With the number of asteroids zipping past Earth on a regular basis, it’s only a matter of time before the planet gets hit by a massive space rock. Depending on certain factors, an asteroid impact on Earth could trigger a global extinction-level event.

Both NASA and the European Space Agencies have their own databases that track near-Earth approaches of asteroids. Although these agencies have not yet detected an asteroid that is guaranteed to hit Earth in the future, many scientists believe that an impact event is inevitable.

According to Express, the scale of destruction caused by an asteroid impact mainly depends on its size and speed. An asteroid that’s about a few feet long or one that’s as big as a house and traveling at a speed of around 30,000 miles per hour can produce energy that’s equivalent to a 20 kiloton bomb upon impact. This is the same type of bomb that was dropped on Hiroshima, Japan in World War II.

The energy that will be released by this kind of asteroid will destroy and flatten reinforced buildings that are within half a mile from the point of impact.

A bigger asteroid, or one that is as tall as a building, can cause a massive explosion that’s equivalent to a 50 megaton nuclear bomb. This would destroy everything within five miles from ground zero. Given the level of the destruction it can cause, this particular type of asteroid has been labeled as a city-killer.

Asteroids that are a mile wide or bigger are capable of obliterating large areas, including entire countries. Their blast energy is 10 million times more powerful than the bomb used in Hiroshima. Anything within 100 to 200 miles from the point of impact would be leveled. It can also cause extensive damage for up to 1,000 miles away.

If this kind of asteroid hits the ocean, it would create towering tsunamis that can travel several miles inland.

Aside from these, the massive explosion from the asteroid’s impact would send so much debris and smoke into the atmosphere that it would block out the Sun and create a nuclear winter for a very long time. The lack of sunlight and toxic air would then cause most living creatures on Earth to eventually die.

asteroid impact
A recently-discovered 250-mile area located in the central Australian outback might be the largest asteroid impact crater ever recorded. NASA/Don Davis