What would happen if a ‘city-killer’ asteroid hit the moon?

While scientists have since said the Earth is safe from the rock, called 2024 YR4, there’s still a chance it will collide with the moon instead. The odds of the rock hitting us decreased as astronomers learned more about it (Picture: AFP)What would happen if 2024 YR4 smashes into the moon? What is 2024 YR4? This is because astronomers have more information about 2024 YR4 to make more accurate guesses. Would have to be a pretty big rock to gouge the moon like this (Picture: Getty Images/iStockphoto)As scary as a ‘city-killer’ asteroid sounds, a space rock would need to be a fair bit larger to pose a risk to the moon, Dr Carpineti says.