Four hundred years ago, the Universe changed. Or, at least, our perception of it did, thanks to Galileo Galilei’s scrutiny of the night sky with a telescope. Within a couple of years, his observations of the Moon, phases of Venus and satellites of Jupiter shattered the old Ptolemaic model of our Solar System. To the church’s dismay, Earth assumed its rightful place as one of several planets orbiting the Sun (see page 28). Marking Galileo’s anniversary, the International Year of Astronomy seeks to remind us of the humbling nature of gazing at the heavens. Through programmes offering cheap telescopes for the masses, teaching materials and global heritage projects, astronomers are.
