A near-Earth supernova is an explosion resulting from the death of a star that occurs close enough to the Earth (roughly less than 10 to 300 parsecs [30 to 1000 light-years] away[2]) to have noticeable effects on Earth's biosphere.
An estimated 20 supernova explosions have happened within 300 pc of the Earth over the last 11 million years. Type II supernova explosions are expected to occur in active star-forming regions, with 12 such OB associations being located within 650 pc of the Earth. At present, there are eight near-Earth supernova candidates within 300 pc.[3][4]
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