Blurs

For more than a century, scientists have tried to answer one deceptively simple question: Where did the Moon come from? The Moon is our closest natural companion, but its origin remains one of the great stories of planetary science. The leading explanation is the giant-impact hypothesis. According to this model, the young Earth was struck by a large planetary body roughly 4.5 billion years ago. Material thrown into orbit eventually gathered together and formed the Moon. It is a powerful explanation. But it is not the only conceivable way to imagine the Moon's origin. What if the Moon wasn't created primarily from Earth at all? What if it was something that already existed? What if, before Earth and the Moon reached their present configuration, another planetary body existed in the inner Solar System — and a catastrophic event destroyed most of it? Perhaps the Moon could be the surviving remnant. This is not the established explanation for the Moon. There is currently no compell...

Look up at the night sky and there is one object that seems so permanent that it is easy to forget how unusual it is. The Moon.  It controls the tides. It brightens the night. It moves across the sky with remarkable regularity. It has influenced calendars, navigation, mythology and human culture for thousands of years. But the Moon is more than something we see. Its gravity interacts with Earth on a planetary scale. It raises ocean tides. It gradually slows Earth's rotation. And, importantly, it helps stabilise the orientation of Earth's rotational axis. So what would happen if the Moon had never existed? Would Earth still have developed oceans? Would the climate have remained suitable for complex life? Would evolution have taken a completely different path? And, perhaps most intriguingly: Would humans ever have evolved at all? There is no way to know for certain. But the physics and geology allow us to explore the possibilities. First, how did the Moon get here? The leading ex...

Look at Saturn and it is difficult not to wonder what Earth would look like with rings. A vast band of ice and rock stretching across the sky. A permanent feature visible from the surface. Shadows moving across the planet as the ring system changed with the seasons. It sounds like science fiction. But Earth may actually have had something resembling a ring system in its distant past. Not necessarily a beautiful, permanent structure like Saturn's — but a temporary ring of debris could have formed around our planet after a massive collision. And the most intriguing possibility is that such an event may have played a role in creating the Moon. Earth wasn't always the quiet planet we know today The young Solar System was a chaotic place. Planets were still forming. Asteroids and planetary embryos were moving through unstable orbits, occasionally crossing paths. Collisions were not unusual. Some were relatively small. Others were catastrophic. The leading explanation for the Moon...