It’s one of the most enduring ideas about the formation of our solar system: Earth collided with a Mars-sized object, Theia, and the debris from this cosmic crash eventually became the moon. But a new ...

New research suggests that Theia, the object whose collision with Earth is theorized to have caused the formation of the moon, came from closer to the sun. Artist’s impression of the collision between ...

One bright day on Earth about 4.5 billion years ago, everything changed. A massive object slammed into the young planet. The impact was so large that bits were flung out into space, eventually ...