It’s hard to imagine a more excellent location than an Australian Outback ghost town. So it is fitting that one such locale, Min Min, is infrequently home to a mystery known as the Min Min Light. It has been sighted off and on (mostly off) for decades, though stories about similar lights are featured in Aboriginal tales that predate those accounts.

A composite report of the light mostly describes a white or color-changing fuzzy disc hovering just above the horizon. The greatest variation in descriptors relates to its luminosity, as it is alternately called dim, bright, or in between.

The first printed account of the phenomenon came from rancher Henry Lamond in 1937. He wrote that he initially that it was an approaching car, but that “it remained in one bulbous ball instead of dividing into two headlights, which it should have done as it came closer.” Additionally, the light, size, and location were inconsistent with a traveling vehicle.

Author Mark Moravec examined some possible explanations for the mystery in his book investigating the subject. Some were pseudoscientific, such as ghosts or alien spacecraft. Others were grounded in known entities, such as natural phenomena like phosphorescence, luminescent insects, light reflection, or ball lighting.

With regard to the bioluminescence hypothesis, scientist Jack Pettigrew argued that the lights may be swarming insects that were contaminated by agents in fungi. Or they might be an owl with a bioluminescence source. However, no bug or bird has been confirmed to have the characteristics, nor is any known bioluminescent source as bright as the Min Min. Similarly, marsh gas has been floated as an answer, but the lights sometimes appear far from any marsh.

Skeptoid’s Brian Dunning ruminated on Piezoelectric effects perhaps being responsible. This effect occurs in some crystals that change shape upon receipt of an electrical current. Dunning notes the opposite is also true, that applying mechanical force to the crystal likewise produces an electrical current. But he also noted there are some challenges with this hypothesis. The effect produces weak electrical voltage but not light. Also, the voltage is measurable only on the crystal and is never projected into the air.

We now move to a possible explanation involving optical science. Pettigrew wondered if the Min Min Light were a manifestation of a Fata Morgana. This refers to mirages caused by a wide temperature difference between air layers, and one in which an object appears higher than its actual position. The phenomenon is the result of the atmosphere’s thermal inversion layers.

And indeed, the Min Min Light often appears in a desert with temperature inversions in the atmosphere. The hollows and ravines trap warm air, and on a cool night at the end of a warm day, the situation is ripe for just such a mirage. With these conditions in place, Pettigrew and his cohorts experimented by parking a car with its headlights on, then traveling six miles in another vehicle, past intervening high ground and out of the line of sight. Upon arriving at their destination, they saw that the headlights resembled past descriptions of the Min Min Light.

There was a second discovery that supported this hypothesis. The morning after their experiment, the team took photos of faraway mountains that displayed the aforementioned distortion. The distortion gradually faded as the atmospheric conditions changed. This lends credence to the idea that a refraction of car headlights over the horizon were reflected and being seen to move in a manner consistent with the Min Min Light.

The answer isn’t as exciting or spooky as some would have hoped, but it is a plausible explanation supported by evidence and research.