On this day, exactly 410 years ago, the last supernova to originate from our galaxy was observed. It is very likely that another will not occur in our lifetime and many lifetimes after that. This is simply because with the Universe being as large as it is the chance that any particular supernova would occur in our galaxy or even in a nearby one in close to zero. And of course like a radioactive source the older the galaxy becomes the more stars with the potential to become supernovas have and so the appearance of these cosmological explosions will become rarer over time. Often it is the concept of scale that makes astrophysics so incomprehensible almost frightening in nature. It is hard to imagine the size of your country compared to yourself, the size of the planet is massive. Even the solar system in beyond imagining. Indeed it is probably true that the human mind has no capacity for imagining the length of a light year or the passing of a millennia. Even the number a million is too big. It hasn’t been one million days since Jesus was born but there have been over 2.5 million people attending one concert before and imagining that many people in one place doesn’t seem too hard. These magnitudes also swing the other way when it comes to thinking about the size of an atom, the duration of an attosecond. Maybe these numbers only have real meaning in theoretical physics and extrapolated mathematics. As if something is beyond human conception can it even be considered real at all?