WEBVTT - What Happens During a Supernova? 0:00:01.840 --> 0:00:07.600 Welcome to Brainstuff, a production of iHeartRadio, Hey brain Stuff, 0:00:07.640 --> 0:00:14.280 Lauren Vogelbomb. Here humans are born, then we grow and die. 0:00:14.760 --> 0:00:17.880 Our life cycles are basically the same as those of 0:00:17.960 --> 0:00:21.840 the massive stars twinkling in the night sky. If we 0:00:22.079 --> 0:00:24.400 exploded in a blaze of glory at the end of 0:00:24.400 --> 0:00:29.400 our time when the cosmosis, most colossal stars go out 0:00:29.440 --> 0:00:33.120 with a bang. The immense interstellar explosion is known as 0:00:33.159 --> 0:00:38.040 a supernova, while smaller stars simply fizzle out. The death 0:00:38.080 --> 0:00:42.320 of an astronomical heavyweight is a showstopper. It spent its 0:00:42.400 --> 0:00:46.080 life cannibalizing its own inerds for fuel and sometimes the 0:00:46.120 --> 0:00:49.560 intererds of a solar neighbor. When there is nothing left 0:00:49.600 --> 0:00:52.159 for it to consume, it collapses in on itself and 0:00:52.280 --> 0:00:56.040 then explodes outward and a depth knell that outshines other 0:00:56.160 --> 0:01:00.520 huge stars and sometimes entire galaxies for days, weeks, or 0:01:00.640 --> 0:01:04.040 even months. Some are so bright that they can be 0:01:04.120 --> 0:01:09.839 seen with a simple set of binoculars. A supernova should 0:01:09.920 --> 0:01:13.080 statistically detonate once every fifty years or so in a 0:01:13.200 --> 0:01:17.360 galaxy the size of our Milky Way, So how do 0:01:17.400 --> 0:01:20.759 you spot one? Identifying a new point of light as 0:01:20.800 --> 0:01:23.920 a supernova as opposed to a high flying aircraft or 0:01:23.959 --> 0:01:27.680 a comet, may be easier than you think. The stars 0:01:27.760 --> 0:01:31.000 about to go supernova change color from red to blue 0:01:31.200 --> 0:01:36.160 due to their increasing temperatures, and supernova maintain some blue 0:01:36.160 --> 0:01:39.080 color due to the Doppler effect. The light from their 0:01:39.120 --> 0:01:44.200 explosions moves towards us so fast that it appears blue plus. 0:01:44.360 --> 0:01:47.960 Unlike a comet or commercial airplane, a supernova won't waver 0:01:48.080 --> 0:01:54.760 from its position. But how do stars self destruct so spectacularly? 0:01:55.800 --> 0:01:59.600 Let's talk about a giant stars life cycle. A giant 0:01:59.600 --> 0:02:02.800 stars starts out when gas and dust buckle under an 0:02:02.880 --> 0:02:07.760 assertive gravitational pull to form a baby star. As the 0:02:07.800 --> 0:02:10.720 material at the center of a fledgling star heats, it 0:02:10.760 --> 0:02:14.880 attracts more interstellar gas and dust. This growth phase can 0:02:14.960 --> 0:02:18.160 take up to fifty million years, followed by another ten 0:02:18.200 --> 0:02:22.959 billion years of shiny adulthood. Stars are fueled by the 0:02:23.040 --> 0:02:26.840 nuclear fusion of hydrogen into the slightly denser and heavier 0:02:26.880 --> 0:02:30.840 element helium. The fusion takes place in the star's core, 0:02:31.120 --> 0:02:34.520 and the energy it produces flows outward, creating the star's 0:02:34.560 --> 0:02:38.360 observable glow and preventing the heavy core from collapsing in 0:02:38.440 --> 0:02:42.560 on itself. When a star starts running out of hydrogen 0:02:42.639 --> 0:02:45.640 to fuse into helium, it's the beginning of the end. 0:02:46.120 --> 0:02:49.799 With less energy radiating outward, the core begins to collapse, 0:02:50.040 --> 0:02:54.400 causing its temperature to spike. Hydrogen fusion continues only in 0:02:54.400 --> 0:02:57.600 the star's outer layers, which causes it to expand it 0:02:57.639 --> 0:03:02.639 becomes a red giant. A red giant will lose its 0:03:02.639 --> 0:03:05.919 outer layers, either by consuming them or releasing them into 0:03:05.919 --> 0:03:10.280 space to become a white dwarf. A white dwarf with 0:03:10.360 --> 0:03:14.960 enough mass will eventually go supernova. Its core will collapse, 0:03:15.240 --> 0:03:18.560 resulting in an explosion that can't compare to any we 0:03:18.639 --> 0:03:22.120 might experience on Earth, unless we were to bundle a 0:03:22.200 --> 0:03:25.359 few Octilian nuclear warheads and detonate them all at the 0:03:25.400 --> 0:03:28.280 same time. Our own Sun isn't big enough to go 0:03:28.360 --> 0:03:32.840 out with such a bang, but stars that are are 0:03:32.880 --> 0:03:37.360 separated into two supernova classes, type one and type two. 0:03:38.200 --> 0:03:40.840 Astronomers learn a lot about stars from the colors of 0:03:40.920 --> 0:03:44.080 life that they emit. Using a device called a spectrograph, 0:03:44.160 --> 0:03:47.040 they can get a clear picture of exactly what elements 0:03:47.040 --> 0:03:52.200 are burning inside a star. In the nineteen forties, astronomers 0:03:52.240 --> 0:03:56.200 noticed that some supernova type one do not contain hydrogen, 0:03:56.640 --> 0:04:00.280 but the others do. Those are type two. In the 0:04:00.360 --> 0:04:05.240 nineteen eighties, as observational technology improved, scientists further divided type 0:04:05.240 --> 0:04:10.120 one supernova into three subcategories, Type one A, which contains 0:04:10.160 --> 0:04:13.880 silicon in their spectra, Type one B, which contain helium, 0:04:14.160 --> 0:04:19.320 and type one C, which contain neither. The stars lose 0:04:19.360 --> 0:04:22.520 elements when stellar winds rip their outer layers away long 0:04:22.560 --> 0:04:28.680 before they go supernova. A Type one A supernova work 0:04:28.839 --> 0:04:31.960 differently than all the other types. A Type one A 0:04:32.120 --> 0:04:34.760 supernova results from a white dwarf that's part of a 0:04:34.800 --> 0:04:37.680 binary system, that is, one that shares an orbit with 0:04:37.720 --> 0:04:40.600 another star and was about twice the size of our 0:04:40.640 --> 0:04:44.719 Sun during its life. The white dwarf's mass allows it 0:04:44.760 --> 0:04:48.120 to fuse elements slightly heavier than hydrogen, so it has 0:04:48.160 --> 0:04:52.880 a stable core of carbon and oxygen. Left to its 0:04:52.880 --> 0:04:56.400 own devices, this white dwarf would eventually decay into a 0:04:56.480 --> 0:05:00.320 black dwarf, but since it's not alone, it has access 0:05:00.360 --> 0:05:04.120 to resources that other stars don't. The more massive of 0:05:04.120 --> 0:05:07.480 the two stars acts like an opportunistic sibling, using its 0:05:07.480 --> 0:05:12.279 gravitational pull to steal matter from the other star. This 0:05:12.480 --> 0:05:16.559 gluttonous star grows until it exceeds what's called the Chindra 0:05:16.680 --> 0:05:20.320 Shaykhar limit, after the guy who discovered it. It's a 0:05:20.400 --> 0:05:23.000 mass of one point four times that of our self, 0:05:23.360 --> 0:05:27.240 otherwise known as one point four solar masses. At this size, 0:05:27.320 --> 0:05:30.719 the white dwarf suddenly has enough heat and pressure in 0:05:30.760 --> 0:05:34.040 its core to fuse carbon, and all of that carbon 0:05:34.120 --> 0:05:38.039 fuses at once, like a thermonuclear bomb going off, blowing 0:05:38.120 --> 0:05:41.960 the star to bits. It leaves behind a gaseous remnant 0:05:42.000 --> 0:05:44.919 that's symmetrical in shape and contains a great deal of 0:05:45.000 --> 0:05:51.200 iron created in the heat of the explosion. Because type 0:05:51.240 --> 0:05:54.320 one A supernovae all explode at the same point in 0:05:54.360 --> 0:05:58.039 their stellar deaths, they all peak at almost exactly the 0:05:58.080 --> 0:06:02.240 same brightness. It's so consistent that type one A supernova 0:06:02.360 --> 0:06:06.760 are also called standard candles. Once astronomers find one in 0:06:06.800 --> 0:06:08.880 a region of space, they can use it as a 0:06:08.880 --> 0:06:12.640 baseline with which to compare and learn about other objects 0:06:12.640 --> 0:06:19.279 around it. Type one, B, one C, and type two supernova, 0:06:19.480 --> 0:06:23.240 despite showing different elements in their spectra, all explode the 0:06:23.279 --> 0:06:28.239 same way. They start out so huge, possibly eight times 0:06:28.240 --> 0:06:31.039 the size of our Sun that they cannibalize themselves to 0:06:31.080 --> 0:06:35.080 the point of collapse. A white dwarf eventually created from 0:06:35.080 --> 0:06:38.080 a star that massive, has so much heat and pressure 0:06:38.120 --> 0:06:42.520 inside its core that lighter elements keep fusing into increasingly 0:06:42.560 --> 0:06:47.280 heavy elements instead of flying off into space. This produces 0:06:47.440 --> 0:06:52.039 enough radiating energy to support the star's increasing weight until 0:06:52.520 --> 0:06:57.719 iron forms. The fusion of iron into heavier elements actually 0:06:57.839 --> 0:07:01.600 uses energy rather than giving it off, so when iron 0:07:01.680 --> 0:07:05.080 begins to fuse, the star's outer layers lose their support 0:07:05.200 --> 0:07:09.920 and begin to fall inward. To understand the huge explosion 0:07:09.960 --> 0:07:12.400 that results, you have to know what's going on with 0:07:12.440 --> 0:07:17.920 the star's tiniest particles. When a white dwarf is massive 0:07:18.000 --> 0:07:20.960 enough to fuse the iron in its core, those iron 0:07:21.000 --> 0:07:25.400 atoms are incredibly hot and densely packed, squashed together like 0:07:25.600 --> 0:07:29.480 sweaty clowns stuck in a circus car. Their sub atomic 0:07:29.520 --> 0:07:34.040 particles collide and the iron atom's nuclei split, leaving behind 0:07:34.120 --> 0:07:38.400 helium nuclei plus a few leftover neutrons, and absorbing a 0:07:38.520 --> 0:07:43.360 lot of energy in the process. That energy was holding 0:07:43.480 --> 0:07:46.920 the star's core up, so without it, the core starts 0:07:46.920 --> 0:07:50.440 shrinking rapidly. It goes from a diameter of some five 0:07:50.480 --> 0:07:55.160 thousand miles to only twelve miles real Suddenly that's about 0:07:55.200 --> 0:08:00.840 eight thousand kilometers to just nineteen. This creates temperature somewhere 0:08:00.840 --> 0:08:03.360 in the region of one hundred and eighty billion degrees 0:08:03.440 --> 0:08:06.400 fahrenheit or one hundred billion degrees celsius, though at that 0:08:06.440 --> 0:08:11.000 point who's really counting. The heat causes protons and electrons 0:08:11.000 --> 0:08:14.400 to fuse together, canceling each other out to become neutrons 0:08:14.560 --> 0:08:18.000 and expelling a bunch of neutrinos in the process. The 0:08:18.040 --> 0:08:21.280 neutrinos can escape, so they do, leaving the core with 0:08:21.320 --> 0:08:25.080 even less energy to hold itself up. The core contracts 0:08:25.120 --> 0:08:27.640 as much as it physically can, but the star's outer 0:08:27.760 --> 0:08:30.920 layers keep falling inward even after there's no more room. 0:08:31.800 --> 0:08:37.840 That's when they rebound in that enormous explosion. All of 0:08:37.880 --> 0:08:40.520 that took a lot of words to explain, but it 0:08:40.520 --> 0:08:45.400 can happen in as little as a quarter of a second. 0:08:45.960 --> 0:08:48.840 The explosion is hot enough to fuse elements far heavier 0:08:48.840 --> 0:08:51.600 than iron, and it releases these elements in a gaseous 0:08:51.600 --> 0:08:54.960 cloud that will become an asymmetrical remnant around the remaining 0:08:55.240 --> 0:09:01.280 solid core. What happens next depends on how massive the 0:09:01.320 --> 0:09:05.000 original star was. If its inner core was less than 0:09:05.080 --> 0:09:08.080 three solar masses, it creates a neutron star with a 0:09:08.080 --> 0:09:11.040 core about as dense as an atom's nucleus and a 0:09:11.120 --> 0:09:16.040 powerful magnetic field. If its magnetic field creates lighthouse style 0:09:16.120 --> 0:09:19.480 beams of radiation that flash toward Earth as the star rotates, 0:09:19.679 --> 0:09:23.640 it's called a pulsar. But when a star with the 0:09:23.640 --> 0:09:27.199 core equal to three solar masses or more explodes, that 0:09:27.240 --> 0:09:31.400 can result in a black hole. A scientist's hypothesize that 0:09:31.480 --> 0:09:34.959 black holes form when gravity causes the stars compressed inner 0:09:34.960 --> 0:09:38.880 core to continually sink into itself. A black hole has 0:09:38.920 --> 0:09:42.079 such powerful gravitational force that it can drag surrounding matter, 0:09:42.320 --> 0:09:47.959 even planets, stars, and light itself into its mall, all 0:09:48.000 --> 0:09:50.760 of their powers of destruction. Aside, a lot of good 0:09:50.800 --> 0:09:54.000 can come of a supernova, and by tracking the demise 0:09:54.040 --> 0:09:58.440 of particular stars, scientists have uncovered ancient astronomical events and 0:09:58.520 --> 0:10:02.400 predicted future changes in the uns. And by using type 0:10:02.400 --> 0:10:06.000 one A supernova as standard candles, researchers have been able 0:10:06.040 --> 0:10:09.560 to map entire galaxies distances from us and determine that 0:10:09.600 --> 0:10:15.440 the universe is in fact expanding ever more rapidly. But 0:10:15.800 --> 0:10:19.719 of course, exploding stars leave more than just an electromagnetic 0:10:19.760 --> 0:10:25.040 signature behind. They also produce cosmic debris and dust. Type 0:10:25.040 --> 0:10:27.679 one a supernova are thought to be responsible for the 0:10:27.760 --> 0:10:31.320 large amount of iron in the universe, and all of 0:10:31.320 --> 0:10:33.640 the elements in the universe that are heavier than iron, 0:10:33.760 --> 0:10:36.960 from cobalt to rent genium, are thought to be created 0:10:37.040 --> 0:10:42.320 during core collapse supernova explosions. After millions of years, these 0:10:42.360 --> 0:10:46.080 remnants commingle with space gas to form new interstellar life 0:10:46.679 --> 0:10:50.840 baby stars that mature, age and may eventually complete the 0:10:50.960 --> 0:10:59.560 circle of life by becoming a supernova themselves. Today's episode 0:10:59.559 --> 0:11:02.720 is based on article how supernova works on HowStuffWorks dot com, 0:11:02.760 --> 0:11:06.000 written by Laureel Dove. Brain Stuff is production of iHeartRadio 0:11:06.040 --> 0:11:08.320 in partnership with how stuffworks dot Com and is produced 0:11:08.320 --> 0:11:11.720 by Tyler Klang. For more podcasts my heart Radio, visit 0:11:11.760 --> 0:11:14.720 the iHeartRadio app, Apple Podcasts, or wherever you listen to 0:11:14.760 --> 0:11:15.679 your favorite shows.