Astronomers have identified a peculiar “moon” that casts a shadow on Earth as it navigates through space. Dubbed quasi-moons, these entities don’t orbit our planet in a traditional manner, yet they maintain proximity as they travel around the sun.
According to a new study published in the American Astronomical Society Research Notes, this space rock may have been a companion to Earth for as long as 60 years.
The object, identified as 2025 PN7, is small enough that it might have evaded earlier detections. While its exact dimensions remain uncertain, researchers estimate it to be around 30 meters (98 feet) in diameter—approximately the wingspan of a typical short-haul airliner—making it the tiniest known quasi-moon associated with Earth.
“With rapid technological progress, we’re identifying near-Earth objects faster than ever,” said Dr. Darren Baskill, an astronomy lecturer at the University of Sussex, in BBC Science Focus. “The sensitivity of digital cameras has improved, allowing us to detect these faint objects, and computers can effectively process vast data sets.”
At its closest approach, this object comes within 300,000 km (186,400 miles) of Earth. Usually, it remains about 384,000 km (238,600 miles) away, but its horseshoe-shaped orbit can take it as far as 297 million km (185 million miles) from our planet.
Consequently, it’s only detectable when nearby, as occurred in August 2025, when researchers from Spain’s Complutense University of Madrid spotted it from the PanSTARRS Observatory in Hawaii.
Upon reviewing historical records, scientists identified it as a potential Earth companion for decades.
“The primary question is, where did 2025 PN7 originate?” Baskill noted. “At its closest, 2025 PN7 will be roughly the same distance from Earth as the Moon, providing insights into the Moon’s possible origin.
“Another clue can be observed on a clear night: the Moon is full of craters. Each impact casts debris into the atmosphere, and some material may escape the Moon’s gravity and be launched into space.”
Another hypothesis suggests that the space rock originated in the asteroid belt, but Baskill states, “It’s challenging to gather sufficient light from such a moving object to determine its chemical composition and origin.”
He further added, “Astronomers must be patient and wait to observe PN7 when it’s at its brightest, closest to Earth.”
2025 PN7 is just one of seven quasi-satellites currently orbiting near Earth. The other is the space rock Kamooarewa, which is the target of China’s Tianwen-2 mission. Launched in May 2025, Tianwen-2 aims to collect samples from asteroids to understand more about Earth’s origins and asteroid formation.
“These near-Earth objects, due to their occasional close passes, might become prime targets for the inaugural mining operations beyond Earth, or even enter Earth’s atmosphere,” Baskill remarked.
PN7 will remain in existence until 2085 when it will be pulled from orbit by gravitational forces.
read more:
Source: www.sciencefocus.com
