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QUESTIONS OF SCIENCE

On the speed of light 'c'

(and what it means in the quest for

evidence of intelligent life elsewhere)

 

First, the 'Laser and Target on a Rail Puzzle'

FIXED LASER

A target sits on a rail 1Km from a laser that’s fixed at the FAR end of the rail. The laser fires a pulse that takes a fixed time ‘t’ to reach the target.

Now the target is placed close to the laser then sent at high speed away from the laser. At the precise instant the target passes that same 1Km point, the laser again fires that same pulse at the now receding target.

This time, when the pulses reach the 1Km point, the target will no longer be there. Instead the target will detect the pulse at t + ‘x’ … moreover, when the pulse is detected by the receding target it will be stretched, as too will the frequency of the light of the pulse. The speed of that light, though, as measured at the target as the pulse passes, will remain at ‘c’, as ever.

 

FIXED TARGET

A laser sits on a rail 1Km from a target that’s fixed at the FAR end of the rail. The laser fires a pulse that takes a fixed time ‘t’ to reach the target (as before).

Now the laser is placed close to the target then sent at high speed away from the target. At the precise instant the laser passes that same 1Km point, the laser again fires that same pulse back towards the target.

This time, when the pulse reaches the fixed target conventional theory predicts that, as when both are fixed, ONLY time ‘t’ will have elapsed (NOT t + ‘x’)…. yet the pulse will be stretched, as too will the frequency of the light of the pulse, exactly as when the target was receding. The speed of that light passing, as measured at the target, will again inevitably remain at ‘c’. 

Now here’s the question: What's the difference between a receding laser and a receding target? Why should the outcome be different when these two objects move away from each other depending on which one we consider fixed and which moving? Is ‘conventional theory’ wrong?  

* * * * *

Wherever light is from, wherever it's headed, and whether I remain still or zoom away in any direction (towards or away from it), still the light will always measure to be moving at 'c' TO ME - AND the same light to someone else moving away from or towards me likewise. Obviously what I (or the someone else) is observing is not what is really happening here.

If two objects in space are moving apart and one emits a pulse of light towards the other, then for an outside observer the pulse will take longer to reach the 'other' than if the objects became static (relative to one another) at the instant the pulse was fired. Or you could say: If at the instant a pulse is fired towards it, the destination object began moving away, then the pulse will take longer to reach it than if it had remained static relative to the source.

This means, from an outside observer’s view, the speed of light must be relative to its source, not destination. Yet, regardless of speed of separation, the destination will always register the speed of that light to be the same: 'c' - including light from any other receding or advancing sources in any direction and regardless of their speed.

So if the relative speed of separation of Earth and a remote galaxy, say, is c/2 then will the light we receive be taking twice as long to get here than we think? Of course, again: when that light does get here its speed will measure to be c.

* * * * *

Do we really always believe we exist at the centre of everything, as when it was thought the sun moved around the Earth until discovered otherwise? Or is the explanation entirely in the phenomenon of time-dilation between two bodies due to their relative speed?

* * * * *

THIS QUESTION does not challenge current theory regarding the speed of light and relativity etc., so there’s no inconsistency with what's currently accepted, as may at first appear. Nor does Doppler have any relevance; that concerns ONLY frequency or wavelength. The problem I aim to address here concerns the speed of light when it can only be deduced - not observed - which is essentially a separate issue from those.

So first, can the difference between what an outside observer would measure in the above examples with objects in space and what the destination would measure on arrival of a pulse of light be due purely to time dilation?

Using the formula:

(this is easy to derive; see: 'time dilation' )

 t’ = t / √ ( 1 - v2/c2 )

 ….there seems to be a discrepancy.

(My knowledge is limited here and other factors may be involved?)

FOR INSTANCE: If an object is launched from Earth at half-c ( c/2 ) and an hour later a beam of light is fired after it, then the beam will reach the object after 2-hours from when the object was launched. An outside observer will see the beam approach the object at c/2, but the object would measure the beam to be passing at c. This appears to show that time-dilation for the object is causing it to age at half the rate of Earth. Yet if the formula is applied then the time on the object moving at c/2 will be 0.707 of that on Earth.

Is the formula incomplete or somehow inapplicable here? The key issue, though, from this reasoning is: Does the light from distant receding galaxies actually travel towards us at a slower rate than we think… that is: are we correct to assume that light is travelling towards us at c just because it measures, inevitably, to be travelling at c when it reaches us (whether we're zooming away from the light or not)?

To repeat for emphasis, the argument might go as follows: To an outside observer, light must be travelling at all kinds of speeds relative to everything else, according to the speed of its source… If an object is moving away from a pulse of light, then to an outside observer that light will take longer to reach the object than if the object was not moving away from the pulse... even if the object ONLY began moving away AFTER the pulse was fired.

You only have to consider two particles being sent in opposite directions, each at, say, 0.8 c... both independently measured... to recognise that outside our little frame of reference the speed that things move in the universe, e-m waves and matter, can be absolutely anything IN FACT. (see link below on 'addition of velocities').

How does a particle on one side of the galaxy know what's happening on the other side and so regulate its speed accordingly.... the concept is clearly absurd. This concerns what's ACTUALLY happening, NOT what anyone might observe.

Resolving the issue might show that distant galaxies are in fact not nearly as distant as we assume, so the rate of expansion of the universe may, after all, NOT be increasing as seems to be the prevailing wisdom these days (?).

If you flew a spaceship from Earth to Alpha Centauri (4.37 light-years away) and back for what you judged a couple of years, say, so your normal watch registered a couple of years had passed, and an atomic clock the same, plus it felt like a couple of years, YET when you got back several decades had passed, and people told you that several decades had passed, THEN who/what would you believe? 

Looking at where the trip had taken you, you'd realise the distance (>8 light-years) for the time you've aged meant you far exceeded c, though no-one observing you from Earth saw that. Moreover, during the trip light would have never seemed to you any different from normal, apart from its wavelength.

You'd say: "...maybe several decades HAVE passed, but that's for YOU, not me. For ME only a couple of years have passed."

You might add: "Light measurements during the trip showed only changes in wavelength, from which our speed could be assessed when observing a fixed light source ahead. Comparing periodic checks of distance from the target by luminosity could also reveal our speed was several times greater than c."

This is the essence of the issue: of people placing themselves at the centre of a situation and being reluctant or unable to simultaneously perceive from another angle, another situation.

The reality is, everything in the universe is its own 'centre' and no other entity can impose its circumstances on another as people always like to do and claim ONLY they are right.... when the fact is they are ONLY right for themselves.

I've sent those observations/questions - months ago - to different sites that claim to examine and address these kinds of science questions. But, surprise surprise, there has been no response.

One site addresses a question that touches a related contentious issue (click on the link for the comprehensive answer):

Addition of Velocities:

"Assume two photons are moving in opposite directions from each other from a common light source. How fast would they be traveling relative to each other? Twice the speed of light? If the speed of light is the ultimate speed limit in the universe, how can something travel twice that speed?"

The answer 'proves' that 2c = c..... 

That may work in theory, which perhaps can somehow be shown to be 'locally' true experimentally? But not when examined deductively. That is, suppose you simultaneously fire two pulses of light in opposite directions at mirrors a certain same distance away and measure how long the pulses each take to receive back - which would be identical - then divide that time by 2 and you'll have the exact time the pulse took from firing to simultaneously hit the mirrors. Divide the distance between the mirrors by that time and you get the 'deduced' relative speed of the two beams. 

I'm not a betting person, but I'd like to bet with the guy who answered that question on 'addition of velocities' of whether my deduction method, were it carried out, would prove me right or wrong. Obviously, I think I'm right.... but who knows? I'd really love to be wrong here, because that would be something extraordinary.

This is merely another example of how everything in the universe is its own centre that operates in a frame of its own - though is shared with everything else until relative speeds comparable to the speed of light are involved....  

Just as Einstein noticed what Newton failed to and modified Newton's work - which is still correct for virtually all practical everyday applications - then maybe what Einstein noticed also needs some modifications to account for other discrepancies.... like distant galaxies receding at close to the speed of light (relative to us) and cosmologists estimating from this that the universe is expanding at an increasing rate: ie, not slowing down as might be expected.

One problem might just be the stupendous scale of everything. Our lifespans are so brief that it's hard to observe significant changes over many generations even. When you consider that it takes 20,000-years for light from the sun to merely reach the edge of the Milky-Way galaxy, and that light from the centre of the Milky-Way takes 30,000-years to reach us, then you get some idea of the scale... which is on an entirely different level to our everday experience of time and distance. It requires a profound leap in imagination to grasp the enormity: on the scale of a 1-metre diameter Milky-Way, a bubble with a diameter of 1,000 light-years around the sun would be hardly bigger than a small marble.

This means the likelihood of contact with other 'civilisations' that must exist by the laws of chance (from 230bn stars - many with planetary systems) is virtually zero, alas.

And when you reflect that it took nearly half the sun's predicted lifetime of maybe 9-billion years with perfect conditions on Earth for hundreds of millions of years before advanced life like us evolved... following various - and relatively very recent - seemingly dead-end life-forms like even huge dinosaurs, existing for many times longer than us yet failed to develop an intellect; when you contemplate that beside those colossal distances then you get a momentary glimpse at reality - and the magnitude of our predicament in the quest for evidence of other intelligent life.

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