What Really Happened to the Dinosaurs

I here is no advance warning. Without alarms, bells, or

I screams, a giant asteroid races at 40,000 miles (64,000 kilometers) per hour toward Earth. The asteroid, the length of more than 100 football fields, crashes near the Yucatán Pennisula in northern Mexico. The explosion is far greater than if every nuclear bomb in every country on the planet exploded at the same time. The meteor leaves a hole in the ground more than 150 miles (240 km) wide. Its effects are immediate and devastating.

The heat from this smoldering extraterrestrial rock instantly melts sand into tiny beads of glass. The crash sets fire to plants and grinds soil and rock into powder. An immense cloud blankets the Earth, as winds carry thick dust around the planet. Earthquakes crack open the land, shoving the ocean waters in all directions. Powerful tidal waves called tsunamis flood the land with water. Volcanoes erupt, spewing hot molten lava from deep within the Earth's mantle through the cracks on the planet's surface. Millions of trees catch on fire. The lava contains sulfur and forms sulfuric acid clouds. Ashes from burned vegetation fill the air.

Within a few weeks, the sun is completely blocked, and temperatures drop on Earth by more than 20°F (11°C). Huge portions of land now lie underwater, leaving little room for land

Earth Land Under Water
The Earth is probably covered with ancient, hidden craters from asteroid and meteorite collisions, like the one illustrated here.These craters are often buried under water or land. Modern technologies, such as radar, help detect them.

animals to live. Raindrops, now made up of sulfuric acid, fall on the Earth. Most of the marine animals and plants living in the ocean die off. They are not used to the frigid water or poisonous sulfuric acid. Photosynthesis stops, and plants die. On land, those that did not die from the immediate blast now have no food to eat.

A mass extinction has begun. When it ends, over 75% of all life on the planet will be dead. This includes every single dinosaur. The date? Sixty-five million years ago.

Since the first dinosaur fossils were found in England in 1820, scientists have been working to understand exactly what caused the dinosaurs' extinction. Was it an asteroid or several asteroids? Or did earthquakes, volcanoes, tsunamis, or sulfuric acid cause the ultimate death of the dinosaurs? This debate continues today, as scientists attempt to solve the mysteries of mass extinction.

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