A black hole begins to form as an aging star abruptly collapses when it ceases . This occurs after the star has consumed its component elements in this order: .
1. Hydrogen
2. Helium
3. Carbon
4. Oxygen
5. Neon
6. Magnesium
7. Silicon
8. Sulfur
9. Iron
10. Core Collapse
Once the star has consumed all its available elements, it undergoes a rapid collapse due to the lack of fusion reactions sustaining it. The gravitational force becomes dominant, causing the star's core to collapse inwards. If the mass of the core is above a certain limit, known as the Chandrasekhar limit, then a black hole will form.