Today, our solar system's asteroids reside between Mars and Jupiter, in a dense region that's known as the asteroid belt. They're thought to all be the remnants from the gas and dust cloud from which planets, suns, and moons were created. Asteroids vary in size; some are so large, they have enough gravitational pull to attract their own moon.

Occasionally, an asteroid's path around our sun intersects with Earth's, and the two bodies collide in sometimes cataclysmic fashion. In the solar system's early days, before the Earth as we know it was ready for life, our world took a serious beating.

But as asteroids dealt our primeval home a pummeling, they also seeded our world for life. When asteroids collided with