The pen is mightier than the telescope

I came across a fun little paper on astro-ph today, that discusses some of the implications of using historical documents to study nearby supernova from the last few thousand years. Every one hundred years or so, in each galaxy, you get about one supernova. In our case, sadly, since we live in the dusty disk of our galaxy, it's expected that we can't actually see a lot of these, and the last observed galactic supernova was over four hundred years ago. There was a nice supernova in a satellite galaxy of our Milky Way in 1987 (creatively named SN 1987A), but other than that we have to look pretty far off to see these objects. Getting data on supernovae that take place closer to us is pretty interesting, and the best bet there seems to be to rely on what information past astronomers managed to write down.

In particular, the four-page paper considers the many historical accounts of a supernova that was observed around 1054, which was the exploding star that produced the Crab Pulsar, a neutron star about the mass of our sun but only about as large as your typical city, which rotates 30 times every second. I was kind of interested in the ways 1000-year-old data were combined with the latest observations to really get a full pictures of these objects, plus it's fun to reflect on the fact that there are some astronomical data reduction techniques that require a calibration for the internal politics of the Chinese court.