This day in space historyStars
By November 11, 1572, a new star in Cassiopeia was brighter than Jupiter. Danish astronomer Tycho Brahe observed and studied it. It was a supernova, the explosion of a star. It stayed visible to the naked eye into early 1574.
Comparing Tycho’s observations with those of other astronomers showed the object lay farther away than the Moon. That challenged the Aristotelian idea that the realm of the stars never changes. The debris cloud is still there, and NASA’s Chandra X-ray Observatory studies it today. Chandra’s distance estimate is about 13,000 light-years from Earth.
13,000 light-years
Distance to Tycho's supernova remnant