The supernova explosion which caused it has been dated to around May 1, 1006 AD when the light caused by it would have been so bright the star would have even been visible on earth during the day.

It was caused by the final death throes of a white dwarf star nearly 7,000 light-years away and was probably the brightest star ever seen by humans.

The image, captured by NASAs Hubble Space Telescope, is a composite of hydrogen-light observations from the Advanced Camera for Surveys in and the Wide Field Planetary Camera 2.

Credit: NASA, ESA, and the Hubble Heritage Team (STScI/AURA)