NASA Survey Counts Potentially Hazardous Asteroids

Observations from NASA’s Wide-field Infrared Survey Explorer have led to the best assessment yet of our solar system’s population of potentially hazardous asteroids. The results reveal new information about the asteroids’ total numbers, origins and the possible dangers they may pose.

Potentially hazardous asteroids are a subset of the larger group of near-Earth asteroids. The PHAs have the closest orbits to Earth’s. They come within about 8 million kilometers (5 million miles) of Earth and are big enough to survive passing through Earth’s atmosphere. PHAs could cause damage on a regional, or greater, scale.

This story is a great extension to NASA Now: Primitive Asteroids: OSIRIS-REx, where Dr. Joseph Nuth discusses a mission to a near-Earth asteroid. This NASA Now program is available on the NES Virtual Campus.

To read more about potentially hazardous asteroids, visit