Time Jumping
In Chapter 4, Isotope, Daniel points out to the FBI that travel to the future is possible if you have the right technology. The easiest way to get there is to hang out near any large gravitational field where, as Einstein’s general theory of relativity tells us, time slows down.
The effects of gravitational time dilation are very real and measurable. Put an ordinary wrist watch in a strong enough field, wait a week, and it will have slowed by hours when you retrieve it. From the watch’s perspective, it has jumped to the future.
It works for people too. You don’t even need to find a black hole (see the movie, Interstellar). A neutron star would do just as well. There are millions more of them and they’re easier to find. At least one neutron star is within 400 light-years from Earth. (Piece of cake to get there with quantum space compression, right?)
If you spent a few months orbiting a neutron star, when you got back to Earth everyone you know would be old or dead. People would say you didn’t age (time slowed down for you). But you’d say that time must have gone faster for them. From your perspective, you’ve jumped to the future.
In 2014, a mistake that launched two European global positioning satellites into an elliptical orbit gave ESA the opportunity to measure time dilation precisely. As it turns out, the atomic clocks onboard those satellites slow down by 200 nanoseconds as they get closer to Earth and speed up as they move away. Time dilation is weird, but very real.
So, just lasso a neutron star and drag it somewhere near Earth (but not too near) and you’ll have a time machine capable of sending you to any year desired. Five orbits and you jump to 2050. Ten orbits and you’re in 2080. Simple.
Of course, it’s a one-way trip. But it’s a trip some people would not hesitate to take. If you were offered a seat onboard a one-way flight to say, 2441, would you take it? Jacquelyn did. A bold move. Nala seemed to think so; she dubbed her Jackie Jetson.
Forward time travel just requires a good spaceship and lots of gravity. But is it possible to move backward in time? Physicists aren’t sure. But unless backward time travel is prohibited by some universal parameter that we don’t yet understand, the most likely mechanism is the same as forward time travel: a strong gravitational field. Among astrophysicists, timelike curves in gravitational fields are an intense area of current study.
A timelike curve is a path through spacetime that never strays beyond the cone of space accessible at the speed of light. In other words, it’s a path that a spacecraft could follow (an ordinary, non-Star-Trek-warp-drive kind of spacecraft).
When influenced by an intense gravitational field, the light cone tips toward warped space (a.k.a., gravity). Enough tipping and the timelike curve twists back on itself, eventually into a complete circle. It’s what astrophysicists call a closed timelike curve, or CTC.
Closed timelike curves come in several forms but they all have one startling characteristic in common: a portion of the path points backward in time. Any spacecraft following that portion of the CTC path would end up in the past. Crazy, but theoretically true and mathematically proven.
CTC’s are not hard to imagine and can be derived from Einstein’s field equations (I can’t, but people smarter than me can). But that’s math, not reality. Physicist Stephen Hawking believed that, in practice, a CTC could not be constructed no matter how hard an advanced civilization might try. He coined the term, chronology protection, a sort-of cosmic prohibition against time travel to the past, though he never identified how the universe might erect barriers along the CTC path.
Other physicists are not so sure those barriers exist. Kip Thorne, an astrophysicist at Caltech (and scientific advisor for the movie, Interstellar), wrote an advanced paper on closed timelike curves, identifying multiple ways in which a CTC could be constructed and then searched for mechanisms that might provide chronology protection. He didn’t find any.
Responding to Hawking’s theorized limitation, Thorne wrote, “The laws of general relativity by themselves do not enforce chronology protection.” Thorne agreed that future advances in our understanding of quantum gravity might ultimately find the cosmic prohibition that Hawking imagined. But based on our current scientific knowledge, the universe appears to allow time travel to the past.
This fact alone makes my head hurt. If travel to the past is allowed, then every paradox that springs up in my story is possible. For example:
An effect that precedes its cause: Becton died in 2023 but his death was caused by a lie from 2053.
An idea with no beginning: A young preacher is told of his future by his older self who then must fulfill his destiny to contact his younger self.
A name plucked out of the air: Father only knew Joshua Swindell’s name because he gave this name to his younger self.
The potential for an infinitely repeating loop: Daniel is called to the future only to meet himself where he learns how to return to the past so that he can grow old and explain it to himself.
Fun stuff? Or brain damaging? You decide.
Additional Dimensions of Time
In Chapter 7, Florida, we first learn about empros time from Marie Kendrick. “Flowing empros,” she says. “I’m not sure what it means, but I overheard Zin and Becton speaking about it a few weeks ago.” When Daniel arrives in Geneva to unravel its meaning, a second dimension of time is not only described, but demonstrated. Daniel examines a frozen world. Chloe even visits tomorrow while flowing in this alternate dimension of time.
I’m with Chloe. I’d love to flow empros. Maybe I’d head to London and take a few of the crown jewels out of their cases. Give a diamond tiara to my wife to wear to her book group and then remake the royal scepter into a really snazzy putter for my next round of golf. Those frozen guards would never catch me. How would they even know?
Or maybe I’d get scientific like Daniel thought he might do. Walking through rain while in empros time would be fun. Each droplet hung in the air. Would you still be able to see a rainbow in empros time? Dimmer, but still there? A stroke of lightning would slowly creep from sky to ground. (Or is it ground to sky?)
Theoretical physicists have long suggested that an additional dimension of time might exist. It’s a component of M-theory, which is an attempt to unite relativistic physics with quantum physics and explain the surprising symmetry between position and momentum that has long puzzled quantum physicists. I’ll explain.
In classical physics (you know, the Isaac-Newton-apple-falling-on-the-head type of physics) two key properties are position and momentum. A baseball arriving over the plate has a three-dimensional position that can be easily measured and even drawn as an arc across the television screen as the pitcher throws the ball. Likewise, the momentum of the ball (its velocity times its mass) can also be measured by a radar gun. We can know both position and momentum at the same time.
But it doesn’t work this way in quantum physics. A tiny particle like an electron orbits the nucleus of an atom, but we cannot know both the electron’s position and momentum. It’s not possible. The universe just doesn’t allow it. It’s called the Heisenberg uncertainty principle, and it basically says you can know the position accurately or you can know the momentum accurately, but never both. No one really understands why this is true.
If you’ve ever listened to a press conference from CERN or Fermilab, you might have heard one of the physicists mention gauge symmetry or symmetry breaking. They use the word symmetry when they’re talking about properties like position and momentum. Symmetry just means that these properties are interchangeable within the mathematics of quantum physics. Nothing about the mathematics is different regardless of whether you’re talking about position or momentum.
But why should these properties be symmetric? Mathematically, they’re quite different. Position is derived only from space—x, y, z. But momentum is derived from time because
momentum = velocity times mass
and
velocity = distance divided by time
; Momentum has a time component, but position does not. That doesn’t seem very symmetrical. Something else must be going on.
One physicist, Itzhak Bars, a professor at the University of Southern California, thinks he has the answer. Bars has developed what he calls 2T-physics to explain the surprising symmetry among these properties. He postulates that position does have a dependency on time, except it’s a brand new kind of time. A second dimension of time.
“If I make position and momentum indistinguishable from one another, then something is changing about the notion of time,” says Bars. “If I demand a symmetry like that, I must have an extra time dimension.”
But where is that other dimension of time? It certainly exists within the 2T-physics mathematics and it solves the symmetry question. But is this dimension real? Will we find it someday, curled up down at the subatomic level of quantum particles? I honestly don’t know, but it’s not beyond the realm of possibility.
CERN
At a sprawling facility on the Swiss-French border, an international team of physicists and engineers are currently exploring the nature of reality by examining the smallest components of our cosmos: quarks, leptons, and bosons. In my previous books, I placed several scenes at Fermilab, in Illinois, where similar particle physics experiments are carried out (mostly related to neutrinos). But CERN is special. They have the world’s most powerful accelerator, the Large Hadron Collider, and that opens the door to some amazing discoveries.
In Chapter 9, Alpha Prime, Daniel and Griffith meet Mathieu and Chloe and are led to a mysterious secret lab (in novels, labs are always mysterious and always secret). Mathieu explains that by studying antimatter, they have discovered an astonishing fact: an antihydrogen ion decays more rapidly than its ordinary matter counterpart, hydrogen. Voilà, they identified a second dimension of time!
Is this science real? Well, there really is a laboratory called Alpha (Building 193 in Meyrin) and the scientists there really do create and study antimatter. They produce antihydrogen atoms and can confine these volatile particles inside a Penning trap for up to sixteen minutes before they annihilate by coming in contact with ordinary matter. (Technical note: there’s no explosion! Just a tiny burst of energy that requires a very sensitive instrument to detect.)
Amazing stuff, given our limited understanding of antimatter and why it’s so rare in the natural world. Alas, as far as I know, the CERN scientists have not measured differences in antihydrogen ion decay rates. But, as they continue to explore the properties of antimatter, maybe they will discover something exotic. It would certainly make for an exciting announcement. Stay tuned.
The Flow of Time
I read a lot of books about time, both fiction and non-fiction. Some are great fun, some are deathly boring. You’d think that any physicist who works in such a fascinating field could tell a good story. Alas, that’s not always true. (I so miss Carl Sagan, the best scientific storyteller we’ve ever had.)
So, let’s focus on the fun stuff.
We all say that time flows, but as Zin points out in Chapter 11, flow has no meaning unless there’s something fixed and unmoving to measure against. If you were floating in a foggy river and couldn’t see the shoreline, you’d have no sense of movement.
So, how do we know time is flowing at all? It may be all in our minds. We see motion—leaves rustling on a tree, cars going by—and we put a mental frame around that motion. A before and after. Ticks of the clock.
Our memories of the past are a powerful psychological influence. We know time is flowing because the now is constantly changing. We remember what happened a second ago. But now it has changed. And changed again.
I sometimes wonder how we would think of time if our brains had evolved without any mechanism to retain memories. Suppose we were perfectly capable of reacting to events, but a nanosecond later that event was completely forgotten. (Clearly an evolutionary disadvantage!) Without any recognition of the past, would we also have no concept of the future? Would we live only in the now and perhaps never have invented clocks?
A significant portion of physicists say that the flow of time is a creation of our mind. It doesn’t really happen, we just interpret physical motion and our memories as movement through a dimension that is, in reality, fixed.
Brian Greene is one of those physicists. In his book, The Fabric of the Cosmos, he expertly demolishes our sense of linear time by exploring the concept of simultaneity. Einstein demonstrated (way back in 1905) that two people moving at high velocity relative to each other will not agree on the timing of an event they both observe. As velocity approaches the speed of light, the rate of time changes significantly making it impossible for multiple observers to agree that a flash of light, for example, happened exactly at 12:04:00 even if their watches were synchronized in advance. Once relativity is considered, there is no such thing as “now”. It depends on your frame of reference.
An intelligent species living in a galaxy far, far away would not agree with us that the universe is 13.8 billion years old. Their now would be different and there’d be no way for us to compare notes (our light-speed communication might take a billion years). Greene takes this notion a step further by pointing out that you can always find a reference point somewhere in the universe that considers now to be any one of those 13.8 billion years or any year in the future. Since there’s no reason to prefer our reference point over any other, it implies that every now since the Big Bang is just as real as the one we experience. Past, present, and future are just an illusion. Every moment in time exists, all at once, equally valid.
Image credit: NASA, ESA, and A. Feild (STScI)
Physicists call this the block universe concept. Every event, past and future, across the immensity of time exists simultaneously as if embedded in a cosmic block of ice. Any notion we have of time passing in our tiny path through this ice is simply a fantasy that plays in our minds.
I’m not fond of the block universe idea even if it is a valid description of the universe. Like most of us, I prefer to think of future events as undetermined, though I realize those events may just be hidden from my current consciousness.
Does the Flow of Time Change?
Let your mind wander back in time to the 1920’s. Southern California. The roaring twenties. Prohibition. Hollywood was producing the first talkies and much of the Los Angeles region was still covered by orange groves. In that setting, American astronomer Edwin Hubble spent many lonely nights at the top of nearby Mt. Wilson observing Cepheid variable stars whose brightness curiously pulsates in a regular rhythm.
The astronomers of Hubble’s day had already figured out that the rate at which these stars pulsate was directly related to their intrinsic luminosity. Stars with a slower beat were naturally brighter. Hubble realized he could use these stars to determine their distance from Earth, a feat that was previously calculated by the far-less-accurate parallax method. By comparing the observed luminosity to the star’s intrinsic luminosity, Hubble could calculate the star’s distance accurately. He found many Cepheids scattered across the sky and plotted their distances on a single chart.
Then Hubble compared the distances with the red-shift of each star’s light which he knew gave a good measure of motion relative to Earth. There was a surprising correlation. Virtually all of the Cepheids were moving away from the Earth and those stars furthest away were moving the fastest. Hubble’s exciting conclusion: the universe was expanding.
It was an astonishing discovery and very unexpected. It changed everything about our understanding of the cosmos. It was the first evidence that the universe was “born” from an initial point (the Big Bang) and the first indication of the age of the universe (now known to be 13.77 billion years – and yes, the number is that precise).
Much later, and after many more measurements, astronomers discovered that not only is the universe expanding, but that the expansion is accelerating. Something, it seemed, was pushing space apart faster and faster every year. To this day, no one know
s what that something is. It’s been given a name: dark energy. There are theories that say dark energy is an intrinsic property of space and that its force has varied with time.
But there’s only circumstantial evidence for the existence of dark energy. No one at Fermilab or CERN or any other lab has found it, though they’re trying. But without dark energy, there’s no explanation for the acceleration of the universe’s expansion. Or is there?
It’s not just the dark energy force that varies with time. Astronomers also claim that the cosmological constant (the energy density of space itself) varies with time (it’s not quite a constant). The same with the Hubble parameter (the rate of expansion)—it also varies with time.
Lots of values that all seem to be variable for some unknown reason. But there’s another explanation. What if time itself is changing? What if time is slowing down? A group of Spanish physicists from the University of Salamanca have proposed exactly that.
According to this radical theory, time is like a spinning coin. Its rate slows as it spins. Ultimately, it will stop altogether. By shifting the change to time, all the other variable parameters become constants. The universe is still expanding, but that expansion is at a constant rate. The cosmological constant really is a constant. So is the Hubble parameter.
This view of the universe is simpler. It even makes a certain amount of sense in a weird way. But no one knows if this conjecture is true. We’ll need more evidence one way or another.
In Quantum Time, Chloe is the scientist who finds some of that evidence. In Chapter 40, Home, she says that her discovery of anchor drift is “just the tip of the iceberg.” Chloe won’t get the Nobel Prize until her work is complete but if time really is slowing down, I’d like to think that someone like her will figure it out.
Submarines
I’m no expert on ballistic missile submarines, but from what I’ve read, you and I are safe from an accidental missile launch. Fortunately, this portion of the story probably couldn’t happen. (I am thankful for the professionalism of our military and I hope my awe for what they do came through as you read the military scenes throughout this book).
The Quantum Series Box Set Page 93