On February 15th (or, depending where you are, the 16th) a hunk of space rock 45 metres across, called 2012 DA14, will buzz Earth in the closest encounter ever recorded for an asteroid of that size. Zipping along at a speed, relative to Earth, of 7.8km a second (4.9 miles a second), it will approach within 27,700km. That may sound a long way away, but it is well inside the orbits of the geosynchronous communications satellites that girdle the planet. Readers in Asia will be best-placed to observe the asteroid. The chart above shows its path through the night sky as seen from Hong Kong. It will be tricky to spot, though. It will be too faint to be visible to the naked eye. A dark sky and a telescope—or a good pair of binoculars—should reveal it. But be quick, for it will be moving fast. When at its closest and brightest (19.24 GMT on the 15th, which is 3.24am on the 16th in Hong Kong) it will traverse a patch of sky about twice the diameter of the full moon every minute.
