I’ve heard of “killer asteroids” in the Solar System. What is the chance of one striking the Earth?
The National Aeronautics and Space Administration (NASA) has classified about 21,000 asteroids and 100 comets as near-Earth objects. Of that group, 2,000 are considered to be “potentially hazardous,” meaning they are in orbits that come within 4.5 million miles of the Earth and large enough to cause massive devastation, should they strike. None has been found to pose a threat to the Earth in the next 100 years. However, astronomers have found only an estimated 40 percent of near-Earth objects. In July, 2019, a previously undetected asteroid that was 424 feet in diameter came within 45,000 miles of Earth. Had it struck, it would have gone off like a very large nuclear bomb.