Here's How Often Small Asteroids Enter Earth's Atmosphere

NASA's Near Earth Object Program released a map showing what more and more people are beginning to realize: that small asteroids enter Earth's atmosphere frequently. What happens to these asteroids, and why didn't we know this before?
Many of the impacts are seen and reported as fireballs. Nearly all burn up in Earth's atmosphere; that is, our atmosphere does its job in protecting us from what would otherwise be impacts to Earth itself.