Complex sentence: It is an example of an intensely magnetic star, known as a magnetar, which is thought to arise from a fairly recent supernova explosion; only four are known to exist for certain within our Milky Way Galaxy.
Split into simpler sentences: It is an example of an intensely magnetic star, known as a magnetar, which is thought to arise from a fairly recent supernova explosion. Only four are known to exist for certain within our Milky Way Galaxy.