An asteroid the size of a football field came extremely close to the Earth last week, and scientists didn’t even know until after it passed us by. Asteroid 2002 MN is 100 metres in diameter and passed by us at a distance of only 120,000km, less than one-third the distance from the Earth to the Moon. This is one of the closest near-misses ever recorded of a spacerock this size; had it actually struck the planet it would have cause considerable destruction and loss of life.