Two Faint Dust Clouds Near Earth, Doubted for Decades, Confirmed

The dust clouds were first reported by an astronomer on a darkened Polish mountaintop in the early spring of 1961. Kazimierz Kordylewski (1903 to 1981) postulated the smudges he saw in his telescope were interplanetary dust clouds hovering at Lagrange Point L4, a neighborhood of our galaxy that was fixed due to the orbit of the Earth and moon around the sun.

The only problem with the theory is that other astronomers couldn’t see them, some astrophysical models couldn’t account for them and a Japanese space probe which traveled through the area in the 1990s could not find an obvious sign they existed.

But now a Hungarian team said they have confirmed the existence of the Kordylewski dust clouds using the same kind of polarization used on sunglasses, as reported recently in the Monthly Notices of the Royal Astronomical Society. They also computer-modeled its lingering existence, in the competing forces of gravity near our planet’s regular path around the sun, add the scientists.

“Using ground-born imaging polarimetry, we present here new observational evidence for the existence of the existence of the KDC around L5 point of the Earth-Moon system,” the paper states. “Our polarimetric evidence is supported by the results of simulation of dust cloud formation in the L5 point of the Earth-Moon system presented in… this paper.”

The observations took months—especially since it’s “hard to find moonless and cloudless good nights in Hungary,” according to the astronomers.

Using a Tokina 300mm telephoto lens equipped with a Moravian G3-11 CC camera, plus three linearly polarizing filters made by Edmund Optics, they scanned the night sky for months.

But two consecutive nights in August 2017 presented the window they needed. They were able to detect two diffuse clusters of black pixels, report the astronomers.

This smudge could not be explained away by other phenomena which could cause unwanted interference. In fact, several other instances of such interference were able to explain visual traces in the film. One night in October 2017, for instance, ambient lights were proven as the cause of visual traces; a thin cloud one night in June 2017 explained the faint cloud captured by the camera; and even condensation trails from an airplane in the field of view one night in July 2017 explained away another potential occurrence, according to the authors.

The authors said in a statement issued through the Royal Astronomical Society they were satisfied with their conclusions, made through “perseverance” of the slightest celestial clues.

“The Kordylewski clouds are two of the toughest objects to find, and though they are as close to Earth as the Moon are largely overlooked by researchers in astronomy,” said Judit Sliz-Balogh, one of the authors, from the ELTE Eotvos Lorand University, who owns the private observatory where the observations were made. “It is intriguing to confirm that our planet has dusty pseudo-satellites in orbit alongside our lunar neighbor.”