An explosion is a rapid expansion of matter driven by an extreme release of energy, generating high temperatures and pressurized gases, and can be classified as either a supersonic detonation (using high explosives) or a subsonic deflagration (using low explosives). These events arise from various natural and artificial causes, including volcanic eruptions from rising magma, high-speed impacts, and human-made chemical or nuclear reactions. In the cosmos, the largest explosions are supernovae, while smaller stellar flares occur on the Sun, and notable terrestrial events like the 1908 Tunguska event resulted from a meteor air burst; even black hole mergers, such as GW190521 observed in 2019, can radiate immense energy as gravitational waves. The most common artificial explosions are chemical, typically involving violent oxidation reactions, with gunpowder being the first invented, followed by Frederick Augustus Abel's nitrocellulose (1865) and Alfred Nobel's dynamite (1866). These reactions are often triggered by a spark or flame, and while they power rocket engines, they can also cause dangerous accidental explosions in fuel tanks and other systems.