WEBVTT FILE 1 00:00:05.460 --> 00:00:10.680 Miles Hatfield: Hello everyone and Happy Halloween. Today, for our Halloween special, 2 00:00:10.680 --> 00:00:19.420 A NASA scientist finally goes on record about the truth behind sprites, gnomes, pixies, ELVEs, trolls, and more. 3 00:00:19.790 --> 00:00:22.970 Of course, we're not talking about the mythical creatures of the forest... 4 00:00:22.980 --> 00:00:28.470 We're talking about the colorful lights that sometimes appear high in our upper atmosphere above thunderstorms -- 5 00:00:28.470 --> 00:00:33.700 more commonly known in scientific parlance as transient luminous events. 6 00:00:33.830 --> 00:00:36.480 I'm Miles Hatfield, NASA science communicator, 7 00:00:36.630 --> 00:00:40.610 and I'm here with Burcu Kosar, NASA scientist and expert on these mysterious 8 00:00:40.620 --> 00:00:47.100 electrical phenomena. Burcu is starting a brand new project called Spritacular that aims to open 9 00:00:47.100 --> 00:00:52.380 up this exciting field of science to broad public participation. We're here to talk about that 10 00:00:52.380 --> 00:00:58.800 project, and the ghostly figures that it studies. So first off, what are sprites and some of these 11 00:00:58.800 --> 00:01:00.540 other things that I mentioned at the top? 12 00:01:00.690 --> 00:01:08.640 Dr. Burcu Kosar: Yeah, um, so sprites, also known as red sprites, due to their dominant red color 13 00:01:08.910 --> 00:01:16.650 are upper atmospheric electrical discharges of air that are connected to thunderstorm systems below. 14 00:01:16.890 --> 00:01:24.630 So what I mean by that is every sprite event in a way has a parent lightning flash. So they're 15 00:01:24.630 --> 00:01:32.130 tightly connected in a way, they happen at about 50 miles up in our atmosphere. And they have 16 00:01:32.130 --> 00:01:39.330 complex morphological features. What I mean by that is, they come in various shapes and sizes, 17 00:01:39.510 --> 00:01:45.810 some of them look like a carrot bunch just pulled out of the ground. Some of them look like columns, 18 00:01:45.810 --> 00:01:52.200 some of them look like angels, and the most fascinating one is actually called "dancing 19 00:01:52.200 --> 00:01:59.520 sprites," they almost flicker like a little light show about the thunderstorm systems. And And also, 20 00:01:59.520 --> 00:02:05.610 we do not really currently understand how they take the shape they do or why they take the shape 21 00:02:05.610 --> 00:02:10.919 they do. It is a very least understood field of research. 22 00:02:11.370 --> 00:02:16.740 Miles Hatfield: How big are we talking? How rare are they? How hot or cold? Are they keeping up 23 00:02:16.740 --> 00:02:18.900 more sense of what sprites are like? So 24 00:02:19.470 --> 00:02:24.660 Dr. Burcu Kosar: what I would say is they are not like the hot lightning bolts, they are relatively 25 00:02:24.660 --> 00:02:31.050 cold. They actually their home is the coldest layer of the atmosphere, which is the upper 26 00:02:31.050 --> 00:02:37.530 sections of the mesosphere, so they are, they're formed by these filamentary plasma channels called 27 00:02:37.560 --> 00:02:44.970 "streamers," they are weakly ionized channels, so they're cooler in comparison to the lightning bolt 28 00:02:44.970 --> 00:02:54.150 itself. They are, they're relatively rare to be able to make them happen, we need very powerful, 29 00:02:54.330 --> 00:03:00.450 positive cloud-to-ground lightning flashes. So what are these positive cloud to ground lightning 30 00:03:00.450 --> 00:03:08.310 flashes? They are very powerful flashes, they they transfer the positive charge from the cloud to the 31 00:03:08.310 --> 00:03:12.840 ground, and they are responsible for generation of sprites. 32 00:03:14.700 --> 00:03:20.130 Miles Hatfield: So why have I not heard of sprites before? Are they very rare? Why? Why don't most 33 00:03:20.130 --> 00:03:21.060 people know about these? 34 00:03:21.090 --> 00:03:27.360 Dr. Burcu Kosar: So I would say it's a relatively new field of research. This field of research 35 00:03:27.360 --> 00:03:35.010 started in 1990s, when a group of scientists were testing a low light level TV camera for an 36 00:03:35.010 --> 00:03:41.910 upcoming rocket mission. And there must have been a thunderstorm relatively nearby. And they captured 37 00:03:41.910 --> 00:03:48.030 sprites on the record for the first time. When they reviewed their footage, they saw these two 38 00:03:48.030 --> 00:03:55.350 massive luminous blobs extending above the active thunderstorm systems. And that is 39 00:03:55.350 --> 00:04:01.980 actually the first milestone image that kickstarted this field of research in atmospheric and 40 00:04:01.980 --> 00:04:09.240 space electricity. After that, there has been many campaigns started to catch them and study them. 41 00:04:09.420 --> 00:04:14.400 There were ground-based campaigns, there were aircraft campaigns, the reason an aircraft's 42 00:04:14.430 --> 00:04:20.790 altitude is very, very good to study or look at these phenomena is the vantage point. When you're 43 00:04:20.790 --> 00:04:27.210 flying around the nearby thunderstorms, you have this great view of the top of the thunderstorms, 44 00:04:27.390 --> 00:04:35.010 which is home for these phenomena that we refer to as "transient luminous events." So another important 45 00:04:35.010 --> 00:04:42.570 thing to mention here is this field of research is actually no stranger to citizen science. Because 46 00:04:42.570 --> 00:04:48.450 when you look at some of the historical anecdotes, people have been describing sightings of these 47 00:04:48.450 --> 00:04:53.880 strange flashes of light above the thunderstorm, almost going back to hundreds of 48 00:04:53.880 --> 00:05:01.830 years, even pilots were seeing them but what they see is actually just a flicker of light, they do 49 00:05:01.830 --> 00:05:09.000 not see these phenomenal detail images that are shared on the on the internet. So that is a still capture 50 00:05:09.000 --> 00:05:15.810 capture ripped off of video footage. So they're very, very fast. So to the human eye, 51 00:05:15.810 --> 00:05:21.270 they're almost like a flicker of liight, like a flash of light. And it is very hard to perceive 52 00:05:21.270 --> 00:05:28.410 color. So people when they look at the aurora, they see these green arcs moving in the sky. For 53 00:05:28.410 --> 00:05:34.080 sprites, unfortunately, that is not possible because they are very brief. And very fast. They 54 00:05:34.080 --> 00:05:37.680 are they're visually beautiful in the still photographs. 55 00:05:40.260 --> 00:05:45.210 Miles Hatfield: So it sounds like you've seen some sprites in person before. Can you tell me what 56 00:05:45.240 --> 00:05:46.110 that was like? 57 00:05:46.200 --> 00:05:52.800 Dr. Burcu Kosar: So I wouldn't say I have seen it. I have captured it on camera about a year ago, I 58 00:05:52.800 --> 00:06:01.380 have been studying sprites for about 15 years now. I did my research work during my PhD. And like I 59 00:06:01.380 --> 00:06:09.210 said, it was it was an opportunity. We recorded a sprite-chasing documentary down in Oklahoma, I had 60 00:06:09.210 --> 00:06:16.320 the opportunity to work with one of the phenomenal sprite-chasers Paul Smith. And we went and we 61 00:06:16.320 --> 00:06:23.760 chased bunch of storms that was over, over a nearby state. And we were lucky enough to capture 62 00:06:23.760 --> 00:06:29.070 a sprite on camera and it was actually column sprites. It was it was a great experience, I would 63 00:06:29.070 --> 00:06:36.960 say because that kind of in a way made me realize how knowledgeable citizen scientists are. And the 64 00:06:37.110 --> 00:06:42.990 amount of information that we can exchange and collaborate and advance this field of research 65 00:06:43.140 --> 00:06:49.350 was really, really great. And, and that's why I'm thinking this project of mine that is going to be 66 00:06:49.350 --> 00:06:55.020 launching this month is definitely a very worthwhile effort. And I'm so excited about it. 67 00:06:55.800 --> 00:06:59.940 Miles Hatfield: Good. Tell, tell me more about what Spritacular is. You mentioned citizen 68 00:06:59.940 --> 00:07:05.760 science. But what does that mean? And how can your average person get involved in something like 69 00:07:05.760 --> 00:07:06.780 this? 70 00:07:06.780 --> 00:07:13.260 Dr. Burcu Kosar: Yeah, so Spritacular is NASA's brand new citizen science project. So citizen science 71 00:07:13.260 --> 00:07:20.310 projects are in a way, a collaboration between professional scientists and members of the public. 72 00:07:20.520 --> 00:07:27.870 So it is almost like an exchange of information. So as a scientist, I look at a lot of scientific 73 00:07:27.870 --> 00:07:34.020 data, I study the physics of this phenomenon. And scientists are very knowledgeable about these. And 74 00:07:34.020 --> 00:07:40.410 we look at satellite data. But when you look at the public and sprite chasers, they are phenomenal 75 00:07:40.410 --> 00:07:46.080 photographers. And not only that, they're very knowledgeable about what they're doing. They're 76 00:07:46.080 --> 00:07:52.650 almost I would, it would be wrong to call them amateurs, they're extremely talented. So they 77 00:07:52.650 --> 00:07:57.780 capture these phenomena. And they want to learn more about what they're capturing and what these 78 00:07:57.780 --> 00:08:04.200 things are. So that's where this project will come in. We want to create a bridge between these two 79 00:08:04.200 --> 00:08:10.680 communities, and enable exchange of information for the advancement of science collaboratively 80 00:08:10.680 --> 00:08:17.790 together. So the way people can participate in this project is, I would say if you live in a 81 00:08:17.790 --> 00:08:24.570 place where thunderstorms frequently happen, and if you happen to own a DSLR camera. And if you're 82 00:08:24.570 --> 00:08:31.290 a little bit patient, and if you like to go outside at night and watch the night sky, this is 83 00:08:31.290 --> 00:08:39.330 actually an excellent project for you. I would say the hardest part of catching a sprite is knowing 84 00:08:39.330 --> 00:08:45.660 where to look. But there will be wealth of information on our website, spritacular.org, 85 00:08:45.870 --> 00:08:51.060 where you can come and learn about these phenomena. And if you happen to observe sprites or 86 00:08:51.090 --> 00:08:56.790 any other TLEs, you can submit your observations to our database which will be used by the 87 00:08:56.790 --> 00:09:03.660 scientific community for research in the future. So if you -- long story short -- if you are passionate 88 00:09:03.660 --> 00:09:11.520 about thunderstorms, if you have some patience and an off-the-shelf DSLR camera, you're off to a great 89 00:09:11.520 --> 00:09:13.620 start to capture these events. 90 00:09:14.280 --> 00:09:19.410 Miles Hatfield: This raises a good question. I mean, probably most people who know about NASA, 91 00:09:19.410 --> 00:09:24.060 know that we've got all kinds of satellites, we've got all kinds of equipment that we use to make 92 00:09:24.060 --> 00:09:30.720 observations of the night sky. What makes a person with a camera on the ground so useful for these 93 00:09:30.720 --> 00:09:32.610 sorts of questions that you're asking? 94 00:09:32.910 --> 00:09:38.520 Dr. Burcu Kosar: So, yeah, so because these events occur in a specific region of the atmosphere as I 95 00:09:38.520 --> 00:09:45.510 mentioned earlier, the best vantage point to observe them are from aircrafts or locations where 96 00:09:45.510 --> 00:09:53.010 storms happen frequently from the orbit satellites see them but it's very hard to resolve the details 97 00:09:53.010 --> 00:09:59.610 of these phenomena. The ground observations give us an excellent vantage point to see the details 98 00:09:59.640 --> 00:10:05.190 and also, they serve as ground truth for satellite observations, if you look at the 99 00:10:05.190 --> 00:10:11.100 satellite data to understand what we captured, and if we have a confirmation from the ground, that is 100 00:10:11.100 --> 00:10:18.450 an excellent source of data point, I would say, and with this project, we are going to be creating 101 00:10:18.600 --> 00:10:26.400 the first ever crowdsourced database of TLEs, which currently doesn't exist. So it is a very exciting 102 00:10:26.400 --> 00:10:32.970 endeavor, it will be open to every scientific community. And we intend to make this a global 103 00:10:32.970 --> 00:10:38.610 project because where powerful thunderstorms happen, you'll have a chance to see sprites and 104 00:10:38.610 --> 00:10:39.960 other TLEs. 105 00:10:40.380 --> 00:10:44.340 Miles Hatfield: So tell me more. What about these other TLEs? Obviously, your your project is 106 00:10:44.460 --> 00:10:50.610 called Spritacular, as I understand sprites are the most common TLE that people are likely to see, 107 00:10:50.610 --> 00:10:53.670 but there's a range of others. Can you say more about what they are? 108 00:10:53.670 --> 00:10:58.560 Dr. Burcu Kosar: Yeah, of course. So the "transient luminous events" is the technical name the science community 109 00:10:58.560 --> 00:11:05.250 gave to refer to these optical emissions above the thunderstorms. So this region is almost literally 110 00:11:05.250 --> 00:11:10.770 like an electrical zoo, we have all sorts of different phenomena. Sprites are one of the like 111 00:11:10.770 --> 00:11:17.130 you mentioned one of the most commonly observed types, but we have halos, we have ELVEs, halos are 112 00:11:17.130 --> 00:11:25.170 almost like a diffuse glow, like in the shape of a pancake. ELVEs are in the shape of a doughnut that 113 00:11:25.170 --> 00:11:32.460 extends radially outward. And we have jets and gigantic jets which shoot up from the 114 00:11:32.460 --> 00:11:39.780 thunderstorm tops, gigantic jets are so massive, they literally create an electrical bridge between 115 00:11:39.780 --> 00:11:46.350 the thunderstorm tops and the ionosphere, effectively coupling two different regions of the 116 00:11:46.350 --> 00:11:52.500 atmosphere. So these are some other types of TLEs that we are interested in, including in our 117 00:11:52.500 --> 00:11:54.960 database for scientific research. 118 00:11:55.260 --> 00:11:57.120 Miles Hatfield: Where do they get these funny names from? 119 00:11:57.960 --> 00:12:03.840 Dr. Burcu Kosar: Yeah, that's a good question. So the first discovered TLE was sprites, and because 120 00:12:03.840 --> 00:12:12.510 of their elusive fleeting nature, they were dubbed as sprites by late Dave Sentman. And after that, 121 00:12:12.540 --> 00:12:18.240 it kind of got stuck. And when the field of research got kicked off with this first 122 00:12:18.240 --> 00:12:25.110 observation, we started discovering more types. And I think the overall theme sort of got stuck. 123 00:12:25.110 --> 00:12:30.450 Some of these names are actually acronyms, but I think scientific field has been a little bit 124 00:12:30.450 --> 00:12:33.510 playful with naming these optical phenomena. 125 00:12:35.850 --> 00:12:42.600 Miles Hatfield: So aside from making bright light shows, and quick, you know, momentary flashes, to 126 00:12:42.600 --> 00:12:49.560 these TLEs have any effect on people on our Earth system as a whole? Are they dangerous in any way? 127 00:12:49.620 --> 00:12:54.330 Dr. Burcu Kosar: Yeah, that is a good question. So they happen as I mentioned earlier, at about 50 128 00:12:54.330 --> 00:13:01.860 miles up in our atmosphere, so they do not endanger us here on Earth. But of course, they 129 00:13:01.860 --> 00:13:08.490 have effect on other Earth systems, such as the global electric circuit. So "global electric 130 00:13:08.490 --> 00:13:17.640 circuit" is the name that we give collectively to circulating currents in our atmosphere. So sprites 131 00:13:17.640 --> 00:13:25.650 and other TLEs being electrical phenomena, they do carry currents. So they provide in a way, feedback 132 00:13:25.680 --> 00:13:32.010 into this global electric circuit. I would say a thunderstorm and lightning flash or sprite or any 133 00:13:32.010 --> 00:13:40.560 other TLE is not an isolated event, it actually feeds back into this larger system that we call 134 00:13:40.560 --> 00:13:47.280 global electric circuit. And another another thing to mention here, sprites locally affect the 135 00:13:47.280 --> 00:13:54.570 atmosphere electrically and chemically and modify its contents. So what this does is this affects 136 00:13:54.570 --> 00:14:01.890 our long-range radio communication systems, and also the atmospheric chemistry changes that they 137 00:14:01.890 --> 00:14:08.400 do locally in the atmosphere. It feeds back into the atmospheric chemistry. So they do have 138 00:14:08.400 --> 00:14:12.390 global effects that we would like to study and understand further. 139 00:14:12.690 --> 00:14:16.440 Miles Hatfield: This stuff is fascinating. Thank you so much for joining me for this discussion. 140 00:14:16.440 --> 00:14:20.970 Burcu. Thank you, everyone. And before you all head out for trick or treating, there's much more 141 00:14:20.970 --> 00:14:25.110 to learn about transient luminous events. Burcu will be sticking around and answering your 142 00:14:25.110 --> 00:14:28.250 questions today, so leave them in the comments below. 143 00:14:28.400 --> 00:14:30.500 Thank you all for joining us and Happy Halloween!