Split Second (15 page)

“Great idea for a story,” said
Walsh. “Apparently, you do
not
want
to piss off the universe,” he added with a broad grin.

Jenna smiled as well. She never thought she’d see the
entire universe compared to a mob enforcer, protecting its interests. “Could
this be why a half-second is the limit?” she said thoughtfully. “Because the
universe is making sure we don’t have enough time to create a paradox?”

Walsh shook his head. “The half-second limit wouldn’t,
necessarily
, ensure that,” he said.
“I’m sure you’ve heard the term
Chaos Theory
,
often called the
butterfly effect
.
This just means there are certain systems for which the slightest change in
initial conditions can cause huge effects, huge uncertainty in the end result.
Edward Lorenz was one of the early pioneers
—
by accident. He was modeling weather systems, and he
wanted to repeat an analysis he had already done, entering interim results by hand.
The computer he used calculated numbers to six decimal places, but to save time
he truncated them to just three. Instead of entering .546124, he entered only
.546. He never thought in a million years this minuscule change would matter in
the least. Only it did. It had huge effects on the end results
—
changed everything.”

Jenna had never heard this story but was fascinated by
it. “So you’re saying that the reverberations of going back less than a second
and making even the smallest change aren’t predictable, and could be a lot more
profound than we could guess?”

Walsh beamed, a proud professor delighted by a
talented student. “I couldn’t have said it better myself,” he said. “Still, despite
this, I believe you’re right. A half-second limit may well prevent major
paradoxes, so the universe isn’t under threat. But even if there is no chronology
protection, even if time travel is the Wild West and anything goes, Chaos
Theory suggests you can’t control it. And you can’t know for sure what impact a
change might have.”

Jenna was utterly spellbound by this discussion, and
her body chose to demonstrate her enthusiasm by forcing a prolonged yawn, and
then another. She shot Walsh an apologetic look as he continued.

“Just to finish the thought,” he said, “let me take an
example from the iconic time travel movie,
Back
to The Future
. I love this movie, but it revolves around human conception,
which provides a perfect example of how you can never replicate history, never
step in the same river twice.”

Walsh took another quick gulp of water and then
continued. “Marty McFly changes the past and has to fix it. He has to be sure
his parents still marry so he and his siblings can be conceived. But this is absurd.
Even if Marty gets his parents together, they’ll fall in love in a slightly
different way, with different timing. A billion tiny variables are changed,
meaning the orgasm his father had that led to Marty’s conception can never
happen the exact same way. Even if there were only a single change created, say
the proverbial butterfly from Chaos Theory flying through the bedroom window
when his parents were having sex, this might cause his father’s ejaculation to
be delayed by Nathan’s forty-five microseconds. Even this minute change would
mean that this time around, the sperm that has Marty’s name on it won’t outrace
the other hundreds of millions of sperm to the goal. Some other sperm will penetrate
the egg instead. Or maybe no sperm will make it and his parents will have to
try again. So even if Marty gets his parents together, he can never put the genie
back in the bottle.”

Jenna’s eyes swam out of focus and she shook her head
vigorously in response. She rose and poured herself a third cup of coffee,
wrinkling up her nose in disgust at the thought of forcing it down, but she was
determined to remain alert until they had exhausted all possibilities.

“Nathan also mentioned something called a block
universe,” said Blake. “What’s that?”

“Time isn’t my area of expertise,” said Walsh, “but I
do know the rudiments. But rather than address the questions Nathan posed in
his e-mail piecemeal, I think it would be better if I gave a crash course on
the nature of time itself. That way you can both put everything into context.”

Jenna glanced at Aaron Blake, who nodded his assent.

“Lecture on,” she said, unable to fight off yet
another yawn. “We’re all ears.”

22

“Sorry I couldn’t take your calls
earlier, Jack,” said Edgar Knight, a three-dimensional view of his always-intense
face hovering in the air above the phone Jack Rourk had purchased from a store
at the foot of Palomar Mountain, fortunately open until nine. “I always seem to
be fighting fires.”

“I understand completely,” said
Rourk.

And he did understand, only too
well. Which is why he couldn’t help but be pissed off at his boss, who had seen
his calls come in repeatedly two hours earlier but had chosen to ignore them,
deciding that whatever he was doing had to be more important than what Rourk
might have to report.

Knight was very smart and had probably
decided that for Rourk to escort his private eye down the mountain and to a
secure location would be laborious and time-consuming, and would probably
include having to knock the hostage unconscious for an extended period before
reviving and interrogating him more fully. Knight had assumed Rourk’s earlier
calls were to provide an interim update.

But this wasn’t the reason for the
calls at all. Knight could never have guessed that Rourk had found the winning
lottery ticket. Had he known, no power on Earth would have prevented him from taking
his calls immediately.

Fighting
fires, my ass
, thought Rourk, barely managing to keep from scowling.

“So what do you have to report?” said
Knight impatiently. He leaned in closer, as though examining Rourk’s image on
his own screen more closely. “What’s wrong with your arm?” he asked.

“The private eye that I had in my
sights was better than I thought. He shot me.”

Knight’s lip curled up in anger and
disgust. “So what are you saying?” he barked. “You lost him! The perfect link
to the girl!”

“I didn’t lose him,” replied Rourk.
“I
let
him get away. And only because
I have great news that makes the search for Jenna Morrison irrelevant.”

And
thanks for asking if I’m okay after being shot
, he thought.
I managed a field dressing, and it’s heavily
bandaged, but I’ll be good as new
.

“What are you talking about?”
demanded Knight, as though ready to choke the life out of the holographic image
in front of him.

“I have the flash drive,” announced
Rourk triumphantly. “Jenna Morrison gave it to this guy for safekeeping, and I
was able to get it. I had the choice of either retrieving the drive or going
after the PI.”

Knight’s hostile expression
transformed into a broad smile immediately. “Outstanding work, Jack,” he said
in delight. “Apologies for doubting you. You made the right choice.” He pursed
his lips. “Can I assume the drive is undamaged?”

“It is. It’s password protected, as
you already know, but in perfect condition.”

“Bring it in. As soon as you can.
Get a few hours sleep and then get it here by eight in the morning.”

“I
should
be able to make that,” said Rourk. “But I can’t guarantee
it. I need to ditch this car and get new transportation, since I have no doubt
my ex-comrades are searching for me by now.”

“I understand. I guess you won’t be
getting any sleep, after all. Don’t steal a car. We don’t want any more heat on
you. Find a car rental place that’s still open. If there isn’t one around you,
I know the ones at the San Diego airport are open until eleven or midnight, so
drive there if you have to. I assume you have alternate ID you can use for the
rental?”

“Yes.”

“Good. So get a car and get your
ass, and that flash drive, over here. And be sure to drive at the speed limit. Got
it?”

“Understood.”

“Great. And Jack . . . fantastic
work.”

Knight was about to end the
connection when he noticed Rourk’s arm once again. “Oh, and Jack, try not to
lose too much blood. I need you to make it here. I’ll be sure to have a doctor
standing by to patch up your arm when you arrive.”

“That would be helpful,” said
Rourk, not exactly overwhelmed by Knight’s concern for his health.

23

“Time is a nightmare,” began Dan
Walsh simply. “No subject is so utterly intuitive, and also counter-intuitive,
at the same time. It’s a subject that really messes with your head. And the
more you know about it, the more this is true. The intuitive perception of time
for most of us is that we are trapped in an instant of time, but one that seems
to be moving. This moment, the precise instant I’m telling you about this, is
now
. But this
now
becomes the past an instant later, before I’ve even finished my
next word. We’re the needle on a record player. We stay in an infinitesimally
thin band we call
now
, while the past
and future are continually unreachable on either side. At least until the
future decides to intersect with our infinitesimally thin needle and play a
note.”

Blake blew out a breath. “Wow.
You just started, and I’m already getting a headache.”

Walsh laughed. “Don’t worry, it
will get much worse.”

He gathered his thoughts and
continued. “As far back as five centuries before the birth of Christ, a Greek
philosopher named Zeno was already assembling a host of thought experiments to
try to understand time. My favorite that addresses the meaning of the
ever-frozen, but ever-moving,
now,
is
called
the arrow
.

“Imagine two arrows, one shot
from a powerful bow, and one held horizontally and dropped straight down from
above. Now imagine a time when the dropped arrow is precisely above the shot arrow.
Take a snapshot of just this instant, frozen in time.”

Walsh paused for a moment to let
Jenna and Blake visualize this in their minds. “Okay, your photograph will show
two arrows, perfectly still, one above the other. And they will look identical
in every way. In this precise instant of time, they
are
identical in every way. So how do they get to the next instant
of time? And how does one arrow know to move toward the target in the next
frame, and one arrow know to begin falling straight down? If time really is
divided into infinitesimal moments, infinitesimal
nows
, and in each one the arrow shot from the bow isn’t moving at
all, what is it about the passage of time that informs the arrow where to be at
the next moment?”

Jenna groaned. “Please tell me
you don’t want us to really try to answer that,” she said.

“No. I’m just trying to give you
a sense of some of the questions that have been asked throughout history. To
ease you into the subject,” he added with a smile.

“But if we forget about Zeno for
a moment,” continued Walsh, “time is the most intuitive concept there is.
Right? At least if we don’t think too hard about it. Who doesn’t know what time
is? We get it. Einstein once quipped that time’s only purpose was to make sure
that everything didn’t happen at once.

“But when you really think about
it, time is also the
least
intuitive concept
there is. How fast does time travel? And
does
time travel? Or do you travel through
time
?
And if you do travel through time, at what rate are you moving?”

The physicist shrugged. “After
all, speed is about how far we move in a given
time
. You drive your car at sixty miles . . .
per hour
. You walk to the store at two feet . . .
per second
. But how fast does time
itself
move?” asked Walsh, throwing out
his hands in a gesture of helplessness. “At one second per second?”

He rolled his eyes. “That’s like
saying you’re walking at a mile per mile. It’s absolutely an absurd and useless
concept.”

“Well, take the Einstein quote,”
said Jenna, proud that she could still channel semi-coherent thoughts in her
state of weariness. “The one you just cited. He said time exists to prevent
everything from happening at once. Which implies that time is change. A car
moves forward. The hand of a clock ticks. And time elapses, moves on.”

“Excellent. This is called the
relational theory
of time. People who
believe this believe time can only be gauged with respect to change. It’s an absolute
requirement. Without change, time can’t exist.
With
change you have
befores
and
afters
. First you weren’t
watching TV. Now you are.” Walsh smiled. “If you believe this theory, then you
believe time could not exist before there was a universe.”

Blake thought about this for a
few seconds and shook his head. “I get why this would be,” he said. “But my gut
feel is that time still passed, even before the birth of the universe.”

“I would tend to agree with the
relational theory,” said Jenna. “Without a universe, there can be no change.
Without change, no time.”

“There are those on both sides
of this issue,” said Walsh. “But already you can see how tricky time can be. And
it seems fairly clear to me that change is also a requirement for humans to
perceive the passage of time. We lay down memory. Our memory changes, and we
know that time has passed. Even if we’re just thinking with our eyes closed, we
have certain thoughts that didn’t used to be there, but are now. Before and
after. Imagine you were given drugs to knock you out for an eight-hour surgery.
No dreaming, no thinking, no observing. Did you experience time during these
eight hours? If I told you I gave you the wrong dose of anesthetic and you were
really only out for eight
minutes
,
would you know I was lying?”

“I doubt it,” said Blake. “You
make a very interesting point.”

“Newton thought time was an
absolute,” continued Walsh. “Dependable. But Einstein turned this on its ear.
He realized that space and time could not be separated. They form the fabric of
what he called space-time. Not three dimensions, but four. Newton thought you
and your friend would always—always—agree on the timing of an event, agree on
when something happened. But Einstein proved this was wrong.
You
might see event A happen
before
event B, while I might see the
exact opposite, depending on our velocities and positions. The faster something
moves through space, the slower it moves through time. If you were traveling at
the speed of light, time would stop altogether.”

Jenna nodded. “Nathan explained
to me that this has been proven over and over. That Einstein’s theory is used
to correct the timing of GPS satellites, or they wouldn’t work correctly. And particles
that decay very quickly take much longer to decay when they’re traveling near the
speed of light, the precise delay predicted by Einstein’s equations.”

“Exactly,” said Walsh
enthusiastically. “It turns out that while objects can move through space and
time at different rates, they all move through
space-time
at exactly the same rate: the speed of light. Always.”

“I’m not following,” said Blake.
“You can’t mean to say that right now, sitting at this table, we’re all moving
at the speed of light.”

“Through space-time, yes, that’s
exactly what I’m saying. When you’re not moving at all in space, you’re moving at
the speed of light, so to speak, through
time
—the
fastest the universe allows you to do so. When you’re moving at the speed of light
through
space
, you stop moving
through
time
. It stops completely. It
turns out that your speed through space, combined with your speed through time,
always adds up to the speed of light.”

“You’ve lost me,” said Blake.
“How do you add your speed through time, which I thought we decided wasn’t even
measurable, to your speed through space?”

“Good question. It’s a bit
complicated, and not important at the moment. What is important is what this
theory says about the nature of time. It suggests that just like all of space
is laid out at once, so is all of time. This is called the
block universe
, which you had asked about, Aaron. In the theorized
block universe, everything that
has
happened, or
will
happen, is already
set in stone. And no particular ‘now’ is privileged.”

“What does that mean?” said
Jenna.

“It means that when you’re here
and your friend is in New York, you believe that both places are equally real,
right? Both exist, and neither location has a better claim to being real than
the other.”

Jenna and Blake both nodded.

“The same should be true of
time. Why is this instant, this now, privileged? Why is it any more real than
the instant you experienced years ago, or will experience years in the future?
It’s all there, all of time, already laid out in its entirety, our
consciousness just isn’t designed to see it. Einstein wrote that for physicists
like himself, the distinction between past, present, and future was only a
stubborn illusion. And we’re talking about the entire life of the
universe
. From the big bang to the
universe’s death, it’s all laid out. Every point in time existing in a block
with every other point, simultaneously. All equally real, and all with an equal
claim to the designation of
now
.”

Blake shook his head, as though
not wanting to believe this could be true. “So what does that say about free
will?” he asked.

“Great question. Doesn’t bode
well, does it?”

“I used to tape football games on
occasion for later viewing,” said Blake. “I’d watch knowing that whatever I was
about to see happen, had already happened. I just didn’t know what that was. I
could gradually watch it unfold, and it would be a surprise to
me
, but it was already set in stone,
like you said.”

He tilted his head, remembering.
“Once I watched a replay of a game after someone accidentally told me the
Saints had won. So I’m watching, and with nine minutes left in the game the
Saints are down twenty-three points. So even though I know how it ends, it
seems impossible to me that this could be right. Surely there’s been some kind
of glitch in reality. Surely the universe will now correct for this. But, of
course, it didn’t. The Saints scored a quick touchdown, followed that up with a
pick six, recovered an onside kick, and so on. They kicked a winning field goal
with one second left in the game.”

A troubled look crossed Blake’s
face. “So is this really what the universe is? A preordained game that has
already been played? We can cheer however we want to, but we can’t affect the
outcome.”

“Very possibly, yes,” said
Walsh. “There are many brilliant scientists who believe this, just as Einstein
did. And many who don’t. I love the football analogy. Another good way to think
of the block universe theory is to compare it to an old-fashioned movie. A
movie made up of thousands and thousands of frames that are quickly moved
through the projector to create the illusion of motion. We’re like players in
this movie. We experience the frames sequentially, but the full movie has
already been made, and is already loaded into the projector. The last frame exists
every bit as much as the first, even if we can’t see it. But the movie plays out
as it has to. Inexorably. Inevitably. It’s all there on the reel,
unchangeable.”

“Sounds pretty horrible,” said
Jenna.

“It really does,” said Walsh.

Blake wore a dour expression. “But
like you said, we aren’t
certain
this
is the case, right?” he asked, looking for reassurance.

“Right. Einstein’s work supports
this view, but we can’t be sure. Sometimes I think the block universe theory is
correct and I’m quite troubled by it. But I’ve also found the idea comforting
at times. If I’m struggling with a problem, I tell myself, it doesn’t matter,
either I solved it, or I didn’t. Either things worked out, or they didn’t. But
either way it’s already happened. It’s already locked in. Just as the past has
already been laid down and I have no power to change it, so has the future. I
just don’t know it yet.”

Jenna sighed. “I have to agree with
your first statement, Dan,” she said. “Time is a nightmare. This must be why
Nathan seemed so excited that he could use his discovery to perform actual
experiments and test these ideas.”

“Exactly,” said Walsh. “Nathan’s work
could help us get a handle on time, and time travel, potentially leading to major
breakthroughs we have yet to imagine.”

“But would people really get this
excited, this quickly?” said Blake. “Enough to kill haphazardly? Just so they can
do some experiments?”

“You wouldn’t think so,” agreed Walsh.

Jenna knew she was now just minutes
away from falling into a coma. She had continued to yawn periodically as Walsh
had spoken and had choked down all the coffee she could bear. She just hoped
she could fight through it just a little longer.

She turned to Walsh. “So what are
some of the time travel theories he’d be able to test? In Nathan’s e-mail, he mentioned
branching timelines and so on. Could you run through the possibilities?”

“I’m far from an expert on time
travel theory,” said Walsh. “But I have read and seen my share of time travel
stories. I can't imagine there's any soil that hasn't already been tilled by a
century of science fiction writers.” He shrugged. “I’m sure you two know as
much about this as I do.”

Blake sighed deeply. “That may
be, Dan, but I have no doubt you’ll do a better job of analyzing and organizing
all of it. So why don’t you start us off.”

“I’d be happy to,” said Walsh.

He paused for a long moment in
thought. “We’ve already discussed one idea. That the universe won’t allow the past
to be changed. It will protect itself. The other end of the spectrum is that it
will allow it, and the tiniest change is amplified through time and has
profound effects. There’s a famous story by Ray Bradbury about a group who goes
back in time sixty-five million years to the age of the dinosaur. They have a
discussion about the possible ramifications of killing a single mouse there.
One character thinks it’s no big deal, but the other explains that killing that
one mouse also kills all of its future descendants
,
possibly billions of future mice over millions of years. And for
want of mice, other species up the food chain die off, finally leading to a
cave-man dying for lack of food, one who wouldn’t have died otherwise. A
critical cave-man at a critical juncture in human development, when mankind was
hanging on by a thread. So killing one mouse sixty-five million years ago can
lead to the extinction of the human race.”