The Physics of Star Trek (2 page)

To resolve this dilemma, sometime after the production of the first Constitution Class
starshipthe
Enterprise (NCC-1701)
the Star Trek writers had to develop a response to the criticism that the accelerations
aboard a

starship would instantly turn the crew into “chunky salsa.”
1
They came up with “inertial dampers,” a kind of cosmic shock absorber and an ingenious
plot device designed to get around this sticky little problem.

The inertial dampers are most notable in their absence. For example, the
Enterprise
was nearly destroyed after losing control of the inertial dampers when the microchip
life-forms known as Nanites, as part of their evolutionary process, started munching on
the ship's central-computer-core memory. Indeed, almost every time the
Enterprise
is destroyed (usually in some renegade timeline), the destruction is preceded by loss of
the inertial dampers. The results of a similar loss of control in a Romulan Warbird
provided us with an explicit demonstration that Romulans bleed green.

Alas, as with much of the technology in the Star Trek universe, it is much easier to
describe the problem the inertial dampers address than it is to explain exactly how they
might do it. The First Law of Star Trek physics surely must state that the more basic the
problem to be circumvented, the more challenging the required solution must be. For the
reason we have come this far, and the reason we can even postulate a Star Trek future, is
that physics is a field that builds on itself. A Star Trek fix must circumvent not merely
some problem in physics but every bit of physical knowledge that has been built upon this
problem. Physics progresses not by revolutions, which do away with ail that went before,
but rather by evolutions, which exploit the best about what is already understood.
Newton's laws will continue to be as true a million years from now as they are today, no
matter what we discover at the frontiers of science. If we drop a ball on Earth, it will
always fall. If I sit at this desk and write from here to eternity, my buttocks will
always suffer the same consequences.

Be that as it may, it would be unfair simply to leave the inertial dampers hanging without
at least some concrete description of how they would have to operate. From what I have
argued, they must create an artificial world inside a starship in which the reaction force
that responds to the accelerating force is canceled. The objects inside the ship are
“tricked” into acting as though they were not accelerating. I have described how
accelerating gives you the same feeling as being pulled at by gravity. This connection,
which was the basis of Einstein's general theory of relativity, is much more intimate than
it may at first seem. Thus there is only one choice for the modus operandi of these
gadgets: they must set up an artificial gravitational field inside the ship which “pulls”
in the opposite direction to the reaction force, thereby canceling it out.

Even if you buy such a possibility, other practical issues must be dealt with. For one
thing, it takes some time for the inertial dampers to kick in when unexpected impulses
arise. For example, when the
Enterprise
was bumped into a causality loop by the
Bozeman
as the latter vessel emerged from a temporal distortion, the crew was thrown all about the
bridge (even before the breach in the warp core and the failure of the dampers). I have
read in the
Enterprise's
technical specifications that the response time for the inertial dampers is about 60
milliseconds.
2
Short as this may seem, it would be long enough to kill you if the same delay occurred
during programmed periods of acceleration. To convince yourself, think how long it takes
for a hammer to smash your head open, or how long it takes for the ground to kill you if
you hit it after falling off of a cliff in Yosemite. Just remember that a collision at 10
miles per hour is equivalent to running full speed into a brick wall! The inertial dampers
had better be pretty quick to respond. More than one trekker I know has remarked that
whenever the ship
is
buffeted, no one ever gets thrown more than a few feet.

Before leaving the familiar world of classical physics, I can't help mentioning another
technological marvel that must confront Newton's laws in order to operate: the
Enterprise's
tractor beamhighlighted in the rescue of the Genome colony on Moab IV, when it deflected
an approaching stellar core fragment, and in a similar (but failed) attempt to save Bre'el
IV by pushing an asteroidal moon back into its orbit. On the face of it, the tractor beam
seems simple enoughmore or less like an invisible rope or rodeven if the force exerted may
be exotic. Indeed, just like a strong rope, the tractor beam often does a fine job of
pulling in a shuttle craft, towing another ship, or inhibiting the escape of an enemy
spacecraft. The only problem is that when we pull something with a rope, we must be
anchored to the ground or to something else heavy. Anyone who has ever been skating knows
what happens if you are on the ice and you try to push someone away from you. You do
manage to separate, but at your own expense. Without any firm grounding, you are a
helpless victim of your own inertia.

It was this very principle that prompted Captain Jean-Luc Picard to order Lieutenant Riker
to turn off the tractor beam in the episode “The Battle”; Picard pointed out that the ship
they were towing would be carried along beside them by its own momentumits inertia. By the
same token, if the
Enterprise
were to attempt to use the tractor beam to ward off the
Stargazer,
the resulting force would push the
Enterprise
backward as effectively as it would

push the
Stargazer
forward.

This phenomenon has already dramatically affected the way we work in space at present.
Say, for example, that you are an astronaut assigned to tighten a bolt on the Hubble Space
Telescope. If you take an electric screwdriver with you to do the job, you are in for a
rude awakening after you drift over to the offending bolt. When you switch on the
screwdriver as it is pressed against the bolt, you are as likely to start spinning around
as the bolt is to turn. This is because the Hubble Telescope is a lot heavier than you
are. When the screwdriver applies a force to the bolt, the reaction force you feel may
more easily turn you than the bolt, especially if the bolt is still fairly tightly secured
to the frame. Of course, if you are lucky enough, like the assassins of Chancellor Gorkon,
to have gravity boots that secure you snugly to whatever you are standing on, then you can
move about as efficiently as we are used to on Earth.

Likewise, you can see what will happen if the
Enterprise
tries to pull another spacecraft toward it. Unless the
Enterprise
is very much heavier, it will move toward the other object when the tractor beam turns on,
rather than vice versa. In the depths of space, this distinction is a meaningless semantic
one. With no reference system nearby, who is to say who is pulling whom? However, if you
are on a hapless planet like Moab IV in the path of a renegade star, it makes a great deal
of difference whether the
Enterprise
pushes the star aside or the star pushes the
Enterprise
aside!

One trekker I know claims that the way around this problem is already stated indirectly in
at least one episode: if the
Enterprise
were to use its impulse engines at the same time that it turned its tractor beam on, it
could, by applying an opposing force with its own engines, compensate for any recoil it
might feel when it pushed or pulled on something. This trekker claims that somewhere it is
stated that the tractor beam requires the impulse drive to be operational in order to
work. I, however, have never noticed any instructions from Kirk or Picard to turn on the
impulse engines at the same time the tractor beam is used. And in fact, for a society
capable of designing and building inertial dampers, I don't think such a brute force
solution would be necessary. Reminded of Geordi LaForge's need for a warp field to attempt
to push back the moon at Bre'el IV, I think a careful, if presently unattainable,
manipulation of space and time would do the trick equally well. To understand why, we need
to engage the inertial dampers and accelerate to the modern world of curved space and time.

EINSTEIN Raises

There once was a lady named Bright, Who traveled much faster than light. She departed one
day, in a relative way, And returned on the previous night.
Anonymous

“Time, the final frontier”or so, perhaps, each Star Trek episode should begin. Thirty
years ago, in the classic episode “Tomorrow Is Yesterday,” the round-trip time travels of
the
Enterprise
began. (Actually, at the end of an earlier episode, “The Naked Time,” the
Enterprise
is thrown back in time three days
but
it is only a one-way trip.) The starship is kicked back to twentieth-century Earth as a
result of a close encounter with a “black star” (the term “black hole” having not yet
permeated the popular culture). Nowadays exotica like wormholes and “quantum
singularities” regularly spice up episodes of
Star Trek: Voyager,
the latest series. Thanks to Albert Einstein and those who have followed in his footsteps,
the very fabric of spacetime is filled with drama.

While every one of us is a time traveler, the cosmic pathos that elevates human history to
the level of tragedy arises precisely because we seem doomed to travel in only one
directioninto the future. What wouldn't any of us give to travel into the past, relive
glories, correct wrongs, meet our heroes, perhaps even avert disasters, or simply revisit
youth with the wisdom of age? The possibilities of space travel beckon us every time we
gaze up at the stars, yet we seem to be permanent captives in the present. The question
that motivates not only dramatic license but a surprising amount of modern theoretical
physics research can be simply put: Are we or are we not

prisoners on a cosmic temporal freight train that cannot jump the tracks?

The origins of the modern genre we call science fiction are closely tied to the issue of
time travel. Mark Twain's early classic
A Connecticut Yankee in King Arthur's Court
is more a work of fiction than science fiction, in spite of the fact that the whole piece
revolves around the time-travel adventures of a hapless American in medieval England.
(Perhaps Twain did not dwell longer on the scientific aspects of time travel because of
the promise he made to Picard aboard the
Enterprise
not to reveal his glimpse of the future once he returned to the nineteenth century by
jumping through a temporal rift on Devidia II, in the episode “Time's Arrow.”) But H. G.
Wells's remarkable work
The Time Machine
completed the transition to the paradigm that Star Trek has followed. Wells was a graduate
of the Imperial College of Science and Technology, in London, and scientific language
permeates his discussions, as it does the discussions of the
Enterprise
crew.

Surely among the most creative and compelling episodes in the Star Trek series are those
involving time travel. I

have counted no less than twenty-two episodes in the first two series which deal with this
theme, and so do three of the Star Trek movies and a number of the episodes of
Voyager
and
Deep Space Nine
that have appeared as of this writing.

Perhaps the most fascinating aspect of time travel as far as Star Trek is concerned is
that there is no stronger potential for violation of the Prime Directive. The crews of
Starfleet are admonished not to interfere with the present normal historical development
of any alien society they visit. Yet by traveling back in time it is possible to remove
the present altogether. Indeed, it is possible to remove history altogether!

A famous paradox is to be found in both science fiction and physics: What happens if you
go back in time and kill your mother before you were born? You must then cease to exist.
But if you cease to exist, you could not have gone back and killed your mother. But if you
didn't kill your mother, then you have not ceased to exist. Put another way: if you exist,
then you cannot exist, while if you don't exist, you must exist.

There are other, less obvious but equally dramatic and perplexing questions that crop up
the moment you think about time travel. For example, at the resolution of “Time's Arrow,”
Picard ingeniously sends a message from the nineteenth to the twenty-fourth century by
tapping binary code into Data's severed head, which he knows will be discovered almost
five hundred years later and reattached to Data's body. As we watch, he taps the message,
and then we cut to LaForge in the twenty-fourth century, as he succeeds in reattaching
Data's head. To the viewer these events seem contemporaneous, but they are not; once
Picard has tapped the message into Data's head, it lies there for half a millennium. But
if I were carefully examining Data's head in the twenty-fourth century and Picard had not
yet traveled back in time to change the future, would I see such a message? One might
argue that if Picard hasn't traveled back in time yet, there can have been no effect on
Data's head. Yet the actions that change Data's programming were performed in the
nineteenth century regardless of when Picard traveled back in time to perform them. Thus
they have already happened, even if Picard has not yet left! In this way, a cause in the
nineteenth century (Picard tapping) can produce an effect in the twenty-fourth century
(Data's circuitry change) before the cause in the twenty-fourth century (Picard leaving
the ship) produces the effect in the nineteenth century (Picard's arrival in the cave
where Data's head is located) which allowed the original cause (Picard tapping) to take
place at all.

Actually, if the above plot line is confusing, it is nothing compared to the Mother of all
time paradoxes, which arises in the final episode of
Star Trek: The Next Generation,
when Picard sets off a chain of events that will travel back in time and destroy not just
his own ancestry but all life on Earth. Specifically, a “subspace temporal distortion”
involving “antitime” threatens to grow backward in time, eventually engulfing the amino
acid protoplasm on the nascent Earth before the first proteins, which will be the building
blocks of life, can form. This is the ultimate case of an effect producing a cause. The
temporal distortion is apparently created in the future. If, in the distant past, the
subspace temporal distortion was able to destroy the first life on Earth, then life on
Earth could never have evolved to establish a civilization capable of creating the
distortion in the future!