In the vast space around our planet, there are some asteroids that could be dangerous to us. They are called Potentially Hazardous Asteroids (PHAs). Even though the chance of one of these asteroids hitting Earth in any given year is low, we need to be cautious because in the past, some big extinction events on Earth were caused by asteroids. In this blog post, we will learn about PHAs, their orbits, and what we are doing to protect ourselves from possible asteroid impacts.
What are Potentially Hazardous Asteroids?
Asteroids are rocks and icy objects that travel around the Sun. Most of them stay in the asteroid belt between Mars and Jupiter. But some PHAs stray from their usual path and come quite close to Earth. These PHAs are usually larger, at least 140 meters wide, and their paths bring them within 7.5 million kilometers of Earth. To give you an idea, that’s about 20 times farther away than the Moon.
Understanding the Risk
While we call them “Potentially Hazardous,” don’t worry too much. The chance of a PHA hitting Earth in any single year is not very high. However, we know that asteroid impacts have caused huge problems for life on Earth in the past. So scientists and space agencies are working hard to find and track these PHAs to understand if they might be a threat to our planet in the future.
Thanks to better telescopes and technology, we have found over 1,000 PHAs so far. Each of these space rocks follows a unique path. Fortunately, we know that none of the known PHAs will hit Earth in the next 100 years. But there are still some we haven’t discovered, and it gets harder to predict their paths beyond that time.
The Double Asteroid Redirection Test (DART)
NASA, the space agency, is doing some cool experiments to keep us safe from asteroids. They have a mission called the Double Asteroid Redirection Test (DART). They plan to send a spacecraft to bump into a small moonlet (a little moon) that goes around a bigger asteroid called Didymos. This experiment will help scientists see if we can change the path of an asteroid, which could be really important if we ever need to protect Earth from one.
Everyday Encounters with Space Debris
Apart from the big PHAs, we also have smaller space rocks and bits of ice that come into Earth’s atmosphere quite often. Thankfully, most of them are very tiny, and they burn up harmlessly in the atmosphere. Sometimes, they create beautiful fireballs and bright streaks across the sky, giving us a lovely show.
While Potentially Hazardous Asteroids may sound scary, we are learning more about them to keep Earth safe. Even though the chance of an asteroid hitting us soon is low, we are taking precautions and studying how to change an asteroid’s path if needed. So, we can admire the wonders of the cosmos and explore space with a sense of security, knowing that we are doing our best to protect our beautiful blue planet.