The sun was gone, the sky getting inky. The wind had started to whip. (And even in the Texas desert, the winter wind can be cold.) I hunkered deeper into my jacket and jiggled for warmth. Behind me, my 16-year-old son loped restlessly back and forth, lupine, waiting. Suddenly a long lanky arm thrust past my face. "There's one!" he cried, pointing at the horizon. "And over there!" his younger brother echoed a moment later.

Off in the distance, about a quarter-mile away, a bright, starlike light glimmered into view just above the horizon, followed quickly by a second one. As the first flickered out, a third took its place, materializing out of nowhere. "Ooo, another one!" I squealed, and again, as yet another twinkled momentarily above the other two. All at once, they disappeared together, as if an invisible hand had snuffed them out.

At my cries, the boys instantly dropped all airs of excitement. "You don't have to say 'Ooo' every time, Mom," they muttered, dripping with teenage sarcasm, and slid their eyes furtively left and right, though there was no one else much around.

That was a mercy for the boys, as it spared them any humiliation at maternal vocals. And it was a treat for all of us to have the viewing station pretty much to ourselves. But it was a shame, I thought, for all the people who weren't there, because on this January night, the Marfa lights were putting on a spectacular display. As we gawked, they blinked on and off, shifted position, appeared high in the sky one moment, hugged the horizon the next.

This time out, the lights were livelier than the first time we'd seen them six months before -- at least it seemed so to me -- and much closer to the descriptions I'd read of them. Still, my skeptical husband couldn't help quipping: "I think the local chamber of commerce just pays a few guys to go out there and stand around with some really big flashlights."

The Marfa lights -- spontaneous bursts of illumination that materialize, year-round, on clear nights over the Chihuahuan Desert in west Texas -- are a bona-fide unexplained natural phenomenon. They've defied scientific rationalization for more than a century. Are they swamp gases? Bent light? Electrostatic discharges? Signal lights from alien spacecraft? Nobody knows where they come from or why they appear when and where they do. Oh, and they have their debunkers, who claim they're nothing more than the headlights of cars driving down the Chinati Mountains. Right.

Bottom line: They've stumped physicists and photographers and engineers, some of the best minds of the nation, for years.

I just love it when that happens.

In the remote, remarkable desert-mountain region of far west Texas, a wedge of country three hours south of El Paso and 11/2 hours north of Big Bend National Park and the Mexican border, the Marfa lights are just about the premier tourist attraction around. That is, of course, if you're looking to attract tourists, which doesn't seem to be that high on the agenda of the folks who live here. They seem fairly content to poke along from day to day in the midst of some of the most spectacular scenery in the continental United States, greeting interlopers politely, warmly, but incuriously. They don't push anything on you, and they don't try to market themselves.

Mostly, in fact, they talk about how little there is to do here. "Well, we're not the big city," a staffer at my son's boarding school in Fort Davis, Tex., mused modestly on our first trip a year ago, helping us consider sightseeing possibilities. He gave us a short list -- historic Fort Davis, the pre- and post-Civil War U.S. Army post after which the town of Fort Davis is named; the McDonald Observatory high on a peak in the Davis Mountains; the scenic loop drive through and around said mountains; the local history museum in Alpine. Then after a pause: "Oh, yeah, and I guess there's always the Marfa lights."

They're called the Marfa lights after the nearest town, a low-lying little burg of 2,424 that supposedly got its name, in turn, from a character in Dostoyevsky's "Brothers Karamazov" (that being the book the railroad executive's wife, who suggested the moniker, was reading when she and her husband passed through this railway watering stop in the late 1800s). Marfa can make a few other claims to fame. It has one of the most beautiful courthouses in Texas, it was the location of the 1956 Elizabeth Taylor-Rock Hudson-James Dean movie "Giant," and it's home to the Chinati Foundation, a celebrated museum of contemporary art begun on an old military base by the late sculptor Donald Judd two decades ago.

Along with mile-high Fort Davis (pop. approximately 1,000) and the appropriately mountainous Alpine (the "big city," with a population of about 6,000), Marfa forms an equilateral triangle enclosing a swath of desert terrain out of which rise majestic volcanic mountain peaks, many higher than 6,000 feet. It's an arid, otherwordly beauty -- like the landscape of the moon, or Mars, maybe, but for the scrubby grasses and bushes, yucca and cactus that stipple the flats and the mountainsides, and the cottonwoods that hug the creek banks. There's sky -- blue as lapis on glorious days or roiling with thunderheads on stormy ones -- every way you turn. Desert though it is, the climate's actually a draw; in the old days, wealthy merchants and entrepreneurs from Dallas and Houston traveled to the Davis Mountains to put up at the Limpia Hotel and enjoy the dry air and pleasant breezes. Yes, the temperatures can reach 110 degrees in the shade, but as you've no doubt heard, when it's this dry, you don't feel it.

What you do feel is the haunting nature of the place, the way it launches you back to another time. A frontier time, when people led hardscrabble lives and braved the wilderness and the elements to make a home in an inhospitable place, where water was scarce and other people scarcer.

The cattle ranchers who staked out vast tracts of scrubland for their steers had to have what it takes to persevere here. Even today, a handful of ranchers, descendants of the first settlers, still control most of the land in and around Fort Davis. At least that's what the elderly lady minding the desk one day in the town's curio-filled Overland Trail Museum told me. (A dusty, unpaved stretch of the local "overland trail," the San Antonio-El Paso stagecoach road that ferried 19th-century travelers between the two towns, still runs through the heart of Fort Davis.) "They decide who gets to move in and who doesn't," she said conspiratorially, as I leafed through a bin of old, laminated turn-of-the-20th-century photos. My husband and I were her only visitors that day. "That's why you don't see a McDonald's or any chain stores around here," she said. "They want to keep Main Street looking like it did 100 years ago."

She didn't sound exactly happy about that, but I was. None of us missed McDonald's. And fast, I'm sorry, just isn't the mode in these parts. "What's your hurry?" Betty Nunnally, the proprietor of Starr's Emporium in Fort Davis, chided my menfolk when they tried to pry me away from her eclectic shop on our most recent trip. "You're in far west Texas now. You got to slo-o-o-w down."

Seems like the right prescription to me. Fits the spell of this place. It tickles me that our cell phone doesn't work everywhere down here, that the Limpia and its sister hostel, the Hotel Paisano in Marfa, don't have phones in the rooms. I love that you might see someone riding horseback down the highway, that you can catch the occasional glint of spur on someone's cowboy boots around town, that one of the oldest working dude ranches is around the bend from Fort Davis. I savor the sense of having stepped into another world, of being in a place that, while modern enough, is still cut off from the narcissistic, plugged-in present.

So I'm sure you'll understand my reaction when, after having read that Marfa's experiencing a yuppie boomlet, I saw a couple of bikers in full tight-shorted, speed-helmeted racing regalia working the scenic loop the day we drove it last July. "Where did you come from?" I screamed. (Don't worry, the car windows were all up.) "Go away!"

The Marfa lights have been around since at least 1883, when a rancher by the name of Robert Reed Ellison supposedly first saw them shining in the distance as he bedded down in the desert one night. Ellison assumed they were Indian campfires. Only when he rode out the next day to the area where he'd spotted them, he found -- cue "Twilight Zone" music -- no remains of any campfires.

Today, there's an official viewing area erected by the Texas Department of Transportation, complete with telescopes and restrooms. It's a little weird to have someone lay out the red carpet for what some people think could be UFO landing lights, but it's nice to be told where to have the best look-see.

Of course, "best" in this case is relative. In fact, it's downright idiosyncratic. For they say that everyone sees the Marfa lights differently. You can be standing right next to someone who's ooh-ing and aah-ing and essentially see . . . nothing. That was my experience the first time out: One of the boys or my husband would point and say "There!" and I'd ask, "Where?" I didn't see many that time, nor on our most recent trip this summer, when the lights seemed sluggish and coy.

Apparently at least one other person had the same experience. "Well, now we can tell the folks back home we done seen the famous Marfa lights -- not," cracked a woman in a group of Texas Junior Leaguers who had descended on the viewing area in a chartered tour bus. I could tell she was disappointed, and I wanted to say, "Come back in the winter." Because I've got my own theory of the lights, you see. I think the cold winter air makes them brighter and friskier, more playful and powerful.

Or maybe it doesn't. Who knows? It's a mystery. And like the place they haunt, a marvel.

Zofia Smardz is an editor in The Post's Outlook section.

Seeing stars at the McDonald Observatory by Fort Davis, Tex.Art and nature in Marfa, Tex.: The mysterious sky lights, pictured at top, and Donald Judd's sculptures at the Chinati Foundation.