A study by NASA using their Wide-field Infrared Survey Explorer (WISE) has led to a new assessment in the number of asteroids that are potentially hazardous to Earth. The results also revealed new information about their origins, and how many asteroids are around Earth.
The PHAs (potentially hazardous asteroids, are a part of a larger group of space rocks near Earth. This specific type has the closes orbit to Earth, at 5 million miles nearby.
According to NASA.com, they are also capable of surviving entry into Earth’s atmosphere, potentially causing massive damage.
Amy Mainzer, NEOWISE principal investigator at NASA’s Jet Propulsion Laboratory wrote that:
“Our team was surprised to find the overabundance of low-inclination PHAs [potentially hazardous asteroids]. Because they will tend to make more close approaches to Earth, these targets can provide the best opportunities for the next generation of human and robotic exploration.”
Space.com reports that the survey found about 4,700 potentially hazardous asteroids, give or take about 1,500 space rocks. Each of these is more than 330 feet wide. Of course, only about 30 percent of these PHAs have been found to date.
According to Huffington Post, Lindley Johnson, a program executive for NASA’s near-Earth object observation program wrote that:
“The NEOWISE analysis shows us we’ve made a good start at finding those objects that truly represent an impact hazard to Earth. But we’ve many more to find, and it will take a concerted effort during the next couple of decades to find all of them that could do serious damage or be a mission destination in the future.”
Previous data from the WISE spacecraft estimated about 20,500 asteroids over 100 meters in length orbited around Earth, but they have not been given the “potentially hazardous” classification.