In a time when we carry around the Internet in our pockets, it can seem like there aren't any mysteries left. But there are, in fact, some things that you can't figure out just by googling. This list is full of mysterious sounds, signals, and transmissions which have no concrete explanations. Scientists have theories about these creepy sounds, but that's all they are - theories.
Perhaps you've heard some of these unexplained noises. If so, now you know you're not alone. Perhaps you have your own theories about what's causing them. Prepare to be baffled by some things that are truly mysterious - and then go on to hear some weird noises from outer space, too.
"The Hum" has been heard in places around the world since the 1970s, most commonly in quiet rural and suburban areas. Some estimate that it can be heard by about 2% of the population, and for those people, it can cause extreme distress, even suicidal despair.
People who report hearing this low rumbling noise usually say they hear it indoors, and that it is louder at night. Possible explanations for the sound include industrial equipment, mobile communication devices, power lines, radio waves, and earth tremors. In some cases, there may be no external sound at all: the humming may be explained by tinnitus, or by spontaneous otoacoustic emissions (SOAE), sounds produced by the ear itself.
Numbers stations are radio stations rumored to be used for sending coded messages between intelligence agencies and spies, a practice believed to have started during the Cold War. Stations such as these would be a useful method of communication because their messages can't be tracked. Even today, with much more high-tech equipment available, "nobody has found a more convenient and expedient way of communicating with an agent," according to espionage expert Rupert Allason.
No government or intelligence agency has ever officially admitted to using these stations, but clues have been found for decades all around the world. In fact, some people think that these numbers stations are still being used for secret purposes today. As the video shows, you can listen in on them yourself.
Bloop was detected by various ocean listening stations in the summer of 1997. During that summer it was heard multiple times, but has not been heard since. Scientists think that the origin of the sound was just west of the southern tip of South America, and that it was probably caused by a large iceberg quake.
However, a more interesting - if much less plausible - theory holds that the sound was made by a living creature, one potentially much larger than a blue whale, maybe even a megalodon, a giant prehistoric shark believed to be extinct since the Cenozoic era. Or perhaps it was H.P. Lovecraft's Cthulhu, a monstrous sea god whose fictional undersea home was located not far from where the Bloop originated?
Electronic Voice Phenomena
Electronic voice phenomena (EVP) are voices heard in the backgrounds of tape recordings, sometimes only apparent when the recordings are played backwards - most famously, in the 60s, when conspiracy theorists claimed that when they played the Beatles song "Strawberry Fields Forever" backwards, they could hear the phrase "I buried Paul," giving rise to a rumor that Paul McCartney had died.
Some people think that these voices come from alien or even ghosts. Skeptics think that these sounds could be just electrical distortion.