Dr Bottke's contention is that the deed was done by one of Baptistina's daughters.

ECONOMIST: Asteroid impacts: Baptistina's terrible daughters | The

First, the surviving debris from the devastating impact has the same composition as Baptistina and her offspring.

ECONOMIST: Asteroid impacts

The result is that the daughters of Baptistina have become scattered farther and farther away from their mother.

ECONOMIST: Asteroid impacts

The largest member of the family in question is called Baptistina, and is some 40km (25 miles) across.

ECONOMIST: Asteroid impacts

But anyone with a pair of field glasses can see for himself what Baptistina's daughters are capable of.

ECONOMIST: Asteroid impacts

Taking into account the circumstances that pertained 65m years ago, Dr Bottke reckons it more than 90% probable that the dinosaur killer was one of Baptistina's daughters.

ECONOMIST: Asteroid impacts

The cluster of Baptistina's young has a gap in it.

ECONOMIST: Asteroid impacts

Critically, the Baptistina family of asteroids - those that were formed when the larger asteroid destructively entered the main belt - were only formed around 80 million years ago.

BBC: Asteroid thought to kill dinosaurs may not be guilty

Scientists believe it would take an asteroid around 10 million years to travel from the main belt to Earth, so "this doesn't give a Baptistina fragment much time to get into a suitable position", said Dr Mainzer.

BBC: Asteroid thought to kill dinosaurs may not be guilty

It is thought to be just over 100m years old (Apollo 17 brought back material from the site, which allowed it to be dated), and it is reckoned by Dr Bottke to be the result of the moon encountering one of the first of Baptistina's progeny to arrive in the inner solar system.

ECONOMIST: Asteroid impacts: Baptistina's terrible daughters | The