THE GREATEST MYSTERIES OF THE UNIVERSE
Black holes are vast masses of gravity. They are born when massive stars collapse. Giant stars, such as Pistol, have huge furnaces inside them. The furnaces produce elements by nuclear fusion, releasing energy as radiation – hydrogen atoms fuse to form helium, which combines in a chain until finally iron is made. Unlike other elements, iron does not produce other elements or release energy, so it keeps building up in the star until it fills up the core. In the ordinary course of their lives, stars have equal amounts of radiation and gravity – there is a balance between the force pulling it in and the force pushing it out. However, when iron fills up the core, this balance is broken. Gravity becomes more while radiation grows less. When gravity shoots up, the force pulling it in grows strong. So slowly but surely, the star starts shrinking, its mass squeezing into a smaller space. This causes its gravitational force to grow stronger. Then, the process speeds up until it explodes as a stunning burst of light and energy called a supernova. After the star explodes, a black hole will be born if it is big enough. A black hole’s mass is so immense that it sucks up everything passing by, including light – black holes appear in space as black spheres with a ring around them called the Event Horizon. Although black holes are smaller than the stars that produced them, that doesn’t mean they are small. The most massive black hole ever discovered, Ton 618, has a staggering diameter of 300 billion kilometres – to put it in perspective, that is 47 times the distance between the Sun and Pluto! Arnav Krishan Ghosh 5B
