What happened to the dinosaurs, anyway? Long ago, dinosaurs roamed the Earth: sweeping through the s

What happened to the dinosaurs, anyway? Long ago, dinosaurs roamed the Earth: sweeping through the skies on great leathery wings, hunting in forests with gnashing teeth, and thundering in herds across the plains. But about 65 million years ago, their world was brought to a sudden, crashing end. Have you ever wondered what caused it?Fossilised remains tell us endless stories about the creatures they were, the world they lived in, and the world that killed them. They tell us that in the past 570 million years, the Earth has been devastated by five major mass extinction events . During these events, 99% of all species that have ever existed were wiped out, but it didn’t happen spontaneously: evidence indicates they’re caused by cosmic impacts smashing into our planet.What are cosmic impacts?The asteroids and comets orbiting our sun are leftovers from when our solar system formed out of a cloud of dusty gas: bits that didn’t end up forming into planets. Earth is battered with a steady shower of them, and although most just burn up in the atmosphere, once in a while, we get one big enough to devastate our biosphere.How much damage can an impact cause?When you think of an asteroid, your mind probably conjures a picture of a burning rock hurtling down through the atmosphere, slamming into the Earth’s surface and creating a massive crater. Earthquakes and tsunamis may also feature in in this vision, since two-thirds of cosmic impacts land in the ocean (because our planet is so covered with them). The impact that killed the dinosaurs struck a shallow sea near Chicxulub, Mexico, and it created tsunamis up to 300m high. We’ve found deposits of marine fossils in Florida, Texas and Haiti that tell us the tsunami rushed 300km inland.The location of the K-T impact crater, Mexico. Source: AtlasobscuraAn impact like this can cause wildfires, which would create huge amounts of smoke, as well as put out chemicals that could case acid rain lasting years. But surprisingly, the biggest threat to life is plain old dust. When they smash into the surface, impacts can hurl massive amounts of dust into the atmosphere, causing long-lasting dust storms that block the sun and darken the world. Without light and warmth, photosynthesising organisms like plants and algae - which rely on the sun for energy - would suffer, and so would all the organisms that depend on them. The asteroid that wiped out the dinosaurs was a devastating event, causing the extinction of three-quarters of the animals living on Earth at the time. But many species survived, including most mammals, birds, turtles, crocodiles, lizards, snakes, and amphibians - and from these lucky creatures, our world today evolved.More cool stuff:Check out this dramatic but super interesting video about researchers “recreating” asteroid impactsWorried about a new mass extinction? See how we might stop a killer asteroid -- source link

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