# Meteor Impact on Earth What happens when rocks from space meet Earth: meteors, airbursts, craters and the dinosaur\-ending impact By RexonFx HnS Topic: Space [Open the interactive Jig](https://ask.jig.com/j/yjq8eVIog7rL) ## Transcript ### 1. A rock from space Space is full of rocky leftovers from when the planets formed\. A big one is called an asteroid, and a small one, under about a metre wide, is a meteoroid\. Each circles the Sun on its own path, and now and then a path crosses Earth\. Drag anywhere to turn the view\. Sizes in space are not to scale: a real asteroid would be far too small to see next to Earth\. ### 2. Shooting stars A small rock rushes into the air at tens of kilometres every second\. The air in front of it is squeezed so hard that it glows, and we see a bright streak called a meteor\. Most meteors burn up high above the ground\. A piece that survives and lands is called a meteorite\. A rock about the size of a car hits our air roughly once a year\. ### 3. A bang in the sky A bigger rock can break apart before it reaches the ground\. In 2013 a rock about 20 metres wide burst some 27 kilometres above Chelyabinsk, Russia\. Its shock wave, a sudden wall of pushed air, broke windows in six cities\. No crater formed\. The shock wave arrived after the flash, just as thunder follows lightning\. ### 4. Hitting the ground Strong iron rocks can survive the trip through the air\. About 50,000 years ago, an iron rock about 50 metres wide struck Arizona at roughly 18 kilometres per second\. Drop it and watch its energy dig a crater in moments\. The blast threw rock outward in a ring and pushed up a raised rim around the hole\. ### 5. Meteor Crater today The crater is about 1\.2 kilometres wide and 170 metres deep, around 24 times wider than the rock that made it\. The cut\-away side shows the layers of sandstone and limestone the blast dug through\. Try a smaller or bigger rock\. A bigger rock carries much more energy, so it digs a much bigger crater\. ### 6. The giant one 66 million years ago a rock about 10 kilometres wide hit near the coast of Mexico's Yucatán\. It left a crater about 180 kilometres wide, now buried under younger rock\. Dust and soot from the impact and from fires spread around the whole world within hours\. That rock was taller than Mount Everest, which is 8\.8 kilometres high\. The globe shows today's coastlines; back then they looked a little different\. ### 7. A long, dark winter The dust and soot blocked sunlight for years, so the planet grew cold and many plants died\. Food chains collapsed, and about three quarters of all kinds of living things, including the dinosaurs except birds, disappeared\. Slowly the sky cleared and life recovered\. Small mammals survived, and over millions of years their descendants spread across the world\. ### 8. Keeping watch Giant impacts are very rare: a rock 1 kilometre wide strikes roughly once in half a million years, and a 10 kilometre one far less often\. Astronomers track asteroids bigger than 140 metres whose paths come within 7\.5 million kilometres of Earth's orbit\. On most nights, the only rocks that reach us are tiny ones making shooting stars\.