The motorcycles were on their way from Bogota, Colombia, to the Atlantic coast, a convoy of young people on fast machines, driving more recklessly than they should. As they approached the bridge over the Sumapaz River, the road narrowed and suddenly there were too many motorcycles on one small patch of asphalt.

Frances Gomez was riding on the seat behind her husband, her arms around his waist.Her friends saw what happened next: the motorcycle lurching, a body arcing through the air, a young woman sinking in the water. Gomez was rushed to the hospital, where she was pronounced dead and then was wheeled to the morgue.

Meanwhile, some other part of Gomez was traveling at great speed in a different direction: down a tunnel, toward a shimmering light and a feeling of unconditional love. And then, lying on the gurney outside the hospital morgue, 22 minutes after being declared dead, Gomez began to breathe again.

She had lived to tell her story about a place of unfathomable vividness and serenity. Like other people who have had near-death experiences, Gomez became a foreign correspondent of sorts, providing us dispatches from a distant land.

But what land? Where was it that Frances Gomez traveled while her body was drowning in the Sumapaz? Was she in heaven? A parallel dimension? On an excursion in her own brain?

And what does her experience, and the experiences of others like her, tell us about our own deaths? About our own lives?

Despite dozens of books on the subject - not only Betty Eadie's "Embraced by the Light," but "The Light Beyond" and "Beyond the Light" and even scores of books without "light" in the title - near-death experiences still mystify and intrigue.

That's what will draw researchers, health-care professionals, "experiencers" and the simply curious to Salt Lake in early October to attend the eighth annual conference of IANDS, the International Association of Near-Death Studies. "The Mystery of the Near-Death Experience" will be held Oct. 8-10 at the Wyndham Hotel, 215 W. South Temple.

The conference will feature near-death luminaries, including Kenneth Ring, known as the dean of near-death studies, and George G. Ritchie Jr., whose account of his own "NDE" during World War II spurred Raymond Moody to write "Life After Life," the first in-depth look at the phenomenon. It was Moody who coined the term "near-death experience."

Twenty-three years later, doctors are still in the dark about near-death experiences, says Diane Corcoran, IANDS president. "If you could look at the e-mail I get, you'd see the pain they're in," she says about experiencers who have been told by doctors that their NDEs are simply hallucinations.

Near-death experiences are quite common, says Bill English, president of the local IANDS chapter. One-third of all people who have had life-threatening traumatic events have had some form of NDE that they can recount, English told a recent meeting of the group.

As usual, the meeting drew several dozen people, nearly all of whom have never had an NDE. Many who attend the monthly meetings are "seeking answers to the lifelong question, `Is there something beyond this existence?' " says English. Some seek comfort after the death of a loved one.

Some scientists dismiss near-death experiences as the random firings of a brain in distress, nothing more than chemicals and mechanisms.

Scientists who probe the temporal lobe of the brain with electrodes can stimulate a person to recall life events and can produce an out-of-body sensation. In addition, deactivation of the occipital cortex can "occur in such a pattern as to give a sensation of light in the middle of the visual field and a feeling that you're moving toward it," notes Brigham Young University professor David Busath, who last year taught a course on near-death studies.

But science, says Busath, still can't explain every part of the NDE phenomenon. Deactivation of the occipital cortex does not account for the being in the center of light that experiencers often relate. A probing of the temporal lobe can produce memories but not the chronological life review that experiencers report, nor the feelings they relate. Many say they not only lived each part of their life again but felt the anger, pain or sadness they caused other people.

Nor can science reproduce or explain why some experiencers who have had out-of-body episodes have been able to accurately report the sighting of objects and people they would not otherwise have known about.

The most famous example, often cited in near-death circles, is critical-care social worker Kimberly Clark Sharp's account of a migrant worker named Maria.

During a cardiac arrest at Seattle's Harborview Hospital, Maria had an out-of-body experience in which she saw a tennis shoe on the ledge of the building. When she was resuscitated, she described the shoe in minute detail: a worn place rubbed by someone's little toe, a shoelace tucked underneath the heel.

Sharp found the shoe, just as Maria had described it, on a ledge not visible from other rooms or from the street.

"There's not yet any theory based on neurochemistry that is capable of explaining all" of the phenomena of a near-death experience, says Ring, professor emeritus and researcher at the University of Connecticut.

"You can say a particular brain state produces a near-death experience," he says. "Or you can say it affords this kind of experience, that it gives you privileged access to a state that in normal life you don't have." That could explain why runners and meditators have reported experiences that sound very much like NDEs.

Near-death experiences are not proof of an afterlife, says Ring, but there is no denying that they have an after-effect. And it is this part of the phenomenon that seems to make up the latest wave of NDE research.

"It changes people's lives in so many beautiful ways," says Ring. People who have had NDEs tend to be more compassionate, more likely to serve, less materialistic, less judgmental, more joyful.

"The NDE, then, appears to promote the emergence of a type of functioning suggestive of the full human potential that is presumably the birthright of all of us," writes Ring in his new book, "Lessons From the Light."

Frances Gomez, now a Salt Lake psychotherapist, is an enthusiastic, glowing woman 37 years after her NDE in Colombia.

"Before my NDE, I would never have been able to survive the death of my husband and my daughter," says Gomez, whose husband died in an industrial accident in 1982 and whose daughter, Charlie, died of breast cancer in 1994. "But I know for a fact where she is. I don't have to doubt whether there's life after death." In her 1961 near-death experience, Gomez says she met her mother, who had died when Gomez was 8.

Barbara Rommer, a Florida physician, has studied the lives and near deaths of more than 300 people. Ninety-three percent of them, she says, report that they have a decreased fear of dying, even if their NDE was itself frightening.

(Five percent of experiencers report having less than positive NDEs. And, although the media and Hollywood like the tunnel and the life review, studies have found that only about 30 percent of NDEs include a tunnel and only 20 percent include life reviews.)

Researchers have also found that experiencers, after their NDE, tend to have more psychic ability, are more allergic and sensitive to noise and light, and sometimes find that watches and small appliances either don't work or tend to act up in their presence, says Rommer.

And sometimes, says experiencer and researcher P.M.H. Atwater, the experiencer just doesn't fit in with what we call the real world. "You're filled with joy and you freak everyone out. And you're puzzled about why people respond the way they do."

For children who have NDEs, the contrast between themselves and the rest of the world - or this world and the more beatific one they left behind - can be difficult, says Atwater. A fifth of the 277 people Atwater interviewed who had NDEs as children attempted suicide within 10 years after the NDE, she says. A third have "serious problems" with alcohol or drugs.

For adult experiencers, the contrast between their new selves and the rest of the world can also be clear.

Lauren Thibodeau, who recently completed a Cleveland State University doctoral dissertation about NDEs and who had an NDE herself at age 22, got this evaluation once when she was a student teacher: smiles too much, appears to be too happy.