Colliding Worlds: How Cosmic Encounters Shaped Planets and Life

Some 4.6 billion years ago, a planetary system was born from a disc of gas and dust surrounding a young star.

Specks of dust, pushed into dense clumps, collided, stuck together, and grew. While the gas disappeared, the growing bodies clashed in a final violent phase, leaving a series of planets, and much debris. The planets jostled and moved around as they sought a stable
arrangement, knocking many small fragments out of the system altogether while others formed a distant icy fringe. The ma...