DarkRange55
Where in the world is John Galt? 🥞
- Oct 15, 2023
- 2,234
Time is, in many ways, an ambiguous concept. It is tempting to think of time as a kind of illusion. For example, if all motion were stopped and everything made completely static, time would appear to freeze, and the configuration you created would seem eternal. Appear is the key word. In reality, this is not the case.
Certain processes such as radioactive decay, quantum tunneling, and other quantum effects cannot be stopped. These processes would continue to occur and would still mark the passage of time. Even the hypothetical decay of the proton, if it occurs in the far future of the universe, would happen as a function of time.
Time is therefore more than just a clock ticking. It is the governing factor of entropy, and it has strange properties. One of these is that the rate at which time passes depends on acceleration. If you travel at extremely high velocity, time dilates relative to your surroundings. To you, time would appear to pass normally, but to observers watching from outside your frame, it would appear to pass much more slowly.
The same effect occurs near massive gravitational sources, because gravity itself is a form of acceleration—specifically, acceleration toward the center of a mass. This means that time passes more slowly closer to massive objects than it does farther away.
Time has also long been associated with the possibility of time travel, a staple of science fiction. Traveling into the future is allowed and is already happening through the normal passage of time. The rate at which you move into the future can be altered through acceleration or gravity. This idea was famously depicted in Interstellar, where a ship landing on a planet near a black hole experiences time passing far more slowly than it does for observers aboard the mother ship.
As an aside, Interstellar was in some ways a missed opportunity. The original concept involved physicist Kip Thorne and was intended to adhere strictly to known physics. In many respects it succeeded, particularly in its depiction of the black hole Gargantua, which remains one of the most accurate visual representations ever shown on screen. In reality, however, there would be an overall brightening on one side of such a black hole that was not depicted.
The planets in the film were far less realistic. While Earth, the final planet discovered, and the O'Neill cylinder habitat were relatively innocuous, the floating ice planet was pure fantasy, as was the extreme time-dilating ocean planet. The tidal forces required to produce those waves would instead pull an ocean into a large oblate bulge, and for such extreme time dilation to occur, the planet would need to be hovering extremely close to a black hole of Gargantua's size.
Returning to the nature of time itself, Interstellar did correctly portray the basic idea of time dilation. What science fiction almost never gets right is backward time travel. If it is depicted, it is almost certainly wrong, because everything we currently understand suggests the universe forbids it.
The only theoretical way to achieve backward time travel would be through faster-than-light motion. This applies across all faster-than-light concepts. If an object could exceed the speed of light through acceleration—which appears impossible—time would move backward relative to the outside universe. Similarly, if one could construct a warp drive or a traversable wormhole, it would also function as a backward time machine.
All of this raises a fundamental question: is time something real, or is it an illusion? Everything we currently know suggests that time is indeed a real physical aspect of the universe. The same appears to be true of space itself. Space behaves like a physical entity—it stretches and expands—yet it is neither an object nor true nothingness. Because of this deep connection, Einstein and others referred to the combined structure as spacetime.
This has led some theories, particularly string theory, to treat time as a dimension. Our universe is often described as having four dimensions: three of space and one of time. Time behaves like a dimension in many respects. We move through it, and it has a direction—forward—commonly called the arrow of time.
Physicists have long struggled to explain why the arrow of time points only forward. Nothing in the fundamental laws appears to forbid it from pointing backward, yet it never does. Some recent work in quantum mechanics suggests that this directionality may be a quantum effect, implying that time truly exists rather than being an illusion.
However, this interpretation may still be wrong. New research has revived an older idea that was largely abandoned in the 1980s. According to this view, time may not be a fundamental component of reality at all. Instead, it may emerge from quantum effects, specifically quantum entanglement.
Quantum entanglement occurs when two particles become linked such that the state of one instantly determines the state of the other, regardless of the distance between them—even across the observable universe. What connects them, or through what medium this connection exists, remains unknown. We only know the effect is real because it can be created and observed experimentally. Although this instantaneous correlation might seem like a way to transmit information faster than light, it does not allow meaningful information transfer. Once again, the universe appears to prohibit such violations.
The question then becomes: what role does the quantum world play in the nature of time itself? In general relativity, time is woven into the fabric of the universe and can warp and dilate. In quantum theory, time is treated very differently. It is considered fixed and external, unlike other properties of quantum objects that can change. To measure time in quantum mechanics, one must use an external clock.
This means that time is fundamentally treated as two different things in general relativity and quantum theory. Many physicists believe this discrepancy should not be ignored, because both theories describe the same universe. There is clearly a missing piece connecting them, and that missing piece may be key to understanding time.
Fairly recent work by Coppo and colleagues revisits an older idea by proposing that time arises because systems are entangled with something that functions as a clock. This clock does not need to be a mechanical device; it only needs to act as a reference system. If an observer were outside the entangled system, nothing would appear to change. In this sense, time is an effect of entanglement.
In their model, the clock consists of a system of tiny magnets entangled with a quantum oscillator. This type of system is well understood and could potentially be tested experimentally. The system is described using Schrödinger's equation, with the addition of a variable representing time as encoded in the quantum states of the magnets.
The researchers then repeated the analysis under the assumption that the oscillator and magnets were large enough that quantum effects were effectively lost in noise, similar to how the macroscopic world behaves. Remarkably, the resulting equations matched those used to describe classical motion, such as a rolling billiard ball, even though the system was still fundamentally governed by quantum mechanics.
If confirmed experimentally, this result would help explain how time emerges consistently across both quantum and classical scales. It would also show that quantum entanglement has a profound influence on the classical universe, offering a new approach to bridging the gap between general relativity and quantum theory.
In this framework, if we perceive the passage of time, it implies that our world is entangled with something else. In a universe with no entanglement, time would not pass at all. Everything would remain static. Some theories even suggest that the early universe may not have been entangled initially, which could explain why it appears to have had a beginning. Before entanglement arose, nothing would have happened.
Testing this idea remains challenging. Many aspects are still poorly understood, including how quantum clocks become entangled and whether separate entangled systems can interact. Nonetheless, the researchers argue that the idea is testable in principle. If successful, it could open the door to an even larger breakthrough: a testable quantum theory of gravity.
Research paper:
I will post a part 2 if anyone has any interest…
Certain processes such as radioactive decay, quantum tunneling, and other quantum effects cannot be stopped. These processes would continue to occur and would still mark the passage of time. Even the hypothetical decay of the proton, if it occurs in the far future of the universe, would happen as a function of time.
Time is therefore more than just a clock ticking. It is the governing factor of entropy, and it has strange properties. One of these is that the rate at which time passes depends on acceleration. If you travel at extremely high velocity, time dilates relative to your surroundings. To you, time would appear to pass normally, but to observers watching from outside your frame, it would appear to pass much more slowly.
The same effect occurs near massive gravitational sources, because gravity itself is a form of acceleration—specifically, acceleration toward the center of a mass. This means that time passes more slowly closer to massive objects than it does farther away.
Time has also long been associated with the possibility of time travel, a staple of science fiction. Traveling into the future is allowed and is already happening through the normal passage of time. The rate at which you move into the future can be altered through acceleration or gravity. This idea was famously depicted in Interstellar, where a ship landing on a planet near a black hole experiences time passing far more slowly than it does for observers aboard the mother ship.
As an aside, Interstellar was in some ways a missed opportunity. The original concept involved physicist Kip Thorne and was intended to adhere strictly to known physics. In many respects it succeeded, particularly in its depiction of the black hole Gargantua, which remains one of the most accurate visual representations ever shown on screen. In reality, however, there would be an overall brightening on one side of such a black hole that was not depicted.
The planets in the film were far less realistic. While Earth, the final planet discovered, and the O'Neill cylinder habitat were relatively innocuous, the floating ice planet was pure fantasy, as was the extreme time-dilating ocean planet. The tidal forces required to produce those waves would instead pull an ocean into a large oblate bulge, and for such extreme time dilation to occur, the planet would need to be hovering extremely close to a black hole of Gargantua's size.
Returning to the nature of time itself, Interstellar did correctly portray the basic idea of time dilation. What science fiction almost never gets right is backward time travel. If it is depicted, it is almost certainly wrong, because everything we currently understand suggests the universe forbids it.
The only theoretical way to achieve backward time travel would be through faster-than-light motion. This applies across all faster-than-light concepts. If an object could exceed the speed of light through acceleration—which appears impossible—time would move backward relative to the outside universe. Similarly, if one could construct a warp drive or a traversable wormhole, it would also function as a backward time machine.
All of this raises a fundamental question: is time something real, or is it an illusion? Everything we currently know suggests that time is indeed a real physical aspect of the universe. The same appears to be true of space itself. Space behaves like a physical entity—it stretches and expands—yet it is neither an object nor true nothingness. Because of this deep connection, Einstein and others referred to the combined structure as spacetime.
This has led some theories, particularly string theory, to treat time as a dimension. Our universe is often described as having four dimensions: three of space and one of time. Time behaves like a dimension in many respects. We move through it, and it has a direction—forward—commonly called the arrow of time.
Physicists have long struggled to explain why the arrow of time points only forward. Nothing in the fundamental laws appears to forbid it from pointing backward, yet it never does. Some recent work in quantum mechanics suggests that this directionality may be a quantum effect, implying that time truly exists rather than being an illusion.
However, this interpretation may still be wrong. New research has revived an older idea that was largely abandoned in the 1980s. According to this view, time may not be a fundamental component of reality at all. Instead, it may emerge from quantum effects, specifically quantum entanglement.
Quantum entanglement occurs when two particles become linked such that the state of one instantly determines the state of the other, regardless of the distance between them—even across the observable universe. What connects them, or through what medium this connection exists, remains unknown. We only know the effect is real because it can be created and observed experimentally. Although this instantaneous correlation might seem like a way to transmit information faster than light, it does not allow meaningful information transfer. Once again, the universe appears to prohibit such violations.
The question then becomes: what role does the quantum world play in the nature of time itself? In general relativity, time is woven into the fabric of the universe and can warp and dilate. In quantum theory, time is treated very differently. It is considered fixed and external, unlike other properties of quantum objects that can change. To measure time in quantum mechanics, one must use an external clock.
This means that time is fundamentally treated as two different things in general relativity and quantum theory. Many physicists believe this discrepancy should not be ignored, because both theories describe the same universe. There is clearly a missing piece connecting them, and that missing piece may be key to understanding time.
Fairly recent work by Coppo and colleagues revisits an older idea by proposing that time arises because systems are entangled with something that functions as a clock. This clock does not need to be a mechanical device; it only needs to act as a reference system. If an observer were outside the entangled system, nothing would appear to change. In this sense, time is an effect of entanglement.
In their model, the clock consists of a system of tiny magnets entangled with a quantum oscillator. This type of system is well understood and could potentially be tested experimentally. The system is described using Schrödinger's equation, with the addition of a variable representing time as encoded in the quantum states of the magnets.
The researchers then repeated the analysis under the assumption that the oscillator and magnets were large enough that quantum effects were effectively lost in noise, similar to how the macroscopic world behaves. Remarkably, the resulting equations matched those used to describe classical motion, such as a rolling billiard ball, even though the system was still fundamentally governed by quantum mechanics.
If confirmed experimentally, this result would help explain how time emerges consistently across both quantum and classical scales. It would also show that quantum entanglement has a profound influence on the classical universe, offering a new approach to bridging the gap between general relativity and quantum theory.
In this framework, if we perceive the passage of time, it implies that our world is entangled with something else. In a universe with no entanglement, time would not pass at all. Everything would remain static. Some theories even suggest that the early universe may not have been entangled initially, which could explain why it appears to have had a beginning. Before entanglement arose, nothing would have happened.
Testing this idea remains challenging. Many aspects are still poorly understood, including how quantum clocks become entangled and whether separate entangled systems can interact. Nonetheless, the researchers argue that the idea is testable in principle. If successful, it could open the door to an even larger breakthrough: a testable quantum theory of gravity.
Research paper:
I will post a part 2 if anyone has any interest…
