Forensic tests are being carried out to establish exactly how a fault at an electricity substation in west Belfast on Friday night led to a brilliant night-time flare and huge bang that rumbled out across the city.
Shortly after 11pm on Friday, witnesses reported seeing huge flashes light up the night sky and the bang that could be heard for miles.
Rumours quickly spread of everything from a lightning strike and thunder to a terrorist bombing.
Lights flickered and dimmed in thousands of homes, with many householders thinking a power cut was imminent.
Others reported that radio broadcasts lost a signal after the incident at Suffolk Road.
However, after speculation on Twitter went wild, NIE Networks said there is no evidence a meteor or some sort of solar flare was to blame.
One witness said: "There were lights flashing blue, red and everything.
"I came out of my house and there was a thick black smoke and a horrible smell."
The actual explanation was much more mundane. NIE Networks spokeswoman Sara McClintock told the Belfast Telegraph: "A piece of equipment failed in one of our substations.
"We haven't yet got the exact cause of why the equipment failed.
"There will be a range of forensic tests on that and that will be done over a number of days."
She said that fortunately such incidents are rare and the pieces of equipment are "fairly robust" - but as with any piece of equipment there can be failures. Ms McClintock added that after the incident, the story "took a life of its own" through social media.
"Because there is electric going through it there could be a bang and a flash, which would be an unusual flash because it is electrical," she said.
"Because they are very sensitive pieces of equipment and feeding power out to many thousands of houses across Northern Ireland, we would have protection systems in place which are designed to kick in and transfer the load so service can continue.
"It would have dipped and a lot of people would have seen their power dip - they were not off - maybe for a second or two."
She said as far as they were aware the incident was not caused by a meteor or some out-of-this-world cause as had been speculated on social media.
"I have been asked that question before," said Ms McClintock.
"It is just a piece of equipment which failed. What I presume people were talking about was solar flares and things like that which can cause disruption because of the electrical fields."
Meanwhile, power went off in homes in the Braniel area of east Belfast on Sunday at 6.08pm due to a fault in an underground cable but was back on at 7.24pm, NIE Networks said.