The Physical Environment

Asteroids and Near Earth Objects

How many Potentially Hazardous Asteroids is NASA tracking that could impact the Earth in the twenty-first century?

More than 210 PHAs are on NASA’s list of most likely objects whose orbital paths may bring them close to Earth’s orbit sometime in the next 100 to 200 years. Scientists have not fully calculated the risks because they still need to figure out the effects of gravity of various planetary bodies on the exact course of the asteroids.


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