WEBVTT FILE 1 00:00:00.050 --> 00:00:03.237 Have you ever tried to listen to your favorite radio station only 2 00:00:03.237 --> 00:00:05.772 to find it garbled or replaced by a different station? 3 00:00:05.772 --> 00:00:08.892 Well if so, you might’ve been the victim of something known as 4 00:00:08.892 --> 00:00:13.130 a “Sporadic-E Layer.” They’re concentrations of electrically 5 00:00:13.130 --> 00:00:16.166 charged gas called plasma in a region of space known as the 6 00:00:16.166 --> 00:00:16.984 ionosphere. 7 00:00:16.984 --> 00:00:20.270 They act kind of like mirrors in the sky, and bounce radio 8 00:00:20.270 --> 00:00:23.373 transmissions over the horizon and interfere with your radio, 9 00:00:23.373 --> 00:00:26.610 kind of like two people trying to talk over each other. 10 00:00:26.610 --> 00:00:29.429 Even though we’ve known about these layers for over 80 years 11 00:00:29.429 --> 00:00:32.633 now, we still don’t fully understand them because they 12 00:00:32.633 --> 00:00:35.202 occur at an altitude that is really difficult to explore. 13 00:00:35.202 --> 00:00:38.689 The air there is so thin that we can’t fly an aircraft, but it’s 14 00:00:38.689 --> 00:00:41.425 just thick enough that if we were to try to orbit a satellite 15 00:00:41.425 --> 00:00:42.759 it would burn up in the atmosphere. 16 00:00:42.759 --> 00:00:45.295 So we’ve only ever been able to explore a handful. 17 00:00:45.295 --> 00:00:48.365 Well, one planet where the atmosphere is much thinner is 18 00:00:48.365 --> 00:00:49.700 the planet Mars. 19 00:00:49.700 --> 00:00:52.469 And one satellite that is currently exploring Mars is the 20 00:00:52.469 --> 00:00:54.037 MAVEN orbiter. 21 00:00:54.037 --> 00:00:56.406 One of the instruments on MAVEN is called STATIC. 22 00:00:56.406 --> 00:00:58.959 It’s designed to measure plasma escaping from the ionosphere, 23 00:00:58.959 --> 00:01:01.995 this upper atmospheric layer of Mars. 24 00:01:01.995 --> 00:01:04.815 And in the data, scientists were seeing that when MAVEN would fly 25 00:01:04.815 --> 00:01:07.150 through a certain region of the atmosphere, POOF! 26 00:01:07.150 --> 00:01:09.686 There was this big density enhancement of this plasma 27 00:01:09.686 --> 00:01:10.971 concentration. 28 00:01:10.971 --> 00:01:13.657 Scientists realized that they had discovered the Martian 29 00:01:13.657 --> 00:01:14.875 equivalent of these layers! 30 00:01:14.875 --> 00:01:17.644 It’s exciting because now we have a place that we can go to 31 00:01:17.644 --> 00:01:20.297 directly explore these layers with a satellite. 32 00:01:20.297 --> 00:01:23.166 MAVEN has encountered more of these layers at Mars than we’ve 33 00:01:23.166 --> 00:01:24.551 ever been able to explore here at Earth. 34 00:01:24.551 --> 00:01:27.688 At Earth, the layers are temporary and unpredictable, but 35 00:01:27.688 --> 00:01:30.374 at Mars they seem to be almost permanent and long-lived at 36 00:01:30.374 --> 00:01:31.908 predictable locations. 37 00:01:31.908 --> 00:01:34.461 Also, scientists found something that they didn’t even know could 38 00:01:34.461 --> 00:01:35.145 exist. 39 00:01:35.145 --> 00:01:37.197 MAVEN discovered the opposite of a layer. 40 00:01:37.197 --> 00:01:39.750 They’re calling it a “rift” and it’s where the sky has been 41 00:01:39.750 --> 00:01:40.550 pulled apart. 42 00:01:40.550 --> 00:01:43.420 And rather than a concentration of this plasma, there’s a 43 00:01:43.420 --> 00:01:44.087 depletion. 44 00:01:44.087 --> 00:01:47.107 Many models said this actually couldn’t happen, but yet they do 45 00:01:47.107 --> 00:01:49.676 exist and we find them at Mars. 46 00:01:49.676 --> 00:01:52.746 This demonstrates how little we actually know, and how much 47 00:01:52.746 --> 00:01:54.398 there still is to discover. 48 00:01:54.398 --> 00:01:57.217 These layers are so common – they happen over our heads all 49 00:01:57.217 --> 00:01:57.884 the time. 50 00:01:57.884 --> 00:02:00.003 You yourself have probably detected one of these with your 51 00:02:00.003 --> 00:02:02.372 own radio, even if you weren’t aware of it. 52 00:02:02.372 --> 00:02:04.691 And who would’ve thought that one of the best ways to explore 53 00:02:04.691 --> 00:02:07.661 them would be to send a spacecraft 300 million miles to 54 00:02:07.661 --> 00:02:10.347 the red planet. 55 00:02:10.347 --> 00:00:00.000 [music]