Relativity of light - light at light speed

chat · 2003-10-23 04:25:18

Just doing a bit of follow up on the light speed question.

In einstiens theory is should take all of the energy in the universe to get anything to light speed.

But what about light itself?
It seems to be already traveling at light speed.
And it is a duality partical in most theories.

My thought is, what is the relativity for light itself?
And why does light not break down to a form with less energy than light over great distances.?

All other radiation forms do break down over time and distance, why not light?

As for speed limitation. i type with 2 fingers so that is my universal speed limit.

Mark Friedenbach · 2003-10-23 17:59:31

And light is a duality partical in most theories.

In quantum theories, yes. To the best of my knowledge, light is considered a wave in general relativity. Obviously it's not, but there's no unified theory yet.

Shaun Barrett · 2003-10-23 23:32:41

Welcome to New Mars, Chat!

I don't pretend to be a particle physicist by any stretch of the imagination but there are one or two aspects of photons that I've learned over the years.

Photons are, by definition, travelling at the speed of light for the medium they occupy at any given moment. This is always true. There is no contradiction regarding the need to supply limitless energy to accelerate them up to light speed because they are deemed to have zero-rest-mass. There's no problem with photons gaining infinite mass at the speed of light because they're massless to begin with. In addition, when a photon is brought into existence by some physical process, it is created already travelling at light speed.

And the reason a photon can travel across the known universe without 'breaking down' is because it is a fundamental particle. Unless it interacts with something else, it is essentially immortal.
There's not much that can go wrong with a photon. It's not made up of smaller 'bits', so you can't break it apart. It's been found that the energy of a photon is proportional to its frequency. Out in the almost endless depths of intergalactic space, there's nothing much to interfere with a photon and change its frequency. As long as nothing does interfere, the frequency stays the same and so, therefore, does the photon's energy ... indefinitely.

So, while matter as we understand it (i.e. according to the Standard Model) has mass and is therefore subject to the constraints of Special Relativity, photons are a whole different ball game.

I hope that helped!

[P.S. Welcome to the TFTC ... the 'Two Fingered Typist
Club'!! ]

chat · 2003-10-24 08:09:27

Hi shaun,

That was a great reply.

I bet you cheated and typed with more than 2 fingers though

I think i have a better understanding of the dynamics of photons after your post.

I've always wondered if light traveling at the maximum velocity anything can go has 0 relativity.
Does light last forever only because it travels at light speed?
With 0 relativity it should be able to go from one end of the universe to the other end in no time relative to the rest of the universe.
If light only lives for 1 second but that second last forever because of relativity.

And thanks for the welcome

Shaun Barrett · 2003-10-24 20:32:39

No, Chat, I assure you I didn't cheat!

I understand your interest in the nature of photons; there's definitely something spooky about the wretched things which can give you headaches just thinking about them!
When I mentioned that photons are fundamental particles, I didn't explore just how fundamental they really are. It's like they're part of the fabric of the universe itself - more so even than space and time. If you look at the work Einstein did, you notice that his equations allow for many things we normally regard as immutable to change. Against all our human intuition, the mass of an object can change, the length of an object can change, time itself can change and empty space can warp and bend. But, against this background of total inconstancy, the speed of light stands sacrosanct!
Your questions about how a photon manages to remain changeless and immortal are probably meaningless, inasmuch as change requires time but time is irrelevant to photons. They appear to be part of the fundamental nature of this universe; as much outside of time as the purported Creator God many people believe in.

That's about as far as my thinking about photons goes! Beyond that, I start to hit against the hard wall of my own intellectual limitations.

If you want more on this subject, you may be better off to direct your questions to Euler, another member of New Mars. I've found Euler to be well informed in such matters and to have a knack for explaining things.

chat · 2003-10-25 07:22:33

Shaun,

I hear you on the headaches from thinking about photons

What were they thinking when they invented the darn things?
And you would think who ever invented them would be pretty darn proud about the invention and leave some schematics lying around somewhere

No such luck on that.
But always great fun to think about, and it keeps the aspirin company in business

dicktice · 2003-10-25 16:54:08

Chat: You are the first person I've come across to wonder if photons are immune (my term) to time. I've often questioned how images from as far away as your telescope allows you to see, remain absolutely unchanged in all their detail. Images composed of unchanging patterns of photons, I mean. Only if the patterns suffer no time-elapse was my conception. Why don't cosmologists dig into such things? Shaun has been grand, but he seems to bog down when his math runs out (that should start something!).

Shaun Barrett · 2003-10-26 02:03:40

Dicktice:-

Shaun ... tends to bog down when his math runs out ...

Ha ha !! :laugh:
Guilty as charged, your honour!
But Dick, you can be quite sure your frustration with my limitations is no greater than mine!!

chat · 2003-10-26 05:27:10

Hi Dicktice,

I can't speak for anyone elses math, but mine decreases proportionally to the coffee supply c=m/s

This is a thought that has puzzled me for ages.

You get on a spaceship that allows you to travel at the speed of light (new Ferrari space ship with all the options) and head to a very distant part of the universe.

The aliens at you destination watch your trip through a very powerful telescope (like vlt but way bigger).

They see you taking an awful long time to get there.
But since you are traveling at the speed of light it takes you no time to arrive.

The aliens great great grandchildren are sure you live forever because millions of generations have seen you heading towards them, and you just don't age, nor does your spacecraft.

If you overshoot the aliens home world just a bit, and they decide to measure and see why.
Do they see you as a wave or a particle? or both?

It seems to answer why light always goes at light speed, and why light seems to last forever.
Well in my mind anyway but then i need another cup of coffee
And i sure wish i had invested in the aspirin companies stock

dicktice · 2003-10-26 09:08:49

Chat: I've been called a "know-it-all" by someone in these forums, but the truth is: I don't know nothin'. I just try to work out things on the spot, to see if someone can straighten me out! So here goes--
Of course, your spaceship wouldn't be able to travel at lightspeed (right?) but if it did, your aliens wouldn't know about you until you reached 'em. Now, I know that's not what you were shooting at, but your thought experiment at least has to conform (like hardcore science fiction) to current theory. So, what's your point? If your spaceship accelerated to (say) half lightspeed by the time it was passing the alien's star. . . . Now, if you restate it from there, maybe we can come up with a description collectively (anyone else?) of what would transpire.

As an aside--my contention that time doesn't exist for photons of electromagnetic radiation, pretty much says what you stated: that light "exists forever."

Preston · 2003-10-26 09:08:56

Correct me if I'm wrong, but it seems to me that quantum mechanics states that the wave function tends to be wavelike, but it describes the position, momentum, etc. of a point particle. So there's nothing mysterious about that, right? We might set up a potential to diffract light, which seems very wavelike, but the wavefunction will just give us the state and probabilities of point particles. Or is there something else that makes the duality hazy somehow?

Gennaro · 2003-10-26 12:21:34

Photons are, by definition, travelling at the speed of light for the medium they occupy at any given moment.
---
When I mentioned that photons are fundamental particles, I didn't explore just how fundamental they really are. It's like they're part of the fabric of the universe itself...

This sounds very much like the prime matter or substratum of Aristotle. Matter without form, that is, no thing yet.

What I like to ask is this. The reason that photons/lightwaves always travel at the same speed is maybe because matter normally behaves like this at a certain speed or energy state? Matter going slower or faster than light simply does not show up as light and that's why the speed of "photons" is always constant.
If so, there would be no need to theorize about universal speed limits only because the speed of light is universal.

Only a layman's musings.

chat · 2003-10-26 12:24:26

dicktice,

My last post was a definite lack of coffee event *lol*
I'm glad you had some idea what i was talking about, because when i read it i didn't *lol*

It was worded poorly.

But you did get the general idea.
I was trying to convey the idea that light itself might be strange because of the speed it travels at.

What if?
Light created that travels faster than the speed of light slips out of time and we never see it created.
Or the fabric of time simply won't allow light to go beyond a set speed.

Light created that travels slower than the speed of light lasts for it's trillionth of a second and again we never see it created.
Or the fabric of time won't allow light to be created at slower than a set speed.

Only the light traveling at the correct speed has the properties to last forever, only due to its speed being exactly that of time.

Light travels from anywhere to anywhere instantly due to the light traveling at the same speed as time, but we see it taking time because of our relativity.
Light never breaks down because it feels no time or space.

Something about the 186,000 mps has an answer to it.
Now if someone only knew what question to ask

Seems logical, but then again so did pet rocks.

Just a thought in pure speculation here

And i agree dicktice, something is really weird and not understood about light.
It just is--isn't a great explination for light.

As for the spaceship It was a ferrari so it was pretty darn fast
And i've been called worse.

chat · 2003-10-26 12:31:38

Hi Gennaro,

You must have been reading my mind.

Gennaro · 2003-10-26 12:32:34

Oh really? I'm flattered.

chat · 2003-10-26 12:35:54

*lol*

I'm just a way slower typer

Gennaro · 2003-10-26 12:47:08

Does that mean I asked the "right question"?

chat · 2003-10-26 15:07:20

Gennaro,

I'm not even sure a correct question even exists.

All questions are valid when no one is sure of the answer.
And since your question was so similar to mine, i deduce that you must have a very brilliant mind *grin*
Therefore the question must be valid

dicktice · 2003-10-27 08:52:26

Chat: I believe you hit upon a neat way to demonstrate time dilation without the Twins so-called paradox requiring acceleration (know what I mean? if not go back to Solar Wind forum posts the last few weeks). You postulate alien observers of a spaceship from Earth, whizzing past at (I suggest) 1/2-lightspeed. Instead of a telescope, let the spaceship broadcast a tv-picture (by laser light or radio) which the clever alien are able to demodulate and view the image raster. When the spaceship stops accelerating, while it approaches the aliens view what they don't know is a slow-motion scene of the cabin interior including passengers and clock. The aliens grow old waiting, and the spaceship passengers less so. Okay, now what do they conclude? Are we any closer to understanding time dilation? I think so. We'll get back to light and photons in due course.

chat · 2003-10-27 11:36:05

Hi dicktice,

If I'm correct your are referring to Einstein's twin theory.
One goes on a stellar visit at high speeds, and one stays home ?
When the traveling twin returns to earth some years later, the one that went is younger.

I like the idea of your thought experiment, it raises some puzzling questions, and it is in much better terms than i tried to do without coffee .

Just a few thought ramblings here
..................................................

Since the TV broadcast is at light speed and sent at that speed, wouldn't the aliens see a normal TV broadcast with no clocks being slowed down, and you in normal motion?

Some time dilation would occur for you the space traveler because your are moving at 50% the speed of light.
But the TV broadcast at light speed????

Or the TV broadcast simply takes pictures of your time dilation and sends them at light speed.

I had to think about that for a while

What the aliens see.

Since it really takes you twice as long to arrive as the TV broadcast does, it should mean the TV broadcast takes pictures of your time dilation and sends them?

When you arrive they believe you live a very long life, but your metabolism is very slow compared to them.
The first thing they offer you in a new clock that works properly

dicktice · 2003-10-27 16:01:36

Chat: It was your "alien observer" approach (nothing I would have come up with) that got me to rethinking the original twins (just as you say) thought experiment--the initial credit's all yours. Now then--

Since the cabin tv scanned-image transmission / reception display-observation, simply replaces the cabin direct image / telescope observation, in each case the cabin is at 1/2-lightspeed relative to the observers, so nothing's changed. I assumed the spaceship would go on by without decelerating, to maintain the cabin activities at "slow motion" during the experiment. In your own words: ". . . the TV broadcast simply takes pictures of your time dilation and sends them at light speed." But if you slow down and stop for a visit, these aliens will try to sell you a brand new Universal Coordinated Time Clock, for sure!

chat · 2003-10-27 20:14:18

dicktice,

*lol*

I know one thing for sure.
If i see slow moving aliens heading this way, I'm selling the farm and buying clock stock. *grin*

dicktice · 2003-10-28 19:11:29

Not so fast, Chat: We've only begun. Now having conjured "timeless light," how are we going to explain the energy of light in terms of wavelength, which comprises timed oscillations. How is red with a wavelength of 1 um (say) differentiated from green with a wavelength of .5 um (say) when no "time" exists for the oscillations to occur? I know, the language is murky, but then so is my mind regarding this. Maybe another thought experiment, or (shucks) math solution will help explain. . . .

Euler · 2003-10-28 20:35:04

I think that the waves themselves do not oscillate. Instead they stay exactly the same and do not change with time. The space the travel through experiences an oscillation only because the portion of the wave that is in that space changes.

chat · 2003-10-28 20:56:50

dicktice,

Ahh i see what your saying.

How can light be a measure of time if light comes in different wavelengths?
Close?

Lets pretend that only the speed of light is a measure or time.
time=c or c=time

Many forms of light can be created with different wavelengths, but the speed of the light is always the same.

Lets pretend that to create a photon you can use any 2 atoms.
Lets also pretend we know how to make them
If you collide 2 hydrogen atoms at a set collision speed and produce 1 photon, you get a set wavelength, but time sets the speed of the escaping photon.

I think its possible to have no time for the light, but different oscillations for the light.

Hope i was on the right track on that?

New Mars Forums

Announcement

#1 2003-10-23 04:25:18

Re: Relativity of light - light at light speed

#2 2003-10-23 17:59:31

Re: Relativity of light - light at light speed

#3 2003-10-23 23:32:41

Re: Relativity of light - light at light speed

#4 2003-10-24 08:09:27

Re: Relativity of light - light at light speed

#5 2003-10-24 20:32:39

Re: Relativity of light - light at light speed

#6 2003-10-25 07:22:33

Re: Relativity of light - light at light speed

#7 2003-10-25 16:54:08

Re: Relativity of light - light at light speed

#8 2003-10-26 02:03:40

Re: Relativity of light - light at light speed

#9 2003-10-26 05:27:10

Re: Relativity of light - light at light speed

#10 2003-10-26 09:08:49

Re: Relativity of light - light at light speed

#11 2003-10-26 09:08:56

Re: Relativity of light - light at light speed

#12 2003-10-26 12:21:34

Re: Relativity of light - light at light speed

#13 2003-10-26 12:24:26

Re: Relativity of light - light at light speed

#14 2003-10-26 12:31:38

Re: Relativity of light - light at light speed

#15 2003-10-26 12:32:34

Re: Relativity of light - light at light speed

#16 2003-10-26 12:35:54

Re: Relativity of light - light at light speed

#17 2003-10-26 12:47:08

Re: Relativity of light - light at light speed

#18 2003-10-26 15:07:20

Re: Relativity of light - light at light speed

#19 2003-10-27 08:52:26

Re: Relativity of light - light at light speed

#20 2003-10-27 11:36:05

Re: Relativity of light - light at light speed

#21 2003-10-27 16:01:36

Re: Relativity of light - light at light speed

#22 2003-10-27 20:14:18

Re: Relativity of light - light at light speed

#23 2003-10-28 19:11:29

Re: Relativity of light - light at light speed

#24 2003-10-28 20:35:04

Re: Relativity of light - light at light speed

#25 2003-10-28 20:56:50

Re: Relativity of light - light at light speed

Board footer