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...

Could some of our ancestors have spent far more of the Ice Age beneath the surface than we realise? When we imagine humans during the Ice Age, we tend to picture hunters crossing frozen landscapes, wrapped in animal skins, tracking mammoths and reindeer across windswept plains. It's an image that has become almost synonymous with prehistoric humanity. But there is another possibility. When conditions became brutally cold, perhaps the smartest place to be wasn't out on the frozen landscape at all. Perhaps it was underground. Humans have been using caves and rock shelters for hundreds of thousands of years. We know that Neanderthals, Denisovans and Homo sapiens repeatedly occupied caves, sometimes during extraordinarily cold climatic periods. But this raises a more intriguing question: Did some human groups retreat into underground environments for much longer periods during the most severe phases of the Ice Age? The answer isn't as straightforward as it might first appear. W...

You are reading these words. You can hear sounds around you. You can remember yesterday. You can imagine tomorrow. You can feel pain, recognise a face and wonder what it means to be alive. All of this feels completely ordinary. But scientifically, it is extraordinary. Somehow, electrical and chemical activity inside roughly three pounds of biological tissue is associated with the experience of being you. We know an enormous amount about the brain. We can observe neurons firing. We can map brain regions. We can measure electrical activity and watch networks communicate. We can even manipulate brain activity and change perception, memory and behaviour. And yet one enormous question remains: Why is there an experience at all? The brain clearly matters Before going further, there is an important distinction. There is overwhelming evidence that consciousness is intimately connected to the brain. Damage particular brain systems and consciousness can be profoundly altered. Anaesthesia can rev...