Asteroids are directly responsible or partially involved in at least three recorded mass extinctions in Earth’s history.
A representative of them is an asteroid that landed in Chixulub, Mexico, at the end of the Cretaceous period 66 million years ago, ending the age of dinosaurs and causing the extinction of 75% of all living things on the planet.
‘Dimorphos’, which NASA conducted a collision test with the ‘Dual Asteroid Orbital Correction Experiment’ (DART) spacecraft this time, is about 160m in diameter, which is not much.
However, it is known to have a destructive power that can turn any city into ruins.
Considering the fact that the asteroid that exploded over Chelyabinsk, Russia in February 2013, breaking windows in six cities and injuring 1,600 people, was only 18 meters high, the danger can be fully guessed.
Asteroids are the remains of rocks used by the solar system to form planets about 4.6 billion years ago, and they vary in shape, size and composition.
Most of them orbit the Sun while being concentrated in the asteroid belt between Mars and Jupiter.
Once in the orbit of this inner planet, it orbits for millions of years before colliding with the sun or the inner planet, or being pushed back into the asteroid belt or beyond.
Scientists are currently focusing on near-Earth celestial bodies that approach Earth within 30 million miles (48 million km) and asteroids with orbits that intersect Earth’s orbit.
It is estimated that there are approximately 26,000 near-Earth celestial objects larger than 140 meters in size.
It is estimated that the 140-meter-diameter asteroid can create a crater of about 1 to 2 kilometers and can destroy a large city and cause mass casualties.
Asteroids with a diameter of more than 1,000m will form a crater of 10km, and asteroids with a diameter of more than 10km will form a crater of 100km, analyzed to lead to the collapse of civilization and the mass extinction of terrestrial life, respectively.
It is calculated that the probability of a 1,000-meter class asteroid colliding with Earth is about once every 500,000 years, and a 10-km class asteroid has a chance of impacting once every 100 million to 200 million years.
Fortunately, 95% of asteroids over 1,000 meters (about 900) have been identified, and all four asteroids larger than 10 kilometers are tracked and controlled.
The problem is that there are an estimated 25,000 140m class asteroids that can collide once in about 20,000 years, but only 10,000 have currently been confirmed.
The remaining 15,000 must be tracked forward to see if there is a risk of collision.
In 2005, the US Congress required NASA to find more than 90% of asteroids larger than 140m that could threaten Earth, but only one is found every day, so it is expected to take 30 years another.
Fortunately, none of the asteroids discovered so far are in danger of colliding with Earth within the next century.
It is estimated that there are around 5 million asteroids with a diameter of 25 meters that can collide with the Earth once every 100 years, but only 0.4% have been discovered so far.
Asteroids of this size can cause air explosions similar to those of Chelyabinsk, which could lead to injuries if they occur in densely populated areas.
There are about 500 million asteroids with a diameter of 4m, of which only 0.1% have been discovered, but it only causes a flash of light once a year, so there is no need to worry.
In July 2019, the asteroid ‘2019 OK’, estimated to be 50-130 m in diameter, can be estimated to have passed approximately 73,000 km from Earth.
If this asteroid collided with the Earth, it was estimated that somewhere up to 80 km of area would have suffered damage.