Astronomers working with a Dark Energy Camera have spotted an asteroid big enough to wipe out life on Earth as we know it.
The asteroid, 2022 AP7, measures 1.5 kilometres wide, the biggest near-Earth asteroid (NEA) found since 2014.
Its orbit is also on a path to intersect with Earth's orbit.
However, Earth will be safely on the other side of the Sun when that happens, a pattern expected to persist for hundreds of years.
The asteroid was spotted in the region within the orbits of Earth and Venus, a notoriously challenging region for observations because asteroid hunters have to contend with the glare of the Sun.
The finding, along with the discovery of two other "rather large" asteroids that are not on a collision course to Earth, was published on Monday in the Astronomical Journal.
"Our twilight survey is scouring the area within the orbits of Earth and Venus for asteroids," said Scott S Sheppard, an astronomer at the Earth and Planets Laboratory of the Carnegie Institution for Science and the lead author of the paper describing this work.
"So far we have found two large near-Earth asteroids that are about 1 kilometre across, a size that we call planet killers."
If an asteroid that size was to hit Earth it would kick dust and pollutants into the air that would linger for years, blocking out sunlight and causing a mass extinction event, study authors said.
But it's not doomsday quite yet.
Luckily for Earthlings, the chance of a collision is tiny because Earth will be on the opposite side of the Sun when 22AP7 is predicted to enter the planet's orbit.
Astronomers expect that this pattern will continue for centuries due to it taking the asteroid five years to complete an orbit around the sun.
Study authors can't currently predict the asteroid's orbit with enough precision to say how dangerous it will become, but they are confident it will stay away from Earth for the time being.
The other asteroids, called 2021 LJ4 and 2021 PH27, have orbits that remain safely interior to Earth's orbit.
"There are likely only a few NEAs with similar sizes left to find, and these large undiscovered asteroids likely have orbits that keep them interior to the orbits of Earth and Venus most of the time," said Mr Sheppard.
"Only about 25 asteroids with orbits completely within Earth's orbit have been discovered to date because of the difficulty of observing near the glare of the Sun."
While 2021 PH27 doesn't pose a direct threat to Earth, it is of scientific interest due to the rock being the closest known asteroid to the Sun.
As such, during the part of its orbit where it's closest to the Sun, the rock's surface becomes hot enough to melt lead.
