Blurs

Trees are usually associated with moderate climates: sufficient rainfall, tolerable temperatures, fertile soil and a reasonably long growing season. Yet trees grow in places that seem to violate almost every rule. Some survive where winter temperatures plunge far below freezing. Others cling to mountainsides where the growing season is measured in weeks. Some endure intense drought, salt spray, volcanic soils or repeated fire. There are forests close to the Arctic Circle, trees growing on isolated volcanic islands and individual trees that have survived for thousands of years. They aren't anomalies in the sense of being impossible. They are examples of just how far evolution can push a plant's ability to survive. What Makes a Place Too Harsh for a Tree? Trees have several fundamental requirements. They need water, but too much water can be just as problematic as too little. They need carbon dioxide and sunlight for photosynthesis. They require nutrients and a stable enough grow...

On 16 July 2024, a meteor crossed the sky over the northeastern United States. It was not subtle. The daytime fireball was seen across several states.  People reported the shockwave. Radar detected the event. And a doorbell camera captured part of its passage. Then a fragment came down in Hillsborough, New Jersey.  It smashed through the roof of a house. At first, it was an extraordinary piece of luck — a meteorite had effectively delivered itself to a laboratory. But the real surprise came later. Scientists examining the rock discovered something preserved inside it that was potentially far more valuable than the meteorite itself. Evidence that salty liquid water had once circulated through the asteroid from which the rock came. Within that altered material were also amino acids and a surprisingly diverse collection of carbon-bearing organic compounds. The meteorite had apparently spent billions of years carrying around the chemical consequences of an ancient extraterrestrial...

Around 2.4 billion years ago, something happened that permanently changed Earth. For most of the planet's early history, free oxygen was scarce in the atmosphere. Then oxygen began accumulating. The consequences were enormous. Atmospheric chemistry changed. Oceans changed. Minerals that had never encountered abundant oxygen began reacting with it. Some organisms were poisoned by the new environment, while others eventually evolved ways to exploit oxygen's extraordinary chemical potential. Much later, oxygen-dependent complex life would become possible. This transformation is known as the Great Oxidation Event. It is one of the fundamental chapters in Earth's history. But there is an intriguing problem. Much of what we think we know about the environmental changes surrounding this transformation comes from something remarkably fragile: the chemical signatures preserved in ancient rocks. And new research is demonstrating just how easily those signatures can be misread. The im...

The Moon seems permanent. It rises, it sets, it controls the tides. It has been there throughout human history. But the Moon we see today is not the Moon that Earth had in the distant past. Our satellite is slowly moving away from us. At the same time, Earth's rotation is gradually slowing. Go backwards far enough and the relationship between Earth and Moon becomes dramatically different. The Moon would have been closer, the tides would have been stronger, Earth would have spun faster. Days would have been shorter. And the night sky would have looked completely unfamiliar. But this raises a more intriguing question. Could the young Earth have had a Moon that was fundamentally different from the one we know today? Not necessarily a different moon in the sense of another permanent satellite. But a Moon occupying a very different orbit, appearing vastly larger in the sky and exerting a much stronger influence on our planet. And could that changing relationship have affected the develo...