Astronomers have detected the largest planet-killer-sized asteroid in eight years, and this huge space rock could slowly move toward the Earth centuries from now.

Researchers who were looking for space rocks within Earth and Venus' orbits using the Dark Energy Camera in Chile found and reported 2022 AP7, which has a diameter of about 1.1 km to 2.3 km.

Lead study author Scott Sheppard and colleagues at the Carnegie Institution for Science in Washington wrote in the Astronomical Journal about 2022 AP7, mentioning it is a potentially hazardous asteroid (PHA).

It is probably in the top 5% of the largest PHAs ever found.

“Any asteroid over 1km in size is considered a planet killer,” said Sheppard, emphasizing that if such an object strikes Earth, the effect would be devastating to life as humans know it.

“The Earth’s surface would likely cool significantly from sunlight not getting to the planet. It would be a mass extinction event like hasn’t been seen on Earth in millions of years,” he said.

However, Sheppard reassured that 2022 AP7 "has no chance to hit the Earth, currently,” at least, Sheppard, noting that it currently crosses the Earth’s orbit when the Earth is on the other side of the sun.

The asteroid, according to Sheppard, will begin to cross the orbit of Earth closer to where our planet is.

Nevertheless, “this will be centuries into the future and we do not know the orbit of 2022 AP7 precise enough to say much about its dangers centuries from now," he added.

Director of the National Near Earth Objects Information Centre in mid Wales, Jay Tate, told The Guardian that 2022 AP7 does not worry him as Earth was a very small target.

“At the moment, anyway, the impact probability is fairly low. I wouldn’t say negligible, but fairly low.”

“The chances of a collision with Earth are very small, and far in the future when we will have hopefully tested and deployed measures to change an asteroid’s path enough to turn a direct hit into a near miss,” he told Euronews.

Can we defend ourselves from potential collisions?

After NASA assured in November that a small moonlet the size of a football stadium was to be hit with a spacecraft the size of a vending machine, the question of how to defend Earth from collisions with possible space objects recently made headlines.

The DART mission (Double Asteroid Redirection Test) was the first and unprecedented test of a planetary defense system created to avoid a potential meteorite collision with Earth and marked the first time humanity altered the motion of a natural body in space.

Dart scientists declared the mission a success during a post-mission news briefing, but they expressed caution, saying it will be around two months before they can determine whether the spacecraft was successful in changing Dimorphos's trajectory.

An approach like Dart, Tate said, might not be suitable for 2022 AP7, considering the asteroid's size, but there were other possible methods.

“Having said that, we’ve got bucketloads of time,” he said, adding multiple Dart-like impacts can be used to shift the asteroid’s path a little at a time.