The night sky might look empty and black, but when you really look out into space, you’ll find that the universe is full of not just stars and planets, but also dust, comets, and asteroids. Many of these celestial objects are being actively studied by scientists. Understandably, asteroids are objects that receive a great deal of attention, especially potentially hazardous asteroids.
But what exactly makes an asteroid “potentially hazardous?” Isn’t any asteroid technically hazardous? These questions probably run through most of our heads when we read articles about asteroids skimming past Earth. Understanding the answers to these questions can help us make sense of those terrifying headlines we see so often.
NASA defines any asteroid that has the potential to make threatening close approaches to Earth as a potentially hazardous asteroid. Essentially, if the asteroid is big enough and comes close enough to the Earth to be concerning, NASA considers it a possible threat. Now, that isn’t to say that every potentially hazardous asteroid is actually a danger. It’s more of a safety precaution than anything.
But the fact that potentially hazardous asteroids do exist is a big part of why countries want to build asteroid monitoring systems. It’s also a big part of why NASA’s recent DART Test was such a big deal. Proving that we can indeed change the orbit of an asteroid by smashing something into it at least gives us some kind of defense against these threatening celestial bodies.
Asteroids have hit Earth before. In fact, we’ve had a few asteroid impacts sneak up on us in the past – with scientists only taking discovering those asteroids shortly before they impacted the Earth’s atmosphere. Of course, if there is a potentially hazardous asteroid barreling towards us, we’re probably going to notice it before it hits the Earth, especially with James Webb and other powerful telescopes out there.
At least, that’s the hope. Of course, the chances of an asteroid hitting the Earth and causing massive damage to cities or even the entirety of the planet isn’t completely unheard of. Scientists believe an asteroid decimated the dinosaurs millions of years ago. And some believe that asteroids may have even helped deliver important life-giving compounds to our planet when it was just a barren rock.
So, having a way to deal with potentially hazardous asteroids will probably continue to be a high priority for many scientists in the coming years.