It is estimated that just one metal-rich asteroid could contain more metal than has ever been used by humanity. Estimates for the mineral wealth of the asteroid belt between Mars and Jupiter equate to roughly $100bn for every person on Earth, while the resources available from near-Earth asteroids could support up to 40 times Earth’s population.
When asteroids collide
Asteroid collisions are rare but fantastic events, when two asteroids of differing size can completely shatter one another. However, the chance of asteroids colliding is roughly equivalent to winning the lottery every day for a week. The only collision event seen by mankind was observed by the Hubble Space Telescope in 2010 (below).
Asteroids are as old as the solar system itself, about 4.6 billion years of age. They formed in the violent and turbulent nebula that gave birth to the Sun and planets. Some were ejected from planets following a collision, such as when Mars was hit by a Pluto-sized object, while others are remnants of failed planetary formation.
Home sweet home
The asteroid belt between Jupiter and Mars is thought to be the result of a planet failing to form between the two planets, due largely to the strong gravitational pull of Jupiter pulling the rocks apart. Beyond the orbit of Neptune is another smaller gathering of asteroids, the Kuiper belt, although its origins are unknown.
Billions among us
There are thought to be billions of asteroids in the solar system. At least one new asteroid has been discovered every year since 1847. However, there are a much larger number of small asteroids. For every one that is more than 10km (six miles) wide, there are 1,000 wider than 1km (0.6 miles) and a million just 0.1km (0.06 miles) in width.