Did life need asteroid bombardment?

A period 3.9 billion years ago when Earth was peppered with impacts by large asteroids may have created an environment in which primitive life could take hold, rather than destroying that life. This is the bold new claim by astrobiologists at the University of Colorado at Boulder, USA.

What we know today as the Late Heavy Bombardment (LHB) hit all the inner planets around 700 million years after the Solar System formed. The Moon and Mercury still bear the scars from this frightful time when fire and rock rained down from the heavens on a regular basis. Nobody is sure what caused the LHB, but the outward migration of the giant planets such as Jupiter and Saturn may have been enough to disturb the orbits of various comets and asteroids, slinging them in our direction.