Asteroids have always been a threat to Earth. In fact, our planet has been hit before. There are still massive craters caused by asteroid strikes in many countries including the United States, Canada, South Africa, and Russia.
Those strikes would have been catastrophic to human life, but because they happened literally millions of years ago, no one alive today seems too concerned about another one. However, some people say we're now overdue.
Well would you look at that! Currently, there is a large asteroid called 3200 Phaethon passing very, very close to Earth. It is approximately five kilometers (or 3.1 miles), wide and has been labeled by NASA as "potentially hazardous".
This is the third largest asteroid recorded to come this close to Earth, and is the closest potentially hazardous asteroid to our blue planet since 1974!