There are trillions of stars in the universe of many types. From red giants to white dwarfs, they vary in size, temperature and density. One particular type is a neutron star. They have many interesting properties, from extreme density, magnetism, and gravity, to the scorching heat that makes our sun feel like a warm tropical beach. The environment of a neutron star is incomprehensibly brutal. Neutron stars are the remnants of stars with a mass four to eight times that of our sun. A neutron star can form when the star goes supernova. A star goes super nova when it runs out of hydrogen to fuse into helium. When all the hydrogen is used up, the star begins to fuse helium and continues to fuse increasingly heavier elements, until it reaches iron. Once the star attempts to fuse iron, the star is effectively dead, because smelting iron requires more energy to start the reaction than it will release. When the star fuses iron, it absorbs energy and gravity begins to compress it because the star is no longer able to fight gravity because fusion in the star has stopped. As soon as the star has been sufficiently compressed, it will begin to merge again, releasing incredible amounts of energy, causing a supernova. When a star goes supernova, it blows away the outer layers of material into space, leaving only the core. If the star were large enough, only the core would remain. Since the nucleus is unable to produce energy through nuclear fusion, gravity begins to compress it on itself. As the star becomes denser and denser, this process accelerates. Once there is no more space, this process stops. One of the many extremes on a neutron star is density. Neutron stars are incredibly small, only twelve and a half miles in diameter... in the center of the paper... which explains why you accelerate while on a swing and pull your arms in. When you release the loaded swing and let your arms and legs flail all over the place, you don't go very fast. However, when you bring your arms and legs closer to your torso, the law of conservation of angular momentum causes you to rotate faster. Although there are trillions of stars in the universe, neutron stars are among the most interesting. From extreme mass to small size, they host some of the most extreme environments you can find. They can create new celestial bodies as easily as they can destroy them. They have many shapes, solitary objects, binary systems, pulsars and magnetars, but they all have similar properties. They all have extreme gravity, rotation speeds, magnetic fields, and densities. All this makes neutron stars unique in a stellar universe.