Here is some more in depth information on how this incredible “field” actually functions:

The magnetic field is generated by swirling liquid metal in Earth’s outer core, and this “geodynamo” requires the release of heat from the planet to drive its churning. Nowadays, this heat flow is aided by plate tectonics— the movement of the plates of rock that make up the planet’s exterior — which efficiently lets heat transfer from Earth’s interior to its surface.

Now, scientists have found that Earth’s magnetic field could be up to 4.2 billion years old — about 750 million years older than had been previously thought.

The researchers investigated magnetically sensitive minerals such as magnetite, a naturally occurring cousin of rust. As molten rock cools, magnetite within it becomes literally set in stone, pointing to the location of Earth’s magnetic poles at the moment it froze. As a result, the oldest samples of magnetite can reveal the direction and intensity of Earth’s magnetic field at the earliest parts of Earth’s history, the researchers said.

Do you think they are right…is this THE factor for an inhabitable planet?

And below is a cool related video with some neat pics and illustrations!

thanks to livescience.com for the great info