How a Supernova Works
In 1572, Danish astronomer Tycho Brahe noticed something puzzling in the night sky: a bright, new (in Latin, nova) star that faded as quickly as it appeared. Until Brahe discovered the disappearing star (which we know today was a supernova, and not a new star but rather a dying star), it was widely believed in the West that the stars never changed [source: Tycho Brahe Museum].
This is the remnant of the supernova Tycho Brahe observed some 400 years ago. The image is a colorized composite of low-energy x-rays (in red) showing debris and high-energy x-rays (in blue) showing the blast wave, plus the visible field of stars around it. [Top image credit: NASA/CXC/Rutgers/K. Eriksen et al.]
Learn more here.