wunder beta☄️ The Asteroid That Killed the Dinosaurs
About 66 million years ago a giant asteroid struck Earth. Follow the evidence for the day the age of dinosaurs ended.
What you’ll learn
- A Sudden EndExplain that a mass extinction about 66 million years ago ended the age of dinosaurs, likely from an asteroid.Dinosaurs ruled for over 150 million years, but about 66 million years ago they died out very quickly in a mass extinction. The leading explanation is that a giant asteroid, roughly 10 km wide, struck the Earth. A mass extinction is when many kinds of life die out worldwide in a short time.
- The Chicxulub ClueDescribe the Chicxulub crater and the worldwide iridium layer as evidence for the impact.Scientists found a buried crater about 180 km wide beneath Mexico's Yucatán Peninsula, near Chicxulub, of exactly the right age and size. A worldwide thin layer rich in iridium — a metal rare on Earth but common in asteroids — marks the K-Pg boundary, below which rocks hold dinosaur fossils and above which they do not.
- What SurvivedExplain how the impact caused extinction through darkness and which animals survived.The impact blasted dust into the sky, blocking sunlight so plants died and food chains collapsed, wiping out the non-bird dinosaurs. Small animals that could hide or eat scraps survived, including birds, mammals, crocodiles, turtles, and insects. Because birds are dinosaurs, dinosaurs never fully disappeared.
Questions this course answers
About how long ago did the dinosaurs' reign end?
The mass extinction that ended the age of dinosaurs happened about 66 million years ago.
What is the leading explanation for the dinosaurs' sudden end?
The leading explanation is that a giant asteroid, about 10 km wide, struck the Earth.
Where is the giant crater from the impact found?
The Chicxulub crater, about 180 km wide, is buried under Mexico's Yucatán Peninsula.
Why is the worldwide iridium layer such strong evidence?
Iridium is rare on Earth's surface but common in asteroids, so a worldwide iridium layer points to an impact.
Why did so many animals die after the impact?
Dust from the impact blocked sunlight, so plants died and the food chains that depended on them collapsed.
Which group of dinosaurs survived the extinction?
Birds are dinosaurs, and they survived — so dinosaurs never completely disappeared.
Grounded in trusted sources
- United States Geological Survey (USGS)
- Natural History Museum
- Smithsonian's National Museum of Natural History
- Britannica
Every Wunder lesson is built from real, reputable sources — never invented.
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