A parade of PLANETARY NEBULAE

One of the most fascinating facts I ever learned about astronomy is that stars don’t last forever: like us, they are born, live a life and eventually die. Okay, so those lives are rather longer than ours, but every single star in the sky is on borrowed time.

Thanks to science fiction, a common misconception is that all stars die in cataclysmic explosions, like the Death Star. The largest do, becoming supernovae that can briefly outshine a whole galaxy, while the smallest ones just shrink and fade away, like forgotten pop stars. In between, the quieter, less attention-seeking stars the size of our own Sun – that is, with diameters of a million kilometres or so – die like celestial souffles, swelling up and then shrinking again; but not before they pop, puff off their outer layers like colourful smoke rings and surround themselves with beautiful shells of gas and dust. Because