There's an interesting phenomenon going on in different locations around the world. People are hearing strange noises coming from the sky that have them stumped. Is it aliens, intrusions from parallel worlds, secret government experiments, or are people being hoaxed or just reacting to noises with perfectly normal explanations?

The latest example of these noises happened in Saskatoon, SK, early in the morning of November 9th, and was recorded by local resident Ernie Werezak:



The sound was also recorded by another local, who goes by the username Deano K on YouTube. There's a definite metal-scraping-on-metal quality to the sound that they heard, however it's strangely similar to noises heard elsewhere.

Marc Perry, a resident of Blackburn, UK, recorded this short video on October 25th. It's a little distorted by winds blowing across the microphone, but it's that same metal-scraping-on-metal sound:



Now, both of these instances certainly have an artificial quality to them, and they very well could be caused by some of the more mundane explanations, like a large trash compactor or train wheels scraping on the tracks.

However, although they're not exactly the same, they share a certain eerie similarity with a noise recorded over Terrace, B.C. at the end of August this year, by Kimberly Wookey,



This same kind of noise was heard in Allen, Texas, in January 2012:



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So, what's the source of these noises?

Well, some really are hoaxes. Claudine Gladue, a student in Edmonton, AB, used a recording of a sound heard over Conklin in mid-January 2012 to film a fake video (which she admitted to). Others are perfectly mundane sounds that are amplified by local geography or buildings. For Terrace, B.C., it was apparently just a city worker grinding down the blade of a snow grader, and many others in winter are very likely caused as snow being moved by these graders slides along the metal blade, causing it to vibrate, combined with the blade scraping against the road. According to CTV News, similar explanations have apparently been offered to Werezak, but he's not convinced.

The air itself can be partially responsible for how strange these noises are. Professor Jean-Pierre St. Maurice, who teaches physics at the University of Saskatchewan, spoke to CTV News about Werezak's recording, saying: "Under the right atmospheric conditions, you can have sound come back toward the ground to propagate along the ground over long distances not too far from where the sound has been emitted. And to make things interesting, in the process the sound will also get distorted if the distances get large."

So, although ideas like UFOs, strange mystical phenomena, or even conspiracy-theory-magnet HAARP might make for more 'interesting' explanations, mundane ones are far more likely.

The real concern about these noises is that they're an annoyance, and suffering through noise pollution can be bad for both mental and physical health. That's why the Canadian government recently funded research to track down things like the source of the famous Windsor Hum. The findings of that study are expected by the end of the year.

Do you have noises like this going off where you live? Leave your story in the comment section below.

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