This picture shows how an artist thinks a big rock from space hit Earth. Some scientists think that a big rock hitting Earth could have killed all the dinosaurs millions of years ago.
Click on image for full size
Courtesy of NASA
New Blow for Dinosaur-Killing Asteroid Theory
News story originally written on April 27, 2009
Many scientists have thought for years that the dinosaurs went extinct
because an asteroid
hit Earth near Mexico in a place called Chicxulub and caused big changes in the Earth’s climate.
Now, scientists have found new evidence that shows it was not an asteroid that killed the dinosaurs. The scientists discovered this by studying the rocks below the crater at Chicxulub. The rocks showed that animals and plants survived after the asteroid hit the Earth, and so when they went extinct it was caused by something else.
The scientists say that the dinosaurs’ extinction was probably caused by volcanoes. When they erupted, the volcanoes would have created lots of dust in the atmosphere and blocked sunlight from reaching Earth’s surface.
Lack of sunlight meant that plants could not photosynthesize and support the life of other animals on earth.
Shop Windows to the Universe Science Store!
Our online store
on science education, classroom activities in The Earth Scientist
specimens, and educational games
You might also be interested in:
Why did the dinosaurs go extinct? No one knows for sure, but there are some explanations that seem to make sense. At the time the dinosaurs and lots of other species died out (which is sometimes called...more
Volcanoes form when hot material from below risesand leaks into the crust. The hot material, called magma, rising from lower ground, gathers in a reservoir called the magma chamber. Eventually, but not...more
There are many different kinds of plants. Some have big leaves. Some have small leaves. Some even have flowers. All plants make their own food. When sunlight hits the leaves of a plant, photosynthesis...more
Scientists have learned that Mount Hood, Oregon's tallest mountain, has erupted in the past due to the mixing of two different types of magma. Adam Kent, a geologist at Oregon State University, says this...more
The Earth's mantle is a rocky, solid shell that is between the Earth's crust and the outer core. The mantle is made up of many different reservoirs that have different chemical compositions. Scientists...more
Some faults look strong and like they wouldn’t cause an earthquake. But it turns out that they can slip and slide like weak faults causing earthquakes. Scientists have been looking at one of these faults...more
The sun goes through cycles that last approximately 11 years. These solar cycle include phases with more magnetic activity, sunspots, and solar flares. They also include phases with less activity. The...more