In 1930, Chandra, an Indian student showed mathematically that massive stars explode into a supernova and then collapse down into neutron stars,or black holes. Before that Scientists assumed that all stars collapsed into white dwarfs when they died. Chandra’s theory was ridiculed as ‘absurd’.
After Betelgeuse goes supernova, it will be brighter than a full moon and visible during the day. It will shine for weeks/months before fading away. It will likely explode within a million years.
The Pillars of Creation, a nebula 7,000 light years away, was destroyed by supernova 6,000 years ago. In a thousand years we will see it destroyed as it takes 7,000 years for the light to reach Earth.