In August, the most spectacular meteor shower of 2017 coincides with transmission: The Perseids! If it's clear, it'll be a great chance to see scores of bright shooting stars streaking across the night sky. As those shooting stars vaporise in the atmosphere, a small part of some of them will fall to earth as dust. This dust will contribute to a total of about 40,000 tonnes of space dust and debris that falls onto our planet every year. In this episode, Chris Lintott and Maggie Aderin-Pocock investigate this mysterious cosmic debris that comes from outer space.