Solving the mystery of the amazing 1987 supernova (Courtesy of James Webb)

On February 23, 1987, scientists discovered a supernova in the Large Magellanic Cloud, one of the closest galaxies to our Milky Way. A supernova is a massive explosion of a massive star at the end of its life. It emits a huge amount of light. Supernova SN 1987A, as the supernova was called, was visible to the naked eye from Earth.

It was visible from Earth for months: the supernova was radiating light with the power of 100 million suns. This was the closest supernova seen with the naked eye in more than 400 years. But make no mistake, “closest” is still very far in space terms. SN 1987A was observed at a distance of 160,000 light-years (one light-year is the distance light travels in one year, ed.).

Long before the actual explosion, astronomers had already described the details of the star in question. It was a giant blue star. Supergiants are the largest and most massive stars in the universe, and blue supergiants are also the hottest of the supergiants. The mass of this blue giant is 20 times the mass of the Sun.