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The Ice Ages
Many people tried to figure out why the "Ice Ages" happened. In the 1920s, a meteorologist (a person who studies the weather, not meteors!) named Milutin Milankovich found a possible explanation: changes in the orbit of the Earth. The basic idea is fairly simple. As you probably already know, average temperatures on Earth depend on the Earth's distance from the Sun. If the Earth was closer to the Sun, the climate would be hotter (like Venus), and if the Earth was farther from the Sun, the Earth would be colder (like Mars). Now if the Earth was the only planet going around the Sun, its orbit would never change and its climate would remain constant. But the Moon and other planets are a part of the Sun's family, and their gravity tugs slightly on the Earth as they pass nearby, causing the Earth's orbit, and also its climate, to change by tiny amounts.

The three main orbital changes Milankovich studied are:

1. changes in the shape of Earth's orbit,
2. changes in the tilt of Earth's axis, and
3. the wobble of Earth's axis.

Each of these changes are cyclical, that is, they repeat over and over. During the cycle of any one of these three changes, the Earth tends to grow a little warmer, and then a little bit cooler. The three orbital changes are actually all happening at the same time, but the length of the cycle of each change is different. Most of the time, the heating and cooling segment of each cycle cancel each other out, giving Earth a lukewarm climate. But sometimes orbital changes combine together to make the Earth's climate either very warm or very cold.

Image of the Earth-- shown once during the warm age and shown again during the ice age.  Please have someone assist you with this.

For example, if the cool segment of the shape cycle occurs at the same time as the cool part of the tilt cycle, and at the same time as the cool segment of the wobble cycle, then Presto-Chang-o, you get an ice age! Its kind of like following directions written by a crazy chef for making a veggie burger. If the directions said: cool the burger, then heat the burger, and then cool the burger again, you would end up with a lukewarm burger. However, if the directions said heat the burger, then heat it again, and then heat it again, you would get "burger flambe." But if the directions said cool the burger, cool it again, and then cool it again, you would get a "glacier burger."

Now the question is: Did orbital changes make an ice age that killed the dinosaurs? Is there any evidence in the rocks for an ice age 65 million years ago? To help you in your search, you might want to find information about Ice Ages, Ice Epoch, Milankovich cycle, glaciers, glacial deposits, or climate changes. Good luck!

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Orbital Changes
Image of a star. The Ice Ages
What Is an Orbit?
The Shape of Earth's Orbit
The Tilt of Earth's Axis
The Wobble of Earth's Axis

 

 
             
     
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Orbital Changes | The Ice Ages | What Is an Orbit? | The Shape of Earth's Orbit | The Tilt of Earth's Axis | The Wobble of Earth's Axis

Giant Impact | Super Nova | Disease | Volcanoes | Orbital Changes | Meet the Dinosaurs | Into the Future

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