Colliding Worlds

Simone Marchi presents the emerging story of how cosmic collisions shaped both the solar system and our own planet, from the creation of the Moon to influencing the evolution of life on Earth.

The Earth emerged out of the upheaval and chaos of massive collisions in the infancy of the Solar System, more than four billion years ago. The largest of these events sent into orbit a spray of molten rocks out of which the Moon coalesced. As in ancient mythological tales, this giant catastrophe marks the birth of our planet as we know it.

Space exploration has shown that signs of ancient collisions are widespread in the Solar System, from the barren and once-habitable Mars to the rugged asteroids. On Earth these signs are more subtle, but still cataclysmic, such as the massive asteroid strike which likely sparked the demise of the dinosaurs and many other forms of life some 66 million years ago. Signatures of even more dramatic catastrophes are concealed in ancient rocks. These events wreaked havoc on our planet's surface, influencing global climate and topography, while also enriching the Earth with gold and other rare elements. And recently, modern science is finding that they could even have contributed to developing the conditions conducive to life.

In Colliding Worlds, Simone Marchi explores the key role that collisions in space have played in the formation and evolution of our solar system, the development of planets, and possibly even the origin of life on Earth. Analysing our latest understanding of the surfaces of Mars and Venus, gleaned from recent space missions, Marchi presents the dramatic story of cosmic collisions and their legacies.


A fascinating story of how our Solar System was formed, and how we have arrived at the current understanding of it, from the unique perspective of cosmic collisions. Information from a few hundred years of planetary and astronomical research to the latest space exploration is marvellously weaved together. The very success of being able to connect diverse subjects in such a coherent and engaging manner attests to the fundamental importance of cosmic collisions, or creative destruction as the author puts it, in our search for the grand theory of planetary formation in the coming years. -- Jun Korenaga, Yale University