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The Earth has a new small satellite, astronomers say.
Asteroid 2026 QQ8 was first spotted in August by Hungarian astronomer Christian Szarnecki, but was only reported by the International Astronomical Union's Minor Planet Center last month.
It is very small - its diameter is only 1-2 meters - and it is located at a distance of more than 500,000 km from our planet, further than the Moon.
Minimoons are small asteroids that fell into the Earth's gravitational field and for some time became its satellites.
Astronomers believe asteroid 2026 QQ8 was captured by Earth's gravity in April, but is expected to leave Earth's orbit in the next couple of months.
Minimoons are not the only temporary satellites of the Earth.
Quasi-moons
Quasi-moons get their name because when viewed from Earth, they appear to orbit around the Earth like the Moon. But in fact, these are asteroids that revolve around the Sun along with the Earth.
One recent example is asteroid 2025 PN7, discovered last August. It has been moving almost synchronously with the Earth for several decades.
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"Quasimoons are interesting because they don't orbit our planet in the same way as the Moon - they just sit nearby," Dr Jennifer Millard, an astronomer, explains to the BBC.
The size of asteroid 2025 PN7 is about 20 meters.
“It’s small—about the size of a small office building. We think it's been around for about 60 years and, based on its current orbit, will be around for another 60 years,” Millard suggests.
None of these "moons" can compare with the Moon, the only true satellite of our planet.
“Although they revolve around the Sun, their path through outer space is very close to that of Earth. They seem to be orbiting around us because they stay so close: sometimes they are in front of the Earth, sometimes behind, but they are not gravitationally connected to it. This is the main difference,” she explains.
However, while moving in their orbits, these asteroids also experience a slight influence of Earth's gravity, which pulls them closer.
All known quasi-satellites of the Earth became such for a while: for decades or even more than a century.
Minimoons
Unlike a quasi-moon, a minimoon actually orbits the planet.
Earth's minimoons are small asteroids temporarily captured by our planet's gravitational field. These could be remnants from the formation of the solar system or other space debris. Typically, minimoons remain in orbit for less than a year.
They're tiny and hard to spot: According to space nonprofit The Planetary Society, only four such objects had been spotted before the discovery of 2026 QQ8, and none of them are orbiting Earth today.
Before 2026 QQ8, the last minimoon was observed in August 2024. The asteroid, designated 2024 PT5, was about 10 meters long.
It is believed to have come from the Arjuna asteroid belt, a group of cosmic bodies moving around the Sun in an orbit similar to Earth's.
However, further analysis of the chemical composition suggested that 2024 PT5 may be a fragment of the Moon thrown into space by an asteroid impact in the distant past.
The object spent only a few months in the vicinity of the Earth, after which it returned to deep space. Some astronomers estimate that it will pass close to Earth again in 2055.
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Phantom Moons
Ghost moons are some of the most mysterious objects. These are believed to be swirling clouds of cosmic dust moving in the same orbit as Earth—they could be either ahead or behind our planet as it orbits the Sun. However, there has not yet been a consensus scientific opinion on whether they actually exist.
Dr. Millard finds this concept quite plausible.
“There’s a lot of dust in space,” she says. “Interplanetary dust particles exist, so it wouldn’t surprise me at all if some of this dust was captured by gravitationally stable points located in Earth’s orbit.”
Are minimoons and quasimoons dangerous?
Although these objects are close to us by astronomical standards, they never come close enough to pose a danger.
Even at their closest point they are several times further from us than the Moon.
On a cosmic scale, this is considered a close distance, but in reality there is no cause for concern.
“It's not like they come screaming out of the dark,” Dr. Millard explains. “If they were approaching us, it would happen very slowly, we would have noticed their approach in advance and we would have had enough time to take the necessary measures.”
Who else has quasi-moons?
Only in recent decades have telescopes become sensitive enough to detect these faint, elusive asteroids.
They are at the very limit of modern technology in terms of brightness available for recording.
The development of computer technology has made it possible to simulate their movement and confirm that these mysterious objects are indeed quasi-moons.
"They're not that uncommon - they're just very hard to spot," says Dr. Millard. “If they are difficult to detect near Earth, you can imagine how difficult it would be to find them in other parts of the solar system.”
To date, quasi-moons have been observed around Jupiter, Venus, Saturn, Neptune and Pluto. Perhaps more will be discovered in the future.
“The solar system continues to be a very active and dynamic place,” adds Dr Millard. “It’s not dead or static—everything here is constantly in motion.”
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