It's the social media sensation that presidents, taosigh, astronauts, sportstars and even grannies couldn't resist, says Kelly O'Brien

A smartphone tilted at 45 degrees above your eyeline is the most forgiving angle, against the flattering beam of a backlit window or a supernova of flash reflected in a bathroom mirror, as you prepare for a night out.

Three astronauts touched down in the dark, chilly expanses of central Kazakhstan onboard a Soyuz capsule today after a 125-day stay at the International Space Station.