Can asteroids be dangerous? While some may pose a risk, the probability of a dangerous asteroid hitting Earth in any given year is very low. Some mass extinction events in history have been linked to asteroid collisions. However, scientists are paying great attention to detecting and cataloging these celestial bodies that could impact Earth in the future. The image shows the orbits of more than 1,000 known Potentially Hazardous Asteroids (PHAs). These chunks of rock and ice, more than 140 meters in diameter, will come within about 7.5 million kilometers of Earth. This is about 20 times the distance between us and the Moon. Although none of them are expected to hit the Earth in the next 100 years, there are still undiscovered PHAs. Moreover, long-term orbit predictions are becoming increasingly difficult. If an asteroid of this size were to hit Earth, it could cause massive tsunamis. NASA's Double Asteroid Redirect Test (DART) will be launched later this year to develop strategies to protect our planet. Of course, much smaller asteroids and ice fragments fall to Earth every day. But they usually pose no threat and can occasionally cause impressive meteor and fireball displays in the sky.

August 29, 2021 Astronomy Photo of the Day (NASA APOD)

Image Source: NASA, JPL-Caltech