The Moon is a mystery. For all its familiarity--the regularity of its phases, the fact that everywhere on Earth it looks the same--the Moon has always been an enigma, a luminous question mark rolling across the night sky.
In this new video from Cosmic Journeys, we learn about some of the latest scientific research into the structure and history of the Moon. In particular, we learn the latest ideas on what is perhaps the greatest of lunar mysteries: the question of how the Moon got there in the first place.
The leading candidate for an answer is the Giant Impact Hypothesis, which posits that sometime in the early stage of the Solar System--about four and a half billion years ago--a large proto-Earth collided with a Mars-sized body named "Theia," causing a huge cloud of material from both bodies to fly out into space. Some of the material remained in the Earth's orbit and coalesced into the Moon. It's a fascinating hypothesis. To see more videos from the same series, visit the Cosmic Journeys channel on YouTube, or the SpaceRip blog.