giant impact hypothesis
Life On Earth Was Seeded by Massive Collision That Formed the Moon
“The giant impact of a rocky planet was required to deliver the unique composition of life-essential elements to Earth.”
It's a Good Thing Early Earth's Magma Oceans Only Melted Half the Planet
A giant collision threatened to "melt the entire planet," but ended up only melting about half of it—and helped form the moon at the same time.