From September 29 to November 24, Earth’s moon was accompanied by an even smaller moon-like object. It was first seen by the NASA funded Asteroid Terrestrial impact Last Alert System (ATLAS) telescope. Although the name including “Last Alert System” can be intimidating to people, the asteroid is no threat. It is on its route rotating the Earth with no collision course, according to npr.org.

Since the rock was too dimly lit from the sun, it will not be visible to the naked eye, or even with a normal telescope. But special telescopes used by astronomers will be able to capture the rock since it is bright enough to be seen through these. The telescope needs to have a diameter of at least 30 inches plus a charge-coupled device or a complementary metal-oxide-semiconductor to be able to see the asteroid, according to space.com.

This is not the first time this has happened. In 2020, astronomers discovered the first mini-moon to be seen, named 2020 CD3. This rock orbited around Earth for over a year. The 2024 mini-moon is named 2024 PT5. It was first spotted by researchers in Southern Africa. The rock has been doing its normal rotation, but in the fall, it will be pulled into the orbit around the Earth. This will make 2024 PT5 look like a mini-moon in high-tech telescopes, according to npr.org.

“The object that is going to paid us a visit belongs to the Arjuna asteroid belt, a secondary asteroid belt made of space rocks that follow orbits very similar to that of Earth at an average distance to the sun of about 93 million miles (150 million kilometers). Objects in the Arjuna asteroid belt are part of the near-Earth object population of asteroids and comets,” professor Carlos de la Fuente Marcos said in an interview with space.com.