Cosmic Ray Font: Supernova remnants rev up ions

In 1572, the Danish astronomer Tycho Brahe created a sensation when he reported that a star suddenly appeared in the sky, blazing brighter than Venus, and then faded from view. Tycho’s “new star” was in fact a supernova, an exploding old star. More than 4 centuries later, observations of the remnant of Tycho’s supernova are still revealing information to astronomers.