For the past 4.5 billion years, Earth has enjoyed the company of a steadfast celestial partner — the Moon, but now, astronomers say they may have spotted another companion quietly orbiting Earth for some
time.
Experts at the Pan-STARRS observatory in Hawaii have spotted a quasi-moon, called ‘2025 PN7’, that has been tagging along after Earth since the 1960s.
They later explained that this cosmic body is actually an asteroid, and – rather than orbiting the Earth – it is orbiting the Sun on a similar trajectory to our planet.
The astronomers discovered after analysing orbital data from the asteroid, which is just 19 metres (62ft) wide.
Researchers found that it has been in a quasi-orbit around Earth for roughly 60 years and is expected to remain nearby for about another 60 years before drifting away. It becomes the seventh known quasi-moon in Earth-like orbit, earning the distinction of being the “smallest and least stable” among them.
Scientists have been aware of quasi-satellites since 1991, when they first discovered ‘1991 VG’ – which some believed to be an alien probe at the time, the Daily Mail reported.
‘Over three decades later, it is now widely accepted that such objects are natural and constitute a secondary asteroid belt that occupies the region in which the Earth-moon system orbits around the sun,’ the researchers wrote.
The quasi-moon is only visible through good telescopes. And although it may appear to be orbiting Earth, it is not gravitationally bound to our planet.
Quasi-moons belong to a unique class of celestial objects known as Arjunas, which travel in harmony with Earth as it orbits the Sun.
Although it might seem like this new companion has been “following” Earth for a long period, its stay is relatively brief compared to another well-known quasi-moon, Kamo’oalewa, which maintains an Earth-related orbit for approximately 381 years.
2025 PN7 maintains a wide range of distances from Earth, anywhere between 2.8 million miles (4.5 million km) and 37 million miles (59 million km). These quasi-moons in Earth-like orbits are ‘full of surprises, ’ co-author Carlos de la Fuente Marcos, from the Complutense University of Madrid, told Live Science.
He explained that the new quasi-moon is “small and faint, with visibility from Earth being quite limited, so it’s not surprising that it remained undetected for so long.”
The Vera C. Rubin Observatory in Chile, which recently became operational, can scan for other quasi-moons and may uncover many more.
