The Alien Invasion of Phoenix, Arizona

Tonight we're going to grab our shotguns, jump into our rambling pickup truck, and chase a massive triangular UFO as it courses silently across the American southwest, for we are (once again) on the trail of the infamous Phoenix Lights.

Perhaps it's the recent 10-year anniversary of the event, or perhaps it's the former Arizona governor's recent confession that he believes they were actually an alien spacecraft, but the Phoenix Lights have been back in the news again. It was the night of March 13, 1997 when a slanting line of bright lights appeared one-by-one in the sky beyond Phoenix, Arizona. Hundreds of photographs and videos were taken by observers throughout the region, making it among the most documented UFO sightings ever. The incident came as no surprise to anyone at nearby Luke Air Force Base (named for World War I ace Lt. Frank Luke), which operates the Barry M. Goldwater Range where a flight of four A-10 ground attack aircraft were jettisoning leftover illumination flares. The flares are typically dropped at lower altitudes, where they are not visible from Phoenix, due to the intervening Sierra Estrella mountain range.

The Phoenix Lights episode is a running joke in the Air Force and especially at the 104th Fighter Squadron of the Maryland Air National Guard, whose aircraft were involved. They don't have desert bombing ranges in Maryland, so the pilots go to places like Arizona for some of their training. The Air National Guard is the Air Force's reserve unit, similar to the Army Reserve.

But the rest of us regular people didn't know anything about this. We all just looked up into the sky, and saw something unlike anything we'd ever seen before. I remember watching it on the news with my wife. I remember my sense of amazement at witnessing something truly unexplainable: Could this actually be alien spacecraft?

Over the next couple of weeks, corroborating reports flooded in, of triangle-shaped craft from as far away as Henderson, Nevada cruising over the southwest, to Prescott, over Phoenix, and off toward Tucson. UFO's are reported nearly every day in most areas by someone, so it's to be expected that the normal background noise of typical reports would be given special attention during a large-scale episode like the Phoenix Lights. And, obviously, such a furor offers an easy opportunity for any clown to go on the news to say that a triangle-shaped craft passed over his house on its way to Phoenix. What would have been truly unusual and shocking is if there had been no other reports from nearby areas. Too bad none of these people owned cameras.

Lots of people in the Phoenix area did own cameras, and they all filmed exactly the same thing. Hundreds of photographs, hours of video, and all of it showing a line of lights in the sky above the city lights of Phoenix, looking toward the Sierra Estrella mountains and the Goldwater Range. Not a single photograph or frame of video showed anything else. This was the most documented UFO sighting in American history, and every last photograph showed exactly the same thing. Plenty of verbal reports told very different stories over the weeks following the incident, but every single photograph showed a simple line of lights beyond the Sierra Estrella.

As has been thoroughly documented, including by a Fox television special, the moment that each light disappeared on the evidential videotapes corresponded exactly with the horizon line of the Sierra Estrella mountains, proving that the lights were behind the mountains, and not over Phoenix.

Here's a story that's typical of the many found on the Internet, from Jan Markham of Gilbert Arizona:

My husband and I were out flying that night in the vicinity of the Stanfield VOR. We clearly saw the flares to our west, over the Goldwater range - a familiar sight to my husband. However, there was a second set of lights that night - the V-shaped formation that was initially shown on film by the local TV networks. That formation, whatever it was, flew directly over us at a much higher altitude than the flares. At the time, we thought it was some sort of military flight, but that never appears to have been acknowledged. I am sure someone knows the truth about those lights, but, please, don't insult our intelligence by telling us they were flares.

Let's spend a moment examining the flare said to be used in the incident. The A-10 drops two different kinds of flare: a countermeasure flare, used to confuse heat-seeking missiles; and an illumination flare, used to light up the ground at night either for the benefit of troops on the ground or to light up a target so it can be visually targeted for weapons release. The illumination flare is the one we're talking about. It's called the LUU-2 air-deployed high intensity illumination flare. It's made by defense contractor ATK Thiokol. The variant in use at the time of the Phoenix Lights incident was the LUU-2B/B. It weights 30 pounds and its canister is three feet long and 5 inches in diameter. Once it ejects its parachute and ignites, it puts out 1.8 million candela for 4 minutes, or 1.6 million candela for 5 minutes. It falls in its parachute at 8.3 feet per second. At 1000 feet above the ground, it lights up an area half a kilometer wide at 5 lux. The LUU-2's pyrotechnic candle burns magnesium, which produces an intense white light. Because it burns so hot, it also ends up burning the aluminum canister, which adds an orange hue to the light for most of the burn. About halfway through the burn, enough of the canister has been burned away that it actually lightens the load and it falls more and more slowly. Once it's almost completely out, an explosive bolt disconnects the parachute and the flare drops, burning out completely sometime hopefully before landing on someone's wood shingle roof.

The Barry M. Goldwater Range is a big place — over 4,000 square miles — and the Phoenix metropolitan area is even larger, about 14,000 square miles. The distance between the two is usually cited at 60 to 80 miles, but as we can see, that's going to depend on a lot. We do know a little about where the A-10's were flying inside the Goldwater Range. The guy who was in the lead A-10, Lt. Col. Ed Jones, says they were near Gila Bend when they ejected the leftover flares, and Gila Bend is just about exactly 50 miles from downtown Phoenix. Mesa and Scottsdale are farther away, so let's take a super rough stab at it, be conservative, and say that the average observer of the Phoenix Lights was 70 miles away from the A-10's. The brightness of the LUU-2 seen from 70 miles away is roughly equal to a star with an apparent magnitude of somewhere between -3.2 and -4.3, which is significantly brighter than any stars visible in the sky, but not as bright as the full moon. The magnitude scale was developed by the astronomer Hipparchus, where +1 represents the brightest star in the sky, and +6 represents the faintest. -3.2 is quite a bit brighter than the brightest star. The noonday sun has an apparent magnitude of -26.7. Thanks to the guys on the Bad Astronomy and JREF forums who helped me with these calculations.

Yet another wrench in the machinery is that all of the above is dramatically affected by atmospheric conditions. It wouldn't take much haze for absorption and scatter to obscure flares completely at that distance, and in the clear conditions predominant over Phoenix, lights are often distorted by an inversion layer, an effect that you can sometimes see when the landing lights of aircraft approaching an airport appear much bigger than they actually are. So we have a computation based on multiple unknown variables, any of which could wildly throw off our results. The one thing we can say with certainty is that the approximate brightness of the Phoenix Lights as seen in the photographs and videos does fall well within the wide range of brightness that's possible from LUU-2B/B flares at 70 miles.

Here's one final fly in the ointment. The photographic evidence itself is not necessarily a valid representation of how the lights would have looked to the naked eye: Still and video cameras are of varying quality and need specific settings to capture lights in the night sky. We have little or no information about the settings used in most of the available photographic and video evidence. Much has been made of a ham-handed spectral analysis of Phoenix Lights photographs and videos by prominent UFO advocate Jim Dilletoso, whose conclusions have been widely discredited since you can't even remotely do a spectral analysis of lights in a photograph and expect there to be any useful similarity to the spectrum of the actual light source, any more than you could expect a photograph of an orange to smell like an orange. Dilletoso found that, based on the colors in photographs, the Phoenix Lights could not have been from any known earthly source. Note that among Dilletoso's other claims to fame is having spent six weeks at an underground alien base in Dulce, New Mexico. Judge his credibility for yourself.

The UFO crowd and conspiracy theorists point out other problems with the flare explanation, most notably that a public relations officer at Luke Air Force Base contacted that night didn't happen to know that flares had been dropped, and so had no explanation for the lights. For this to be a real problem, you have to assume that everyone involved in training exercises immediately communicates every tactical detail of what they do, and their own personal estimation of its possible consequences, to the base PR officer. The officer also said that the Air Force had no operations over Phoenix that night, which was of course completely true. The A-10's were a great distance away and well inside their Military Operating Area airspace. This statement has been taken by the conspiracy theorists as evidence of a conspiracy, so discussing it is just beating a dead horse. The only other dissenting evidence put forward is the mass of eyewitness accounts following the triangle shaped craft on its journey across the southwest. Unfortunately all such stories are in direct contradiction with all photographic evidence. These witnesses had as much opportunity to document their sightings as did the people in Phoenix. The fact that they did not must be met, unfortunately, with a shrug. There are simply too many other reasons they might be saying what they're saying, and their reports are precisely contradicted by a mountain of hard evidence.

The Phoenix Lights were flares. Deal with it.

By Brian Dunning
Follow @BrianDunning