The video provides a comprehensive overview of the life cycle of a neutron star, starting from its formation as a supernova and ending with its eventual death.
Neutron stars are the remnants of massive stars that have exhausted their fuel and collapsed under their own gravity. The process of a star's life is driven by a delicate balance of gravity and nuclear fusion. As a star exhausts its hydrogen fuel, it begins to burn heavier elements like helium, carbon, oxygen, silicon, and eventually iron. When the iron fuel is exhausted, the fusion process stops and the star's core is crushed, leading to a supernova explosion.
The supernova explosion is so powerful that it can outshine entire galaxies. The remaining core of the star, now a neutron star, is incredibly dense, with a mass around a million times that of the Earth compressed into an object about 25 kilometers wide. The neutron star's gravity is so strong that it can even bend light, allowing us to see the front and parts of the back of the star.
The neutron star's interior is composed of layers of iron left over from the supernova, squeezed together in a crystal lattice. As we go deeper, the nuclei are squeezed closer together, eventually forming a dense material known as nuclear pasta. This material is so dense that it may be the strongest material in the universe.
Neutron stars are also known to spin very fast, creating pulses of radio waves due to their magnetic fields. These radio pulsars are the best-known type of neutron star, with about 2,000 known in the Milky Way.
The video concludes by discussing the potential for neutron stars to merge in a kilonova explosion, which could lead to the creation of heavy elements. This process is believed to be the origin of most of the heavy elements in the universe.
The video also mentions that our entire technological modern world was built out of the elements neutron stars made in eons past, sending these atoms on a thirteen-billion-year journey to come together and make us and our world.
1. Neutron stars are one of the most extreme and violent things in the universe.
2. Giant atomic nuclei, only a few kilometers in diameter, but as massive as stars.
3. They owe their existence to the death of something majestic.
4. Stars exist because of a fragile balance.
5. The mass of millions of billions of trillions of tons of hot plasma are being pulled inwards by gravity.
6. Hydrogen fuses into helium, releasing energy which pushes against gravity and tries to escape.
7. As long as this balance exists, stars are pretty stable.
8. Eventually, the hydrogen will be exhausted.
9. Medium stars, like our Sun, go through a giant phase, where they burn helium into carbon and oxygen, before they eventually turn into white dwarfs.
10. But in stars many times the mass of our Sun, things get interesting when the helium is exhausted.
11. For a moment, the balance of pressure and radiation tips, and gravity wins, squeezing the star tighter than before.
12. The core burns hotter and faster, while the outer layers of the star swell by hundreds of times, fusing heavier and heavier elements.
13. Carbon burns to neon in centuries, neon to oxygen in a year, oxygen to silicon in months, and silicon to iron in a day.
14. And then… death. Iron is nuclear ash. It has no energy to give and cannot be fused.
15. The fusion suddenly stops, and the balance ends.
16. Without the outward pressure from fusion, the core is crushed by the enormous weight of the star above it.
17. What happens now is awesome and scary. Particles, like electrons and protons, really don’t want to be near each other.
18. But the pressure of the collapsing star is so great that electrons and protons fuse into neutrons, which then get squeezed together as tightly as in atomic nuclei.
19. An iron ball, the size of the Earth, is squeezed into a ball of pure nuclear matter, the size of a city.
20. But not just the core; The whole star implodes, gravity pulling the outer layers in at 25% the speed of light.
21. This implosion bounces off the iron core, producing a shock wave that explodes outwards and catapults the rest of the star into space.
22. This is what we call a supernova explosion, and it will outshine entire galaxies.
23. What remains of the star is now a neutron star. Its mass is around a million times the mass of the Earth but compressed to an object about 25 kilometers wide.
24. It’s so dense that the mass of all living humans would fit into one cubic centimeter of neutron star matter. That’s roughly a billion tons in a space the size of a sugar cube.
25. Put another way, that’s Mount Everest in a cup of coffee.
26. From the outside, a neutron star is unbelievably extreme. Its gravity is the strongest, outside black holes.
27. Light is bent around it, meaning you can see the front and parts of the back.
28. Their surfaces reach 1,000,000 degrees Celsius, compared to a measly 6,000 degrees for our Sun.
29. Neutron stars are celestial ballerinas, spinning many times per second.
30. This creates pulses because their magnetic field creates a beam of radio waves, which passes every time they spin.
31. These radio pulsars are the best-known type of neutron star.
32. About 2,000 are known of in the Milky Way.
33. These magnetic fields are the strongest in the universe, a quadrillion times stronger than Earth’s after they’re born.
34. They’re called magnetars until they calm down a little.
35. But the absolute best kind of neutron stars are friends with other neutron stars.
36. By radiating away energy as gravitational waves, ripples in spacetime, their orbits can decay, and they can crash into and kill each other in a kilonova explosion that spews out a lot of their guts.
37. When they do, the conditions become so extreme that,