once every five to ten years. now to our other out-of-this-world story. an asteroid the size of a city block is hurling towards the earth now. that has many people wondering what kind of experience will we have? will it be like this? that was the scene when a meteor slammed into southern russia last month. it exploded and shattered windows for miles. about 1500 people were hurt. as for today s asteroid, though, we re told not to worry. though it is 262 feet wide, it will only get within about 605,000 miles to earth. that s less than half the distance from the moon. joining us right now from los angeles is nasa astronomer amy mizer. good to see you, amy. good to see you, too. will anyone be able to actually see this asteroid as it passes by? 600,000 miles away? yeah.