An unexpected asteroid named 2019 OK just flew between Earth and the moon, hammering home the need for continued improvements in both finding and tracking potentially hazardous asteroids. (Credit: Illustration via Pixabay)

Earth had a close encounter Thursday morning when Asteroid 2019 OK sped by at 1:22 GMT, at a speed of nearly 55,000 miles (88,500 kilometers) per hour. The closest it came to Earth was just under 45,000 miles (72,500 km), a safe distance, but still much less than the dista