Heaven : Are there bright lights and angels? Can you surf? Everybody’s wondering what gives in the afterlife.

In heaven, Peter Kreeft found himself in an immense cathedral, surrounded by thousands of souls dressed in white robes. Suddenly, a door swung open and voices whispered, “Hush! Here he comes.” Kreeft, assuming it was the Lord, watched as “in stumbled a fat, disheveled, bewildered German man.” It was Ludwig van Beethoven--and the robed souls welcomed him into Paradise by singing the “Ode to Joy” from his Ninth Symphony.

Then Kreeft woke up.

But even though this visit was just a dream, Kreeft knows the place better than most people. A philosophy professor at Boston College and author of two books on heaven, he is one of the latest in a long line of afterlife explorers.

For centuries, heaven has been imagined by poets, debated by theologians and mapped out by visionaries who claim to have been there.

What they describe is a realm of floating lights, colors that can be tasted, and creatures with flesh and bone fashioned from emeralds. It is a dimension where time runs backward and forward, water turns into glass and--for Mormons--dead souls rule their own planets.

Today, there is a new surge of speculation about what lies beyond the grave.

The graying of baby boomers, the passing of their parents and the specter of AIDS are “making people think about death,” says religion historian Colleen McDannell. “People who aren’t supposed to be dying are dying.”

Books with such titles as “Embraced by the Light” and “Life After Life” have bobbed to the top of bestseller charts. Talk shows buzz with guests recounting near-death experiences.

And philosophers grapple with such questions as, “If heaven isn’t in outer space, why did Jesus ascend skyward to get there?” “Will Paradise get boring?” and even, “Is there surfing in the afterlife?”

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For a place that’s supposed to be eternal, the afterlife sure has changed a lot over the years.

Ancient Jews, who sometimes tried to contact the dead through seances, believed that all spirits went to a dark, silent underworld cave called Sheol, says McDannell, a University of Utah professor who co-authored “Heaven: A History” (Yale University Press, 1988).

It wasn’t until six centuries before Christ that the concepts of heaven and hell began forming. That’s when two Jerusalem poets composed Psalms 49 and 73, introducing the idea that good people would get preferential treatment after death.

But details were scarce. The original heaven was thought to be an eternal study hall, says Richard Hecht, a religious studies professor at UC Santa Barbara. The righteous sat at desks, learning from God.

Then Christianity arrived--and the concept of heaven lurched through a series of transformations.

In the book of Revelation, for instance, the celestial kingdom featured lightning, a glass ocean and six-winged, multi-eyed animals guarding the Almighty’s throne.

By the end of the 2nd Century, it had metamorphosed into a land of free-flowing wine, banquets and super-fertile humans giving birth to platoons of children. That, in turn, gave way to St. Augustine’s mysterious vision.

While sitting in a villa in Italy, Augustine wrote, he and his mother were transported to Paradise, an experience so emotionally intense that she lost all desire for earthly pleasures. “The (vision) had severed her from worldly attachments as well as loosening her soul from her body,” McDannell and co-author Bernhard Lang write. “Within a fortnight, (she) was dead.” Later images of heaven reflected cultural trends, the authors say. As cities came to prominence in the 12th and 13th centuries, heaven took on an urban look, with buildings and streets made of jasper, gold and pearls.

The Renaissance produced a sensuous afterlife of fragrant gardens, angelic melodies and the ability to kiss another person from thousands of miles away “with the same pleasure as when the lips actually meet,” they write.

From there, concepts of Paradise have seesawed between austere, God-centered eternities and earthly landscapes full of activity. The latter became especially popular after a middle-aged Swedish mining official’s alleged visit to the next world.

In 1744, the story goes, Emanuel Swedenborg encountered a supernatural force that hurled him to the ground, forced him to pray and then took him to the land of the dead. What he saw--parks, cities, strange weddings and “garments that shown like flaming light”--started an avalanche of afterlife speculation, McDannell says.

In the United States, more than 50 books about heaven were published between 1830 and 1875. And by the turn of the century, the increasingly modern hereafter was equipped with theaters, time-travel machines, amusement parks, suburbs and schools.

Even Mark Twain jumped into the debate, slamming one account--which envisioned departed souls playing pianos, eating gingersnaps and living in Victorian cottages--as “a mean little 10-cent heaven about the size of Rhode Island.”

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Today, although nearly 80% of Americans say they believe in heaven, the old imagery has lost much of its allure.

“When the skies roll back like a scroll and the angelic trump sounds,” says author Kreeft, “many will simply yawn and say, ‘Pretty good special effects, but the plot’s too traditional.’ ”

Clerics and theologians also seem jaded. Some no longer believe in an afterlife; others ignore heaven in favor of social justice issues.

“Even evangelicals shy away from this topic,” McDannell says. “They are focused on the Bible and it doesn’t give a lot of clues (to what heaven is like). It’s more exciting to talk about (Armageddon) than about whether we’ll have harps or electric guitars (in Paradise).

“So what’s happening, more than ever, is that there’s a gap between intellectual, seminary-trained ministers and the average person. Theology is not providing any reassurance about what will happen to people after death,” so the vacuum is being filled by movies, books, near-death visions and alternative religions.

Hollywood’s “theologians,” for instance, have presented their versions of the great beyond in such films as “Ghost,” “Defending Your Life” and Diane Keaton’s documentary, “Heaven.” In the latter, one boy theorizes that the deceased will walk on cotton balls, eat pale food and--as a result of heavenly sex--give birth to “little dead people.”

Sports columnists, too, are turning into amateur Augustines. Scott Ostler, in a 1993 piece on Paradise, imagined God’s kingdom as a realm with “absolutely no Astroturf or phony, man-made surfaces for any sport. Even billiards will be played on real grass.”

Some of the most startling accounts of the afterlife, however, come from people who have “died” and been brought back to life.

Much of the imagery is reminiscent of LSD hallucinations. Near-death returnees speak of “imbibing colors” and being permeated by fragrances or music. On a recent episode of NBC’s “The Other Side,” a boy who nearly drowned at age 4 recalled traveling through a rainbow-colored tunnel to a cathedral full of shimmering crystals. He also spoke telepathically with a bumblebee.

Another ex-deceased talked about “being in the presence of a golden tree made of millions of tiny lights,” says Mally Cox-Chapman, a Connecticut journalist whose book “The Case for Heaven” is due out in spring.

Cox-Chapman suggests that the estimated 8 million near-death experiences in recent years are God’s way of helping modern society to believe in an afterlife.

“If an Ezekiel or Mohammed were in the world today,” she says, “they’d be diagnosed as delusional and locked up. So we have people in our high-tech temples (hospitals) telling our high-tech priests (doctors) that they’ve been to heaven.”

Actually, back-from-beyond episodes date to ancient times. The apostle Paul, possibly after being stoned and left for dead in Lystra, wrote that he was temporarily taken to heaven. And medieval records have yielded scores of afterlife eyewitnesses, although the testimonies differ significantly from their 1990s counterparts.

During the Middle Ages, most people went to hell or Purgatory, says Carol Zaleski, a religion professor at Smith College and author of “Otherworld Journeys: Accounts of Near-Death Experience in Medieval and Modern Times” (Oxford University Press, 1987). Also, those who did reach heaven were more likely to meet the patron saint of their church than to reunite with relatives, as is now commonly reported.

Not surprisingly, then, skeptics ascribe near-death visions to a combination of cultural influences and biochemical reactions in the brain, which continues to function several minutes after the heart stops.

Critics of Betty J. Eadie’s best-selling story, “Embraced by the Light” (Gold Leaf Press, 1992), note that she claims to have revived after being dead up to several hours--a medically impossible feat--and that she refuses to release hospital records. Other observers are amused that all the New Agers who admire her book apparently don’t realize that Eadie is Mormon and that her work is infused with Latter-day Saint teachings.

“The book is very LDS,” McDannell says. “It fits in quite nicely (with Mormon theology).”

Perhaps that accounts for some of its appeal.

“Most Christian churches have given up any kind of ritual connection with the dead,” McDannell says. “But people want that . . . (especially) when they lose someone they love. Mormon (rituals) allow you to help someone after they’re dead. And I think that’s one of the reasons their religion is growing so quickly.”

In Mormon heaven--a place of glass and flames--families will reunite and be given control of their own planets. Like God, a former human himself in LDS theology, resurrected Mormons become divine beings who populate these new planets by having sex and sending their spirit offspring to inhabit mortal bodies.

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Other speculation about heaven involves everything from time travel to surfing.

To explain the vagaries of eternal time and space, for example, Kreeft steamrolls past Einstein’s theory of relativity to create a fifth dimension (no, not the pop-soul group of the late ‘60s) and even a sixth dimension.

“Time is like a floor, and our lives in time are like buckets of water spilled out along that floor,” he writes in “Everything You Ever Wanted to Know About Heaven . . . but Never Dreamed of Asking” (Ignatius, 1990). “Eternity is like all the water gathered together in a bucket.”

Thus, time travel becomes possible. On Earth, “the past is dead and closed and therefore unchangeable. . . . But for those in eternity, all time is alive.”

The sixth dimension is also where Jesus went during his ascension, Kreeft says: The Bible passage that describes him rising into the clouds “was not meant literally, as if you could follow him in an airplane and watch him pierce the stratosphere. But I don’t think it was just symbolic, either. I think (the apostles) saw something (real). He moved upward and changed dimensions simultaneously.”

Another mystery Kreeft ponders is the possibility of afterlife surfing. “I ask myself seriously if (it exists) because it is the most mystical experience I know on Earth,” he explains. And Kreeft believes all earthly pleasures are a foretaste of heavenly joys.

His conclusion: Wave-riding might not take place literally, but “it isn’t zapped away (either). It will be perfected and intensified . . . (into) surfing in God.”

Of course, that brings up the boredom-frustration dilemma: If heaven is changeless perfection, won’t people eventually get tired of it? Likewise, if perfection is always just out of reach, won’t people be eternally frustrated?

There are no easy answers, concedes Father Augustine DiNoia, a theologian for the National Conference of Catholic Bishops. “I think we have to trust God on that one. . . . He is infinitely interesting.”

DiNoia compares Paradise to having friends over to watch a football game. “The game is important, but being together is what people look forward to. . . . Heaven is like any (earthly) fellowship, only to the nth degree. . . . It is an ultimate personal communion with God and other people.”

Some observers prefer more traditional descriptions of the afterlife.

Jeffrey Burton Russell, working on a heaven history to complement his four-volume set on the devil, is mesmerized by Dante’s surreal vision of rivers of liquid light and flesh and bone of emerald.

McDannell and Lang write about Martin Luther’s afterlife, in which “the Elbe River will flow with pearls and precious stones, the sky will be able to send a shower of coins, and trees may have silver leaves (and) golden apples.”

“Today’s theologians have gotten too abstract,” Russell says. “The tradition is much more powerful.”

Another holdover from the past is Purgatory.

Indeed, one of the most surprising developments in modern heavenology is that a concept once considered anathema by Protestants is winning endorsement from evangelicals and fundamentalists.

“There are some major, big-name (conservative) theologians who now believe in an ‘intermediate stage’ before heaven,” says Gary R. Habermas, co-author of “Immortality” and a philosophy professor at Jerry Falwell’s Liberty University. “They don’t call it Purgatory, but there’s not a big difference between what they’re saying and what Kreeft describes.”

Kreeft, drawing on the writings of C.S. Lewis, another evangelical favorite, likens Purgatory to a sort of cosmic bathroom, “where you wash up for heaven.”

“At the moment of death, we are still imperfect,” he says. There has to be a place where a life review occurs and “all the effects on your character from sins, vices, bad habits and ignorances are washed away.”

Of course, not everyone wants to get to heaven.

In the goofy Weekly World News supermarket tabloid, for example, a Pittsburgh man who supposedly died and went to hell before doctors revived him says Satan’s kingdom is a better bet.

It’s loaded with fast cars, free booze, babes in bikinis, slot machines and greasy fried food, he reported. “When (they) told me it wasn’t my time yet, I was really disappointed. . . . I want to be having fun with all those dudes down there. But I guess Satan has plans for me here on Earth.”

The 51-year-old bachelor also said he intends to lead a sinful life so he doesn’t end up in heaven by mistake: “I know where the fun is now. No way do I want to spend eternity with a bunch of boring goody two-shoes in Paradise.”

Which Way, L.A.?

* In January, Roy Rivenburg took a similar look at changing conceptions of hell. For a reprise of that story, check the TimesLink on-line service, California Living.

Details on Times electronic services, B4.