Earth's Carbon Came From Smash-up With a Planet

                Most of the Earth’s life giving carbon may have come from a collision about 4.4 billion years ago between our planer and embryonic planet similar to mercury, scientists found. Researchers studied how carbon based life developed on Earth, given that most of the planet’s carbon should have either boiled away in the planet’s earliest days or become locked in Earth’s core. The challenge is to explain the origin of the volatile elements like carbon that remain outside the core in the mantle portion of our planet.