Much that is captivating when being pursued ceases to be of interest once the goal is met. Now that the Cubs have won the World Series, I no longer care if the Cubs win the World Series. Now that I know who Deep Throat was, I don’t care who Deep Throat was. One of the most enduring mysteries is whatever became of the Roanoke colonists. I read about this, encourage the continual search for clues, and would be greatly interested for about a week if a definitive conclusion were reached. But knowing the answer would cause my interest in the colony to diminish quickly then evaporate almost completely. 

While it’s far less fascinating than lost colonists and their Croatoan carving, another unsolved mystery relates to the Hum. This is a phenomenon where a low rumbling sound can be heard in certain places by select people. It can happen anywhere, but it mostly associated with Taos, N.M., and to lesser extents in Bristol, England; Auckland, New Zealand; and Kokomo, Ind.   

Sufferers describe it as akin to the idling of a distant diesel engine. Earplugs help some of them, suggesting this is indeed an audible phenomenon. But others report that earplugs make no difference, indicating it’s an internal ear issue.

As to what the cause might be, speculation has included insects, meteors, industrial equipment, high-pressure gas lines, seismic activity, and secret government projects. But these are all without backing and there’s no proof as to what’s going on. Others have suggested radio waves, but those produce a high-pitched sound that is opposite of what synthesized Hums sound like (synthesized Hums have been created by those who experience it so the rest of us will have some idea what they are going through).

The most conspiracy-happy speculation focuses on HAARP. However, the frequency of Hum reports did not increase when HAARP operations began, nor has the sound ever been reported near the site. Finally, like radio waves, the potential acoustic effects of HAARP signals are completely different from simulated Hums.  

Previously, some suspected LORAN, an extinct radio navigation system. But when LORAN went away, the Hum continued, so that explanation was out. Still others blame cell phone networks, but that explanation fails for the same reason as the HAARP and radio waves claims do. The emitted signals are far too high to be responsible for a low rumbling sound. This hypothesis only has currency among a paranoid crowd that sees cell phones, WiFi, wind turbines, and the like as being behind an array of health problems, all of which existed centuries before these technological developments. 

Mass hysteria has also been suggested, but that also falls flat, if only for linguistic reasons. Even in Taos, just two percent of residents report having ever heard it. So even if this is an auditory hallucination, it’s not on a large scale. As to hysteria, that generally suggests unwarranted panic and few people are freaking out about this, though extremists think the government or other powerful entity is behind this for mind control purposes.  

Brian Dunning of Skeptoid wrote about the Hum and it turns out he might have first-hand experience with it. He suffers from tinnitus and relates this anecdote:

“It sounds nothing like the Hum. However, by yawning or by tightening the tensor tympani muscle inside my ear, I can induce a loud, low-frequency rumble. When I do this, it sounds exactly like the Hum. It’s not hard to think that some people may have this condition chronically, and since this is the exact sound described by Hum sufferers, it’s virtually certain that some variation on this condition is the explanation for some of them.”

Still, Dunning concludes that the Hum does not exist as a single worldwide phenomenon. Rather, he and others perceive a low rumble under certain conditions. Some are likely hearing an actual audible sound from an undiscovered source while others may be plagued by tinnitus or similar condition. Still others may be having auditory hallucinations while a different group of sufferers may have heightened hearing that combines with an undiscovered geophysical phenomenon to produce the sound. Others may be experiencing spontaneous otoacoustic emissions, which arise through cellular and mechanical causes within the inner ear. With it still being largely a mystery, we cannot even rule out it being part of a secret sinister strategy. Maybe someday we know, I just kind of hope not.