Over 160,000 years ago a white dwarf went supernova in the nearby dwarf galaxy we call the Large Magellanic Cloud. Its light traveled through space and reached Earth around 670 years ago. That’s the new estimation that astronomers have worked out. By studying the shell of debris from this dead star, they were able to rewind the clock and work out when it might have been visible in the sky.
The Large Magellanic Cloud is a companion galaxy to our own, the Milky Way. It is visible in the night sky of the Southern Hemisphere with another dwarf galaxy, the Small Magellanic Cloud. Supernova SNR 0519−69.0 has been studied for a long time and now a combination of optical observations from Hubble and X-ray data from NASA’s Chandra observatory has provided a more detailed view of how fast the shock wave from the explosion is expanding.
The fastest shocks are moving at 5,820 kilometers (3,620 miles) per second. The slowest shocks average about 1,670 kilometers (1,040 miles) per second. The reconstruction of the expansion of these shockwaves places the explosion at about 670 years ago plus or minus 70 years.
Taking the decade of the 1350s as indicative of the time of the explosion, a very different world would have potentially seen the supernova in the sky. The One Hundred Years' war was in its initial phase, with the famous victory of the Battle of Poitiers. The Black Death made its first appearance in Europe. In China, the Red Turban Rebellion was just beginning, which will lead to the beginning of the Ming Dynasty.
The supernova was likely visible to the naked eye as it was a Type Ia supernova. While still far away enough to not be visible during the daytime, people across the Southern Hemisphere might have suddenly spotted a bright new star in the Large Magellanic Cloud.
This star might have been visible to the people of the Mediaeval Kingdom of Zimbabwe, which spanned over 200 years and saw the construction of elaborate stone buildings in Southern Africa. The Inca empire on the Western side of South America also saw its formation and subsequent expansion during the period when the supernova took place.
It is estimated that around 1 million aboriginal people lived in Australia at the time, with 600 tribes or nations, and speaking 250 languages. During the time of the supernova, members of the Kilwa Sultanate might have reached Australia, as some coins from this kingdom were found in the Northern Territory of the County.
The study is accepted for publication in The Astrophysical Journal and available on the ArXiv.