In an earlier excerpt, we discussed the concept of space-time continuum or fabric, namely that it is a 4-dimensional fabric defined by 3 spatial dimensions (X, Y, Z) and the time (T) dimension. We will not delve into the question again - you can read the March 17 post, Fabric and the inner cloak of the universe should you be interested - but we realize that the concept of a 4-dimensional universe, with Time being the fourth dimension, may be an abstract notion.
Einstein’s general relativity proposes, and the proposals have been scientifically validated, that Time is also relative and the clock ‘ticks’ differently depending on where one is measuring it. This notion of Time as a dimension, has given rise to many implications in Science-Fiction, where writers have found seemingly scientific possibilities for time travel, i.e., we can move along the Time dimension, without any changes to the 3 spatial dimensions, which then will allow us to return to the past, or the future at that spot.
One of Charlene’s students recently asked her if she has a simple way to explain how operating in this 4th dimension could allow for fast travels. For the lack of a better conceptual framework, Charlene downgraded the question by one dimension, and answered the question through 3 dimensions, which we will present below.
- Take our standard 3-dimensional world, and imagine a 2-dimensional creature that can only operate in left and right, the plane. It does realize that there is something else, maybe a 3rd dimension, because it feels the rain drops, but it cannot see, nor move in the vertical direction.
- Now imagine this creature walking along in a supermarket’s parking lot and encountering one of those concrete ledges/slabs that block the cars from crossing over to the forward slot during the parking manoeuvre.
- When it reaches this slab, the 2-dimensional creature cannot continue straight, nor can it climb over the slab, for it can only conceive and operate in right and left.
- Consequently, for it to continue its path, it has to deviate, turn right or left, and walk along the slab until the end of its length, and then turn left or right to continue going forward. By then, it has spent much time and energy to overcome the little bump that is the 10cm high slab.
- A 3-dimensional creature, however, depending on its size and perspective, can either jump, or walk or crawl over the hurdle and proceed straight ahead, thus saving much time and effort. But, the necessary condition would be that the creatures be able to operate in this third dimension.
Returning to our departing question, we can extrapolate this 2-D living in a 3-D world to a 3-D living in a 4-D universe, and assume that if we develop the methods and the technology to jump over the hurdle we could accomplish the feat of time travel or near-instantaneous long-distant journeys.
We have thus, once again, stumbled upon premises of a fictional science emanating from a real science.
May 5, 2023, Cambridge,
Berta Seintan, PhD & Charlene Wardin, PhD