Religious leaders prophesying a date for the apocalypse have always faced a unique challenge to their credibility: Everyone who's tried that before has turned out to be wrong.
But the predictions continue. A week ago, concerns flared in Palmdale when a small Christian group was reported missing after taking off into the night on a mysterious religious trip. Authorities said the group, led by a Salvadoran immigrant, left farewell letters to loved ones that indicated their belief that the end of the world was near.
The 22-hour search that followed commanded attention from media outlets worldwide, but scholars say the idea of end times followed by a messianic arrival is an ancient one that spans religions. In Christianity, the concept often includes an event referred to as the "rapture," when Christ will return in spectacular fashion and separate the "sheep" (his followers) from the "goats" (nonbelievers).
The idea can be a comfort to the disenfranchised, a guarantee that justice will be served and scores settled, said theology scholar Cecil Robeck Jr. In a time of joblessness and economic frustration, Robeck said, that pledge can be particularly appealing.
"People are desperate. When someone says, 'You're in a terrible situation now, but if you'll follow me, I'll make it OK,' people are hungry, they need hope, they'll follow," said Robeck, a Pentecostal minister and professor of church history at Fuller Theological Seminary in Pasadena.
That appeal is part of the reason that the concept of the rapture, when true believers are expected to be lifted into heaven, is most common in churches with poorer, less educated congregations, Robeck said.
The Palmdale group was said to be predominantly composed of recent Salvadoran immigrants. Former neighbors said its leader, Reyna Marisol Chicas, 32, had left school after fifth grade and struggled to find steady work.
The group was discovered Sunday comfortably gathered in a Palmdale-area park, ending a 22-hour search. No arrests were made and no criminal charges have been filed, according to the Los Angeles County Sheriff's Department. But Chicas was placed into an involuntary mental health evaluation after she appeared disconnected from reality and failed to recognize her children, authorities said.
Group members called Chicas an inspiration. She was said to have been a congregant at a nearby church before breaking away not long ago. The Palmdale area is sprinkled with predominantly Latino churches, where it's not unusual for congregants to form groups that meet separately and incorporate nonconventional beliefs, area residents said.
Richard Flory, a USC sociologist who studies religion in America, said the idea of the rapture can be a persuasive tool for conversion.
"It brings a subliminal fear," he said. "It says you better be ready because this thing can happen at any time."
Those who expect the end of the world also often believe that there will be signs that it's coming, the scholars said. Natural disasters, such as major earthquakes and fires, often bring spikes of apocalyptic forecasts.
An evangelical Christian website, RaptureReady.com, features a regularly updated "rapture index" that gauges the imminent approach of the world's end. It's calculated by adding quantitative measurements for a number of supposed apocalyptic signs, including volcanoes, drug abuse, drought and liberalism.
But even many ardent believers dismiss the idea that the rapture can be predicted.
Tim LaHaye, an evangelical Christian minister, became famous with "Left Behind," his hugely popular series of novels about the end days. LaHaye's work, modern-day stories based on the Book of Revelation, has been criticized for going too far in its extreme and violent depiction of the end of the world and its aftermath.
But even LaHaye said that while spreading word of the concept is a blessing, forecasting its date is misguided.
"They're disobeying the Scripture, which says no man knows the day or the hour. Anytime anyone sets a date, they're wrong because no one knows that date," LaHaye said. "It's just unguided enthusiasm. Every day you read the newspaper, and ask, 'Is there any hope for the world?' It's just getting worse and worse, and people think there's got to be something better."
As for why forecasters of end times and the rapture still gain followings despite their poor track record, Robeck explains it in secular terms.
"People still go to Las Vegas because they hope they will win," he said. "I used to live in Las Vegas. They never will."