Astronomers have spotted three near-Earth asteroids that were lurking undetected within the glare of the sun. One of the asteroids, called 2022 AP7, is the largest potentially hazardous object posing a risk to Earth to be discovered in the last eight years. Their findings were published Monday in The Astronomical Journal.
According to the publication, the asteroids belong to a group found within the orbits of Earth and Venus, but they’re incredibly difficult to observe because the brightness of the sun shields them from telescope observations.
To avoid the sun’s glare, astronomers leaped at the chance to conduct their observations during the brief window of twilight. An international team spied the space rocks while using the Dark Energy Camera located on the Víctor M. Blanco 4-meter Telescope located at the Cerro Tololo Inter-American Observatory in Chile.
Scientists say 2022 AP7, is 1.5 kilometers (0.9 miles) wide and has an orbit that could bring it within Earth’s path in the future, but it’s difficult for them to know when.
“Our twilight survey is scouring the area within the orbits of Earth and Venus for asteroids,” said lead study author Scott S. Sheppard, an astronomer at the Earth & Planets Laboratory of the Carnegie Institution for Science in Washington, DC, in a statement.
“So far we have found two large near-Earth asteroids that are about 1 kilometer across, a size that we call planet killers.”
Scientists determined that the asteroid crosses Earth’s orbit, but it occurs when Earth is on the opposite side of the sun – this pattern will continue for centuries since it takes the asteroid five years to complete an orbit around the sun. But over time, the asteroid’s orbital movement will be more in sync with Earth’s.
Scientists don’t know the asteroid’s orbit with enough precision to say how dangerous it could become in the future, but for now, it “will stay well away from Earth,” Sheppard said.
The team expects to find more planet-killer asteroids in their survey over the next couple of years. Scientists believe there are about 1,000 near-Earth objects larger than 1 kilometer in size, and surveys over the last decade have found about 95% of them.