From Charles Goodwin
Leaving aside anything Einstein may have said on the matter, I hope Lee Baxter chooses the site for his faster-than-light “sweeping” skyscraper carefully (31 January, p 39). It would be terrible if the mailbag were to collide with Uranus at that sort of speed – which a quick calculation indicates could happen – as it would cause an explosion that would be visible all the way to Alpha Centauri.
Leeds, UK
