Relics of the solar system .
Sure asteroids can be destructive.
Asteroids escaped the erosion, heat and chemicals that have altered ancient rocks on Earth, and represent our best chance for glimpsing the primordial solar system. The oldest known fossils are cyanobacteria like this filamentous Palaeolyngbya from Archaean rocks of western Australia, dated 3.5 billion years old. Yeomans is one of a growing number of scientists who believe asteroids and comets played a crucial role in the origin of life.