Can you explain to me how time is regarded as the 4th dimension? Does it mean that if we assume time as a dimension then an object traveling to different time period is possible?

Question

Can you explain to me how time is regarded as the 4th dimension? Does it mean that if we assume time as a dimension then an object traveling to different time period is possible?

In: 1302

Answer 1

Disclaimer: I don’t come from a scientific background, this is just how I visualise things.

Imagine a 1D object as a horizontal line. It has no depth, no height, only width (our one dimension).

To get a 2D object, you have to add height (our second dimension). If you layer a bunch of these 1D horizontal lines one above the other, you get a 2D plane. Visualise it as a piece of paper with no thickness.

So we got from a 1D line to a 2D plane by laying the 1D shapes side-by-side.

Let’s do the same again to get a 3D shape. This time we’re adding depth (our third dimension). Imagine placing all of your 2D pieces of paper on top of each other to form a stack. Now you have a 3D cube!

Great! So every time we’ve layered our shapes side by side to add in another dimension. But how can we possibly do this with 3D shapes to get a 4D object? If you place lots of 3D cubes next to each other you just get one really long rectangular 3D shape!

The trick is, we need to break out of our current dimension. Adding more cubes to the 3D cube would be like adding more length on to the end of the 1D line to get a longer 1D line, or adding more height to the 2D plane to get a longer (but still flat) 2D plane.

Here’s where time comes in. It’s the next dimension. Imagine our cube passing through time; it exists at each second, one after another. Kind of like an old-fashioned movie where still images are played next to each other really fast to create the illusion of a single, moving object, when really it’s lots of individual images side-by-side. To get a 4D object we need to place these 3D cubes side-by-side through time, with one 3D cube at each point in time to create a single 4D object stretched through time. The cube can change over time; you could squish it and stretch it, and it would appear to be a single 4D object that’s getting pulled about, rather than a succession of 3D objects that are a slightly different shape to the one before and the one after.