1 00:00:09,467 --> 00:00:13,555 This is an image of the Crab Nebula, which is one of the most famous 2 00:00:13,555 --> 00:00:16,975 and most well-studied astronomical objects ever. 3 00:00:17,726 --> 00:00:20,603 It's one of the touchstone images from the Hubble Space Telescope. 4 00:00:21,938 --> 00:00:23,690 It's just the most beautiful, 5 00:00:23,690 --> 00:00:26,192 awe inspiring image you can imagine. 6 00:00:26,776 --> 00:00:29,988 Technically, it's actually called a pulsar wind nebula, 7 00:00:30,238 --> 00:00:35,452 and we can connect it to events in history going back to the year 1054, 8 00:00:35,452 --> 00:00:37,203 where Chinese astronomers 9 00:00:37,203 --> 00:00:40,498 recorded the appearance of a new star, which they called a guest star. 10 00:00:40,874 --> 00:00:43,960 That got incredibly bright, that you could see it during the daytime, 11 00:00:43,960 --> 00:00:47,839 which we now know was a supernova explosion that was visible 12 00:00:47,839 --> 00:00:51,634 to the naked eye during the day for about two weeks, maybe longer. 13 00:00:54,304 --> 00:00:56,973 What we're seeing here, this filamentary structure 14 00:00:56,973 --> 00:01:00,810 is actually density variations in that material. 15 00:01:01,227 --> 00:01:05,273 So as that material was spewed from the star in the supernova explosion, 16 00:01:05,607 --> 00:01:09,027 it's still got the fingerprints of that explosion. 17 00:01:09,152 --> 00:01:13,656 It's still expanding out into the surrounding medium. 18 00:01:13,907 --> 00:01:16,659 So what we're able to see are knots of material 19 00:01:17,202 --> 00:01:19,621 made up of things like oxygen, sulfur. 20 00:01:19,829 --> 00:01:23,666 And in this full color image, the oxygen is coming out separately 21 00:01:23,666 --> 00:01:26,795 from the sulfur where the the greenish, yellowish 22 00:01:26,795 --> 00:01:29,130 tinge is really oxygen heavy. 23 00:01:31,841 --> 00:01:35,762 Embedded in this nebula is the pulsar at the center. 24 00:01:36,137 --> 00:01:38,056 And it's very energetic, 25 00:01:38,056 --> 00:01:42,644 so it's spewing out energy at all wavelengths, actually. 26 00:01:42,894 --> 00:01:48,358 And some of that energy is being captured by the material surrounding the pulsar. 27 00:01:48,691 --> 00:01:51,903 And then that material glows and it glows in a certain wavelength 28 00:01:52,278 --> 00:01:54,948 or color, depending on what it's made of. 29 00:01:54,948 --> 00:01:59,369 So all the material that we're seeing here is actually from the star itself. 30 00:01:59,369 --> 00:02:02,747 It's been blown out in that supernova explosion, 31 00:02:03,498 --> 00:02:07,377 but it's being illuminated by the pulsar in the center. 32 00:02:09,045 --> 00:02:09,629 Oxygen is 33 00:02:09,629 --> 00:02:13,550 such an important element of life on the planet Earth. 34 00:02:13,550 --> 00:02:15,844 We are breathing in oxygen as we speak. 35 00:02:16,261 --> 00:02:18,888 Where did that oxygen come from? 36 00:02:18,888 --> 00:02:21,224 It came from the hearts of stars. 37 00:02:21,683 --> 00:02:24,686 They made the oxygen in fusion and they expelled it 38 00:02:24,686 --> 00:02:26,312 back into the interstellar medium. 39 00:02:26,312 --> 00:02:28,606 We're actually watching that happen here. 40 00:02:28,606 --> 00:02:32,277 Maybe someday there will be a planet there with an atmosphere that includes oxygen 41 00:02:32,277 --> 00:02:35,530 that can be breathed by living organisms like us.