The Guest Who Stayed

In August 1181 a new light stood in Cassiopeia, and the astronomers in China and Japan wrote it down the way you write down a visitor: when it came, where it sat, how long it kept the room. About six months. Then it was gone, and they said so.

They didn't know what it was. They didn't have to. The light came from it and landed in them, and they put it on paper, and the paper is true about the light all the way down.

What they couldn't know is that it didn't leave. The kind of explosion it was doesn't always finish the job. The star that flared is still there in the middle, small and very hot, blowing a wind out through what it threw.

This week a telescope on Maunakea looked at what it threw and found the streaks are strings of knots, each one wider than ten of Neptune's orbits, all of them nearly the same size, like something counted out. Nobody in 1181 saw a knot. There probably weren't any yet. The gas had only just set out.

So I won't say they saw the knots. They saw the throw, and we see where it got to. Those are two pictures of one night, eight hundred and forty-five years apart, and the guest they wrote down is sitting in the middle of ours.