Category Archives: Time Travel

Abstract fractal pattern resembling a cosmic or underwater scene with glowing blue and white textures.

How Negative Energy and Time Travel to the Past Are Connected

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Today’s science knows precious little about negative energy. The best example we have of creating negative energy in the laboratory is the Casimir effect, which we briefly discussed previously, but will now discuss in detail. Let us start by discussing the energy associated with a vacuum. Vacuums contain energy. One simple experiment to prove this is to take two electrically neutral metal plates and space them closely together in a vacuum. They will be attracted to each other (i.e., the Casimir effect). At approximately 10 nm (i.e., 1/100,000 meters) separation, the plates experience an attraction force of about one atmosphere (i.e., typically, the pressure we feel at sea level on Earth). What is causing this force?

The energy in a vacuum is termed “vacuum energy.” Surprisingly, it appears to obey the laws of quantum mechanics. For example, the energy will statistically vary within the vacuum. When the vacuum energy statistically concentrates, it gives rise to virtual particles, which is termed a “quantum fluctuation.” When the metal plates are spaced closely, relatively few virtual particles can form between the plates. A much larger population of virtual particles can form around the plates. This larger population of particles exerts a force on the outside of the plates. This force is the Casimir-Polder force, and it pushes the plates together. However, another strange physical phenomenon is also occurring between the closely spaced plates. In quantum mechanics, every particle has a “zero-point energy.” Even a vacuum is said to have a zero-point energy. The zero-point energy, or the “ground state,” is the lowest energy level that a particle or a vacuum may have. By reducing the space between the plates, some physicists believe we are reducing the normal zero point energy of the vacuum between the plates. When this occurs, those physicists argue the vacuum energy between the plates is negative energy (i.e., below the zero-point energy).

The scientific community is not in complete consensus regarding the properties or even the existence of negative energy. Physicists are able to mathematically model negative energy and use those models to make predictions regarding the theoretical behavior of negative energy. While the mathematical models do not prove the existence of negative energy, it is instructive to consider their predictions, and their implications to time travel. Here are the salient features of negative energy based on the mathematical modeling:

• Negative energy implies the existence of negative mass. This, of course, begs a question. What is negative mass? Negative mass is a hypothetical concept in theoretical physics. Anglo-Austrian mathematician and cosmologist Hermann Bondi suggested its existence in 1957. If it exists, it is the negative counterpart of normal (i.e., positive) mass and exhibits unusual properties. For example, normal masses exhibit attractive forces, known as gravitational attraction. Negative masses would exhibit repulsive forces. However, be careful not to equate negative mass with antimatter. The vast majority of the scientific community holds that antimatter is still positive mass. Based on this consensus, they predict antimatter would exhibit the same properties as positive mass. For example, two antimatter particles would exert an attractive force on each other, not a repulsive force. The implications of negative mass on time travel are ambiguous, since the existence of negative mass itself is ambiguous.

• Several in the scientific community suggest that a negative energy vacuum would allow light to travel faster than a normal positive energy vacuum. If this theory proves to be correct, it could have major implications for time travel. For example, there is speculation that this property may allow people to travel faster than the speed of light in a negative-energy vacuum bubble. Previously, we have discussed that as a mass approaches the speed of light, time dilates (i.e., time slows down for the mass). If the mass exceeds the speed of light, the implication is that it can travel into the past. We will discuss this further in the next chapter.

• Stephen Hawking and other physicists suggest that negative energy is required to stabilize a “traversable wormhole,” an entity that would allow a person, object, or information to travel between two points in time or space. Wormholes are a hypothetical shortcut between two points in time or two points in space. There are solutions to Einstein’s general equations of relativity suggesting the theoretical existence of wormholes. However, we have no observational evidence that they exist in reality.

Until we can find a way to produce negative energy and apply it experimentally to determine its effect on time, we can only speculate.

Source: How to Time Travel (2013), Louis A. Del Monte

A silhouette of a person with a clock face behind them, symbolizing the concept of time and human existence.

The Greatest Engineering Challenge to Time Travel

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Without doubt, harnessing sufficient energy is  the largest obstacle to time travel. For example, time dilation (i.e., forward time travel) is only noticeable when mass approaches a significant fraction of the speed of light or sits in a strong gravitational field. To date, we have been able to accelerate subatomic particles to a point where time dilation becomes noticeable. We have also been able to observe time dilation of a highly accurate atomic clock on a jet plane as it flies over the airport, which contains another atomic clock. Using sensitive instruments, we can measure time dilation. We have also been able to measure time dilation due to differences in the Earth’s gravitational field. However, these differences are only evident using highly accurate atomic clocks. Our human senses are unable to detect a high mounted wall clock moving faster than our wristwatch, which gravitational time dilation predicts is occurring.

The fastest humankind has traveled is 25,000 miles per hour, using the Apollo 10 spacecraft. The speed of light in a vacuum is approximately 186,000 miles per second. This means that a spacecraft would have to go about 13,000 times faster than Apollo 10 for humans to experience noticeable time dilation, or a speed of about 90,000 miles per second, which is roughly half the speed of light. Today’s science has not learned to harness the amount of energy required to accelerate a spacecraft to a velocity of 90,000 miles per second.

Let us consider a simple example to illustrate the amount of energy required to achieve the above velocity. If we have a mass of 1000 kilograms (i.e., 2204 pounds), and we want to accelerate it to 10% the speed of light, the resulting kinetic energy would be about 1017 (i.e., a 1 with 17 zeros after it) joules, whether you calculate the kinetic energy using Newton’s classical formula or Einstein’s relativistic formula for kinetic energy. To put this in perspective, it is more than twice the amount of energy of the largest nuclear bomb ever detonated. It would take a modern nuclear power plant about ten years to output this amount of energy.

The above example gives us a conceptual framework to understand the amount of energy that would be required to accelerate a sizable mass, 1000 kilograms, or 2204 pounds, to just 10% the speed of light. If we wish to accelerate the mass, for example, a spacecraft, to a greater percentage, the energy increases exponentially. For example, to accelerate to 20% the speed of light would require four times the amount of energy.

Today’s engineering is unable to harness this level of energy. In the popular Star Trek television series and movies, the starship Enterprise is able to travel faster than the speed of light using a warp drive, by reacting matter with antimatter. Factually, there is almost no antimatter in the universe. This is one of the mysteries associated with the big bang science theory, which I discussed in my book, Unraveling the Universe’s Mysteries. In theory, during the big bang, matter and antimatter should exist in equal quantities. Our observation of the universe, using our best telescopes, detects almost no antimatter. However, Fermi National Accelerator Laboratory (Fermilab) in Illinois is able to produce about fifty billion antiprotons per hour. This, though, is a miniscule amount compared to the amount needed to power a starship. According to Dr. Lawrence Krauss, a physicist and author of The Physics of Star Trek, it would take one hundred thousand Fermilabs to power a single lightbulb. In essence, we are a long way from using matter-antimatter as a fuel. In addition, the Enterprise was able to warp space. This provided a means to skirt around Einstein’s well-established special theory of relativity, which asserts no mass can travel faster than the speed of light. There is no similar physical law that prohibits space from expanding faster than the speed of light. If we are able to manipulate space, similar to our discussion of the Alcubierre drive in the previous chapter, then scientifically the spacecraft could collapse space in front of it and expand space behind it. However, the Alcubierre drive requires negative energy. Today’s science is unable to create and harness negative energy in any significant way.

Therefore, topping our list of major scientific obstacles regarding time travel is generating huge amounts of energy, in either positive or negative form.

Source: How to Time Travel (2013), Louis A. Del Monte

M-theory

Are There Any Real Time Machines? Part 2/2 (Conclusion)

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Are there any real time machines?

In my opinion, we are in about the same place space travel was at the beginning of the twentieth century. At the beginning of the twentieth century, all we knew about space travel came from science fiction. We knew that birds could fly, and this observation provided hope that human air flight would eventually be possible. However, at this point we could only fly using balloons, which was a long way from controlled air flight. We knew about projectiles, such as cannonballs and simple rockets, and this provided hope that one day humankind would be able to travel into space. However, at the beginning of the twentieth century we were still three years away from building the first successful airplane. The first successful airplane did not come from a well-respected theory or formal scientific investigation. Most early attempts at air flight tended to focus on building powerful engines, or they attempted to imitate birds. The early attempts at air flight were dismal failures. The first successful heavier-than-air machine, the airplane, was invented in 1903 by two brothers, Orville and Wilbur Wright. They were not scientists, nor did they publish a scholarly paper in a scientific journal delineating their plans. Quite the contrary, the two brothers had a background in printing presses, bicycles, motors, and other machinery. Clearly, their background would not suggest they would invent the first airplane and lead humankind into space. However, their experience in machinery enabled them to build a small wind tunnel and collect the data necessary to sustain controlled air flight. From the beginning, the Wright brothers believed that the solution to controlled air flight lay hidden in pilot controls, rather than powerful engines. Based on their wind tunnel work, they invented what is now the standard method of all airplane controls, the three-axis control. They also invented efficient wing and propeller designs. It is likely that many in the scientific community in the beginning of the twentieth century would have considered aeronautics similar to the way the scientific community in the early part of the twenty-first century considers time travel—still something outside the fold of legitimate science. However, on December 17, 1903, at a small, remote airfield in Kitty Hawk, North Carolina, the two brothers made the first controlled, powered, and sustained heavier-than-air human flight. They invented the airplane. It was, of course, humankind’s first step into the heavens.

I believe the invention of the airplane is a good analogy to where we are regarding time travel. We have some examples, namely, time dilation data, and a theoretical basis that suggests time travel is potentially real. However, we have not reached the “Kitty Hawk” moment. If Dr. Mallett makes his time machine work, and that is a big “if,” numerous physicists will provide the theoretical foundation for its success, essentially erasing any errors that Dr. Mallett may have made in his calculations. He will walk as another great into the history of scientific achievement.

My point is a simple one. The line between scientific genius and scientific “crank” is a fine one. When Einstein initially introduced his special theory of relativity in 1905, he was either criticized or ignored. Few in the scientific community appreciated and understood Einstein’s special theory of relativity in 1905. It took about fifteen years for the scientific community to begin to accept it. Einstein was aware of the atmosphere that surrounded him. In 1919, he stated in the Times of London, “By an application of the theory of relativity to the taste of readers, today in Germany I am called a German man of science, and in England I am represented as a Swiss Jew. If I come to be represented as a bête noire, the descriptions will be reversed, and I shall become a Swiss Jew for the Germans and a German man of science for the English!”

Dr. Mallett is on record predicting a breakthrough in backward time travel within a decade. Only time and experimental evidence will prove if his prediction becomes reality. Even if the Mallett time machine works, it would still represent only a baby step. We would still be a long way from human time travel, but we would be one step closer.

Source: How to Time Travel (2013), Louis A. Del Monte

science of time & time dilation

Are There Any Real Time Machines? Part 1/2

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There are no existing time machines capable of sending humans forward or backward in time. The closest we have come to time travel is using particle accelerators to cause subatomic particles to experience time dilation (i.e., forward time travel). There is a significant amount of time dilation data available. Particle accelerators succeed in achieving time dilation by accelerating subatomic particles close to the speed of light. Unfortunately, though, backward time travel has no similar body of experimental data. The major problems with creating backward time travel appear to fall into three categories:

  1. Backward time travel appears to require negative energy, based on arguments made by American theoretical physicist Kip Thorne and British theoretical physicist/cosmologist Stephen Hawking. Many in the scientific community acknowledge that negative energy likely exists, and point to the Casimir effect, discussed previously, as an example in nature. However, today’s science is unable to harness negative energy in any meaningful way to make a time machine.
  2. Many in the scientific community, like physicists Dr. Olum and Dr. Everett, believe the amount of energy required to twist space sufficiently for spacetime manipulation and enable Dr. Mallett’s time machine to work is enormous. Conceptually, we may be talking about the amount of energy provided by a star, similar to our own sun. Harnessing this level of energy is far beyond today’s science. Science’s best efforts to study high-energy physics has to date been confined to particle accelerators, such as the Large Hadron Collider. There is no experimental evidence that Dr. Mallett has succeeded in manipulating spacetime.
  3. Many in the scientific community are concerned with causality violations, especially regarding backward time travel. However, as we learned in the section titled “Twisting the arrow of time,” there can also be causality violations regarding forward time travel. The causality violations are generally termed “time travel paradoxes,” which we will discuss in detail in the next chapter.

Having made the above points, I think it is important to point out that some physicists believe subatomic antimatter particles travel in the opposite direction in time (i.e., backward in time) versus their matter counterparts. For example, some physicists assert that positrons, the antimatter equivalent of electrons, travel backward in time, while electrons travel forward in time. In solid-state physics, if we consider a current flowing in a semiconductor, electrons in a semiconductor move as a current in one direction, while the “holes” (i.e., the position the electron occupied in the semiconductor, which becomes vacant when the electron moves as a current) move in the opposite direction. Physicists differ on whether the “holes” represent positrons (i.e., actual physical antimatter particles). I mention this for completeness. There is no scientific consensus that antimatter travels backward in time.

Where does this leave us? I think this question deserves a complete answer. Stay tuned for part 2.

Source: How to Time Travel (2013), Louis A. Del Monte

Multiple overlapping clock faces with various times, creating a surreal and abstract time concept in blue tones.

Do Time Travel Paradoxes Negate the Possibility of Time Travel?

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Do time travel paradoxes spell doom to time travel? The short answer is no. Many in the scientific community do not think time travel paradoxes present an insurmountable barrier to time travel. Many physicists have suggested solutions to time travel paradoxes. In fact, discussing them all would result in a book. I will discuss the major ones. For the sake of convenience, I have divided them into four categories:

  1. Multiverse hypothesis—The multiverse hypothesis argues that time travel paradoxes are real, but they lead to alternate realities. The most famous theory in this category is American physicist Hugh Everett’s many-worlds interpretation (MWI) of quantum mechanics. According to Everett (1930–1982), certain observations in reality are not predictable absolutely by quantum mechanics. Instead, there is a range of possible observations associated with physical phenomena, and each is associated with a different probability. Everett’s interpretation is that each possible observation corresponds to a different universe, hence the name “many-worlds.”  Let us consider a simple example. If you toss a coin in the air, it can come down heads or tails. The probability of getting heads is equal to the probability of getting tails. If you toss the coin, and it comes down heads, then there is another you, in another universe, who observes tails. This sounds like science fiction. However, according to a poll published in The Physics of Immortality (1994), 58% of scientists believe the many-world interpretation of quantum mechanics is true, 13% are on the fence (undecided), 11% have no opinion, and 18% do not believe it. Among the believers are Nobel laureates Murray Gell-Mann and Richard Feynman, and world-famous physicist/cosmologist Stephen Hawking. In our everyday reality, many of us would reject the many-world interpretation of quantum mechanics because we do not experience it directly. However, let me point out, we do not experience the individual atoms of a book when we hold it. Yet, we know from sophisticated experimental analysis that the book is a collection of atoms. Unfortunately, in the strange world of quantum mechanics, our intuition and experience rarely serve us. I leave it to you to formulate your own conclusions.
  2. Timeline-protection hypothesis—The timeline-protection hypothesis asserts that it is impossible to create a time travel paradox. For example, if you travel back in time and attempt to prevent your grandfather from meeting your grandmother, you fail every time. If you attempt to shoot yourself through a wormhole, the gun jams, or something else happens, which prevents you from changing the past. Several other paradox resolutions fit under this category. They are:
    • The Novikov self-consistency principle, suggested by Russian physicist Igor Dmitriyevich Novikov in the mid-1980s, which asserts anything a time traveler does remains consistent with history. For example, if you travel to the past and attempt to keep your grandfather from meeting your grandmother, something interferes with any attempt you make, causing you to fail in the attempt. In other words, the time traveler is unable to change history.
    • The self-healing hypothesis theory, which states that whatever a time traveler does to alter the present by traveling to the past sets off another set of events to cause the present to remain unchanged. For example, if you attempt to prevent Abraham Lincoln’s assassination, you may succeed in preventing John Wilkes Booth from carrying out the assassination only to find someone else assassinated Lincoln. In essence, time heals itself.
  3. Timeline-corruption hypothesis—The timeline-corruption hypothesis suggests that time paradoxes are inevitable and unavoidable. Any time travel to the past creates minute effects that inevitably alter the timeline and cause the future to change. For example, if you inadvertently step on an ant in the past, it changes the future. Popular science fiction literature calls this the “butterfly effect,” namely, that the flutter of a butterfly’s wings in Africa can cause a hurricane in North America. Under this theory, anything you do will have a consequence. It may be small and benign. Alternatively, it may be large and disastrous. The destruction-resolution hypothesis fits in this category. It holds that anything a time traveler does resulting in a paradox destroys the timeline, and even the universe. Obviously, if the destruction-resolution hypothesis is true, any time travel would be disastrous. However, I doubt the validity of the destruction-resolution hypothesis, since we are able to perform time dilation (i.e., forward time travel) experiments with subatomic particles using particle accelerators.
  4. Choice timeline hypothesis—The choice timeline hypothesis holds that if you choose to travel in time, it is predestined, and history instantly changes. This implies you can time travel to the future and leave an item there that you will need sometime in the future. It will be there for you when the future becomes the present. For example, assume you are in New York City, and someone is about to assault you. You have no escape or means of protection. According to the choice timeline hypothesis, you can use your time machine to travel to the future. You hide a gun near the place where the assault is about to occur. When the assault occurs, you retrieve the hidden gun and scare off the attacker.

There are numerous other time-paradox resolution hypotheses. Most fall under one of the above categories, or are not as popular as the above. I left them out in the interest of clarity and brevity. The four categories above give us a reasonable framework to understand the major time-paradox resolution theories, and the current thinking regarding their impact on the timeline.

The majority of the scientific community does not think time paradoxes inhibit time travel. For example, Kip Thorne, an American theoretical physicist and professor of theoretical physics at the California Institute of Technology until 2009, argues that time paradoxes are imprecise thought experiments which can be resolved by numerous consistent solutions. The scientific consensus appears to be that time paradoxes may or may not occur, but they do not exclude the possibility of time travel. This position appears validated by the time dilation (i.e., forward time travel) experiments routinely performed using particle accelerators.

This post is based on my book, How to Time Travel (2013)