# Relationship between speed and time

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### #1 D3nt

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Posted 07 March 2006 - 07:02 PM

Perhaps someone can help me with understanding this; my high school physics class fell far short of what I expected.

As you approach the speed of light, time slows. Understanding the concept that time is relative to the observer is easy. What I don't understand is why time slows the faster you go. The articles on time dilation I was able to find on the internet were of little help, and so I've been forced to contemplate the "how" of it just as I was with the notion that time is relative (As mentioned before, my physics teacher did a fairly poor job). Through my thoughts, I could come to only one conclusion. I will set it out, as best I can, to see if I my idea matches the actual "why".

In my approach, I've focused on the human brain, whose electric synapses, I assume, fire and send information at the speed of light throughout the brain. To my way of thinking, as one approaches the speed of light, going about 292,000 km/s, then the electrical impulse is not moving the nanometer through the brain, but through 292,000km + the nanometer. This would delay the effects initiated by the cause, ie - the thought to raise my hand would take that little bit longer to go into action, and therefore, my entire perception of time would slow.

Is this anywhere close to why time actually slows with the increase in speed? If not, could you please remedy my misconception?

Dent

### #2 arkain101

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Posted 07 March 2006 - 08:51 PM

It was a mathamatically requirment for time to become flexible for the equations to work.

It is assumed that the speed at which electromagnetic energy (which is light) will always travel the same speed relative to the observer. This means that he who travels fast will always get the same results when measuring the speed of light (which can be done with a lazer).

Now obviously in order for light to remain the same speed (distance/time) when an observer increases his speed in reference to a rest point like earth, the observer who is moving will have to have his time slow down as he speeds up to keep light traveling at the same distance/time as he sees it. See if light cant change in V of distance/time regardless of your V, the time must be the one to give and flex.
Light which is 186,000'ish miles/second.

Experiments have been performed to test this mathematical principal and 'succesful' results have been found.
It is a very confusing subject to get really deep into, and alot of gives and takes have to be created for it to become acceptable. This theory has many skeptics and many followers.

But if you still get confused...Think of this quick example.

If your on a train that was traveling 100,000miles/second, and you threw a ball that represented a light photon from the back of the train to the front it would have to (if it was light) travel away from you at C (186,000ish miles/sec) and if I was on earth at 0 miles/second watching you drive by me at 100,000miles/second, the ball would have travel how fast light is. And so obviously you can work it out that, the only way for the light to have these two different speeds relative to you and me is for the time in ones observation point to change.

Here is some of my opinion on the subject. Even if the light that comes from certain objects will display as fast or slower in time relative to other observers when velocities come in to play does not directly imply that the actual matter of the object will experience some kind of different time zone.
In countless experiments I have read on the subject, several explanations use an example of a photon moving through a train example. A photon Can not be detected unless it comes towards and interacts with the matter that is testing it. So I get a little discouraged with the examples, since the only way to 'see' the photon moving in the train is to have it hit you.
I still have alot to read on the whole subject but a simple man would assume from tests and experimental data from redshift and michelson and morely experiments that light is infact never the same velocity and of course this would throw time dialation special relativity out the window. Then again, leave it to the physicists I guess.

### #3 Jay-qu

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Posted 07 March 2006 - 11:08 PM

basically the faster you go through space the slower you go through time - and hence the slower you go through space the faster you go through time.

In Brian Green's book 'The elegant universe' he explains it that you always travel at c, but on an 'angle' through spacetime so that your velocity is broken up between space and time - a photon travels only through space and not time, the slower you go through space the faster you move through time.. not sure if that would help in your understanding, but I found it a good example.

### #4 D3nt

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Posted 07 March 2006 - 11:30 PM

It helps a little, but the question of "why" remains evasive. Arkain mentioned that it was a mathematical necessity, that time must slow down so that c can remain constant. Time is therefore the only variable in the formula for time dilation, but can it really be that the causality of events is based on nothing more than the need for the formula to be correct? If time and space are on two different "angles" say, x and t, then why is it that my speed through x affects my journey through t, where x is space and t is time. Is there nothing more that causes time dilation than a mathematical assertion and angles which of necessity must be interlaced (no passage through x can occur without t)? It is, as Arkain pointed out, a very confusing subject, and my mind is trying to grasp for something more solid.

Dent

### #5 Jay-qu

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Posted 07 March 2006 - 11:40 PM

well I struggle to expain something that I myself scarcly grasp.. I have had no formal teaching of this subject, but hopefully by the end of this year I will

### #6 Qfwfq

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Posted 08 March 2006 - 03:11 AM

Welcome to Hypography D3nt!

It helps a little, but the question of "why" remains evasive. Arkain mentioned that it was a mathematical necessity, that time must slow down so that c can remain constant.

Obviously, the necessity isn't only mathematical, or I could choose any cock-and-bull formula and say that reality must be some odd way, just to make my formula "work"!

You might look up the Michelson-Morely experiment, but things go further back than that. The principle of relativity was very much accepted since Galileo and Newton. When Maxwell figured out the equations of electromagnetism, by putting together all experimentally based formulae about electric and magnetic phenomena, these showed there to be a velocity of propagation for these fields, still known as "the speed of light", but this seems in conflict with the principle of relativity unless one imagines there to be some kind of medium throughout space, hypothetically named ether. Opinions varied but the matter seemed unexplainable when the most precise interferometric tests showed that we see the same speed of light, uninfluenced by Earth's motion. All kinds of ideas were tried, as ways to make ends meet, including Einstein's 1905 paper: "On the electrodynamics of moving bodies"

For some time this did not seem much more plausible than other ideas and was at first little understood but it began to gain support and Minkowski set a neat manner of seeing it, with less need for the plethora of examples and arguments about how we measure things. Einstein's paper makes it seem there's something highly special about light but, instead, it is just one thing that is confined to travel at the speed c which is actually a property of space-time geometry. What Jay-Qu quotes from Brian Greene could more precisely be said that a body's speed is always c through space-time, while through space it can be anything up to c. Time dilatation is just an effect of the appropriate coordinate transformations, formally similar to ordinary rotations. Look at your ruler edge on, it doesn't look as wide as when you look at it transversely, if you consider depth you realize it hasn't changed size.

### #7 kamil

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Posted 08 March 2006 - 04:13 AM

First of all, Welcome to hypography

The reason for time dilation is better explained through a diagram, this link has a very good animation describing it:

http://www.phys.unsw...tm#simultaneity

Scroll up to the top of the pag and you will see an animation showing time dilation.

Basically, all conclusion of relativity come from the two postulates of relativity, which are:

1.) all inertial frames(frames moving at the same speed) have the same laws of physics.

2.) Speed of light 'c'' is always measured the same, regardless of teh motion of the source or the observer.

So if a light beam traveling a distance of 'y' upwards takes time 't' both for a stationary observer and an observer in motion.
But an observer that is stationary will observe the light beam of a moving 'light clock ' to be slanted due to the speed(as shown in the diagram). So the light beam must travel a longer distance, BUT!! remember the 2nd postulate!!! the light must move at the same speed. Meaning that it will take a longer time for the light to complete its journey. But an observer in motion will see the light beam as moving straight upwards, so it will complete the journe quicker. So t>t' :

This might be a bit confusing with words but the diagram should be a good aid.

### #8 HydrogenBond

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Posted 08 March 2006 - 08:14 AM

A simpler model would result if time was considered a substance instead of a mere reference phenomena. As we approach C, the kinetic energy adds to the time quanta to make a higher level quanta. It then takes more stationary reference time to process the larger time quanta. This stretches out the amount of reference time to create a change of state.

One may ask how does kinetic energy increase time quanta? Kinetic energy is 1/2MV2. While velocity is distance/time. The time connection is one of the three aspects of kinetic energy. Kinetic energy also makes provisions for mass and distance, too. Special relativity shows how these are related.

### #9 D3nt

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Posted 08 March 2006 - 09:00 AM

Thank you all for your many insights into this phenomena. Jay Qu, I did not mean to sound impudent in my last post, and I meant no disrespect to your offer of help. If you took it as such, I apologize, I was just struggling to understand something that isn't very easy to understand. Qf, the allusion to the ruler edge was nice, and after my exams today, I plan to research the documents suggested. Thank you for that. Kamil, I got a chance to check the link you posted, and to me that reinforced the idea that my supposition may have been correct; the ticks of the clock slow down as they must travel a further distance. To me, that the synapses in the brain would also travel further, and thus the body would experience a temporal slow-down. Also, thank you for welcoming me . Lastly, Quantum, could you maybe expound on this a little? I think it's interesting, but through it's brevity I can't really wrap my head around it. Thank you all once again for your numerous posts; I hardly expected such a reaction, especially to such a mind boggling question.

Dent

### #10 Qfwfq

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Posted 08 March 2006 - 09:45 AM

I imagine Jay-qu meant to say that it isn't an easy topic, so don't worry if you have difficulty with it.

One important thing to keep in mind is, suppose you are in a capsule travelling at 99% of c: people tend to say that "time will be slower" but what does that mean? To you inside the capsule everything is normal, the same as being still. In fact, you have every right to say you are still and the rest of the universe is rushing the opposite way. To you, everybody else's time will be slow and to them, your time will be slow. Odd?

### #11 Pyrotex

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Posted 08 March 2006 - 10:12 AM

...suppose you are in a capsule travelling at 99% of c: people tend to say that "time will be slower" but what does that mean? To you inside the capsule everything is normal, the same as being still. In fact, you have every right to say you are still and the rest of the universe is rushing the opposite way...

Excellent point.
Einstein's Relativity is a set of equations intended to predict what one would observe.

"You" are the observor on the Earth (let's say). And someone else is in the capsule traveling at 99% c. "You" will observe that "their" time will be slower. This is not about what happens to time. This is not about what would happen to "you" if "you" were in the capsule. It is a prediction of what "you" would observe.

Now, let's switch it all around. "You" are in the capsule at 99% c. What would "you" observe? Inside the capsule everything is normal. Look out the window and "you" would observe time on Earth to be slower.

Is time actually flowing slower on Earth? Wrong question. Relativity does not address that. In most thought experiments, the question doesn't even make sense. That is, the answer is unapproachable even in principle. Relativity predicts what "you" will observe. If you keep that straight, then Relativity really isn't all that difficult.

Most folks make the mistake of setting up a thought experiment with the observer on (say) Earth, then "jumping" to the rocket ship and wondering what is "really" going on there! That doesn't work.

### #12 InfiniteNow

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Posted 08 March 2006 - 11:45 AM

I would like to also extend my welcome to you D3nt. As you have probably ascertained from the responses here, there doesn't seem to be just one right answer. This is probably why your instructor had such a tough time with the concept. Even people who have studied this for decades struggle with the strangeness which is light and time.

The observer travelling close to the speed of light doesn't sense anything different. Much like when you fly on a plane... it doesn't "feel" like you're going 500 mph, but you are. However, somebody at rest "relative" to the plane sees you moving super fast.

The twin paradox is an interesting way of seeing the relative differences in the experience of time.

What so often distracts us from the truth of situations is our desire to understand it in simple everyday terms. Time is wacky, interesting, and elusive.

Don't be so hard on the teacher. He or she is probably asking the same questions you are, and just doing their best to piece it all together.

Cheers.

### #13 D3nt

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Posted 08 March 2006 - 11:55 AM

Oh, don't worry, I'm not insulting my teacher's ability. Our class skipped right over relativity and the subsequent physics associated with it. Thank you for your welcome, and thank you all for your responses. It seems that most establish the fact that time is relative. As you mentioned, there are people who have struggled with this concept their whole lives, and I didn't really expect an explanation of why time dilation physically occurs. But through your responses I now have a plethora of information and sources I can reference, as well as feel slightly justified in my own theory (from my first post). You all have been a monumental help, and any additional insights would certainly be appreciated.

Dent

### #14 HydrogenBond

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Posted 08 March 2006 - 12:21 PM

The point that pyrotex made about what goes on inside a space capsule traveling near C provides insight. One will notice that only mass, distance and time are impacted by velocity, via special relativity, yet all the laws of the physics will remain the same. This means that all the forces of physics are adjusted with only changes in mass, distance and time.

In other words, if one threw something tiny out their space ship, it would hit the earth with the punch of something coming from a particle accelerator. If a charged dust particle floating inside the ship left the ship, its magnetic field, at its near C velocity, would be enormous in the earth reference. Yet inside the ship this is all adjusted so life goes on as usual.

The implication is that mass, distance and time relativity, due to velocity, adds up to all the needed adjustments in the laws of physics. If they were not adjusted by these three, the laws of physics would not be the same in all references. When I said that time, and even distance, are more just than reference guages, it has to be so, because mass relativity alone could not adjust the laws of physics, especially the EM force.

### #15 arkain101

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Posted 08 March 2006 - 09:01 PM

I have a different explanation for time dialation with a law in physics that I discovered, tested, and concluded on my own doing.

All frequencies of light emmiting objects on the move will act in two different ways relative to the observers action of view. The literal act of the observer tracking the moving object will transform the object to apearing as it would at res,t while having a static view point as the object passes by will cause the object to appear in motion and as so will create distance between the pulses of any and all frequencies.

According to this, I began to ponder if what we call time dialation in situations like particle accelerators and fast moving sateliites is infact just streaking (gapping) the data within the electromagnetic wave, resulting in the difference of 'time'.

here is an example. If I have a paintball gun that shoots 1 shot per second and I shoot at your from posistion A that is 50m away and we are both at rest, you will be hit by 1 ball every second. Now If I am to drive passed you at around 100mph and shoot at the same frequency, the balls will not continue hitting you every 1 second, the time between each shot will change as my posistion changes from each individual shot, keeping in mind I have perfect aim and hit you every time.
When the distance is decreasing between us the should remain 1 sec intervals but as i move along and distance between us increases so will the time in which each shot hits you.

### #16 arkain101

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Posted 08 March 2006 - 09:03 PM

I hope my logic is right on that, lol, i kinda just came up with it on the fly.

### #17 Qfwfq

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Posted 09 March 2006 - 05:04 AM

I was meaning to get to:

In my approach, I've focused on the human brain, whose electric synapses, I assume, fire and send information at the speed of light throughout the brain. To my way of thinking, as one approaches the speed of light, going about 292,000 km/s, then the electrical impulse is not moving the nanometer through the brain, but through 292,000km + the nanometer. This would delay the effects initiated by the cause, ie - the thought to raise my hand would take that little bit longer to go into action, and therefore, my entire perception of time would slow.

Is this anywhere close to why time actually slows with the increase in speed? If not, could you please remedy my misconception?

I'll try to remedy where you're stumbling.

First, neurosignals are electrochemical and travel far slower than light, slower even than sound. They travel very slowly indeed. Even EM signals travel at c in vacuo but not when there's too much material around.

Second, you are neglecting 292,000km - the nanometer. Not all of the signals will be going the same way as the motion.

More fundamentally, remember what Pyro and I have been saying. He hits the nail right on the head with:

Is time actually flowing slower on Earth? Wrong question.

Never forget that right now, at the same time as you are sitting still in your chair in your house or wherever, you are also travelling at incredible speeds with this planet, solar system and galaxy, and even these speeds are low compared with that we are travelling at according to each particle in the solar wind.

Your brain works exactly the same when you are zipping along at 99% of c and so does anything else in the spaceship. Think about the ruler I mentioned, suppose we are both looking at two rulers, exactly equal except that ruler A is positioned edge-on to me and ruler B is edge-on to you. I'll insist that B is a lot wider than A and you'll keep calling me a numbskull because A is a lot wider than B. Neither of us is right at all.