The Phoenix Lights, 1997: two events, one night, endlessly confused

On the evening of 13 March 1997, an enormous number of people across Arizona reported lights in the sky. It became the most-reported UFO event in American history, and almost every argument about it since has been made worse by one fact that is not in dispute: there were two events, roughly three hours apart, and they have different explanations.

Event one: the formation, around 8pm

The earlier event was a V-shaped formation of lights that moved from the north of the state southward across Phoenix over about half an hour. Witnesses in different towns reported it in sequence, consistent with something travelling.

The strongest conventional candidate is a formation of aircraft. A flight of A-10 Thunderbolts was operating in the region that night, and a loose V of aircraft at altitude produces exactly this: lights moving together, no visible airframe against a dark sky, and an apparent single object if the observer assumes the lights are connected.

That last assumption is the whole case. Many witnesses reported a solid dark mass occluding stars between the lights. Others reported gaps. Which of those is right cannot be settled by more testimony.

Event two: the flares, around 10pm

The later event was a line of stationary lights over the Estrella mountains southwest of Phoenix that appeared, hung, and faded one by one. This is the sequence in almost all the famous video.

The Maryland Air National Guard subsequently confirmed that its aircraft dropped illumination flares on the Barry Goldwater Range that night. Flares on parachutes, seen from Phoenix with the mountain range hiding their descent, produce precisely the observed behaviour — a line of lights that hovers and then extinguishes in order as each burns out or drops behind the ridge.

Why the confusion persists

Because each side gets to be right about a different event. Sceptics point to the flares, which are established, and treat the case as closed. Believers point to the 8pm formation, which the flares do not touch, and treat the flare explanation as a cover story.

Both are describing something real. They are describing different things.

What would have settled it

Radar. The formation crossed a large area of monitored airspace over half an hour, and civil and military radar coverage existed. Whether that data was examined at the time, and whether it survives, is not clear from the public record — and it is the single thing that could have answered the question while it was still answerable.