What is a potentially hazardous asteroid? One is heading near Earth next week

A POTENTIALLY hazardous asteroid that's bigger than any building on Earth is expected to shoot past our planet next week on January 18.

Asteroid 7482 (1994 PC1) is estimated to be around 3,551 feet wide and is expected to shoot past at around 1.2million miles away.

You may wonder why an asteroid that stays millions of miles away from Earth is labelled as potentially hazardous.

Cautious space agencies like Nasa actually have a few criteria for an asteroid to meet before they give it this title.

What is a potentially hazardous asteroid?

Nasa's Center for Near Earth Object Studies (CNEOS) explains on its : "Potentially Hazardous Asteroids (PHAs) are currently defined based on parameters that measure the asteroid’s potential to make threatening close approaches to the Earth."

Large fast-moving space objects that come within 4.65 million miles of Earth are considered to be "potentially hazardous" by cautious space organizations.

One small change to their trajectories could spell disaster for Earth.

An asteroid would also need to be 460 feet or larger in size to be considered potentially hazardous by Nasa.

Thousands of near earth objects (NEOs) are tracked by scientists to monitor whether they're on a collision course with our planet.

Nasa lists them in its table.

When will an asteroid hit Earth?

No one really knows for sure when an asteroid could hit Earth but experts can make some logical estimations.

Asteroid 2010 RF₁₂ is a small asteroid that currently has the greatest known probability of hitting Earth.

Fortunately, it shouldn't cause much damage.

Nasa has given it a 1 in 22 of hitting Earth in 2095.

The good news is that Asteroid 2010 RF₁₂ is only 23 feet wide.

It's small size means there's little danger of much harm arising, but it could still cause some destruction.

Plans to save Earth from asteroids

Some experts are worried that Earth isn't yet ready to defend itself from potentially deadly asteroids.

SpaceX CEO Elon Musk once sparked concern by tweeting: "a big rock will hit Earth eventually & we currently have no defence."