Excerpt from 'Question Answered'

A Dude named Democritus

Democritus was an ancient Greek. In fact, he was young at some point but eventually became a philosopher. He lived over 2,000 years ago. Modern philosophers like Dr. David Darling, who earned his PhD at Manchester University, credit Democritus with the original idea that life must live outside Earth. Dr. Darling is reviving the idea.

In his online Encyclopedia of Science, Dr. Darling explains that the planets are not entirely separate worlds, despite traditional beliefs. When a large asteroid falls to Mars, for example, the impact throws debris into space. Very large impacts throw huge amounts of debris into space, and over the course of millions or billions of years, some of the debris reaches the Earth, where it falls in the form of meteorites. The Earth is 4.57 billion years old so plenty of material has transferred between the neighboring planets. Geologists offer the Martian meteorites on Earth as evidence.

This is a really cool picture of the rover. Image courtesy of the National Aeronautics and Space Administration.

Another meteorite comes from the asteroid Vesta. The meteorite and the asteroid share a common chemical composition.

Both Jupiter and Earth come from the original planetary nebula that formed the Solar System. And over the course of 4.57 billion years, material may have transferred between the two bodies, or between one of the Jovian moons and Earth. During those billions of years, an asteroid may have impacted a Jovian moon, sending debris into space. Eventually, such debris may have gravitated to Earth’s surface as a meteorite. But currently scientists have only found meteorites from Mars, Vesta, and the moon.

Alternatively, debris from a large meteorite collision here on Earth might find its way into space. For very large meteorites, like the one that hit near the Yucatan peninsula and killed the dinosaurs, debris might be thrown into space.

An asteroid transferring materials between a small Jovian moon and Earth is an even more likely scenario. A large asteroid might for example, collide with one of the small Jovian moons and survive the collision. Material from each body might transfer. As the asteroid approaches the Sun, collisions with other asteroids might send debris to Earth.

Copyright, 2012. Wade Hobbs.