24.320 was a really interesting accidental discovery by this guy Jansky. 0:13:24.559 --> 0:13:27.640 He was hired by the Bell Telephone Company. They wanted 0:13:27.679 --> 0:13:30.520 to beam radio signals across the Atlantic, and they were 0:13:30.559 --> 0:13:34.400 worried that thunderstorms would generate radio interference, so they hired 0:13:34.520 --> 0:13:37.440 him to like listen to the radio spectrum carefully and 0:13:37.440 --> 0:13:39.960 see if you could understand these forms of interference. So 0:13:40.000 --> 0:13:43.839 he built basically a huge radio telescope, the first radio telescope, 0:13:43.880 --> 0:13:46.400 just to gather radio waves, and he heard a lot 0:13:46.480 --> 0:13:51.600 of stuff that he couldn't explain as coming from Earth. Interesting, 0:13:51.679 --> 0:13:55.560 totally unintended, totally unintended. It was like a fascinating little 0:13:55.600 --> 0:13:58.400 piece of science. He heard this weird hiss he couldn't explain, 0:13:58.520 --> 0:14:00.679 and actually he discovered that it was related with the 0:14:00.800 --> 0:14:03.160 rotation of the Earth, which is how he knew it 0:14:03.200 --> 0:14:06.160 wasn't coming from the Earth. It's like seeing something in 0:14:06.160 --> 0:14:08.320 the sky. You see it once a day, so you 0:14:08.400 --> 0:14:11.040 know that, like as the Earth is turning, it's appearing 0:14:11.160 --> 0:14:13.520 in the sky. But he was looking at the sky 0:14:13.640 --> 0:14:15.840 in a different spectrum, right, He was looking at the 0:14:15.840 --> 0:14:19.080 sky in the radio waves, and what he was actually 0:14:19.120 --> 0:14:22.960 listening to was radio emissions from the center of the galaxy. 0:14:23.440 --> 0:14:25.320 And so here was like a whole new way to 0:14:25.960 --> 0:14:28.560 listen to this guy to look out at the universe. 0:14:28.720 --> 0:14:31.960 Nobody ever thought that there are natural sources of radio 0:14:32.000 --> 0:14:34.600 waves out there in the universe, and by listening to 0:14:34.640 --> 0:14:37.280 them we could tell what's going on. And the whole 0:14:37.320 --> 0:14:40.560 field is hilarious sort of because nobody really did anything 0:14:40.600 --> 0:14:43.280 about it until at ten years later, when this guy 0:14:43.320 --> 0:14:47.280 outside Chicago built the world's first radio telescope by himself 0:14:47.560 --> 0:14:50.960 in his backyard, and he was basically the only radio 0:14:50.960 --> 0:14:55.200 astronomer in the world for about ten years. A pioneer, 0:14:55.360 --> 0:14:59.440 A pioneer absolutely in his backyard. This thing is huge. 0:14:59.720 --> 0:15:02.360 It's one of these big dishes. So Jansky's first one 0:15:02.680 --> 0:15:04.520 was just like a string of antennas on a big 0:15:04.560 --> 0:15:07.760 wheel that he could turn and then whever. He built 0:15:07.760 --> 0:15:10.680 the first dish to sort of like concentrate radio waves 0:15:10.760 --> 0:15:12.920 and collect them together. And that's the sort of radio 0:15:13.000 --> 0:15:15.880 dish that we have now. Like Arisibo until recently was 0:15:15.920 --> 0:15:19.040 a big radio telescope, and we have other big radio telescopes. 0:15:19.080 --> 0:15:21.360 You can see them. They are these huge dishes, and 0:15:21.360 --> 0:15:25.480 they have to be big because radio has very long wavelengths, right. 0:15:25.560 --> 0:15:27.760 I guess it's sort of like you know, maybe astronomers 0:15:27.760 --> 0:15:29.600 at the time we're still busy trying to figure out 0:15:29.640 --> 0:15:32.160 what they were seeing in the visible light spectrum, and 0:15:32.200 --> 0:15:35.720 so nobody thought to look in other wavelengths. Yeah, exactly. 0:15:35.840 --> 0:15:38.360 There's still plenty of astronomy to do invisible lights. People 0:15:38.360 --> 0:15:40.400 are still doing it now, but you know, there's a 0:15:40.400 --> 0:15:42.960 lot of spectra out there, and the universe looks different 0:15:43.280 --> 0:15:46.480 at different spectrum. You know, different things glow at different temperatures. 0:15:46.560 --> 0:15:49.000 Some things are very bright in the UV and very 0:15:49.120 --> 0:15:51.680 dark in the visible light, or they're very strong radio 0:15:51.680 --> 0:15:54.200 emitters and they're very quiet and invisible, and so it's 0:15:54.240 --> 0:15:57.120 sort of like looking at the universe in color instead 0:15:57.160 --> 0:15:59.760 of in black and white. You can see different things 0:16:00.080 --> 0:16:03.359 light up in different things being dark at different frequencies, 0:16:03.800 --> 0:16:06.360 and so it's sort of like extra colors to the universe. 0:16:06.400 --> 0:16:08.640 It's really a great way to sort of understand what's 0:16:08.680 --> 0:16:11.520 out there, right right. It's a great romantic line. And 0:16:11.600 --> 0:16:15.080 hear you're glowing in the X rayspector, all right, So 0:16:15.120 --> 0:16:17.880 that was a bit his that he heard back then. 0:16:18.120 --> 0:16:21.240 But now we're hearing a roar and it's sort of 0:16:21.320 --> 0:16:24.040 unexplained to what's the history of this roar when we 0:16:24.120 --> 0:16:27.680 first started listening to it or seeing and who did it. 0:16:27.800 --> 0:16:31.560 So there's an experiment developed called the arcade instrument. Arcade 0:16:31.600 --> 0:16:34.520 is one of these tortured acronyms that stands for absolute 0:16:34.680 --> 0:16:39.520 radiometerr for cosmology, astrophysics, and diffuse emission. But it's basically 0:16:39.560 --> 0:16:43.600 a really sensitive radio antenna attached to a balloon and 0:16:43.640 --> 0:16:46.080 it goes up into the atmosphere and it listens to 0:16:46.640 --> 0:16:49.880 radio waves. And they're trying to really accurately measure these 0:16:49.880 --> 0:16:52.760 sources of radio waves because they want to understand things 0:16:52.800 --> 0:16:55.360 like the very early universe. They want to listen to 0:16:55.360 --> 0:16:58.280 the cosmic background radiation and detect to see if, like 0:16:58.600 --> 0:17:00.840 the first stars in the univer gave it a little 0:17:00.840 --> 0:17:03.600 bit of hot spots here and there. So they launched 0:17:03.600 --> 0:17:06.879 this probe something like ten fifteen years ago, and it 0:17:06.960 --> 0:17:09.600 was one of the most sensitive probes to radio waves, 0:17:09.640 --> 0:17:13.480 and they heard this crazy hiss that they couldn't explain. Wow, 0:17:13.600 --> 0:17:15.240 where did they launch it? Was this one of these 0:17:15.280 --> 0:17:18.760 like antarctic balloons or was it outside Chicago, also the 0:17:18.840 --> 0:17:21.560 epicenter of radio astronomy. It was launched from a spot 0:17:21.560 --> 0:17:25.320 in Texas. NASA has a scientific balloon facility there, and 0:17:25.359 --> 0:17:27.360 this thing is not just like a normal balloon. It's 0:17:27.359 --> 0:17:30.040 one of these like massive weather balloons, and as it 0:17:30.080 --> 0:17:32.479 goes up it gets really really big. And this thing 0:17:32.520 --> 0:17:36.440 went up to thirty seven kilometers above the Earth's surface. 0:17:37.480 --> 0:17:39.560 All right, So then they send out this balloon and 0:17:39.600 --> 0:17:41.800 they I guess we're able to point it. Can they 0:17:41.840 --> 0:17:44.640 pointed around, and that's when they heard this roar. They 0:17:44.720 --> 0:17:46.960 can't point it. It just sort of like floats around. 0:17:47.040 --> 0:17:49.199 They don't steer it. But it has a bunch of 0:17:49.200 --> 0:17:52.560 antennas on it, so you can get directional information about 0:17:52.560 --> 0:17:54.760 the signals you're picking up based on like when they 0:17:54.880 --> 0:17:57.439 arrive at the instruments. It's sort of like parallax or 0:17:57.480 --> 0:18:01.040 like binocular vision, and so they and tell where things 0:18:01.080 --> 0:18:03.159 are coming from. And so you know, they saw a 0:18:03.160 --> 0:18:05.560 lot of the expected stuff in the radio. You can 0:18:05.600 --> 0:18:08.600 see the Sun, you can see the galactic center, you 0:18:08.640 --> 0:18:12.000 can see Jupiter, you can see other galaxies that are 0:18:12.040 --> 0:18:14.919 putting out radio waves, and that's sort of what they expected. 0:18:15.080 --> 0:18:18.720 But they also found this sort of like overall signal, 0:18:18.800 --> 0:18:22.479 this uniform HIS that nobody had ever heard before, and 0:18:22.520 --> 0:18:27.199 it's much much stronger than anything they expected. Interesting. All right, 0:18:27.240 --> 0:18:29.800 let's getting too a little bit more in detail of 0:18:29.840 --> 0:18:32.280 this his, and then let's talk about where it could 0:18:32.320 --> 0:18:34.240 be com firm and what it could be. But first 0:18:34.320 --> 0:18:48.520 let's take a quick break. All right, we're talking about 0:18:48.520 --> 0:18:54.320 the space roar, a mysterious signal that the arcade instrument 0:18:54.720 --> 0:18:59.080 detected on a balloon kilometers up in the sky. Now, Daniel, 0:18:59.119 --> 0:19:02.400 this is different than the cosmic microwave background radiation, right, 0:19:02.440 --> 0:19:05.600 the CMB r F. That's right, This is different from 0:19:05.640 --> 0:19:10.400 the CMB. No are we're not living in the marvel universe. 0:19:10.600 --> 0:19:13.560 The CNB does emit in the radio. Right. Part of 0:19:13.600 --> 0:19:16.080 the CMB is in the radio spectrum. It's a bit 0:19:16.119 --> 0:19:19.160 of confusing terminology here because sometimes waves in this part 0:19:19.240 --> 0:19:22.840 of the spectrum are called radio sometimes they're called microwaves. 0:19:23.080 --> 0:19:26.480 Through the same thing. Essentially, anything longer than a millimeter 0:19:26.600 --> 0:19:28.480 you could call a radio wave, or you could call 0:19:28.480 --> 0:19:30.520 it a microwave. So you could also call it the 0:19:30.600 --> 0:19:34.919 cosmic radio background m So it is sort of like 0:19:35.040 --> 0:19:39.040 the cosmic microwave background, but it's just at a different wavelength. Yeah, exactly. 0:19:39.040 --> 0:19:42.040 They were looking for at the slightly longer wavelength portion 0:19:42.320 --> 0:19:44.680 that's not as well studied. Because what they wanted to 0:19:44.760 --> 0:19:47.680 understand was can they see like the heat the light 0:19:47.760 --> 0:19:50.520 put out from some of the first stars in the universe, 0:19:50.680 --> 0:19:53.280 which would have emitted in the radio. That was sort 0:19:53.280 --> 0:19:56.600 of their scientific goals, like measure this part of the 0:19:56.640 --> 0:19:59.879 spectrum really really accurately, and then study it for hints 0:20:00.000 --> 0:20:02.800 about the formations of the first stars, which they hoped 0:20:02.800 --> 0:20:05.880 would leave a little fingerprint on this part of the universe. Oh, 0:20:05.920 --> 0:20:07.960 I see. They sent that Bluna up to study the 0:20:08.040 --> 0:20:12.600 CMB specifically, but in the radio wave wavelength, Yeah, exactly, 0:20:12.880 --> 0:20:16.200 and to study sort of the longer tails of the CNB, 0:20:16.359 --> 0:20:19.960 which people haven't studied as precisely using like Kobe and 0:20:20.000 --> 0:20:22.800 Plunk and w MAP and those other satellites. So it 0:20:22.800 --> 0:20:26.560 has a slightly different sensitivity than other instruments. So sort 0:20:26.560 --> 0:20:29.440 of the first time people looked with this precision at 0:20:29.480 --> 0:20:32.359 this part of the spectrum. All right, So then I 0:20:32.359 --> 0:20:35.160 guess they expected to hear like a background his but 0:20:35.240 --> 0:20:38.240 what they found was not quite what they were expecting 0:20:38.280 --> 0:20:41.440 to find. Yeah, they expected to find the CMB, as 0:20:41.440 --> 0:20:43.720 we talked about, that's part of the spectrum. They also 0:20:43.760 --> 0:20:46.520 expected to hear sort of like a diffuse background, you know, 0:20:46.560 --> 0:20:48.840 like all the galaxies that are out there they admit 0:20:48.960 --> 0:20:51.359 in the radio, especially if they have a strong black 0:20:51.400 --> 0:20:53.600 hole at their center, they're gonna be giving off a 0:20:53.600 --> 0:20:55.840 lot of radio waves, So you expect sort of just 0:20:55.880 --> 0:20:58.639 like a diffuse source of noise out there in the 0:20:58.720 --> 0:21:02.320 universe in radio waves. But they heard this hiss. That's 0:21:02.359 --> 0:21:05.400 not The CMB comes at a different wavelength, and it's 0:21:05.520 --> 0:21:08.560 much much stronger than what you would expect just from 0:21:08.600 --> 0:21:11.920 like all the galaxies emitting. It's like six times larger 0:21:12.000 --> 0:21:15.600 than what we can explain. Wait, why can it be 0:21:15.680 --> 0:21:18.080 the CMB. Well, we know the CMB pretty well. The 0:21:18.119 --> 0:21:20.600 CMB is what you expect from like a two point 0:21:20.680 --> 0:21:23.840 seven degree kelvin black body emitter, So we know it's 0:21:23.840 --> 0:21:26.320 spectrum and we know it's intensity. And this is just 0:21:26.480 --> 0:21:29.760 much bigger than the CMBs. That's not consistent with what 0:21:29.840 --> 0:21:32.880 you would expect from the CMB, I see, And it's 0:21:32.960 --> 0:21:34.879 much bigger than what you would expect from just a 0:21:35.040 --> 0:21:38.800 general like din of the universe, like the general radio 0:21:38.840 --> 0:21:42.240 wave background of the universe. Yeah, exactly. And it's the 0:21:42.280 --> 0:21:45.080 most sensitive instrument in this area. And it also has 0:21:45.119 --> 0:21:48.399 an absolute calibration, which is the reason we first heard it. 0:21:48.520 --> 0:21:51.199 Most of the radio balloons and other things listening to 0:21:51.240 --> 0:21:53.480 this part of the spectrum before would always just do 0:21:53.520 --> 0:21:56.280