On this day in 837, Halley’s Comet came the closest to the Earth in the entirety of human history. It came within almost three million miles (0.03 AU), which, by astronomical standards, is nothing. It is estimated that its tail spanned 60° across the sky. To see it today would be awe inspiring. To most of the people at that time, it was probably terrifying.
I’ve written before about going out to the beach in the early morning in 1986 to see it. The comet was at a distance of 0.42 AU and nothing but a smudge on the sky. It was the worst observational opportunity for at least 2,000 years. I remember seeing Carl Sagan speak on his book tour for Comet and he said that if anyone was alive in 2061, it would be a much greater show. And in 2134, it would be spectacular.
What did he mean? In 2061, we will at least be on the same side of the sun when Halley’s comet reaches perihelion. Unfortunately, I can’t find any data on just how close we will come. But in 2134, we will come within 0.09 AU. That should be quite a show. Of course, as time goes on, the comet gets smaller and smaller, so if we really want to dream, we should imagine being around in 837.
It’s these kinds of things that make me regret our short lifetimes. Usually, the changes of the human body, the degradation of the mind, make me welcome death — at least eventually. Not that one can reasonably complain. I mean, did we not just get to see the unmasking of Pluto in real time? And I still thrill to see the occasional shooting star. Every time has its advantages. And I’ve lived during the most exciting time in the history of astronomy.