Tens of thousands of asteroids—that we know of—are roaming our solar system. These are building blocks made up of metal, silicates, and ice left over from the beginning of time when the planets (Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune) and their moons were assembling.
Click here for original story, What are meteorites? I visit and study the craters they’ve left across our planet
Source: Phys.org