A supernova represents one of the universe's most spectacular and consequential events—the explosive death of a massive star that releases more energy in seconds than our Sun will produce in its entire 10-billion-year lifetime. These cosmic detonations can briefly outshine entire galaxies containing hundreds of billions of stars, reaching absolute magnitudes of -19 or brighter.</p><p>Two primary types occur: Type Ia supernovae result from white dwarf stars exceeding the critical Chandrasekhar limit of 1.4 solar masses, while Type II supernovae mark the collapse of stars at least eight times more massive than our Sun when their nuclear fuel is exhausted. The explosion propels stellar material outward at velocities exceeding 10,000 kilometers per second, creating expanding shock waves that can be observed for millennia.</p><p>Perhaps most remarkably, supernovae forge and distribute elements heavier than iron—including gold, silver, and uranium—throughout the cosmos. Without these stellar furnaces, rocky planets and life as we know it couldn't exist. The famous Crab Nebula, visible today, originated from a supernova observed by Chinese astronomers in 1054 CE, while SN 1987A in the Large Magellanic Cloud provided unprecedented insights into stellar death when it erupted in 1987. Modern astronomers use Type Ia supernovae as "standard candles" to measure cosmic distances and study dark energy's effects on universal expansion.
Examples
**Example:** The supernova SN 1987A, observed in 1987, was the brightest supernova visible from Earth in nearly 400 years. The Crab Nebula is the remnant of a supernova that was observed by Chinese astronomers in 1054 CE.