Space Hole number 31 March 2015 Email What happens when a black hole is swallowed by another black hole? Jamie Malone, London, UK This article appeared in print under the headline “Hole number” Topics:cosmology Advertisement Sign up to our weekly newsletter Receive a weekly dose of discovery in your inbox. We'll also keep you up to date with Âé¶¹´«Ã½ events and special offers. Sign up