The Hubble Space Telescope allowed us to observe a supernova just during the explosion. This is due to the fact that its appearance was foretold. For the first time, the use of complex calculations related to the theory of relativity made it possible to capture the supernova nicknamed Refsdal when it exploded. It’s the first time such a feat was achieved by exploiting the gravitational lensing of that galaxy cluster MACS J1149.5 + 2223, which bent the light from that star showing the explosion several times in different areas of the sky.