A team of astronomers and physicists has confirmed the 5-decade-long theory that dust clouds orbit the Earth. These elusive dust clouds move with the Earth and Moon " like three edges of a triangle " at a stable 4,00,000 kilometres from the Earth.
The study picks up from a 1961 study by Polish astronomer Kazimierz Kordylewski, who reported that he saw patches at the L4 and L5 Lagrange points. He speculated that these patches were dust clouds. That speculation could only now be confirmed.
Over many further studies, the dust clouds were traced to one of five 'Lagrange points' near the Earth-moon system. Lagrange points are located near two large celestial bodies (like the Earth and Moon, or Earth and Sun). At these points, the combined gravitational pull of the two large objects perfectly cancels out the centripetal force of an object at that location. These points aren't always stable but are of immense value for space research. A spacecraft at a Lagrange point will need a minimal amount of fuel to maintain position. As zany as it sounds, scientists have even considered relocating pollution from the Earth to those points.
Representational image. Image courtesy: NASA
Two such points in space " L4 and L5 " form an equal-sided triangle with the Earth and Moon, where the 'Kordylewski clouds' confirmed by the new study are located. Lagrange points in space are neither fixed nor stable and are affected by external forces like fly-by comets or variations in the Sun's gravitational pull.
In the Earth-Moon system, earlier research has identified L4 and L5 as places where space dust may collect " at least temporarily. While these celestial dust bunnies were theorized in 1961 by Kordylewski, the task of confirming their existence as the Earth and Moon's constant companion proved tough till recently.
"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," Judit SlÃz-Balogh, one of the study's authors from the Royal Astronomical Society, told the press.
"It is intriguing to confirm that our planet has dusty pseudo-satellites in orbit alongside our lunar neighbour."
The team behind the study is looking into exactly how stable these clouds are and whether the dust poses a threat to astronauts or spacecraft that pass through them.