An enormous asteroid approximately the size of a football pitch skimmed Earth last month, catching astronomers unaware. The incident was all the more serious because the 2019 OK space rock hurtled past Earth at a distance of 40,400 miles (65,000km) – only one fifth of the distance to the Moon. Although it is extremely unlikely to occur anytime soon, an apocalypse asteroid really could one day hit Earth.
The damage an asteroid can inflict on Earth is dependent on three factors: its size, speed and composition.
An asteroid’s composition is mainly determined by how close it is to the Sun.
Those nearest the Sun are mostly made of carbon, while ones further away are composed of silicate rock.
Even modest asteroids hurtling from the heavens will boast a great deal of energy.
Should an asteroid the size of a house impacted Earth at 30,000 mph, its would boast an amount of energy approximately equal to the 20 kiloton bomb that destroyed Hiroshima.
Such an asteroid could flatten reinforced concrete buildings up to half a mile (0.8km) from ground zero, extensively damaging any city.
An asteroid similar in size to a 20-story building (200ft), possesses an amount of energy equal to the largest nuclear bombs made today – up to 50 megatons.
Such a space rock would flatten reinforced concrete buildings even five miles (eight kilometres) from ground zero.
This could consequently obliterate most major cities in the US.
Even mile-wide asteroid are known to exist, which have the destructive force of 1 million megaton nuclear bombs.
This is the energy equivalent to 10 million times greater than the bomb that levelled Hiroshima.
It’s able to flatten everything for 100 to 200 miles out from ground zero.
Should a mile-wide asteroid directly hit London it would destroy everything to Brussels and Amsterdam, as well as cause extensive damage perhaps 1,000 miles out — that’s as far away as Sarajevo and Naples.
The quantity of dust and debris thrown into the atmosphere would block out sunlight and cause most living things on Earth to die.
If an asteroid that size landed in the ocean, it would triggered tidal waves hundreds of feet high that would completely erase the coastlines in the vicinity.
In 2028, the asteroid 1997XF11 will come perilously close to Earth but will miss the planet.
If something were to change and it did hit Earth, the mile-wide asteroid would impact Earth at approximately 30,000 mph.