WEBVTT FILE 1 00:00:00.000 --> 00:00:04.504 Text on screen: Why does space weather matter to us on Earth? 2 00:00:04.504 --> 00:00:15.632 Well, space weather is this whole field of understanding solar storms – huge eruptions that happen on the sun and travel through the whole solar system and sometimes they impact the Earth. 3 00:00:15.632 --> 00:00:28.278 And these solar storms interact with our electronics, with our technology and in some cases they can create a radiation environment, which is hazardous to space travelers. 4 00:00:28.278 --> 00:00:40.523 So it is critical that we understand them both to make sure we can keep them from impacting our technological society as well as making our astronauts and future travels to Mars safe. 5 00:00:40.523 --> 00:00:45.161 Text on screen: How has STEREO changed our understanding of the sun? 6 00:00:45.161 --> 00:00:55.889 Well, the great thing about STEREO is we now have a new perspective – we can see the sun from the side, we can see the sun from the back for the first time in history. 7 00:00:55.889 --> 00:01:07.033 In the past we only saw things looking straight at the Sun from the Earth and saw them coming directly at us. It’s very difficult to see how fast things are, what their real structure is. 8 00:01:07.033 --> 00:01:22.298 But, then once you move out to the side or even to the back you have additional perspectives, which really show you the structure, the shape, how these things are traveling, how fast they’re traveling and ultimately to better understand them. 9 00:01:22.298 --> 00:01:32.542 So STEREO has given us this unique view, which has allowed us to understand space weather in ways that we never have before. 10 00:01:32.542 --> 00:01:37.097 Text on screen: We're gearing up for the solar event of the century in the US - the August 2017 solar eclipse. How does an eclipse help us understand the sun? 11 00:01:37.097 --> 00:01:54.080 An eclipse, in particular a total eclipse, is a really unique opportunity to see the lower part of the sun’s atmosphere called the corona. And this is something that is very difficult to see unless the sun’s disk is completely blocked out. 12 00:01:54.080 --> 00:02:09.312 This outer part of the sun’s atmosphere is millions of times dimmer than the sun’s disk, so the moon blocking it out allows us to see this and to see it from the ground. And this is important because this is the area where all the action happens. 13 00:02:09.312 --> 00:02:25.428 This is where solar storms originate, where the eruptions come from and this means that during a total solar eclipse we can finally look at all this really amazing structure in ways that we normally couldn’t do. 14 00:02:25.428 --> 00:02:30.433 Text on screen: NASA has an upcoming mission that will for the first time touch the sun. Can you tell us about that? 15 00:02:30.433 --> 00:02:47.383 Well, not too long from now in a couple of years, NASA will be launching a mission called the Solar Probe Plus. And this mission is going to literally travel to the sun. This is the first time mankind has gone to the sun. 16 00:02:47.383 --> 00:03:01.564 And we’re going to fly through the sun’s atmosphere – sort of like flying over the cloud tops – scooping up, looking at what’s happening as well taking samples and measuring the sun’s atmosphere. 17 00:03:01.564 --> 00:03:19.716 So this is going to be happening in the area that we are talking about during a total solar eclipse and an area that STEREO allows us to see, but now we are going to be there. We are not just going to be looking from a distance, but we are going to be there, in person, for the first time in history. 18 00:03:19.716 --> 00:03:24.220 Text on screen: We heard STEREO-B was giving NASA the silent treatment for a while. Can you tell us what happened? 19 00:03:24.220 --> 00:03:40.336 Well all spacecraft have to deal with interference from the sun. The sun is very bright. It puts out light in all different wavelengths – every wavelength you can think of – and so, it often becomes a source of noise for spacecraft. 20 00:03:40.336 --> 00:03:59.656 But generally that noise is only over a very short period of time. Because STEREO has traveled back around behind the sun, when we looked to the spacecraft we have a period of over three months that it was extremely noisy and we were unable to communicate with the spacecraft. 21 00:03:59.656 --> 00:04:12.168 Unfortunately, for STEREO-B, one of the two spacecraft, when we past that period of silence we were not able to regain contact with STEREO-B. 22 00:04:12.168 --> 00:04:20.860 So it hasn’t – we’ve only been able to regain some contact after almost 24 months of silence. 23 00:04:20.860 --> 00:04:25.365 Text on screen: Why are you so excited about STEREO, this anniversary and how NASA studies the sun? 24 00:04:25.365 --> 00:04:46.836 Well, STEREO is really exciting in the first place because it is the first time that we have seen the entire sun, 360 degrees, all at the same time. So that is the first time in history that we as – uh – human beings have been able to see the whole sun at once. 25 00:04:46.836 --> 00:04:56.562 So that in itself is very, very amazing. But also on top of that, STEREO was only really designed to be around for two years and we’ve had it now for ten years. 26 00:04:56.562 --> 00:05:16.165 So, not only is it a scientific marvel in terms of what it has enabled us to understand about space weather and solar storms, but it’s an engineering marvel. It is - was the first time we were launching two spacecraft like that, in that kind of orbit, and it still keeps on ticking after all this time. 27 00:05:16.165 --> 00:05:33.950 So, it’s really an exciting, exciting mission for NASA for science, for technology, engineering. And it is something we hope continues to go on and continues to bring back new and exciting information – uh – over the next few years. 28 00:05:33.950 --> 00:05:38.454 Text on screen: Where can we learn more? 29 00:05:38.454 --> 00:05:49.749 Go to www.nasa.gov/sunearth to find out more about STEREO and all the other solar missions that we have here at NASA.