‘City killer’ asteroid to pass harmlessly between Earth and moon

Rare close encounter will occur this weekend, when the space rock will be visible through binoculars and small telescopes

An asteroid big enough to wipe out a city will pass harmlessly between Earth and the moon's orbit this weekend, missing both, while providing scientists a chance to study the object close up.

Asteroid flybys are common but Nasa said it was rare for one so big to come so close and that events like this occurred only about once a decade. Scientists estimate its size to be somewhere between 40 and 90 metres in diameter.