It is indeed true that our beloved Earth has missed some major asteroids whose impact could have been catastrophic.
So, what happens when Earth is hit by an asteroid?
Whenever there’s a collision between astronomical objects its known as impact events. These impact events can have major physical consequences. There are some variables which determine the degree of impact, these variables are location, size and the speed angle of the asteroid and the composition of the asteroid.
Earth was formed about 4.5 billion years ago. Since then asteroids and comets have routinely slammed the planet. An asteroid has to be more than a quarter mile wide to be able to cause a global disaster. Researchers have estimated that such an impact would raise enough dust into the atmosphere to effectively create a “nuclear winter”.
Can you imagine having a Game of Thrones winter in real life?! That surely will be abysmal. According to NASA, asteroids large enough to cause a global disaster strike Earth only once every 1000 centuries and to be born in that century, well its simply hard luck.
Smaller asteroids strike Earth every 1,000 to 10,000 years. They have the capacity to destroy a city, if hit on land or cause devastating tsunamis if they hit the ocean.
Our Close Calls With Asteroids
- Asteroid Florence
A mountain size space rock cruised past Earth in September 2017. It was roughly 4.4 kilometers wide and came within a 7 million kilometers of Earth. Only about 10 asteroids as big as Florence exist in near Earth space, a then researcher claimed.
Astronomers also determined that Florence is a super fast spinner, completing one rotation every 2.4 hours. If Florence had hit us there would have been immense damage but luckily it was a miss.
- Asteroid 2019 OK
On July 26, 2019 scientists were stunned by a city killer asteroid that just missed Earth. Alan Duffy, who is lead scientist at the Royal Institution of Australia, woke up to his phone flooded with calls from reporters wanting to know about a large asteroid that Earth just missed that day. “I was stunned, this was a true shock.”, he said while talking to the Washington Post.
This asteroid wasn’t the one that scientists had been tracking for a long time and it appeared out of nowhere. NASA revealed that the rock was large, about 57 to 130 meters wide and moving fast along a path that brought it within about 73,000 kilometers of Earth, which is less than one-fifth of the distance to the moon and what Duffy considered “uncomfortably close.”
The asteroid’s presence was discovered only by separate astronomy teams in Brazil and the United States but information about its size and path surfaced just before it shot past Earth. It was considered the largest asteroid to pass this close to Earth in quite a number of years. Scientists later predicted that if the “City Killer Asteroid” would have hit the Earth it could have resulted in devastating damage. “It would have gone off like a very large nuclear weapon”, scientists said. This was indeed a sobering reminder about how real astronomical threats can be.
An asteroid larger than a football field zoomed past the Earth at a distance closer than our moon on 5 June, 2020 and we did not know about it until it had already passed. The asteroid is considered to be the largest in nine years and would have been big and fast enough to deliver a nuclear sized explosion if it had hit the Earth.
2020LD was discovered on June 7, it was two days after it buzzed between the Earth and the moon. It was around 89 to 200 meters wide and passed within 306,000 kilometers of the planet, according to NASA’s tracking data. That’s about 80% of the distance to the moon. It was first detected in Hawaii.
- 1998 OR2
1998 OR2 passed the Earth on April 29, 2020. It passed at a safe distance. It’s the biggest asteroid to fly by Earth this year so far. It was about 2 kilometers wide and mostly spherical.
Closest approach was April 29 around 4.56am. Asteroid 1998 OR2 is classified as a potentially hazardous asteroid. Fortunately, we dodged the hit and it passed at a safe distance of about 4 million miles. This is the most recent close call Earth has had with an asteroid.
We have been fortunate enough that we missed some major asteroid hits. If we were hit by these asteroids then their impact would have been devastating. Asteroids like Chelyabinsk or the 1908 Tunguska Event are the times when we weren’t lucky enough to dodge the hit. They did not only cost us physical infrastructural damage but we also lost many lives in these disasters.
Since these are naturally occurring events there’s nothing much that we can do to stop them. But we can definitely try to avoid the hits, and the most effective way is to identify as many asteroids as possible, map their orbits and then work out a way to either destroy or deflect them.
The unidentified misses that we have are the major potential threats which need to be handled very meticulously, because a little slacking off may lead to wiping off of an entire city or much more.
It may seem fascinating to discuss these close encounters and even intriguing to some extent. But these discussions also knock at our consciousness about the potential risk, we could be at without even knowing about it!