Con Edison says an electrical fault at a substation in Astoria, Queens caused an electrical arc lighting up the sky over New York City while causing some flight delays and scattered power outages. It happened shortly after 9 p.m. at the Astoria East and North Queens Con Edison plant on 20th Avenue and 32nd Street in Astoria.

Initially thought to be a transformer explosion, Con Ed issued a statement explaining what happened: "An electrical fault on a section of 138,000-volt equipment in one of our Astoria substations caused a transmission disturbance and a sustained electrical arc flash, creating the blue light people witnessed. The equipment that malfunctioned is associated with voltage monitoring within the substation."

An electric arc is defined as "a visible plasma discharge between two electrodes that is caused by electrical current ionizing gasses in the air." Electric arcs occur in nature in the form of lightning.

The equipment, which malfunctioned is supposed to monitor voltage, was somehow damaged and allowed that voltage to escape instead.  

Within minutes of the incident, fire officials said they were fielding numerous calls for reports of explosions in the Long Island City and Astoria areas. Despite those initial reports, Con Ed says there was no explosion and no electrical fire. Any fire that might have occurred was out before FDNY arrived on the scene, officials said. People also flocked to social media to find out what happened and to share their views of the so-called "Astoria Borealis."

New York Governor Cuomo addressed rumors of an "alien invasion" after visiting the Con Ed facility and seeing the damage for himself.  

"I saw the equipment. I saw the damage. I saw what was burned. What it was is what it has been represented to be, which was an electrical malfunction," he said, and then held up what appeared to be an "alien" mask. "I'm told it's a piece of safety equipment for workers, which I believe. There's no truth to the alien invasion or alien UFO landing." Contributing to all this, the cloud cover and general atmospheric conditions resulted in the incident refracting across the sky, turning it blue over a large region.

It is unclear how long the electrical arc flash was sustained, but it probably wasn't longer than a couple of minutes. Con Edison will analyze the oscilloscope data to figure that out. The root cause of the electrical fault remains under investigation, although it was likely a malfunction in the relay system. a spokesman said. One Con Edison employee was nearby when the incident happened, but not injured.