Changing History: “Timeless”

The initial episode of NBC’s new time travel series, Timeless (premiered Oct. 3, 2016), does a neat job of handling the classic trope of changing the past.  There’s more to that kind of plot than generally meets the eye.

Spoiler Alert!The following necessarily contains spoilers for the first Timeless episode, so if you haven’t seen it and want to, be careful when scrolling down.  I’ll drop another alert message at the point where the spoilers begin.Poster for Timeless

The Lure of the Past

Oddly enough, travel to the past fascinates us more than travel to the future.  One might expect it to be the other way around.  After all, we’ve been to the past.  The first classic time travel tale, H.G. Wells’ The Time Machine, concerned itself exclusively with the future.  But it’s backwards time travel that lets us imagine changing the present by altering its causes—and produces the causal tangles that are unique to time travel stories.

Larry Niven’s essay “The Theory and Practice of Time Travel” (found in All the Myriad Ways) points this out:  “When a child prays, ‘Please, God, make it didn’t happen,’ he is inventing time travel in its essence. . . . The prime purpose of time travel is to change the past; and the prime danger is that the Traveler might change the past.”

The Past Doesn’t Change

Some stories assume that the past can’t be changed.  The time stream protects, or heals, itself automatically once the moving present has passed.  There was an old-time SF story (anyone remember the title?) in which successive attempts to change history misfire because of progressively more unlikely accidents.  The gun misfires.  The bullet misses.  A bystander intercepts the bullet.  A meteor knocks the gun out of the assassin’s hand.  The hypothesis has an air of fate about it, as in the Greek myths.

But unchangeability needn’t be a matter of fate.  It may simply reflect the fact that the past event has already happened, incorporating any interventions from the future that may have taken place.  There is a single past event, which is the product of all its causes, whether they come from the event’s past or its future.  As TV Tropes puts it, “You Already Changed the Past.”  Robert A. Heinlein wrote some of the most famous time travel stories using this approach to generate “constructive” or “ontological” paradoxes—By His Bootstraps and “—All You Zombies—”.

A technology that only allows viewing the past, rather than interacting with it, falls into a similar category.  There’s no chance of changing things; we’re mere observers.  Isaac Asimov’s The Dead Past leaps to mind.

These kinds of stories are fun, but they don’t have quite the emotional appeal of “Make it didn’t happen.”

How A Change Propagates

Suppose, then, that we can change the past.  How exactly is that supposed to work?

A writer sometimes introduces a sense of urgency into the plot by imagining that a change in history propagates through reality in a process that itself takes time (of some sort).  This is what creates the tension in Back to the Future.  We can see Marty’s family gradually disappearing as his disruption of history works its way forward.  Presumably Marty disappears last because he was conceived last.  If he doesn’t reestablish history before he disappears, it’s all over.

This makes a weird sort of sense, because natural processes do normally propagate gradually.  Even gravity has its waves.  But it does result in the curious phenomenon of a reality that isn’t entirely self-consistent.  Marty’s parents never got married, but Marty himself is still inexplicably there.  (For the moment.)

It makes more sense, maybe, to picture the change as taking effect instantaneously.  Take away the causal “supports” for something, and it’s no longer there at all.  This assumption would have made Back to the Future a much shorter movie—and highlighted the “Grandfather Paradox” at the core of its plot.  The time lag gives Marty a chance to cure the paradox before it fully takes effect.

What Happens to the Traveler?

But we’re assuming that the causal ripple from history’s change follows the time traveler even when the traveler’s world line has looped around into the past.  What if that isn’t how it works?  (We’re inventing a theory of time travel; we can make what assumptions we wish.)  If the traveler is absent from the future when the change “gets there,” will the traveler be affected at all?

If the traveler is affected by the same change that affects everything else, we get a time stream that’s more consistent, but harder to tell a story about—because no one in the story will remember the change.  The traveler’s memory alters along with everything else.  (There’s an old SF story about this, too—and it only works because the reader is outside the story’s time stream.  At the end the bizarre monster that was human on page one proclaims, ‘the time experiment is over, and nothing has changed.’  The story only works from an omniscient point of view.)

So a time travel story almost always assumes that the traveler, who was out of the affected time region when the change occurred, remembers the old when she encounters the new.

Here Be Spoilers!

You Can’t Go Home Again

Here’s where Timeless comes in.  Villains of some sort—or are they?—steal the secretly developed time machine and set off to change history.  Our three heroes take the older prototype vehicle (a little less streamlined than a DeLorean) and follow.  They don’t quite succeed in preventing their adversaries from altering the past.  The Hindenburg explodes on its return trip, rather than on its arrival in America.Hindenburg disaster

When our heroes come back to the present, their colleagues believe the zeppelin had always exploded on its return trip—because the change in history has affected them.  The three travelers have to explain to them what’s changed.  In a sense, they no longer belong in the world from which they set out.  It’s an unusual and interesting situation for a TV series.

The Butterfly Effect

So far, we haven’t seen what larger alterations or political ramifications may have resulted, in this new world, from the deaths of several prominent figures on what was now the Hindenburg’s ill-fated second flight.  But the personal implications turn out to be devastating.

Butterfly effect graphicThe screenwriters also have a good handle on another time travel staple, the “butterfly effect,” named for the metaphor that in a massive chaotic system, a butterfly flapping its wings on one continent might result in a tornado in another (or, possibly, named for a classic Ray Bradbury short story).  When main character Lucy Preston comes home from her adventure in the past, she is overjoyed to find that her mother, comatose when Lucy left, is now perfectly healthy.  But Lucy is appalled to find that her beloved sister never existed.  How could the Hindenburg’s altered history have anything to do with this, she cries—and now she has new, and very mixed, motivations as to setting time back on its original course.

The show thus picks up on a theme that’s frequently neglected in a tale about changing the past.  Each change has unpredictable ramifications.  Marty McFly comes home to find his parents much improved, his siblings successful, and the despised Biff reduced to a cipher.  But what of all the people in town who will have interacted with the changed McFlys and Tannens over the past thirty years?  If even minor events can have large long-range effects, it may not be so easy to confine a temporal change to the intended consequences.

This means that our Timeless heroes may have no way to put things back the way they were.  The change may be essentially irreversible—a sort of temporal entropy.  Anything they do to counteract the bad effects of the original change will lead to still more alterations.  They really can’t go home again.

If the writers carry through this fascinating, if rather chilling, line of thought in subsequent episodes, we may get some really interesting story lines—as time goes on.

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How to Stage an Alien Invasion

We love our alien invasions.  Since The War of the Worlds (1897), poor Earth has suffered a steady stream of hostile arrivals—frequently from Mars, but recently from farther afield, as the possibility of other intelligent life in our solar system wanes.

We have one coming up this month, with the June 24 movie premiere of Independence Day:  Resurgence, a sequel to one of the more successful invasions of the last twenty years.  It seems like a good time to look closely at our opponents.

Footfall, a 1985 novel by Larry Niven & Jerry Pournelle (still available in print), is not only a great yarn, but a textbook model of how to write a modern invasion story.  We can look at it as a test case, like an existence proof in mathematics:  What kinds of conditions have to be fulfilled for a believable alien invasion, given what we now know about other planets?

 

Let’s define the target.  We’re talking about the good old classic invasion story, where the bad guys show up in person, make a direct assault, and we beat them.  That isn’t the only possibility.  There are other variants, such as infiltration, or scenarios where the Earthlings lose and end up a subject species.  But let’s look at what premises make a triumphant Independence Day-style plot viable.

 

It was easy for Wells.  His relatively nearby Martians could fire off a series of cannon shells, more or less, to land on Earth, break out their tripods, and mount their campaign.  Wells’ tour de force ending, of course, has the Martians beaten not by human opposition, but by humble bacteria.  (Arguably the best moment in the original Independence Day is when Jeff Goldblum realizes we can best the enemy by using a contemporary analogue of the Wellsian microbes—a computer virus.)

But modern invaders have to come from a greater distance.  Regrettably, none of the plausible abodes of life in the solar system have panned out.  Gone are old-time SF’s sweltering jungles of Venus, the canal-crossed deserts of John Carter’s Mars.  Until we’re ready for an attack by potential microbes from Europa, or hypothetical floating denizens of Jupiter’s atmosphere—neither of which, if they exist, have shown any signs of capability for interplanetary excursions—we have to look to interstellar sparring partners for a really good invasion.

This intensifies a long-standing problem with invasion stories.  If they got here, and across the interstellar gulfs at that, their technology must be literally light-years ahead of ours.  How can we expect to beat critters with such vastly advanced technology?  The balance of power is inherently skewed against us.

Paired with this is the question of motivation.  Why are they here?  What do the invaders want that would drive them to come all the way to Earth for it?

This is the easiest place for invasion stories that aren’t built on sound science to go astray.  We need only mention the 1983 TV mini-series “V,” which, though it had many admirable aspects, fell sadly short on the science side.  V gives not one, but two, implausible motives for the seemingly-benevolent Visitors.  They’re here to steal Earth’s water—as if there weren’t vast amounts of ice scattered around our solar system, and probably most other systems, for the taking.  And they’re here to eat us; apparently not only are humans compatible with a completely alien biology, but we’re a tastier treat than more edible and obtainable animals.  Sensible extraterrestrials need a better reason to traipse across the light-years than a local hamburger shortage.

 

Niven & Pournelle’s epic adventure handles both these questions so beautifully that it might have been plotted specifically to answer them.

Our not-quite-friendly visitors, the fithp (the singular is fi’), arrive in a large interstellar vessel, which launches smaller ships to conduct the attack.  Why are they here?  They’re looking for Lebensraum — living space.  The fithp have been exiled from their homeworld as the result of a conflict among factions—like the Protectors in Niven’s novel Protector.  They need a new place to live.  Among other things, this means “defeat is not an option”:  they can’t go back.  That ups the stakes.

But this exile premise also solves some of the balance-of-power problems.  The fithp’s resources are strictly limited.  There won’t be any reinforcements.  They can’t bring anything more from their homeworld.  All we have to do is defeat this batch of opponents, and we win.

Niven & Pournelle strengthen this limitation on the aliens, and incidentally increase scientific plausibility, by making their mother ship Message Bearer a slower-than-light vessel — a Bussard ramjet.  Their journey takes decades.  This distances the fithp even further from any potential homeworld support.  The authors also use it to introduce another twist:  there’s dissension between the space-born fithp, on one hand, and those who lived on their homeworld and are now awakened from suspended animation, on the other.  This division becomes important as the plot develops.

Without having to account for faster-than-light travel, Niven & Pournelle can give the fithp technology that isn’t too far ahead of our own.  Human numbers—and political, psychological, social characteristics—can make up for the technological imbalance.

In addition, the fithp don’t fully understand their own technology.  They’ve learned a lot of it from records left by their Predecessors, rather than developing the science themselves. This makes them less able to innovate.  By contrast, the humans’ response is a masterpiece of improvisation.  We make the best of what we have.  This, too, helps even the scales.  (Lesson for humans:  Continue fostering that STEM education.)

 

In the course of this worldbuilding, Niven & Pournelle give us fully fleshed-out aliens, with a coherent culture and society, understandable but different from our own — not an easy task.  Among other things, the fithp are sympathetic characters.  They are people, not just faceless attackers.  We see events from their viewpoints as well as our own.  This makes the story not only more believable, but more interesting.

 

The original Independence Day scores modestly on these two plausibility counts.  Motivation:  The aliens travel the stars like locusts, stripping planets of their resources.  No details are given, but the basic idea is not unreasonable, particularly in light of contemporary environmental concerns.  Balance of power:  We’re hopelessly behind in technology—but the aliens’ laziness (using our own satellites for signaling), Goldblum’s bright idea, and a captured alien ship get us (barely) over the hump of the willing suspension of disbelief.

We’ll see shortly how these premises play out in the Independence Day sequel—applying the Niven & Pournelle standard.