# The “Getting home faster” effect

By Colin Walls

We are told that we live in a 4-dimensional universe – three spacial dimensions and time as the fourth. It seems that people with mathematical brains far superior to mine can do calculations in four dimensions that make sense, so this model must be accurate. But it always seems strange to me how time is the odd one and behaves in ways quite different to the other three …

First off, we can move quite freely in any direction defined by the three spacial dimensions and, within bounds, we can do that at any speed. Time, on the other hand progresses in just one direction [except in Sci Fi, of course] and at a constant rate. It is also possible to reduce spacial dimensions to, say, two – a plane – or one – a line – or none – a point – an it all makes sense. But the absence of time is [for me anyway] inconceivable. You can even (just about) imagine four or more spacial dimensions. Think of a 4-D hypercube that has a volume of x^4; a slice through it would be a 3-D cube (like a slice through a cube is a rectangle). Is our 3-D universe actually a slice through a 4-D one, which, in turn, is a slice through a 5-D one and so on?

I begin to wonder whether the human perception of time is actually fundamental to its nature. We all know that time seems to progress at different rates under different circumstances. As one gets older, time seems to go by faster. A recent theory is that time goes slower as you have more surprises in life. Older people often have more ordered lives, so time marches quicker.

I have noticed an odd thing (and I am not alone in this observation) about moving through spacetime. Imagine you are driving to a nearby city. The journey will take a specific period of time and this will be much the same tomorrow as it was today, assuming you drive at about the same speed and traffic and weather are the same. The return journey takes about the same time as the outbound trip. But is does not feel that way.

Traveling somewhere for the first time takes a specific period of time and that probably feels about right; the GPS said it would be an hour and you know what 60 minutes driving feels like. The drive home again almost always feels faster. Likewise, making the journey again the next day will feel faster. Is that just because you have some familiarity with the route and, hence, have an idea what is coming up next? I am not sure why that would make it feel faster. It is almost like your journey through spacetime is being lubricated or aided in some way.

So, here is my thought: Maybe, as we move through a vector in spacetime, we plow out a 4-dimensional “groove”. The path for the return journey or a subsequent repeated journey is then eased by having this channel carved out. Since everything about quantum mechanics seems very unlikely and unintuitive, what is to say that this is not a kind of personal quantum-mechanical mechanism that ties the individual to the specific vector.

There is a further step that might give some validity to this idea. Perception is everything. So, what if someone perceives that they make a trip – i.e. they go on a simulated journey using virtual reality technology. Would doing the actual journey then seem faster.

[BTW, this week I am in California – the home off the off-the-wall idea. Maybe it is rubbing off on me …]

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This article first appeared on the Siemens Digital Industries Software blog at https://blogs.sw.siemens.com/embedded-software/2019/10/10/the-getting-home-faster-effect/