It’s official: Earth has more than just one moon out there in its orbit.
Well, sort of. National Geographic reports that a pair of particulate clouds–“dustballs,” in essence–have been located in Earth’s orbit at a distance roughly equal to that of the moon itself. The unusual formations were suspected to have existed for decades already, although this was only recently confirmed by a team of Hungarian astronomers and physicists with Eötvös Loránd University.
Located around 250,000 miles from Earth, these outer space dustballs, known as “Kordylewski clouds,” are roughly the same distance from Earth as the moon, although they are much wider–as much as nine times–than the Earth.
Despite their size, they are apparently extremely difficult to find, too.
The clouds were first spotted as far back as 1961 by Polish astronomer Kazimierz Kordylewski, and are among a variety of other supposed natural objects or formations hypothesized to accompany the moon in orbit around the Earth. Since Kordylewski’s initial observation, the unusual clouds had remained unconfirmed by other observers; some even doubted whether they existed at all.
“It is intriguing to confirm that our planet has dusty pseudo-satellites in orbit alongside our lunar neighbor,” study co-author Judit Slíz-Balogh told National Geographic.
In past articles here at MU, I’ve chronicled the odd history of past searches for a hypothetical “second moon” in orbit around the Earth. Although there has never been convincing evidence that such a feature–generally referred to as a “moonlet”–has ever existed, there have been some notable cases where scientists thought they might be on the verge of such a discovery.
In fact, going all the way back to the 1840s, Frederic Petit, then director of the observatory of Toulouse, claimed to have spotted a second moon in orbit around Earth; a few decades later, Canadian weather reporter E. Stone Wiggins made similar claims, which were widely publicized in periodicals at that time (you can read more about these early searches for Earth’s second moon in my article here).
Clyde Tombaugh, the astronomer renowned for his discovery of Pluto, was tasked with searching for a secondary moon-like object orbiting the Earth beginning in 1954, and concluded after a three-year search that no such objects could be found. Prior to Tombaugh’s search for Earth’s mystery moonlet, notable sightings of objects in orbit around Earth had also been made by Dr. Lincoln LaPaz, who claimed to have seen such a satellite prior to the launch of Sputnik 1 by Russia on October 4, 1957.
Alleged sightings by LaPaz and others of mysterious orbital objects were the likely inspiration behind later claims made by Major Donald Keyhoe, arguably one of the most popular UFO advocates of his era. Keyhoe later described in his book Aliens From Space what appeared to be a reference to LaPaz’s sighting:
“During 1953, the AF began experiments with new long range radar equipment. While making the initial tests, AF operators were astonished to pick up a gigantic object orbiting near the equator. Its speed was almost 18,000 miles an hour. Repeated checks showed that the tracking was correct. Some huge unknown object was circling Earth, six hundred miles out.”
Keyhoe and others who wrote about the U.S. Government’s apparent interest in finding moonlets in the 1950s helped spawn theories of an alleged “alien satellite” popularly known as the “Black Knight” satellite. Theories appearing online propose a number of wild theories about this alleged object, which include the claim that this “alien” satellite has orbited Earth since around the end of the last Ice Age (I give a complete breakdown of the history of the “Black Knight” in my article here, covering how a number of separate claims from over the decades became interwoven into a single UFO conspiracy theory over time).
In light of the latest discovery of these Kordylewski dustballs (I wouldn’t necessarily call them “moons”, seeing as how they are merely particulate clouds… and certainly not genuine “moonlets”), it is nonetheless interesting that additional orbital features have finally been confirmed alongside Earth’s moon.
With any luck, they won’t prove to be problematic: as National Geographic notes, these clouds form naturally around areas that result from the centripetal forces between objects like Earth and the sun “balancing out” their gravitational pulls, which are known as “Lagrange points.” NASA has used these areas in the past as fuel-efficient parking lots for satellites, whose performance might end up being hindered if tossed into the mix with concentrated clouds of space dust.
The Hungarian team’s research was featured in Monthly Notices of the Royal Astronomical Society.