Sydney residents left confused by a ‘mysterious hum’: ‘Alien-like’

Aussies have been complaining about a mysterious rumbling sound that lasts ‘all night long’ – and they’re convinced it has nothing to do with roadworks.

Residents in North Sydney, particularly those in Crows Nest and St Leonards, have vented their frustrations about the ‘constant’ and ‘repetitive’ hum that many claim has been appearing on and off for years.

The noise switches from a rumbling hum to a more ‘electronic warble’ that many have dubbed ‘alien-like’ and ‘all consuming’. 

One local thought it was thunder at first but when it lasted a few days she assumed it was due to the new underground metro train station.

‘Does any one else hear a low rumble sound that comes and goes rhythmically, every few seconds?’ the woman wrote on Facebook on May 26. 

‘It lasts all night and at first we confused it for thunder or the underground metro being built, but it’s constant and it’s been lasting for days.’ 

Several offered suggestions as to what the odd hum could be and questioned if it’s noise from trains, water pumps, extraction fans, planes or construction. 

Conspiracy theorists, however, had a ‘clear’ answer: aliens. 

Others who claimed to have heard the noise said they feel like they’re ‘going mad’. 

‘Yes I have heard the same [sound]. For us it starts around 5pm and seems to end after a few hours and has been happening for the last week,’ one resident on the same street wrote. 

‘The first night it happened I was searching for the sound and noticed I could hear it louder when putting my ear to the wall, this makes me think it’s subterranean vibrations. 

‘I would imagine the tunnelling for the metro would be done so if there’s tunnelling happening for Warringah freeway that could be an explanation.’

Another man said: ‘I thought I was going mad trying to explain this weird rumbling earthmoving sound the other night. I can sleep through anything so I’ve moved on but I wonder if this is the same thing. Will listen out for it tonight.’

Another neighbour wrote: ‘I know that sound very well. I was hearing it last year.’

A North Sydney Council spokesperson said they urge locals to get in touch if the issue continues. 

‘In order to investigate the noise, Council would need to receive a report from the community,’ the spokesperson told Daily Mail Australia. 

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‘If any person has a noise pollution problem, they can contact Council, advise of the details of the problem, and we can then investigate.’

This isn’t the first time residents in North Sydney have complained about a weird hum. 

In November 2022 a man heard a ‘weird low frequency hum’ at 6am and had no idea what was causing it. 

‘Wondering if anyone else nearby is hearing the sound?’ he wrote.  

In September 2021 a man in the area complained about a ‘loud repetitive beeping sound’ that is only heard at night. 

‘I think it’s coming from one of the building sites but can’t nail it down (it echoes!). It beeps every ten to 15 seconds,’ he wrote.

For decades scientists have been baffled by the phenomenon known as the Bristol Hum – where thousands of people around the world have reported hearing indistinguishable sounds emanating from the sky.

The mystery even featured on an episode of the hit US TV show, The X-files, in 1998.

The first investigation into the Phenomenon was carried out in 1973 and examined 50 residents living in the UK city of Bristol that claimed to be hearing a ‘low throbbing background noise’ – often early in the morning.

Since then thousands of people across the globe have also experienced the strange sound – in the American state of New Mexico it’s referred to as the Taos Hum and in Canada’s Ontario locals know it as the Windsor Hum.

Over the years, conspiracy theorists have blamed the noise on secret military experiments, alien spacecraft and a host of other paranormal explanations.