Marfa, a town of 2,100 in deep West Texas, is so remote the nearest Walmart is three hours away.

It's so isolated, the more prosperous residents fly planes as well as drive cars.

It's so rugged it is ringed by blue mountains and the starkly beautiful Chihuahuan Desert.

Nevertheless, tourists come from all over to see Marfa's acclaimed contemporary art museum, the location of the film classic Giant and the Marfa Lights, a very occasional, naturally occurring and much-discussed light show in the vast night sky.

"Here is a real scientific puzzle that still exists in this modern day and age, and nobody has solved it yet," says retired aerospace engineer James Bunnell. "You just don't find that every day."

There's no shortage, however, of theories.

Just the other day reporters and editors around the country received an e-mail about California videographer and self-described cryptozoologist Jonathan Whitcomb.

(A cryptozoologist searches for animals that are considered to be nonexistent by traditional biologists. Take, for example, the Loch Ness monster and Bigfoot.)

Whitcomb's theory about the lights?

He thinks they may be flying dinosaurs.

Even the earliest Native American settlers have tried to explain the night lights, best viewed a few miles east of town.

Bunnell, who has studied the phenomenon for the past nine years, says those early citizens thought the lights must be falling stars.

"That's a pretty logical deduction, even though it's wrong," Bunnell says.

Over the years, other explanations have ranged from the plausible to the preposterous.

In 1883 a young cowhand saw the flickering orbs while driving cattle and wondered if they were Apache campfires.

Others have imagined the yellow-orange lights to be dancing devils, ghosts, invading soldiers, owls with lights under their feathers and most recently, the dinosaurs.

Whitcomb's theory, loosely, is that the flying creatures emit a light or a glow that attracts insects. Then bats eat the insects, and the dinosaurs (he calls them ropen, pterosaurs and pterodactyls) feed on the bats. During the cooler months of the year, he says, the flying predators may chase rabbits, owls and rattlesnakes instead of bats or bugs.

While Whitcomb has been effective in broadcasting his views, he acknowledges that he has no scientific training, has never been to Marfa and has not seen the creatures whose patterns and habits he attempts to describe. He did make a trip to Papua New Guinea to investigate flying predators there but saw none.

The videographer has had an e-mail exchange with Bunnell, who lives in Fort Worth.

The Texan offered Whitcomb no support or encouragement.

Some people just can't get past their belief that dinosaurs are extinct, Whitcomb says.

Bunnell, 70, grew up in Presidio County and graduated from Marfa High School. He was always interested in the nocturnal light show and, as a young man, meant to solve the mystery. "But I got busy with life," he says.

Bunnell was retired when he happened to stop at the Marfa Lights roadside park and viewing center nine miles east of town.

"I just got lucky," Bunnell says. "The lights are rare, but I got one of the really good displays."

Inspired, Bunnell began collecting nightly video starting in 2003. Eventually his monitoring system included nine cameras that ran all night every night. Studying the data on his home computer, he came to understand the lights' frequency and behavior.

People think they see the naturally occurring light shows all the time, Bunnell says, but they're probably seeing car headlights on Highway 67 instead.

The car lights move from left to right in a repeating pattern, Bunnell says. The bona fide Marfa Lights, which appear in the night sky only 10 to 15 times a year, look like balls of light that split apart, then melt back together. Some seem to stand still. Some streak across the sky vertically or, more commonly, horizontally. Sometimes one will turn off and another will turn on as if connected by a light switch.

"It's quite a show," Bunnell says. "Once you see it, you won't forget."

After all these years of study, Bunnell does have tentative theories that might explain the light displays. He's written three technical books on the subject, but here's the simple and condensed version:

Roughly 30 million years ago, a series of volcanoes erupted in and around Marfa, spewing ash. Today, underground, those huge plates of igneous rock still move and rub against each other. When enough pressure and friction builds up, the rocks act like batteries and produce an electromagnetic anomaly that causes the light show.

"But the details," Bunnell says, "we still don't understand."

The Marfa Lights are not unique; similar light shows appear in Italy, Australia, Norway and other spots around the globe.

Also, sometimes people report that they are seeing mirages, and they are correct, Bunnell says.

But the mirages and the electric light shows are different, he says, and the light shows are a lot more interesting.

Karl Stephan, an engineering professor at Texas State University, has been working with Bunnell to solve the Marfa Lights mystery once and for all.

Stephan has the highest regard for Bunnell but says there's still much work to do.

"It may be geological activity that creates electrical activity, but it's all speculation at this point," Stephan says. "There are no proven facts."

Meanwhile, he's considered but discarded the theories from Whitcomb, the California videographer and cryptozoologist.

Says Stephan, "I encourage Mr. Whitcomb to come to Marfa and spend six months there before he says anything more about dinosaurs."