Scientists say the threat of a newly discovered asteroid has risen slightly in the past few weeks, as the world's telescopes rush to track its course.

A nearly 98 percent chance it won’t hit us is pretty good. Second, while that’s definitely a massive rock, it’s not like a dinosaurs-killing size. Three hundred feet wide is about on par with the asteroid that exploded over Siberia in 1908 (also known as the 1908 Tunguska Event).