Earth has two so-called "dust moons", researchers say, after their study confirmed the presence of astronomical clouds orbiting our planet.

Key points: Dust clouds first described in 1961, but their existence was doubted

Dust clouds first described in 1961, but their existence was doubted Researchers say they've finally photographed the clouds

Researchers say they've finally photographed the clouds Location could be used to park telescopes in the future

The clouds, however, are practically invisible.

They were found about 400,000 kilometres from Earth by Hungarian researchers, and are extremely faint, which previously gave rise to scepticism about their existence.

The clouds were first reported by Polish astronomer Kazimierz Kordylewski in 1961, who made the discovery while investigating two points in the Earth-Moon system where two gravitational forces interact in a way that stabilises the position of objects, known as a Lagrange point.

It was near one of these points, called L5, where Dr Kordylewski noted two "bright patches", now known as the Kordylewski dust cloud.

This collection of space dust was thought to move around Earth as the Moon moves along its orbit, according to the Royal Astronomical Society.

However, as the clouds were difficult to observe, and their existence was doubted by some scientists.

But now researchers say they have captured images of the clouds using a polarising filter system attached to a camera lens.

Polarised light reflected from the dust was picked up by the camera, thus confirming the elusive clouds.

The Kordylewski dust cloud, represented by bright red pixels, is visible around L5. ( Judit Sliz-Balogh )

"The Kordylewski clouds are two of the toughest objects to find, and though they are as close to Earth as the Moon, they are largely overlooked by researchers in astronomy," study co-author Judit Sliz-Balogh said in a Royal Astronomical Society statement.

"It is intriguing to confirm that our planet has dusty pseudo-satellites in orbit alongside our lunar neighbour."

Ms Sliz-Balogh, along with Andras Barta and Gabor Horvath, described the clouds in a research paper published in the Royal Astronomical Society's November issue.

The location of these dust clouds could be potential sites for orbiting space probes, the Royal Astronomical Society proposed.

Future research will look into the Kordylewski clouds to determine whether the dust could threaten equipment parked there.