Are you suggesting the HK was being sarcastic? I can't believe it, no it simply cannot be true.

there is indeed evidence to suggest she may have been, unbelievable as that may sound to many here

Actually, no, I wasn't.

What if photons really do get tired? Wouldn't they appear to slow down to us, and shift to the red?

Not seen that yet, any good?

Not exactly news.

that would require them to be living, animate beings. IFAIK there is no evidence to suggest that, but anything is possible in the world of theoretical physics

But is anyone looking for the evidence. We already know the speed of light is not actually a constant, and can vary under different local conditions.

If light particles/photons/waves lost enough energy that they simply stopped, but still retained enough mass to be detected, there's your dark matter.

Obviously, I'm not a theoretical physicist, and I could be talking complete horlicks. But then it's those kinds of leaps of intuition that drive science forward.

What is "speed"?

We define it as the distance travelled in unit time.

The "speed of light" is the universal constant relating mass and matter. It is time and space that vary.

Open question: once light has passed through a denser medium, say a prism or water, which has slowed it down, does it then speed up again once it leaves?

In regards to the tired photon/dark matter theory I think we may have strayed in to the first stage of learning in regards to quantum mechanics: unconcious incompetence. It must be more complicated than that surely?

Good question. Perhaps it's still moving so quickly in our locality that it still seems to be at the usual speed.

I don't mind being shot down in flames. I throw these ideas out there on the principle that sooner or later I might hit on something worthwhile.

I'll assume that's rhetorical, but answer anyway...

The observed speed "slows down" through the medium with a higher refractive index, and then returns to "normal" when it escapes.

However, it never really "slowed down". It's just that it couldn't take a direct route, and had to go around all those annoying obstacles you find in lumps of stuff.

cheers.

I think we are still way back in the stone age with regards to science. We are still trying to use stone-age methods - such as bashing atoms together to find bits. Reminds me of smashing bits of coal/rocks together to find hidden gems. Consequently, in this lifetime, I don't think we will ever get to the mystery of the universe or the 'verse.

Personally, I believe that we are in a 'verse next to other 'verses but separated. Best analogy I can think of is foam bubbles. There's no evidence for this, but it's what I believe is our existance.

As for 'deities', I think that there probably is one and we're still in the dark about it. There was a time where it was inconceivable that atoms existed. Didn't mean atoms didn't exist. Just that we didn't have a way of finding and measuring them. Ditto with 'God' or whatever you want to call him/her/it.

As I said, I wonder if our rudimentary and underdeveloped minds are capable of comprehending the "truth" about what really goes on. Humans are well known for their inability to see beyond their own sphere of existence. We are all generally self-centred to a degree and oblivious to the world around us a lot of the time. Perhaps the same is true about the bigger picture.

True, we may be at a similar point regarding the Universe(+) as we were when we looked into the distance, saw the horizon, and believed you would fall off the edge...