Look up at the night sky and it’s easy to think planets have just always been there, quietly circling the Sun like they were carved from stone. They weren’t. Every planet you can name, Earth, Mars, Jupiter, Saturn, started out as nothing more than a speck of dust floating in a cloud of gas. So […]
Right now, under your feet, sits a planet built entirely from leftover dust and gas that once orbited a star still switching on. That’s the short answer to how did Earth form: gravity slowly pulled cosmic debris together over tens of millions of years until it became the rocky world we call home. Here’s what […]
Here’s something wild to sit with for a second. Right now, as you read this, you’re standing on a rock that used to be part of a drifting cloud of gas. So is everyone you’ve ever met. That’s really where the story of the formation of the Sun begins, and it’s a lot stranger, and […]
Look up at the night sky and you’re staring at the answer to one of humanity’s oldest questions. Where did we come from? So what is the nebular hypothesis, and why do scientists still lean on an idea that’s over 250 years old? In short, it’s the leading explanation for how our Sun, Earth, and […]
How did the solar system form? It started as a cold, quiet cloud of gas and dust, just floating out there in space. Somehow that shapeless cloud turned into the Sun, eight planets, hundreds of moons, and billions of icy rocks. That leap sounds almost impossible. But scientists have actually pieced the whole story together, […]
If you stepped outside on Earth 4.5 billion years ago, you would not survive one single breath. The atmosphere during the Hadean eon was not blue, not breathable, and not friendly. It was a thick, scorching, orange haze made of steam, carbon dioxide, and volcanic fumes, sitting on top of an ocean of melted rock. There was no sky as we know it. There was no oxygen. There was, in fact, almost nothing that resembled the planet you are reading this on right now.
The Hadean eon began about 4.6 billion years ago when Earth first formed out of dust and rock circling the young sun. It ended roughly 4.0 billion years ago, based on the age of the oldest intact rocks we have ever found
Earth’s first oceans formed at a time when our planet looked nothing like the blue marble we know today. Picture a world covered in glowing magma, battered by space rocks, and too hot for a single drop of liquid water to survive on its surface. Then, somehow, that changed. Water pooled into basins, and life eventually crawled out of it.
Roughly 4 billion years ago, something battered the Moon, Earth, and their neighbors with an unusual number of asteroid and comet strikes. Scientists call it the Late Heavy Bombardment — and the evidence is written into Moon rocks, ancient Earth minerals, and the orbits of giant planets. But is it fact, or a myth? The science is more contested than you’d think.
Most people assume Earth always looked like Earth. Mountains, oceans, blue skies. But understanding what Earth was like in the Hadean era forces you to throw out everything you think you know.