Let's hope we find the right kind of black hole

AT A time when financial black holes loom on all sides, it will be a relief to get a glimpse of the genuine article. Astronomers hope soon to have an image of the giant black hole at the heart of the galaxy (see “The monster at the centre of the galaxy”), so anyone still sceptical of the existence of these gravitational monsters should make the most of the next few months. It may be your last chance to doubt. Unless, of course, the thing fails to show up. To find that the only real black holes are of the…