Exploding and colliding stars, seen as supernovae and cosmic gamma-ray bursts, produce the brightest and most powerful radiation outbursts in the Universe. Their observation to a distance of billions of light-years gives us information about the accelerated expansion of the cosmos. When a neutron star or a black hole is produced during the explosion, this releases in a very short time more energy than a star such as our Sun produces in its whole lifetime.
On the one hand such an event can be very destructive, but on the other hand there would not be any planets, plants or animals without these cosmic catastrophes. These explosions drive the galactic matter cycle, during which many generations of stars and supernovae form the heavy elements (heavier than helium) before these are – scattered by the stellar explosions into the surrounding universe – being recycled in new stars and planetary systems.
The astrophysicist Hans-Thomas Janka studies the complex, physical processes in supernova explosions with computer models. In the next Café & Kosmos he will talk about the fascination regarding these events, the large challenges represented by the exact modelling of the explosion in three dimensions, and the hopes (and fears) connected with the next stellar explosion in our Milky Way.