Blurs

Sometimes a fossil is more than the remains of a dead animal. Sometimes it is a geographical mystery.  A creature is discovered thousands of miles from where scientists expected it to be. A tropical species turns up in what was once a surprisingly cold region. A land animal appears on an island separated from the mainland by an ocean. A familiar species is found in rocks that suggest an environment completely unlike the one its living relatives inhabit. These discoveries can force scientists to reconsider ancient geography, climate and migration. But they also raise a more intriguing question: How many times have we underestimated the ability of prehistoric animals to cross the planet? The world they inhabited wasn't the world we know today. Continents moved. Seas appeared and disappeared. Land bridges formed and vanished. Ice sheets expanded. Deserts became grasslands, and forests spread across regions that are now frozen or barren. Coastlines also migrated by hundreds of kilometr...

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 at a satellite image of Earth today and it is tempting to think we understand its major landscapes. Forests occupy certain regions. Deserts occupy others. Grasslands stretch across broad areas. Ice dominates the poles. But today's Earth is only a snapshot. The planet has been through countless versions of itself. There have been periods when enormous areas that are now deserts were covered in vegetation. Forests have existed near the poles. Sea levels have risen and fallen dramatically. Glaciers have advanced across continents. Warm climates have extended much farther towards the poles. And ecosystems have appeared, expanded, fragmented and disappeared. Some of these vanished worlds were enormous. Some may have covered areas comparable to modern continents. Their plants, animals and ecological relationships were eventually transformed or destroyed. Yet the question remains: How much of Earth's ancient forest history has effectively disappeared? And could some of the ecosys...