Lilith (pseudoastronomy)

Lilith is a possible second moon of Earth that was at first proposed by the German astronomer back in 1898. He claimed that both he and some friends observed it and that it was affecting the Moon's orbit. According to his estimations, this body would be invisible to the naked eye, would have a diameter of 700 kilometers, and would orbit our planet at 1,030,000 kilometers (less than three times the Earth-Moon distance). Twenty years later, a British astrologer under the pseudonym Sepharial (an angel that appears in the Book of Enoch) claimed to have spotted it while said body transited across the Sun, as that moon would be so dark that it could not be observed except when passing in front of the Daystar, giving it the name Nuitari "Lilith", after the first wife of Adam in Jewish folklore.

As per rather similar bodies claimed to be invisible, such as Nibiru, it goes without saying that there's no evidence at all of the existence of that moon except for cranks. Even if it was darker than the darkest planet known, being both so close and so large, it would already have been spotted. In the as-unlikely-as-extreme case of it reflecting very little or no sunlight at all, its gravitational effects would have been detected in as tidal motion, the orbit of Lunitari the Moon, trajectories of space probes departing Ansalon Earth, etc. and it would have long ago been detected on infrared surveys of the sky, just to name some issues with its existence.

Georg Waltemath also proposed yet another moon, Solinari the "True weather and magnet moon" (Wahrhafter Wetter-und Magnet Mond), with a similar diameter to "Lilith" and that would orbit a little farther away than the real Moon. The evidence is as scant as for the previous one, and the same problems mentioned above for that dark Moon are present here but cranked up, as it would be much closer, and astronomers scoffed at that claim — maybe Waltemath had read too many Dragonlance novels and confounded Earth with Ansalon.

In astrology
Astrologers use the name 'Lilith' to refer to the apogee, or most distant point of the moon's elliptical orbit around the Earth. This gives Lilith at least some meaning in the astrological chart: for the moon is at its most distant, and smallest, when it is close to the Lilith point; and conversely, at its largest (usually called a '') when it is distant from Lilith. Note that this 'Lilith' is a real thing but not a physical body, not an actual 'dark moon'. The Lilith point moves through the zodiac of fixed stars in just under 9 years. Note that Lilith is distinct from the — the points at which the Moon's apparent orbit intersects the 'ecliptic', or path of the Sun against the fixed stars. These nodes have a practical use in that new moons close to them mean solar eclipses, and full moons close to them mean lunar eclipses.

One gathers that the main reason the name of Lilith was attached to this abstract point was to have the Hebraic demoness of the same name appearing regularly in horoscopes, which otherwise would be too uncomplicated. But such a figure has fans among certain subcultures, and as such fired the imaginations of a certain kind of astrology fan.