Dimensions and Time Travel
27 Apr 2025home > blogs
Dimensions
Let’s go back to the basics.
One dimension - A Line. Imagine an ant in a thread. That ant can move only forward or backward. One directional movement only.
Two dimensions - A Square. Imagine a ladybug on a sheet of paper. That ladybug can move forward or backward, left or right, or any combination of these movements. Two directional movements.
Three dimensions - A Cube. Imagine a fly trapped inside a cubical box made of glass. That fly can move forward or backward, left or right, up or down, or any combination of these movements. Three directional movements.
Fourth dimension - Is there one?
Our human brain can comprehend only three dimensions. We can deduce or extrapolate with mathematics and physics, but we will never be able to perceive and believe it. Try explaining a rainbow to your cat or dog; they simply don’t have the color receptors to understand the multitude of colors you can experience.
Everything you perceive in this universe is three-dimensional, spatially.
But everyone talks about time being the fourth dimension, Albert Einstein’s space-time fabric concept explaining the relativity theory, Christopher Nolan’s Interstellar movie, where time is constructed as a spatial dimension and so on.
The first 3 dimensions are spatial. We cannot comprehend any more spatial dimensions. But, that’s not enough for science enthusiasts. What else can they add to these dimensions?.
Oh wait, there is time.
Let’s add time as the fourth dimension. But, how would you explain it?. Instead of the movements to explain the dimensions, let’s use the example of meeting someone in a specific place and time. That means we need to have three dimensions to locate the person in space and one extra dimension “time” to meet the person at the agreed time. All is well.
When visualized this way, I actually get confused. It contradicts two properties of spatial dimensions (there are more, I am using these 2 for simple explanations).
- The current dimension is an continuous stacking of previous dimensions. (i.e) A cube is an continuous stacking of squares. A square is an continuous stacking of lines.
- The individual dimension cannot perceive the higher dimensions. (i.e) If you stack continuous square papers on top of each other, each square is still two-dimensional in properties, only the collection of them would appear three-dimensional, a cube.
Time as a fourth dimension, contradicts both of these properties.
- Time is not an continuous stacking of any of the three dimensions. It’s not spatial. It’s temporal.
- Time is perceived in all three dimensions.
Thus, I would like to perceive time as not a fourth dimension, but a concept to measure the duration between two events, across all the dimensions. Let’s change the visualization to this.
So far with me?
Time is not a dimension. It’s a measure of the duration between events.
Time Travel
In simple terms, time travel is going back in time.
- To explain time travel, let’s establish some constructs,
- The Big Bang was the beginning of the universe.
- Heat Death is the end of the universe.
- Time is the duration between the beginning and the end
- Let’s divide the time into 1000 slices for simple imagination/calculation
- Let’s assume we are in slice 10.
- Time moves forward with no effort. (i.e) it automatically moves from slice 10 to slice 11 and so on.
When we intend to travel back in time, we are essentially saying, let’s move the universe from slice 10 to slice 9. (i.e.) every single atom, subatomic particle, and dark matter should be moved in space (3 dimensions) to its previous state - Slice 9.
Time travel is a re-arrangement of everything in the universe to its previous state.
Some Thoughts
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How much energy would be needed to move everything in the universe?. It must be bigger than all of the energy available in the universe.
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Since the attempt to re-arrange the whole universe is happening within the universe itself, would it ever go back to its earlier state?. The attempt must involve some tools and technologies which must vanish moments before the universe goes back to its previous state.
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On the other hand, what if, we could re-arrange the universe from outside the universe?. That would be wonderful, but that would destroy our whole understanding of the current universe and would require new physics to explain the boundaries of the universe and what’s beyond that.
Given these questions,
Do you think time travel is possible?
No. No. No. That’s not how the novels and movies told us about time travel.
I’m talking about me, being able to go back in time and kill my grandfather and see what happens?.
You know, that’s the kind of time travel I am interested in.
I get it now.
Localized Time Travel
By the new definition of time travel - we mean that a human being with his/her body, clothes, knowledge about current events, and any other objects he/she holds or he/she is in (like a car) to be transported back in time.
In simple terms, the whole universe is moving forward in time, we want to send a human being back in time (i.e.) send a collection of molecules with life, back in time. Let’s call it localized time travel.
Thought 1
If we want to send a person from point A to point B, we can safely assume that both point A and point B exist. That’s a prerequisite.
Let’s say, I want to go from San Francisco in 2025 to San Francisco in 1925. To move me from San Francisco in 2025 to San Francisco in 1925, both versions of San Francisco must exist simultaneously.
What if I want to go to New York?. So, two versions of New York must exist. What if I want to go to Tokyo in 1900. So, another version of Tokyo must exist. What if I want to go to Mars, or Kepler, or some faraway black hole? You see, the places could be infinite.
For this to happen, the very first slice of time, the universe splits into two. The first one stays in the first time slice and the second one moves on with time. At the end of the second slice, universe splits into two again, creating a total of 3 universes. It must continue to split till the last slice of time. If we narrow the “slice of time” from “billions of years” to seconds or even narrower time period, we would have more copies of universes than the no.of atoms in each of them. That’s an unfathomably large number of universes.
There will be one copy of universes for each state change in the universe (i.e.) one electron moved a bit in one atom in the entire universe. This action of creating a copy of an universe would break all the existing laws of physics. And each copy of the universe has a real mass that occupies real space. So, we need infinite space to store the infinite copies of the universe.
Every place in this universe at every slice of time must exist simultaneously. (i.e.) the past, the present, and the future - all must exist simultaneously.
Thought 2
Let’s assume that such infinite copies of the universe exist in an infinite space simultaneously and we can travel to any point in the past or the future.
How would we go?.
Our physical body has real mass. The maximum speed in the universe is capped at the speed of light. Even if we know exactly, where is San Francisco in 1925, we would have to transport this body through multiple universes to reach San Francisco in 1925. How long do you think it would take, even if you are traveling at a theoretically impossible speed of light?. Billions/Trillions of years?. That would be the most boring travel of our entire humanity.
Wait, what about warmholes - a theoretical tunnel in space that connects two distant points in space.
Of course, let’s include warmholes. Remember, we are not restricting the time travel to a specific place or time. I should be able to transport this human body to any point in space at a specific time. That means every single point in space should be connected to every other point in space.
Time here, is not a measure of duration between two events. We represent all of these durations / slice of time, as an individual 3 dimensional universe. (Close to Interstellar’s idea, but at a cosmic scale)
Infinite warmholes connecting infinite points in space in infinite universes
I can’t help but think that it would be nothing more than a dot occupying no space where nothing exists. (Ignore this statement, if you don’t comprehend it’s meaning)
We didn’t even discuss how to send a human back in time. We are simply discussing the prerequisites for localized time travel.
Given these prerequisites for time travel,
Do you think time travel is possible?
When the pre-requisites are setup, time travel to the past and the future could be simply walking through a portal or a door. Or as it was portrayed in Christopher Nolan’s Interstellar.
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