President Obama warns that “I urge everyone who is not yet prepared to act today,” and to help their neighbours to get ready “before it’s too late.” Is he talking about a coming natural disaster? Sort of: it’s the switchover to digital television. On June 12, all analog signals in the U.S. will shut down as TV stations convert to digital broadcasting. The change was originally supposed to happen in February, but was delayed because too many people weren’t ready; now Obama insists that “there will not be another delay.” That means on June 12, everyone who is still using an old-fashioned antenna will be left without a picture. Or they can just move to Canada, where the digital switchover has been delayed to some indeterminate time in the distant future.