An amateur Russian astronomer has observed a Supernova in M82, a galaxy that is only 12 million light years away (a walk to the chemist on cosmic scales).
The supernova has been confirmed as a Type Ia supernova. These supernovae occur when a white dwarf in a binary system accretes enough mass from the companion to surpass the Chandrasekhar mass. The increase in mass triggers the supernovae.
Type Ia supernovae are used as “standard candles” to measure the distance of galaxies in the Universe and this is the first Type Ia event in our neighbourhood in the last 30 years.