they would reappear at different intervals. ... What do you think?

Let's see. How are you measuring the intervals?

if your hypothesis that photons are constantly accelerating is correct

I'm not sure that is the hypothesis -- mine or anyone else's. That is to say; I'm not sure that "The SoL is not constant" (Or "The SoL is (and has been) constantly [sic] increasing since the Big Bang; is the same as saying "photons are constantly accelerating".

The problem starts with understanding that whole thing about the 'expanding universe'. People generally get that all the galaxies have their own motion, relative to us and everything else. And headline "they are all moving away from each other" is taken as read by most of us.

The tricky bit that goes over a lot of peoples heads, especially science correspondents and other media types, but the rest of us, including some you'd think would know better, is the fact that the reason, and indeed the only way for all the galaxies to be moving apart from all the other galaxies (in the large), is if the universe itself is actually getting constantly bigger. The very fabric of space-time is increasing. Space itself is accruing more space.

The favorite demonstration of this is dots drawn on a semi-inflated balloon. You blow the balloon some more and all the dots move apart from each other. The problem with that demonstration that is glossed over, is that the dots themselves also get bigger, so the relative distances between them stay proportionally the same.

It's like the unit of distance increased. Although we as outside observers of the system (the balloon the dots and the distances between them) can perceive the change, if the were some (tiny; the relative size of humans to the universe) living creatures on the surface of the balloon, then they wouldn't be able to perceive the change because their rulers, and indeed themselves, along with everything would also increase in size, so everything would appear to be exactly the same.

Which brings me back to the both the description of the hypothesis and your proposal for testing it.

If space started as a singularity, an infinitesimally small point of nothingness; and has grown to its current measured observed size over 13.8 billion years, and the speed of light has be constant and the same constant right from the beginning, then we have a measure -- and a stupidly large number 130558080521615040000000000m -- for the size.

If however, the SoL started at zero 13.8 billion years ago (that becomes questionable under this scenario; but I need a number here), and has reached it current speed now, then the rate of that acceleration is Δs / Δt = 299792458 / 130558080521615040000000000 = 2.2962382473934021910889055687635e-18 m/s², so tiny that even if we had units of time and distance that were not tied to the SoL; it would require there be decades (if not centuries) between observations, before the change would be sufficient for our best atomic clocks to detect.

And finally, the basis of the experiment you propose is (I think) that because older things are further away, the light arriving to us must have started out more slowly than 'new light' from close by, and thus the two must be traveling at a different speeds; but that isn't so. If the SoL itself is accelerating, rather than the photons we measure in terms of it, then all light, new or old, near or far, would, at any given moment in time be traveling at the same speed -- the SoL. It's just a different SoL today than it was a century, or millennia, or a second, ago.

And if you accept the indivisibility of space & time; that they are aspects of the same thing as General Relativity suggests, and space is, and has been expanding since 'the beginning'; and the thing that links the two is the constant c; then doesn't that mean that time -- as in the length of one second or one day; not the totality of seconds or days since the BB -- must also be expanding. It would be the only way for the constant to remain constant.

But the problem with time changing is that we have artifacts going back 5 or 6 thousand years Ancient Egypt, Sumerian, Inca, Maya, that record time in physical objects; with sufficient accuracy that we can wind back the clock and align them with celestial bodies in their positions then -- by sight; no units of measure tied to SoL to mess with things -- and they line up. And those thousands of years are sufficiently long that if time were moving at a different rate, it would show up.

So if space is expanding and time is constant; then the only thing left to account for the variance is c.

Now I need to switch my brain off before I go mad :)

The problem with that demonstration that is glossed over, is that the dots themselves also get bigger, so the relative distances between them stay proportionally the same.

... their rulers, and indeed themselves, along with everything would also increase in size, so everything would appear to be exactly the same.

No; that would be the case if quintessence were the only factor, but at smaller scales other forces dominate. At the scale of planets, solar systems, and galaxies -- and even within galactic clusters -- gravity predominates. That is, things are pulled together "faster" than expansion drives them apart. And at even smaller scales, other forces (electromagnetic, nuclear) predominate even over gravity. In the balloon analogy, there is no other factor besides expansion. That's a weakness of the analogy.

I reckon we are the only monastery ever to have a dungeon stuffed with 16,000 zombies.

that would be the case if quintessence were the only factor, but at smaller scales other forces dominate.

Yes. But I wasn't alluding to the existence of really minuscule intelligences who's lives would be ruled by quantum phenomena. The balloon is a human-sized analogy for the universe itself, and the inference is that an external observer to the Universe would be able to perceive things that we as occupants cannot.

---

With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'

Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.

"Science is about questioning the status quo. Questioning authority". I knew I was on the right track :)

In the absence of evidence, opinion is indistinguishable from prejudice.

I chime in, you may call me a crackpot after this :-P

The problem starts with understanding that whole thing about the 'expanding universe'. People generally get that all the galaxies have their own motion, relative to us and everything else. And headline "they are all moving away from each other" is taken as read by most of us.

The 'expanding universe' notion happens to be just one of the possible explanation of the red shift of light. Another possible explanation is that gravitation isn't always positive (attractive) but slightly negative after a certain distance, travelling from a gravitational center, resulting in repulsion and causing slowdown of light, or lower frequency. Which doesn't mean, that the universe is not expanding! It might well be (and it sounds reasonable) that space unfolds as time goes along, since they are coupled. I'm not sure about space being the same size, it could be shrinking by the time...

History of science shows that things look overwhelmingly different after opening ways of thinking different. Take the transition to the heliocentric view, for instance. And there's always some neglected evidence at the root of such change.

Take the 'beginning of time'. There is no 'before' before that beginning, since 'before' is nonsensical without time. At the 'moment' time comes into existence (which moment is 0, zero, niente, zilch, since there's nothing to place that moment into or relate it to), it must come into existence threefold: as past, present, and future, so there are three zeroes here, and without those three zeroes there would be no transition. As time goes on, space unfolds. This is rather different from the big bang theory ;-)

Or look at the earth. Did the continents crack apart from Gondwana just because? or is it that at some time of its life earth has been "blown up", i.e. been growing? Does it still grow? Is the energy (=matter) absorbed from the sun equal to the amount irradiated? Hmm...

I personally believe that e.g. the Maxwell equations, Newtons gravitational laws, even Einsteins equations - do describe special cases of something more general.

perl -le'print map{pack c,($-++?1:13)+ord}split//,ESEL'

I personally believe that e.g. the Maxwell equations, Newtons gravitational laws, even Einsteins equations - do describe special cases of something more general.

I certainly can't, and won't argue with that. The great unifying theory is the Holy Grail of the subject.

I'm not so sure about the rest of it; but then I'm not that sure about anything to do with this subject. Every time I think I've got a handle on some corner or other; I read yet another learned opinion and learn better; or different; or less.

I often find myself thinking, usually late at night or early hours, that I've suddenly had some, fleeting, nebulous, breakthrough in my understanding of some aspect or other; but when I wake up in the morning, I'm all better :)

---

With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'

Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.

"Science is about questioning the status quo. Questioning authority". I knew I was on the right track :)

In the absence of evidence, opinion is indistinguishable from prejudice.

Hello BrowserUk,

As jdporter says, the expanding balloon analogy is not the best. The two I’ve seen are:

1. baking raisin bread (see the animation in Metric_expansion_of_space)
2. stretching rubber sheet (see http://www.felderbooks.com/papers/cosmo.html, section II)

— the point in each case being that while the “space” (bread dough, rubber sheet) expands, the entities in it (raisins, thumbtacks) do not:

In fact, not everything grows as the universe expands. In the example of the rubber sheet, the distance between thumbtacks keeps increasing but the thumbtacks themselves remain the same size. Similarly, while distant galaxies are pulled away from each other by the expansion, smaller objects like meter sticks, people, and the galaxies themselves are held together by forces that prevent them from expanding. So we expect that billions of years from now galaxies will still be roughly the same size they are today, but the distances between them will on average be much larger.

A minor point:

And if you accept the indivisibility of space & time; that they are aspects of the same thing as General Relativity suggests, ...

I believe that the concept of spacetime is actually a corollary of Special Relativity. If anyone is interested, I can recommend the book Simply Einstein: Relativity Demystified (2003) by Richard Wolfson as an excellent introduction for the layman (like me). It has a section which explains in detail the rationale for viewing space and time as aspects of a unified spacetime in the light of Special Relativity.

BTW, the “taster” paper you cite up-thread seems to say only that the speed of light may not be constant over time. Why do you assume that this implies it is increasing?

Athanasius <°(((>< contra mundum

Iustus alius egestas vitae, eros Piratica,

the expanding balloon analogy is not the best.

Agreed. But it is still the one I've most often seen presented. "The favorite"; rather than my favorite.

I guess my favorite is the stretchy rubber sheet with heavy spheres represent stars and planets and demonstrating the gravity wells and imprinted lines showing the curvature that results; but it's still an inherently two dimensional analogy (despite that dips give a third dimension).

I still find it hard to imagine a gravity well in 3 dimensions, and I guess that's because you need be in the fourth dimension to envisage it.

I have inordinate trouble with going above 3D; but I don't see that as a limitation, but rather as a deeper awareness of the underlying incongruity of trying to visualise something we can never really see. For example, this tesseract animation just demonstrates the limitations of trying to visualise higher dimensions with inherently 3D brains and devices.

If you want to make your brain go soggy, try to visualise a 4D sphere analog :) Then go here and see if you think the author's animation does it for you? (The write up is ... interesting also.)

---

With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'

Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.

"Science is about questioning the status quo. Questioning authority". I knew I was on the right track :)

In the absence of evidence, opinion is indistinguishable from prejudice.