In 1572 a new star blazed out in the sky, so bright it could be seen during the day. The astronomer Tycho Brahe described it in his book De Stella Nova, giving us a word we use even today to describe a crappy little Vauxhall. Apparently he caused ripples by proving it lay quite a way beyond the orbit of the moon, which wasn't officially possible - though even he might have been surprised to know quite how far away it was.
Now, the BBC tells us, astronomers around the world are seeing it again, because light that shot off in the opposite direction is reflecting off clouds of interstellar dust particles and coming back at us.
Is this not utterly astonishing and utterly cool? What an amazing universe we live in.