Where Did Our Moon Come From? We Asked a NASA Scientist

Where did our Moon come from? Over the years, there have been several theories, but most scientists think it’s likely that a Mars-sized object smashed into Earth, creating what we now see in the sky. NASA scientist Caitlin Ahrens shines a light on the Moon's mysterious origins: http://solarsystem.nasa.gov/moons/earths-moon Producers: Jessica Wilde, Scott Bednar Editor: Matthew Schara Credit: NASA