Welcome to Brainstuff, a production of iHeartRadio, Hey brain Stuff, Lauren Vogelbomb. Here humans are born, then we grow and die. Our life cycles are basically the same as those of the massive stars twinkling in the night sky. If we exploded in a blaze of glory at the end of our time when the cosmosis, most colossal stars go out with a bang. The immense interstellar explosion is known as a supernova, while smaller stars simply fizzle out. The death
of an astronomical heavyweight is a showstopper. It spent its life cannibalizing its own inerds for fuel and sometimes the intererds of a solar neighbor. When there is nothing left for it to consume, it collapses in on itself and then explodes outward and a depth knell that outshines other huge stars and sometimes entire galaxies for days, weeks, or even months. Some are so bright that they can be
seen with a simple set of binoculars. A supernova should statistically detonate once every fifty years or so in a galaxy the size of our Milky Way, So how do you spot one? Identifying a new point of light as a supernova as opposed to a high flying aircraft or a comet, may be easier than you think. The stars about to go supernova change color from red to blue due to their increasing temperatures, and supernova maintain some blue
color due to the Doppler effect. The light from their explosions moves towards us so fast that it appears blue plus. Unlike a comet or commercial airplane, a supernova won't waver from its position. But how do stars self destruct so spectacularly? Let's talk about a giant stars life cycle. A giant stars starts out when gas and dust buckle under an assertive gravitational pull to form a baby star. As the material at the center of a fledgling star heats, it
attracts more interstellar gas and dust. This growth phase can take up to fifty million years, followed by another ten billion years of shiny adulthood. Stars are fueled by the nuclear fusion of hydrogen into the slightly denser and heavier element helium. The fusion takes place in the star's core, and the energy it produces flows outward, creating the star's observable glow and preventing the heavy core from collapsing in
on itself. When a star starts running out of hydrogen to fuse into helium, it's the beginning of the end. With less energy radiating outward, the core begins to collapse, causing its temperature to spike. Hydrogen fusion continues only in the star's outer layers, which causes it to expand it becomes a red giant. A red giant will lose its outer layers, either by consuming them or releasing them into space to become a white dwarf. A white dwarf with
enough mass will eventually go supernova. Its core will collapse, resulting in an explosion that can't compare to any we might experience on Earth, unless we were to bundle a few Octilian nuclear warheads and detonate them all at the same time. Our own Sun isn't big enough to go out with such a bang, but stars that are are separated into two supernova classes, type one and type two. Astronomers learn a lot about stars from the colors of
life that they emit. Using a device called a spectrograph, they can get a clear picture of exactly what elements are burning inside a star. In the nineteen forties, astronomers noticed that some supernova type one do not contain hydrogen, but the others do. Those are type two. In the nineteen eighties, as observational technology improved, scientists further divided type one supernova into three subcategories, Type one A, which contains silicon in their spectra, Type one B, which contain helium,
and type one C, which contain neither. The stars lose elements when stellar winds rip their outer layers away long before they go supernova. A Type one A supernova work differently than all the other types. A Type one A supernova results from a white dwarf that's part of a binary system, that is, one that shares an orbit with another star and was about twice the size of our Sun during its life. The white dwarf's mass allows it to fuse elements slightly heavier than hydrogen, so it has
a stable core of carbon and oxygen. Left to its own devices, this white dwarf would eventually decay into a black dwarf, but since it's not alone, it has access to resources that other stars don't. The more massive of the two stars acts like an opportunistic sibling, using its gravitational pull to steal matter from the other star. This gluttonous star grows until it exceeds what's called the Chindra
Shaykhar limit, after the guy who discovered it. It's a mass of one point four times that of our self, otherwise known as one point four solar masses. At this size, the white dwarf suddenly has enough heat and pressure in its core to fuse carbon, and all of that carbon fuses at once, like a thermonuclear bomb going off, blowing the star to bits. It leaves behind a gaseous remnant that's symmetrical in shape and contains a great deal of
iron created in the heat of the explosion. Because type one A supernovae all explode at the same point in their stellar deaths, they all peak at almost exactly the same brightness. It's so consistent that type one A supernova are also called standard candles. Once astronomers find one in a region of space, they can use it as a baseline with which to compare and learn about other objects
around it. Type one, B, one C, and type two supernova, despite showing different elements in their spectra, all explode the same way. They start out so huge, possibly eight times the size of our Sun that they cannibalize themselves to the point of collapse. A white dwarf eventually created from a star that massive, has so much heat and pressure inside its core that lighter elements keep fusing into increasingly
heavy elements instead of flying off into space. This produces enough radiating energy to support the star's increasing weight until iron forms. The fusion of iron into heavier elements actually uses energy rather than giving it off, so when iron begins to fuse, the star's outer layers lose their support and begin to fall inward. To understand the huge explosion that results, you have to know what's going on with
the star's tiniest particles. When a white dwarf is massive enough to fuse the iron in its core, those iron atoms are incredibly hot and densely packed, squashed together like sweaty clowns stuck in a circus car. Their sub atomic particles collide and the iron atom's nuclei split, leaving behind helium nuclei plus a few leftover neutrons, and absorbing a lot of energy in the process. That energy was holding the star's core up, so without it, the core starts
shrinking rapidly. It goes from a diameter of some five thousand miles to only twelve miles real Suddenly that's about eight thousand kilometers to just nineteen. This creates temperature somewhere in the region of one hundred and eighty billion degrees fahrenheit or one hundred billion degrees celsius, though at that point who's really counting. The heat causes protons and electrons to fuse together, canceling each other out to become neutrons
and expelling a bunch of neutrinos in the process. The neutrinos can escape, so they do, leaving the core with even less energy to hold itself up. The core contracts as much as it physically can, but the star's outer layers keep falling inward even after there's no more room. That's when they rebound in that enormous explosion. All of that took a lot of words to explain, but it can happen in as little as a quarter of a second.
The explosion is hot enough to fuse elements far heavier than iron, and it releases these elements in a gaseous cloud that will become an asymmetrical remnant around the remaining solid core. What happens next depends on how massive the original star was. If its inner core was less than three solar masses, it creates a neutron star with a core about as dense as an atom's nucleus and a
powerful magnetic field. If its magnetic field creates lighthouse style beams of radiation that flash toward Earth as the star rotates, it's called a pulsar. But when a star with the core equal to three solar masses or more explodes, that can result in a black hole. A scientist's hypothesize that black holes form when gravity causes the stars compressed inner
core to continually sink into itself. A black hole has such powerful gravitational force that it can drag surrounding matter, even planets, stars, and light itself into its mall, all of their powers of destruction. Aside, a lot of good can come of a supernova, and by tracking the demise of particular stars, scientists have uncovered ancient astronomical events and
predicted future changes in the uns. And by using type one A supernova as standard candles, researchers have been able to map entire galaxies distances from us and determine that the universe is in fact expanding ever more rapidly. But of course, exploding stars leave more than just an electromagnetic
signature behind. They also produce cosmic debris and dust. Type one a supernova are thought to be responsible for the large amount of iron in the universe, and all of the elements in the universe that are heavier than iron, from cobalt to rent genium, are thought to be created during core collapse supernova explosions. After millions of years, these remnants commingle with space gas to form new interstellar life baby stars that mature, age and may eventually complete the
circle of life by becoming a supernova themselves. Today's episode is based on article how supernova works on HowStuffWorks dot com, written by Laureel Dove. Brain Stuff is production of iHeartRadio in partnership with how stuffworks dot Com and is produced by Tyler Klang. For more podcasts my heart Radio, visit the iHeartRadio app, Apple Podcasts, or wherever you listen to your favorite shows.