A mile-wide asteroid with its own moon is on a path to fly by Earth this weekend.
Astronomers say the asteroid, known as 1999 KW4, will pass within 3.2 million miles on Saturday. Experts say that distance is close, but safe. Stargazers with eight-inch diameter telescopes might be able to catch a glimpse. The next time the asteroid will be visible from Earth will be in 2036, when it will be even closer.