# Relativity in Real Life

I have no formal training at all in relativity. But I was just wondering if our perception of time is altered by different events. Here are some examples I had in mind:

• If I touch a stove for 10 seconds versus enjoying chocolate for 10 seconds would I experience a time distortion? An observer who records the 10 seconds would have an objective sense of time.

• If I ran "very quicky" for 10 minutes would I experience a "slowing down" of time since I am exerting more effort?

Do these examples have nothing to do with relativity? In "real relativity" do things actually slow down when we approach the speed of light? For example, if I was going near the speed of light would I notice the hand on my watch go by slower?

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Relativity even if observable, can not be felt in low speeds. You should get to the speed of light. – Saeed Neamati Jul 18 '11 at 12:48
I think it is worth having let this run for a while because the confusions here ("time changes in relativity" versus "time flies when you're having fun") is common enough, but eventually I think we should ask "Is this about physics?". Opinions from the crowd on keep it or kill it are welcome. – dmckee Jul 18 '11 at 16:25
@dmckee: Although I agree that the question is not about physics, it is about a subject that is often confused with physics. At least, I had a similar question asked of me once, with the asker also thinking that it is a physics question. On that basis I suggest an answer of "This question is not physics even though it appears so to the layman" and close it at that. Other similar questions that will surely pop up can then be duped to this one. – dotancohen Mar 2 '12 at 9:05

Relativity has nothing to do with how things "feel". Time dilation, for example, is not a manifestation of the fact that it's more enjoyable to eat chocolate than to touch a stove. The results of the theory of relativity refer to measurements made by observers with absolutely no... feelings. They describe the fundamental reality of physical processes, a reality that is revealed by measurements of time intervals and distances, among other observables.

For the second part of your question, you wouldn't notice anything out of the ordinary for things that you don't move with respect to. It's only when you observe phenomena that happen in reference frames in motion with respect to you that things start looking weird. For example, something that you know has a length of 1 m when it's sitting next to you, might suddenly appear to be shorter if it's flying by you.

As for moving close to the speed of light, it will certainly make your clocks tick slower, but only as observed by an observer, call him Scott, who you're moving with respect to. You, looking at your clock (which is not moving with respect to you), would see no difference in the way it ticks before and after you started moving. However, if you look at Scott's clock, that would seem to be running slower than yours, simply because, from your perspective, Scott is moving with respect to you. According to you, Scott's clock is running slower, and, according to Scott, your clock is running slower. Furthermore, in your respective reference frames, you are both right. That's the essence of the theory of relativity.

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S: Then why is it that when I run....my clock seems to run slower. It is attached to my wrist. – Shawn J Jul 18 '11 at 5:20
@ Shawn J - this is because you have a variable subjective sense of time. It's a neurological/psychological thing and has zilch to do with relativity. – Richard Terrett Jul 18 '11 at 5:37
@ShawnJ: Besides, even if you are running at 0.99 at the speed of light along with your watch, you will see the time as going normall because relative to yyou, the watch is stationary. Only to an observer who is stationary with respect to you, the watch will go slower. – centralcharge Jul 3 '13 at 13:36

Relativity can be a bit of a daunting 'brain-breaker' when you're new to it, but in the simplest terms, you don't feel the effects of The Special Theory of Relativity at all - there's nothing to feel; in a way, that's kind of the point, but it's also why it can be hard to understand.

In your first example, you may experience time at different speeds between pain and pleasure, and indeed feel the difference in time, but it has nothing to do with relativity. In this instance, it's about your own perceptions. I've heard it postulated that adrenaline 'speeds up' the mind (temporarily), so you may experience more 'stuff' in the same amount of time than without the adrenaline (the theory goes that it's to help us make decisions quicker when we are in danger).

As an analogy, think of your brain as having its own clock ticking away inside that lets you know how much time has passed. When the adrenaline is released the brain clock speeds up, and after a minute, your brain clock may have ticked 90 times, whereas your watch will only have ticked 60 times - time seems to have slowed down for you.

You may probably have experienced this in a way that you've noticed before - the second time you watch a movie, some of the action scenes that in your memory felt like they "lasted ages" now seem a lot shorter. This is because the first time around, you didn't know what was going to happen so there was more adrenaline pumping, and your perception of time slowed down because your brain clock was ticking faster - it might have ticked, say, 200 times for the scene. The second time around, you know what's going to happen already, so there's less adrenaline, and your brain clock may tick only 150 times, and so the scene seems shorter.

Obviously, there's isn't REALLY a little clock ticking away inside your brain, but it's a handy way of picturing what's happening with your own perception of time!

But as I say, none of that is to do with relativity at all.

Your second example is trickier to answer as it combines motion with exertion, so I'll break it down.

First of all, physical exertion also releases adrenaline into the blood, so the 'speeded up brain clock' scenario takes effect. So yes, you may experience time running slower than normal. Again, though, nothing to do with relativity.

However, if you could run "very quickly" in physics terms (this means approaching the speed of light), relativity will start to affect you, but not in a way that you might expect.

This time, time really will slow down (nothing to do with adrenaline) because of relativity. Your watch will tick slower, you will appear to shrink, and you can start to experience 'events' at the same time that your friend, who is standing still, would say happened one after the other.

But the key part of this, in relation to your question, is that you won't actually feel any of this, because YOU are affected by it all. To YOU, your watch is still ticking at the right speed. To YOU, you are still the same size.

It will only be when you stop running and look at your friend's watch that you'll notice that time slowed down for you. Your watch might say you went running for 8 minutes, whilst your friend's says you went running for 10.

Now this is the brain-breaking part: Relative to your point of view, you really did only run for 8 minutes. However, relative to your friend's point of view you ran for 10 minutes. BOTH of you are right. In fact, as there is no fixed point in space, you can't even say which of you was moving and which of you was stationary: it's all relative, and that's why they call it the theory of relativity.

(I apologise if reawakeningk a 7 month old question is 'bad form' around here, but I felt that as the question was asked in fairly lay terms, none of the answers, though accurate, were explained in a sufficiently simplistic manner.)

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To my understanding your question seems to be getting at explaining some neurological/psychological phenomenon and seek some possible explanations from Physics. To my knowledge the current research has not come to such a stage ( neither it was intended to, i guess, i don't know much about such things ) where you can attempt to explain neurological/psychological phenomenon from basic laws of Physics such as SR. I hope my answer serves as a compliment to AndyS's.

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This answer is illucid as it seems to suggest that formulating an understanding of psychology from physical first principles would explain perceptual time dilation, and that perceptual time dilation and relativistic time dilation are somehow related - this is simply not the case. Perceptual psychological time dilation can be adequately accounted for by the quickening of consciousness that accompanies a stressor, and is probably evolutionary baggage from the time when our ancestors had to think fast or get eaten. – Richard Terrett Jul 19 '11 at 8:23
I won't give a -1 but this answer seems to suggest that SR really does (!) explain the false believefs in OP's OP question post......-1,-1,-1...+1,+1,+1, because the answer isn't wrong,..., evaluates to 0 because -1-1-1+1+1+1 = 0! - 1 = 0... Ok,! most of my comment goes to 0 in useful ness... – centralcharge Jul 3 '13 at 13:59

You will never "feel" relativistic effects in real life, because the differences are waaay too small.

But here's a few examples of relativity in real life:

Your GPS device, and the satellites it's connecting to, need to apply relativistic corrections to keep their signals in perfect sync and ensure sufficient precision when determining your position. Without those corrections, your GPS device would be less precise.

In a non-relativistic universe, the metal gold would reflect light in a slightly different way, and it would not exhibit its characteristic color. It would look silvery. Its trademark hue is tributary to relativistic effects in the electron cloud in the gold atom.

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Would silver look different in such a universe? – compman Oct 25 '11 at 17:00