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Supernovae

A supernova is a powerful and luminous explosion of a star. These occur during the last evolutionary stages of massive stars or when a white dwarf—a dense stellar remnant—is triggered into runaway nuclear fusion. A supernova can briefly shine as brightly as an entire galaxy. These explosions matter because they expel material across space, creating the building blocks for new stars and planets. Supernovae are a major source of elements like oxygen and iron in the universe, and their expanding shock waves can trigger the formation of new stars. They also help astronomers measure cosmic distances, revealing that the universe is expanding faster than expected.

Sources

• en.wikipedia.org: “A supernova (pl.: supernovae) is a powerful and luminous explosion of a star. A supernova occurs during the last evolutionary stages of a massive star, or when a white dwarf is triggered into runaway nuclear fusion.”
• en.wikipedia.org: “The peak optical luminosity of a supernova can be comparable to that of an entire galaxy before fading over several weeks or months.”
• en.wikipedia.org: “Supernovae can expel several solar masses of material at speeds up to several percent of the speed of light. This drives an expanding shock wave into the surrounding interstellar medium, sweeping up an expanding shell of gas and dust observed as a supernova remnant. Supernovae are a major source of elements in the interstellar medium from oxygen to rubidium. The expanding shock waves of supernovae can trigger the formation of new stars.”