Scientists have confirmed the existence of two giant clouds of dust circling the Earth at a distance of about 400 thousand kilometers from its surface. Their findings were presented in the journal MNRAS.
“Clouds of Kordylevsky are two of the most inconspicuous objects in the immediate vicinity of the Earth. They are about the same distance from it as the Moon, which is why astronomers never actually notice them. Therefore, we are very pleased that we have been able to confirm the existence of these two pseudo-satellites of our planet,”says Judit Sliz-Balogh from the University of Budapest (Hungary).
Back in the 18th century, scientists established that small celestial bodies can move in the same orbit with the planet if they are located near points in front of or behind it, where the gravity of the Sun and the planet is balanced.
Thousands of such objects, or "Trojan asteroids", were found a long time ago in the orbits of Jupiter, Mars and Neptune, but until recently, scientists could not find a single such asteroid near Earth. As the researchers say, "Trojan" satellites of the Earth are very difficult to find, as they are very close to the Sun, if you look at them from the surface of our planet.
To date, only six Earth quasi-satellites are known - 2016 HO3, 2010 TK7, 2003 YN107, 2004 GU9, 2001 GO2, and 2002 AA29. All of them, except 2016 HO3, rotate along very unstable trajectories, and some of them have already stopped following the Earth and left its orbit a few years or decades after their discovery.
Schliz-Balogh and her colleagues added two more objects to their host - the so-called Kordylevsky clouds, which have managed to acquire a mythical and very controversial status over the past half century.
The Polish astronomer Kazimir Kordylewski was the first to speak about their existence. Observing two Trojan points in Earth's orbit in 1961, he noticed that one of them contains a large accumulation of dust, eclipsing the light of the Sun and stars.
This statement, as noted by Schliz-Balogh, was met with skepticism from the scientific community, since astronomers did not believe that such large objects could remain stable at these points. Later, scientists have repeatedly checked the calculations of Kordylevsky, but could neither confirm nor disprove them.
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Hungarian astronomers have come up with an ingenious technique to find traces of these clouds and estimate their size. They began to observe not the heat and light that their dust particles can emit, but how collisions with them change the polarization of the Sun's rays passing through the "Trojan" points.
This is how the artist imagined the clouds of Kordylewski / G. Horváth.
After several months of observation, Schliz-Balogh and her colleagues were able to find traces that sunlight was linearly polarized by almost 20% in the L5 region, a "Trojan" point located directly behind the Moon.
Analyzing its properties, scientists came to the conclusion that the object was generated not by one, but by two clouds of dust, each of which is about three times larger than the main natural satellite of the Earth. It is not yet clear how stable they are and how long they "chase" the moon, orbiting with it around our planet.
Schliz-Balogh and her colleagues plan to find answers to these questions by observing the Kordylewski clouds with more powerful orbiting telescopes that will not be affected by light pollution and dust in the atmosphere.
