# The Naked Scientists Forum

### Author Topic: What defines the speed of light?  (Read 3433 times)

#### MikeS

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##### What defines the speed of light?
« on: 23/07/2011 07:49:40 »
What defines the speed of light?

It could be said, it just is.  I find this a very unsatisfactory answer.  Let’s try and find the real answer using just the concept of time.

Photons travel instantaneously, they exist in only the now.  Another way of looking at this is they travel at infinite speed.

How can a photons infinite speed be measured to approximately 300,000 Km per second in a vacuum.  Surely, infinity is infinity?

Let’s take a brief look at time.  What are its attributes?  There is an arrow of time and it can ‘flow’ (be dilated or contracted) at different rates.  At the two extremes time can ‘flow’ infinitely fast (ultimate contraction) or it can ‘flow’ ultimately slow (ultimate dilation) and stop.  ‘Infinitely’ slow (stopped) is a finite  quantity.

Where time stops can be viewed as an absolute.  It is a very similar concept to the temperature of absolute zero.  You cannot go colder, that is where the scale ends.  Time cannot ‘flow’ slower than stopped.

To a photon, the clock has stopped.  It cannot go faster than that.  To do so would require the reversal of time.

The faster anything moves, the slower time passes (dilates).  This puts an upper limit on speed as ultimately the clock stops.  The same upper limit is reached when viewed from the perspective of energy and mass.

Although this is in the new theories section, it is not meant to represent a new theory; rather a simple explanation of what defines the speed of light.

If anyone would like to debate any of the above points, please be specific.
« Last Edit: 23/07/2011 09:29:39 by MikeS »

#### Phractality

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##### What defines the speed of light?
« Reply #1 on: 23/07/2011 21:59:00 »
It is said that time stands still for a photon because, in your frame of reference, the photon is moving at the speed of light. As a clock approaches the speed of light in your frame of reference, it slows down from your point of view. But a photon is not a clock; a clock must consist of matter; it must have cycles that can be counted so that you can perceive that time is passing from the clock's point of view.

In the photon's frame of reference, the universe is contracted to zero thickness in the direction of travel. That is why, from the photon's point of view, no time passes between point A and point B. The distance, from the photon's point of view, is zero, so the time to get there is zero.

From your point of view, the distance is not zero, so time does pass as the photon goes from A to B. That is true from the viewpoint of every observer, and every observer perceives the same speed of light. If that doesn't make sense to you, then you don't yet have a good understanding of special relativity. Watch a few more videos, and eventually, it will become clear to you.

#### yor_on

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##### What defines the speed of light?
« Reply #2 on: 25/07/2011 11:40:28 »
A simple way to define it is to acknowledge that we can see a recoil, and we can see a annihilation. but we can not see what lies in between those two. And if it isn't 'there' then it is very hard to define a time to it 'not' being there :)
=

The recoil I'm talking about is when the photon has left. So it's not the photon we see having it..
« Last Edit: 25/07/2011 11:42:15 by yor_on »

#### MikeS

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##### What defines the speed of light?
« Reply #3 on: 27/07/2011 07:17:09 »
It is said that time stands still for a photon because, in your frame of reference, the photon is moving at the speed of light. As a clock approaches the speed of light in your frame of reference, it slows down from your point of view. But a photon is not a clock; a clock must consist of matter; it must have cycles that can be counted so that you can perceive that time is passing from the clock's point of view.

In the photon's frame of reference, the universe is contracted to zero thickness in the direction of travel. That is why, from the photon's point of view, no time passes between point A and point B. The distance, from the photon's point of view, is zero, so the time to get there is zero.

From your point of view, the distance is not zero, so time does pass as the photon goes from A to B. That is true from the viewpoint of every observer, and every observer perceives the same speed of light. If that doesn't make sense to you, then you don't yet have a good understanding of special relativity. Watch a few more videos, and eventually, it will become clear to you.

There is nothing to say that it does not also slow down from the photons point of view.  Time dilation from travelling at approaching light speed is equivalent to time dilation from gravity.  Time dilation from gravity is a known and tested fact.  Where gravity is sufficiently intense time stops, as in a black hole for example.

A photon is a clock as it has a measurable and totally accurate frequency.
Scientists who specialize in the accuracy of time have created a new kind of clock—an optical atomic clock—that "ticks" one million billion times per second and is at least 20 times more stable than current atomic clocks that are based on microwaves.

Although it will take several decades for the technology to be tested and accepted by the international timekeeping community, optical atomic clocks have the potential to be 100 to 1,000 times more accurate than current
John Roach
for National Geographic News
July 13, 2001
http://news.nationalgeographic.com/news/2001/07/0712_atomicclock.html

Gravitational time dilation tests
   In 2010 gravitational time dilation was measured at the Earth's surface with a height difference of only one meter, using optical atomic clocks.[16
http://www.sciencemag.org/content/329/5999/1630

A photon is not just a clock, it’s the universes master clock.

Yes, I agree.

Yes, that's the whole point.  That's why the photon has a finite speed.
I haven’t made this point very clear so have added to the original post in my next post.

« Last Edit: 27/07/2011 07:25:17 by MikeS »

#### MikeS

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##### What defines the speed of light?
« Reply #4 on: 27/07/2011 07:22:40 »
What defines the speed of light?

It could be said, it just is.  I find this a very unsatisfactory answer.  Let’s try and find the real answer using just the concept of time.

Photons travel instantaneously, they exist in only the now.  Another way of looking at this is they travel at infinite speed.

How can a photons infinite speed be measured to approximately 300,000 Km per second.  Surely, infinity is infinity?

Let’s take a brief look at time.  What are its attributes?  There is an arrow of time and it can ‘flow’ (be dilated or contracted) at different rates.  At the two extremes time can ‘flow’ infinitely fast (ultimate contraction) or it can ‘flow’ ultimately slow (ultimate dilation) and stop.  ‘Infinitely’ slow (stopped) is a finite  quantity.

Where time stops can be viewed as an absolute.  It is very similar concept to the temperature of absolute zero.  You cannot go colder, that is where the scale ends.  Time cannot ‘flow’ slower than stopped.

To a photon, the clock has stopped.  It cannot go faster than that.  To do so would require the reversal of time.

The faster anything moves, the slower time passes (dilates).  This puts an upper limit on speed as ultimately the clock would stop.  The same upper limit is reached when viewed from the perspective of energy and mass.

Whilst a photon exists in its own timeless world, its nevertheless in a universe dominated by gravity where gravity everywhere dilates time.  Everywhere, in the universe ‘feels’ the effects of gravity.  Therefore everywhere in the universe is feeling the effect of dilated time.  It can be extrapolated backwards, that without gravity time would be infinitely contracted.  It is mass that gives an arrow to time so without mass time would be infinitely contracted in both directions at once.  (Everything happens at once with no causality.  There is no time, as we know it.)  Mass causes gravity causes time.  However, that is an oversimplification.  In a black hole, a place of infinite gravity time is infinitely dilated, it stands still.  From the point of view of the photon, there is no such thing as time as it travels instantaneously.  Put the two together and the interaction of gravity and energy equals time.  To put it another way, gravity ‘slows’ photons to create time.  We can never be aware of this ‘slowing’ as time dilates in just the right manner to compensate, to ensure the speed of light in a vacuum remains a constant.

Whilst a photon exists in its own timeless world, it still experiences causality, as it exists in a universe that contains time.

#### MikeS

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##### What defines the speed of light?
« Reply #5 on: 27/07/2011 09:38:13 »
A simple way to define it is to acknowledge that we can see a recoil, and we can see a annihilation. but we can not see what lies in between those two. And if it isn't 'there' then it is very hard to define a time to it 'not' being there :)
=

The recoil I'm talking about is when the photon has left. So it's not the photon we see having it..

yor_on

Just because we can't see it does not mean it is not there.  To define it as not there adds considerably to the complication.

#### Phractality

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##### What defines the speed of light?
« Reply #6 on: 29/07/2011 19:49:51 »
MikeS,

Speed is distance divided by time. In its own reference frame, a photon travel zero distance in zero time. Zero divided by zero is not infinity. The speed of light is the same in every reference frame by definition.

#### MikeS

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##### What defines the speed of light?
« Reply #7 on: 30/07/2011 07:45:01 »
What defines the speed of light?

Another way of looking at this is they travel at infinite speed.

MikeS,

Speed is distance divided by time. In its own reference frame, a photon travel zero distance in zero time. Zero divided by zero is not infinity. The speed of light is the same in every reference frame by definition.

I was considering it from the point of view that any distance divided by zero time is infinity.  I did say that it was another way of looking at it. Infinity is an awkward concept and doesn't always mean the same thing. I no doubt should have avoided using it.

#### The Naked Scientists Forum

##### What defines the speed of light?
« Reply #7 on: 30/07/2011 07:45:01 »