WEBVTT FILE 1 00:00:01.050 --> 00:00:05.000 [Music throughout] My name is 2 00:00:05.000 --> 00:00:09.050 Karl Battams, I’m a computational scientist at the Naval Research Lab, and for nearly 17 years 3 00:00:09.050 --> 00:00:13.050 I’ve been in charge of NASA’s Sungrazer Project. The Sungrazer Project is 4 00:00:13.050 --> 00:00:17.000 a citizen science project that allows anyone in the world to discover new comets 5 00:00:17.000 --> 00:00:21.000 that are seen in images recorded by the joint ESA/NASA SOHO satellite. 6 00:00:21.000 --> 00:00:25.050 Recently, the project has reached a very special milestone: 7 00:00:25.050 --> 00:00:29.050 SOHO has found 4000 previously unknown comets in nearly 8 00:00:29.050 --> 00:00:33.000 25 years. So I want to share with you my favorite comets 9 00:00:33.000 --> 00:00:37.050 that SOHO has discovered. [#4 Twin Comets] These were a pair of bright comets, 10 00:00:37.050 --> 00:00:41.050 both members of what’s known as the Kreutz group, which is a very large 11 00:00:41.050 --> 00:00:45.050 family of comets that all follow the same path in space. 12 00:00:45.050 --> 00:00:49.050 Unfortunately, and like nearly all of SOHO’s comets, these guys were completely 13 00:00:49.050 --> 00:00:53.050 vaporized by the Sun’s radiation. [#3 SOHO 422] Most of 14 00:00:53.050 --> 00:00:57.050 SOHO’s comets are what we call sungrazers, which means they follow an orbit that almost 15 00:00:57.050 --> 00:01:01.050 grazes the surface of the Sun. But we’ve also discovered a lot of comets 16 00:01:01.050 --> 00:01:05.000 that stay just a bit further away from the Sun, and, unlike sungrazers, 17 00:01:05.000 --> 00:01:09.000 manage to at least partially survive passing by the Sun. This comet, 18 00:01:09.000 --> 00:01:13.000 SOHO’s 422nd discovery, was found back in 19 00:01:13.000 --> 00:01:17.050 2002. Here we see it swinging around the sun at a seemingly safe 20 00:01:17.050 --> 00:01:21.050 distance. Unfortunately, it kind of looks to me like this comet may 21 00:01:21.050 --> 00:01:25.050 have turned entirely to dust towards the end of the movie. 22 00:01:25.050 --> 00:01:29.000 It can be hard to know the exact fates of comets like this because 23 00:01:29.000 --> 00:01:33.050 they’re often impossible to locate from Earth because they’re so close to the Sun. 24 00:01:33.050 --> 00:01:37.050 [#2 C2015 D1] One of the great things about SOHO’s comet discoveries 25 00:01:37.050 --> 00:01:41.000 is they also teach us things about the Sun. Here we see what looks like a 26 00:01:41.000 --> 00:01:45.050 typical bright sungrazer racing through the LASCO cameras and in this case disappearing 27 00:01:45.050 --> 00:01:49.050 behind LASCO’s solar occulting disk. And normally this is 28 00:01:49.050 --> 00:01:53.050 the last we see of them. But this comet, to our absolute astonishment, 29 00:01:53.050 --> 00:01:57.050 was also visible in images recorded by NASA’s 30 00:01:57.050 --> 00:02:01.050 Solar Dynamics Observatory, which looks at the Sun’s million-degree atmosphere 31 00:02:01.050 --> 00:02:05.050 in extreme ultraviolet light. This was the first time anyone had ever 32 00:02:05.050 --> 00:02:09.050 seen something like this. We were completely blown away by this result. And 33 00:02:09.050 --> 00:02:13.050 we can use comets like this almost like remote probes. They 34 00:02:13.050 --> 00:02:17.050 allow us to learn about the environment close to the Sun 35 00:02:17.050 --> 00:02:21.050 by watching how the comet is reacting within that 36 00:02:21.050 --> 00:02:25.050 really extreme environment. [#1 The 4,000th] Finally, this is certainly not 37 00:02:25.050 --> 00:02:29.050 the biggest or brightest comet SOHO has ever found, but for me it’s 38 00:02:29.050 --> 00:02:33.050 absolutely one of the most important. This is SOHO’s 4000th 39 00:02:33.050 --> 00:02:37.050 comet discovery. That’s a truly remarkable milestone for this mission to reach. 40 00:02:37.050 --> 00:02:41.050 Particularly as it was never designed to look at 41 00:02:41.050 --> 00:02:45.050 or discover comets. This milestone is also a huge testament to 42 00:02:45.050 --> 00:02:49.050 the NASA and ESA scientists and engineers in support 43 00:02:49.050 --> 00:02:53.050 teams that have kept SOHO running so well all these years. 44 00:02:53.050 --> 00:02:57.050 And of course, probably most of all, it’s a testament to the 45 00:02:57.050 --> 00:03:01.050 army of citizen scientists who have contributed so much 46 00:03:01.050 --> 00:03:05.050 free time to scouring the SOHO images and 47 00:03:05.050 --> 00:03:09.050 helping us realize all of this incredible science that we’ve gained so far. 48 00:03:09.050 --> 00:03:13.050 Here’s hoping for another 4000 comets. 49 00:03:13.050 --> 00:03:17.050 [Music fades] 50 00:03:17.050 --> 00:03:21.050 [Music] 51 00:03:21.050 --> 00:03:25.056 [Music]