About 4.5 billion years ago, when Earth was still young and molten, a Mars-sized object called Theia collided with our planet. This catastrophic impact is believed to be the origin of our Moon. The Giant Impact Hypothesis explains how this collision ejected material into orbit around Earth, which eventually coalesced to form the Moon we see today.
When Theia struck Earth at an oblique angle, the collision released enormous amounts of energy, equivalent to billions of nuclear bombs. The impact was so powerful that it vaporized both the impactor and a significant portion of Earth's outer layers, creating a massive debris disk around our planet.
The debris from the impact formed a hot, molten disk around Earth. This disk contained vaporized rock and metal that slowly began to cool and condense. The material in this disk orbited Earth at different speeds, with inner particles moving faster than outer ones, creating a dynamic system of swirling debris.
Through the process of accretion, smaller debris particles gradually collided and merged to form larger chunks. Over millions of years, these chunks continued to grow through gravitational attraction, eventually coalescing into a single large body that became our Moon. This process took approximately 100 million years to complete.