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  • Neutron stars are one of the most extreme things in the universe!

  • They're like giant atom cores,

  • Kilometers in diameter,

  • Unbelievably dense and violent,

  • But how can something like this even exist!

  • The life of a star is dominated by two forces being in balance

  • It's own gravity,

  • and the radiation pressure of it's fusion reaction.

  • In the core of stars, hydrogen is fused into helium.

  • Eventually, the hydrogen in the core is exhausted.

  • If the star is massive enough, helium is now fused into carbon.

  • The cores of these massive stars become layered like onions,

  • as heavier and heavier atomic nuclei build up at the center.

  • Carbon is fused into neon, which leads to oxygen, which leads to silicon.

  • Eventually, the fusion reaction hits iron, which can not fuse into another element.

  • When the fusion stops, the radiation pressure drops rapidly.

  • The star is no longer in balance.

  • and if it's core mass exceeds about 1.4 solar masses, a catastrophic collapse takes place.

  • The outer part of the core reaches velocities of up to 70,000 kilometers a second,

  • as it collapses towards the center of the star.

  • Now, only the fundamental forces inside an atom are left to fight the gravitational collapse.

  • The quantum mechanical repulsion of electrons is overcome,

  • and electrons and protons fuse into neutrons packed as densely as an atomic nucleus.

  • The outer layers of the star are catapulted into space, in a violent supernova explosion.

  • So, now we have a neutron star!

  • It's mass is between 1 and 3 suns, but compressed to an object about 25 kilometers wide!

  • And 500,000 times the mass of Earth, in this tiny ball, that's roughly the diameter of Manhattan.

  • It's so dense that one cubic centimeter of neutron star, contains the same mass as an iron cube 700 meters across.

  • That's roughly 1 billion tones, as massive as mount Everest, in a space the size of a sugar cube.

  • Neutron star gravity is pretty impressive too!

  • If you were to drop an object from 1 meter over the surface, it would hit the star in one microsecond,

  • and accelerate up to 7.2 million km/hour.

  • The surface is super flat, with irregularities of 5 millimeters maximum,

  • with a super thin atmosphere of hot plasma.

  • The surface temperature is about 1 million Kelvin, compared to 5,800 kelvin for our sun.

  • Lets look inside the neutron star!

  • The crust is extremely hard, and is most likely made of an iron atom nuclei lattice,

  • with a sea of electrons flowing through them.

  • The closer we get to the core, the more neutrons and the fewer protons we see

  • until there's just an incredibly dense soup of indistinguishable neutrons.

  • The cores of neutron stars are very, very weird.

  • We are not sure what their properties are, but our closest guess is super fluid neutron degenerate matter,

  • or some kind of ultra dense quark matter called: quark-Gluon plasma.

  • That does not make any sense in the traditional way, and can only exist in such an ultra extreme environment.

  • In many ways, a neutron star is similar to a giant atom core.

  • The most important difference is that atom cores are held together by strong interaction, and neutron stars by gravity.

  • As if all this wasn't extreme enough lets take a look at a few other properties.

  • Neutron stars spin very very fast, young ones, several times per second.

  • And if there's a poor star near by to feed a neutron star, it can rotate up to several hundred times per second.

  • Like the object PSRJ1748-2446ad, it spins at approximately 252 million km/hour.

  • This is so fast that the star has a rather strange shape.

  • We call these objects pulsars, because they emit a strong radio signal.

  • And the magnetic field of a neutron star is roughly 8 trillion times stronger than the magnetic field of Earth.

  • So strong that atoms get bent when they enter it's influence.

  • Okay, I think we got the point across.

  • Neutron stars are some of the most extreme, but also some of the coolest objects in the universe.

  • Hopefully, we will one day send spaceships to learn more about them, and take some neat pictures!

  • But we shouldn't get too close!

  • Subtitles by: Mohammed Abdulhak (m_abdulhak@outlook.com)

Neutron stars are one of the most extreme things in the universe!

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