East of Marfa, in the high desert of Presidio County, US Highway 90 runs along the northern edge of a broad plain called Mitchell Flat with the Chinati Mountains on the far horizon. Nine miles out of town the Texas Department of Transportation built a pull-off, and in 2003 the town turned it into the Marfa Mystery Lights Viewing Center, with mounted binoculars, a circular adobe restroom and bronze plaques. Most clear nights there are people there, and most clear nights they see lights.
What happened
The lights appear low to the southwest after dusk as white, yellow or orange points. They brighten and dim, wink out and return somewhere else, sometimes seem to split in two or merge, and occasionally look red, green or blue. Distance is impossible to judge: observers cannot say whether a light is a mile off or twenty. The Handbook of Texas records the local tradition that a young cowhand, Robert Reed Ellison, saw them in 1883 while driving cattle through Paisano Pass and took them for Apache campfires, that Joe and Sally Humphreys saw them in 1885, that cowboys searched the mountains for a source in 1919, and that pilots from Midland Army Air Field hunted for them during the Second World War without success.
The Ellison story is the foundation of the claim that the lights predate the motor car, and it is weaker than it looks. As Brian Dunning noted in 2007, there is no written record of Ellison’s sighting; the account comes from his descendants, and the memoir he wrote in 1937 about his years in the region does not mention lights at all. The first published description of the Marfa lights appeared in a magazine article in 1957.
The investigation
In May 2004 twelve members of the Society of Physics Students at the University of Texas at Dallas camped at Fort Davis for a long weekend and ran a set of experiments from the viewing area. One of them, Jeff Klenzing, later told Texas Monthly that of eight planned tests three worked well. The team used a traffic counter on US 67, the road that climbs south from Marfa toward Presidio, a chase car with a radio link, lasers and high-speed video. They found that the frequency of lights seen to the southwest tracked the volume of traffic on 67, and that when their own car parked on the highway and flashed its headlights, a “Marfa light” appeared at the viewing area. Daytime photographs showed the highway’s course lying exactly where the night lights appeared. Their report was issued in 2005.
Michael Hall, a Texas Monthly writer who had seen the lights a dozen times and did not believe the headlight explanation, went back in February 2006 to test it. From the platform he located US 67 through binoculars some twenty miles away, watched a truck crawl along it, and as the sun set saw the first glint appear precisely on the line of the road. The lights he and the other visitors then watched, pulsing and dimming, were in the same place.
A second line of work came from Texas State University, where Karl Stephan and students spent twenty nights at the site with a telescope and spectrometer. By measuring how much a light’s spectrum was absorbed by atmospheric oxygen at 762 nanometres they could estimate its distance, and so separate headlights and ranch lights from anything closer. The method was published in the American Journal of Physics in 2009 and developed in Sagar Ghimire’s 2010 thesis. The retired aerospace engineer James Bunnell, who has photographed the lights for years, argues that a small subset behaves in ways headlights cannot and keeps automated cameras on the flat.
The explanations
The behavior that makes the lights seem alive is what headlights do when seen across twenty miles of desert at night. Temperature layers over the ground bend the light, so a car cresting a rise flares, fades as it dips, and reappears to one side; two cars become a light that splits. The Handbook of Texas lists the same mirage-like effect as the most plausible cause. Other proposed explanations, from piezoelectric discharge to swamp gas to the ghosts of conquistadors, have no evidence behind them, and attempts by television crews to triangulate the lights showed only that they were not where they appeared to be.
Where it stands
The lights are real and anyone can see them. The mystery is mostly a mystery of distance. What cannot be settled is whether anything was seen on Mitchell Flat before the highway existed, because the only evidence is memory passed down in families. The verdict is mostly false: the famous display is traffic, and the residue is unproven.