20 Euro Silver Supernova Coin P

A cosmic spectacle

Supernova captures a phenomenon that was first recorded just over a thousand years ago. The year was 1054 and the Chinese and Arabic astronomers who observed the phenomenon noted a brightness that increased with remarkable speed. This was the result of something we now know to be caused by the massive explosion of a star with a mass roughly ten times that of the sun itself – a phenomenon we now know to be a supernova.

After millions of years, the star in question had run out of hydrogen nuclei ‘fuel’ and, stabilised throughout the duration of its life by the pressure created by the nuclear fusion taking place within it, had collapsed under the effect of its own gravity. This occurred first in the outer layers before rebounding explosively. Since then, the stellar remnant and wind pulsar, known as the Crab Nebula, has been moving away from the former centre of the explosion at a speed of several million kilometres per hour.

At the centre of the Crab Nebula lies a small rotating neutron star known as the Crab Pulsar. Thanks to its magnetic field, the Crab Pulsar emits large amounts of energy and illuminates the Crab Nebula. In doing so, it creates the amazing cosmic spectacle of the supernova.

Coin motif

With a waved edge and a convex reverse, Supernova also has a concave obverse that depicts the Crab Nebula, the remnant of the supernova observed in 1054, which is some 6,500 light years away from Earth and around 11x7 light years in size. ‘NGC 1952’ refers to the catalogue designation of the Crab Nebula. In the centre of the coin, reference is also made to is the rapidly rotating Crab Pulsar, a source of cosmic radiation. The coin’s reverse features a coloured illustration of the Crab Nebula, based on an image taken by the Hubble Space Telescope.