What is ‘time’ – exploring the fourth dimension.
To begin, ‘time’ and the fourth dimension are two completely separate ideas, unlike common belief. Before I begin discussing the fourth dimension, I want to clear up what ‘time’ actually is. Time is a subjective measurement created by humans to record, keep track of and plan events occurring in the universe. If another intelligent race exists elsewhere in the universe, chances are they have their own measurement of ‘time’, but their ‘second’ would be completely different to ours. Think of how both the imperial and metric system of measuring distance are both valid ways of doing so, but have very different intervals. But if these measuring systems did not exist, that doesn’t mean that distance would suddenly cease to exist. It is exactly the same with time in relation to the fourth dimension. The fourth dimension is ‘duration’ – i.e. the opportunity for the unfolding of events to occur, and time is simply our way of measuring it..
Almost everybody on the planet has come to believe that we exist in a three-dimensional universe, as that is what we perceive. However, this is not the case – we exist within the extended idea of the fourth dimension. I’m going to break it down and create a step-by-step guide to ‘reaching’ the fourth dimension.
Remember: this description is just a way to help with visualising the dimensions. First, we start at zero; the ‘zeroth’ (or zero) dimension, which is a point of indeterminate size. Now, take two zero-dimensional points and connect them with a line – we have now reached the 1st dimension, length. Now imagine a series of one-dimensional lines bunched together side by side, Planck lengths apart. We are left with a two-dimensional plane. Do the same again but with these two-dimensional planes and we arrive at the third dimension.
Okay so we’ve reached the third dimension. Surely we don’t need to go any higher – we exist in a three-dimensional world, don’t we? Short answer: sort of. As I said earlier, the fourth dimension is the unfolding of events, or ‘duration’. Without this duration, the universe as we know it would not exist. Of course, in the absence of duration, the Big Bang would not have happened as it would not have had the opportunity to. If we, hypothetically, take the universe as it exists now and view it from the third dimension, we would in fact not be able to see anything. Light needs an opportunity, this fourth-dimensional duration, to travel. If it cannot travel, it remains completely static, meaning there would be no way for our eyes to perceive anything. Similarly, all universal bodies, from subatomic particles to galaxies, would still exist but would also, of course, be static; there would be no movement, interaction or development whatsoever. How could there be without duration?
Because the third and fourth dimensions are so connected (space-time), it is imperative to explore how the two interact. Physicist Julian Barber, on the third dimension, suggested: “In my view of the universe, it’s just like a huge collection of snapshots which are immensely, richly structured. They’re not in any communication with each other, they’re worlds unto themselves… In some very deep sense, the universe, a quantum universe, is static. Nothing changes.”
From this analogy, imagine that these ‘snapshots’ are arranged like frames (Planck frames) in a flip-book, all one unit of Planck time away from the next. The fourth dimension is like the hand flipping through the flip-book. It is the tool to move through these frames to create the apparently continuous ‘motion’ of duration – what we perceive as the progression of ‘time’.
Conclusion (TL:DR): The fourth dimension is ‘duration’, i.e. the opportunity for events to unfold. Time is completely unrelated to the fourth dimension – it is simply our way of measuring it, similarly to how miles measure distance.
Check out YouTube user 10thdim‘s series ‘Imagining the Tenth Dimension’ for a great visualisation of all 10 dimensions. Much of his work helped with this post: http://www.youtube.com/user/10thdim?feature=watch.