Supernova (Paperback)

High Quality Content by WIKIPEDIA articles A supernova is a stellar explosion that is more energetic than a nova. It is pronounced / su p r no v / with the plural supernovae / su p r no vi / or supernovas. Supernovae are extremely luminous and cause a burst of radiation that often briefly outshines an entire galaxy, before fading from view over several weeks or months. During this short interval a supernova can radiate as much energy as the Sun is expected to emit over its entire life span. The explosion expels much or all of a star's material at a velocity of up to 30,000km/s (10% of the speed of light), driving a shock wave into the surrounding interstellar medium. This shock wave sweeps up an expanding shell of gas and dust called a supernova remnant.