Now, in 2020, we have even more insight. The 3D image reveals that the Crab Nebula—which you can spot in the constellation Taurus—is not a classic supernova remnant where one big blast wave heats gases to millions of degrees. It’s actually a pulsar wind nebula, which burns a little cooler but still packs a punch. Essentially, it consists of a neutron star, which is the hyper-compacted, super dense core of the star that died in 1054. This core blasts out radiation pulses 30 times a second in a very precise manner, which in turn energizes the surrounding gasses and lights them up into what we see as the Crab Nebula.