WEBVTT FILE 1 00:00:06.715 --> 00:00:08.341 This image was taken to celebrate 2 00:00:08.341 --> 00:00:11.720 the 26th anniversary of Hubble's launch. 3 00:00:12.303 --> 00:00:14.639 Every year, every anniversary, we try to find 4 00:00:14.639 --> 00:00:18.476 a new image used to celebrate it so that over the years we've done 5 00:00:18.518 --> 00:00:23.273 all sorts of objects from star clusters to nebulae to external galaxies. 6 00:00:23.356 --> 00:00:26.484 But for the 26th, we chose this one. 7 00:00:27.652 --> 00:00:30.071 This is the Bubble nebula, in the constellation 8 00:00:30.071 --> 00:00:34.242 Cassiopeia, and it's about 7,100 light years distant from us. 9 00:00:34.743 --> 00:00:38.121 I like this image because of the variety of things you can see in it. 10 00:00:38.955 --> 00:00:41.624 Obviously, you've got the massive star at the center. 11 00:00:41.624 --> 00:00:46.212 Big ring here is a bunch of material thrown off the star and it's 12 00:00:46.254 --> 00:00:48.256 been able to travel out that far. 13 00:00:50.258 --> 00:00:51.342 The star threw off 14 00:00:51.342 --> 00:00:54.721 material relatively symmetrically around the star, 15 00:00:54.804 --> 00:00:59.142 but the interstellar material is the preexisting material in the area around 16 00:00:59.142 --> 00:01:02.937 the star was much denser on this side, which actually makes sense 17 00:01:02.937 --> 00:01:05.440 because you've got this huge blob of material up here. 18 00:01:05.440 --> 00:01:07.484 It makes sense that there's more material near that 19 00:01:07.484 --> 00:01:10.820 and there is on this relatively empty spot at the bottom of the image. 20 00:01:10.820 --> 00:01:15.366 So as the material came off the star, it runs into much denser material 21 00:01:15.366 --> 00:01:19.496 going up to the upper left. And that A, slows it down. 22 00:01:19.579 --> 00:01:20.413 So it's not going 23 00:01:20.413 --> 00:01:24.793 as far in that direction. And B, heats it up, so it's glowing much more. 24 00:01:24.793 --> 00:01:27.962 Whereas the material that came off to the bottom right didn't 25 00:01:27.962 --> 00:01:29.506 run into very much. 26 00:01:29.506 --> 00:01:31.508 So it's going unimpeded. 27 00:01:31.508 --> 00:01:34.761 It's moving out faster and getting further away from the star, 28 00:01:34.761 --> 00:01:36.471 and it's also not heating anything up. 29 00:01:36.471 --> 00:01:39.015 So you're not seeing anything glow down in that region. 30 00:01:39.015 --> 00:01:42.727 So it's a matter of what the material around the star was in one direction. 31 00:01:42.727 --> 00:01:46.189 It was unimpeded and basically able to go out long distances. 32 00:01:46.189 --> 00:01:47.148 In the other direction, 33 00:01:47.148 --> 00:01:51.486 it ran into resistance right away and effectively couldn't go very far. 34 00:01:51.653 --> 00:01:54.656 But it's giving us a nice light show in the process. 35 00:01:55.907 --> 00:01:57.742 It's a pretty massive star. 36 00:01:57.742 --> 00:02:01.871 We think it started out at about 60 times the mass of the sun, 37 00:02:02.038 --> 00:02:03.623 and because it's been throwing off 38 00:02:03.623 --> 00:02:07.544 material over time, it's lost about a quarter of that mass, 39 00:02:07.544 --> 00:02:12.423 about 15 solar masses and is now down to about 45 solar masses. 40 00:02:12.423 --> 00:02:15.468 Large stars like that have relatively short lives. 41 00:02:15.468 --> 00:02:19.097 They're fast and furious, but they go through life very, very quickly. 42 00:02:19.597 --> 00:02:23.017 Something like the sun last 10 billion years. Something like this. 43 00:02:23.017 --> 00:02:26.980 you're talking tens of millions of years instead of billions of years. 44 00:02:27.188 --> 00:02:30.150 So plenty of material left to go supernova. 45 00:02:30.150 --> 00:02:33.862 You need a star to have something like 1.4 times 46 00:02:33.862 --> 00:02:37.699 the mass of the sun, at least, before it's a candidate for a supernova. 47 00:02:38.032 --> 00:02:41.911 So at 45 solar masses, it’s going to supernova, no question.