No time like the present.

What's with the fascination over Michael Crichton's Timeline and Jurassic Park--or with other summer blockbusters that promise to take us back to the future? Why are we relishing that form of escape? Patrick McCormick thinks it's about time to ask.

SUMMER BRINGS VACATIONS AND SENDS US SCURRYING to every point of the compass in search of a beach, cabin, or theme park where we might find a little respite or adventure "far from the madding crowd"--or at least away from the tedium of our daily routines. And if we hanker for travel in another dimension, if we've got our heart set on zipping off into the future or dropping back into the recent or Paleolithic past--what then? Well, even if our local travel agent can't yet book us passage on the Titanic, get tickets for a night at Ford's Theater, or send us on a dinosaur safari, there is plenty of action for wannabe time travelers down at the local cineplex or bookstore.

Wherever popcorn and paperbacks are sold, time travel is already available to any soul adventurous enough to leap into a wormhole.

In Michael Crichton's latest techno-thriller Timeline (Random House, 1999), the creator of Jurassic Park, Lost World, and Congo entertains us with yet another rollicking tale about adventurous academics wandering off where angels fear to tread. This time, however, our little band of Indiana Jones clones (a group of extraordinarily well-funded Yale historians) has not been dropped into the jungle in search of dinosaur DNA or hyper-intelligent primates. Instead, they've been faxed (via quantum teleporter) back into 14th-century France to retrieve priceless medieval relics for an out-of-control billionaire who wants to bring the History Channel to life. Unfortunately, their welcoming committee--a host of decidedly unfriendly and cavity-laden knights-errant slogging out the Hundred Years' War--takes to them like the Black Death. And before you can reset your sundials to the Middle Ages, our heroes have figured out that there's no place (or time) like home.

The leap isn't as big in Frequency (New Line Cinema), Gregory Hoblit's early summer blockbuster about a New York cop having a ham radio conversation with his (until now) long-dead dad. Thanks to a little interference from the aurora borealis, officer John Sullivan (Jim Caviezel) is able to reconnect with his firefighting father (Dennis Quaid), warn the senior Sullivan about his impending death, solve a serial murder, and join his dad in a play-by-play commentary on those amazing '69 Mets. In a movie that nicely meshes Field of Dreams, Back to the Future, and The Sixth Sense, the trip into the past is just as exciting as Crichton's Timeline but feels a lot more like going home.

These are, of course, not the first time-travel tales to come our way at the box office or bookstore. In 1895, H.G. Wells penned his classic Time Machine, recounting the adventures of an anonymous inventor who journeys far into the future, and soon thereafter Mark Twain wrote of a napping New England mechanic who woke to find himself A Connecticut Yankee in King Arthur's Court. In the '30s and '40s, dozens and dozens of time-traveling stories appeared in science fiction magazines like Amazing Stories and Astounding Science Fiction, and through the years writers like Isaac Asimov, Arthur C. Clarke, and Ursula K. LeGuin have written hundreds of time-traveling tales. In the '60s Madeleine L'Engle wrote her Newbery Medal winner A Wrinkle in Time. Shows like The Twilight Zone, Star Trek, and Time Travelers recounted countless tales of people stepping through all sorts of time portals and windows.

In the more recent '80s and '90s, Star Trek captains went into the past to save the whales, the planet, and the universe. Michael J. Fox drove a DeLorean Back to the Future three times, Arnold Schwarzenegger's Terminator dropped in twice from the 21st century, and Scott Bakula did a Quantum Leap into just about every childhood memory Baby Boomers could muster.

BUT TIME TRAVEL ISN'T JUST FOR SCIENCE fiction writers anymore. In 1905, Einstein's special theory of relativity implied we could leap into the future by traveling at or near the speed of light. (And why did this never come up every time a Star Trek ship popped into warp drive?) A decade later Einstein argued in his general theory of relativity that space and time were curved and that there might be tunnels (wormholes) connecting distant regions of space-time. Physicists at Caltech have suggested these wormholes could theoretically be used for travel into the past. Still; aside from the immense practical difficulties of achieving light speed and constructing stable wormholes, most scientists have traditionally dismissed the notion of time travel because of a problem known as "the grandfather paradox." This refers to the danger that time travelers could annihilate themselves (and thus cancel their trip) by killing their ancestors. Recently, however, Oxford physicist David Deutch has suggested that, according to quantum mechanics, time travelers would actually be visiting the past in parallel universes--and that we could change history there without endangering our own present. Zowee!

The real question about time travel may not be whether it's possible--but just why it's such a popular notion. Some of the appeal is probably simple curiosity. Like the clowning heroes in Bill and Ted's Excellent Adventure, we'd all probably enjoy a chat with Socrates, DaVinci, or Joan of Arc. And who wouldn't like to watch the landing at Plymouth or the Battle of Gettysburg without relying on the colorless commentary of a Western Civ textbook?

No doubt the notion of zipping into the future seems particularly appealing when we're stuck in a committee meeting or forced to watch somebody else's home videos. (Wouldn't life be great with a fast forward button?) Or maybe we're attracted to the financial advantages of time travel. We could pop into the future for some great stock tips--or drop back a dozen years and pick up some Microsoft shares. And just think how useful time machines would be to the witness protection program. Who would think of looking for a gangster's moll in a 13th-century nunnery?

I suspect the real appeal of time travel, however, has something to do with regret and with our own desire to undo past mistakes or get a second chance at missed opportunities.

Before Wells or Twain created their time traveling adventures, John Greenleaf Whittier noted that "of all sad words of tongue or pen, the saddest are these: `It might have been!'" Down through the years the fictional heroes in their time machines have invariably gone back into the past in hopes of correcting or preventing some personal or public catastrophe, of setting history on a different or better course. In Back to the Future (I, II, and III), in Peggy Sue Got Married, and in Frequency, Michael J. Fox, Kathleen Turner, and Jim Caviezel pop into yester-year to repair some family wound. And in series like Quantum Leap, Time Travelers, and The Twilight Zone, Bakula and others "strive to put right what once went wrong" by interrupting the assassinations of Lincoln and Kennedy, preventing Hitler's rise to power, or rescuing the Titanic.

WITHOUT THE AID OF TIME MACHINES or quantum teleporters, many of us live out private versions of these fantasies of alternate universes and corrected lives. We may not ponder how we would have stopped Booth or Oswald. But in quiet moments, before falling asleep at night or while driving home alone, it's not so uncommon to review our own missteps and imagine other choices, other responses we might have made--some light, some pretty serious. More than a few of us have rehearsed (and re-rehearsed) scenarios where we did finally say and do the right thing, acting out little psychodramas where we play a better, nobler version of ourselves.

In private places, we try to rewrite history all the time.

There are, as far as I can tell, no time machines in the New Testament (though one could argue, I suppose, that the appearance of Moses and Elijah at the Transfiguration involves visitors from another time) and no opportunity to change the past.

What Jesus does offer us there, though, is a way of living with our mistakes and catastrophes--a call to repentance and an offer of forgiveness. He doesn't take away the tragedies or accidents that haunt us. He doesn't give us back the lost moments or opportunities that we let go by. But he does offer us the grace to live in the only time we have, the present. With repentance we can at least stop being imprisoned in the past, doomed to recycle the same mistakes over and over.

And with forgiveness we have the chance to move into the future reconciled with our past. It may not be rocket science (or quantum mechanics), but until somebody comes up with a machine to change history, I'll be content with these two gifts from the one "who takes away the sins of the world."

By PATRICK MCCORMICK, an associate professor of Christian ethics at Gonzaga University in Spokane, Washington.