The asteroid 2018 AH is expected to be roughly 190 meters long, similar to the Tunguska asteroid, making it far more devastating than a nuclear weapon.
According to NASA’s asteroid tracker, a massive asteroid the size of the Washington Monument will approach Earth in late December, causing damage considerably larger than an atomic bomb if it hits.
This asteroid, dubbed 2018 AH, is predicted to be roughly 190 meters diameter and will fly by Earth on December 27.
The asteroid, which is expected to pass by at a distance of more than 4.5 million kilometers, is unlikely to harm the Earth. The distance between the Earth and the Moon, by comparison, is roughly 384,000 km, or about a twelfth of that.
2018 AH, on the other hand, has passed Earth before — and at a far closer distance.
It flew past the planet in 2018 at a distance of 296,758 kilometers, roughly three-quarters of the distance between the Earth and the Moon. Because of its dimness, it had gone unnoticed, and scientists missed it.
No asteroid of such size has come close to Earth since then, and none is projected to until 2028, when the huge, almost kilometer-long 153814 (2001 WN5) arrives. But it won’t hit the earth, passing at a distance of roughly 249,000 kilometers — even closer than 2018 AH.
But what if an asteroid the size of 2018 AH collided with the Earth?
Normally, it’s tough to get an accurate guess because size fluctuates so much. However, astronomers have a fair sense of how catastrophic it would be in this situation because something similar has happened previously.
A 17-meter asteroid burst in the atmosphere of Russia in 2013.
The last time an asteroid of this size hit Earth was in 1908, above the Podkamennaya Tunguska River in Russia.
This asteroid was similar in size to 2018 AH, if not smaller. The asteroid exploded many kilometers above the area, causing widespread destruction for thousands of kilometers. For comparison, “Little Boy” was a 15-kiloton atomic bomb dropped over Hiroshima during WWII, while “Fat Man” was a 20-kiloton bomb dropped over Nagasaki three days later.
According to Encyclopedia Brittanica, a US government report at the time stated that Hiroshima suffered 135,000 casualties, or more than half of its population, and Nagasaki 64,000, a third of its population.
The death toll from the Tunguska event was extremely low, however, with only around three people thought to have been killed in it, due to how remote and sparsely populated the region was. But the damage was still evident, with about 80 million trees completely flattened, winds of around 27 km., a second bursting around and a loud noise heard far and wide. Tremors and air waves were felt as far away as even Washington and Indonesia.
The few eyewitness accounts that do exist recounted the terrifying explosion, strong winds, tremors and incredibly loud noises.
“The sky split in two and fire appeared high and wide over the forest,” recounted a man who was about 65 kilometers south of the explosion.”The split in the sky grew larger, and the entire northern side was covered with fire,” he said.
“At that moment I became so hot that I couldn’t bear it as if my shirt was on fire; from the northern side, where the fire was, came strong heat. I wanted to tear off my shirt and throw it down, but then the sky shut closed, and a strong thump sounded, and I was thrown a few meters. I lost my senses for a moment, but then my wife ran out and led me to the house.
“After that such noise came, as if rocks were falling or cannons were firing; the Earth shook, and when I was on the ground, I pressed my head down, fearing rocks would smash it,” he said.
“When the sky opened up, hot wind raced between the houses, like from cannons, which left traces in the ground like pathways, and it damaged some crops. Later we saw that many windows were shattered, and in the barn, a part of the iron lock snapped.”
The Tunguska event is the largest in recorded history – though larger prehistoric ones happened – and is one of the largest explosions ever recorded, far more powerful than many nuclear bombs.
If 2018 AH hit, it could cause something similar.
According to NASA, any asteroid 140 meters in diameter or larger could have a potentially catastrophic impact if it crashed into Earth.
The destructive nature of asteroids, even small ones, is something well-known to experts, with space agencies around the world monitoring for potential catastrophic impacts, as well as researching potential means of stopping them.
One method for possibly stopping the impact of an asteroid is through the use of deflection, which would mean launching something to slightly alter its path. The most prominent of these efforts is the Double Asteroid Redirection Test (DART) Mission currently underway, the result of efforts by NASA and the Applied Physics Laboratory.
In layman’s terms, it means punching an asteroid with a rocket with enough speed to change its direction by a fraction of a percent.
The DART Mission is humanity’s first real attempt at testing a defense against an asteroid impact and was launched towards the Didymos binary asteroid system.
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