Mystery boom - stock
Experts are baffled by reports of an explosion heard across south-west Sydney with no identified sources nor any indication as to where it came from.

Authorities received multiple reports from residents saying they heard an "explosion" on Saturday night, but found no evidence of an explosion.

Fire and Rescue NSW and NSW police responded to the calls, but said they found nothing, not even a fire, to indicate an explosion had taken place.

Mystery surrounds the incident, with reports the sound was heard across Marrickville, Roselands, Bardwell Park, Campsie and Belmore.

Residents reported windows shaking, and that the sound was something like an explosion or a backfiring car, but with no visual indicators.

With no indication of an explosion or of damage of some sort, and no identifiable source, residents are left to wonder if there was an other-worldly nature to the sound.

NSW police said there were no active investigations into the incident and that they had received numerous calls about the apparent explosion, but do not know the source.

"There was numerous calls made to emergency services but the source of the noise could not be located/identified."

The RFS also confirmed they had not located the source of the sound, saying that it could not have been electrical as there was no blackout or consequences to the sound.
I actually caught it on a VM, it shook my house here in belmore !!! We went outside and saw huge smoke clouds! the weird thing is there is nothing anywhere in the news or social media, yet ppl across a huge area heard it????

— selinaa (@selinamoila) May 8, 2021
Sydney airport has also similarly confirmed there was no incident on Saturday night, eliminating the chance it was a backfiring jet plane or an incident on the runway.

Brad Cucker, astrophysicist at ANU said there was nothing from space that could explain the noise.

He explained that any kind of celestial incident would have been heard far beyond just south-west Sydney, and would have been seen.

"If you're going to get something like a meteor falling from the sky, you're going to usually see a very bright blue or green flash."

"And when they're big enough to cause a sonic boom, or to be heard, they're big enough to burn pretty bright in the sky."

Comment: Horse hockey. Not all meteors exploding in the atmosphere are visible.

"It just seems weird that no one saw anything."

The Department of Defence have not responded to a request for comment on the incident.

Residents responded to a call out posted on Facebook by Seven News Sydney, saying it had sounded like a gas explosion.

"Yes, we are still trying to work out what it was. It sounded like a gas explosion ... We live in Bexley," Tina Tidroi wrote.

"Yes I heard it from Bexley North. Didn't sound like fireworks, sounded liked an actual explosion or could be a collision, like the rocket remains," said Tamires Alessandri

"Its a mystery," wrote Rowena Phillips, "My parents heard 2 bangs and the house shook on the second one. They are in Clemton Park near Kingsgrove North HS so it must have been in Kingsgrove area. Some here in Canterbury heard it too."