An asteroid that could level a city now has a 3.1-percent chance of striking Earth in 2032, according to NASA data released Tuesday—making it the most threatening space rock ever recorded by modern forecasting.

YR4 has a small chance of hitting Earth in 2032, but as astronomers make more observations about its trajectory, the odds of a collision seem to be increasing

The chance that a city-killer asteroid will impact Earth in 2032 is steadily rising. Here's what you need to know.