The moon formed inside a hot cosmic doughnut, scientists say

Since ancient times, people have marveled at the moon, worshipped the moon, written songs about the moon — and wondered how it came to be.

In recent decades the scientific consensus has been that the moon formed billions of years ago from debris cast off when a Mars-sized object dealt Earth a glancing blow. But a radical new theory holds that some long-ago giant collision actually disintegrated Earth, causing it to balloon out into a vast doughnut-shaped cloud of vaporized rock, which the scientists who developed the theory dubbed a "synestia." They say the moon subsequently formed within this cosmic maelstrom. Read more.