michel123456

That's not my fault! The cosmological principle is: "the working assumption that observers on Earth do not occupy an unusual or privileged location within the universe as a whole, judged as observers of the physical phenomena produced by uniform and universal laws of physics." Now, if you analyze "location within the universe as a whole" you can say that the word "location" does not describe a point in space, but an event in spacetime. And that's it!

Yes. And my comment on that was that if Krauss is right (as it looks), then the current cosmology model is most probably wrong. It is not conceivable (IMHO) that we currently live a privileged period of the Universe, a period so special that allows us to observe the Universe in a different way than future generations on future planets would observe. To me, there MUST be nothing special in our position in space (cf cosmological principle) and in time: IOW there is no privilege to our position in spacetime.

Your skecth represents a scaling factor. Now i realize you & Icarus2 must be correct, and I must be wrong in posts #4 & 15 since the OP sketch represents a scaling factor too. Interesting way to link acceleration with scaling.

???? Sorry I understand nothing.

I'd thought that tidal locking time was profoundly unknown. But thank you for the info, Janus.

I added 2 tangents with intersection points A & B. The vector is tangent to the circle, so if I am correct the observer upon Earth should not observe any receding speed for objects at points A & B. Note: I understand that the vector at A & B is not parallel to vector at Earth, but in order to observe the vector substraction, you have to wait for several million years. If your measure is instantaneous (IOW seconds, minutes or even years), you cannot measure it. Right? or wrong?

You see that there are 2 sketches in the above image, with an equal sign in-between.

----------- Enjoying the silence. ----------

Now I know how to call a diapason in English.

I don't understand why that matters. "detecting" a photon means litteraly "catching" or "taking away" a photon. It does not matter whether it is before or after the slit, what matters is that detection happens before the photon hits the screen.

In the double slit experiment, doesn't "observing" mean "catching a photon" and thus "disturbing the experiment"? To me, the result of the double slit experiment means it is similar to a destructive testing.

If I am correct the objects moving tangentially (in the left sketch) should be observed as not receding at all (on the right sketch they should have only lateral speed). That would suggest a specific region* of the sky should be observed as not receding, and as much as I know that is not the case. So I agree with the "no" of Iggy. *i guess a paraboloid of revolution or roughly a disk if the centre is very far away.

I agree to make "lateral superluminal motion" a new topic. I'd thought that "lateral" motion for light is not observable. We don't see the light that does not come to us. We only catch the photons that hit our eyes (or our instruments) so that "lateral motion" for light (or superluminallight) is a kind of peculiar concept to me. Please enlight me.

O.K. Is there any equation around with m^4 or kg^2, or J^56 ?

Sure. You have a point. I understand that you are not sure if you can put a link here to your work. I am not a Mod, so I cannot answer that. But I am willing to have a quick look.

usually this kind of argument is used as an attack, not as a support. Lemaitre was a priest. IIRC Friedmann's work supports equally an expanding, contracting or steady state universe. quoting from wiki and from this other wiki article . So, paraphrasing: a model was created 100 years ago by a priest, -- endorsed by Einstein -- solved for accelerated expansion by Sean Carroll and many others, and popularized by Krauss..

Interesting.

You should use a dynamic graph to show what happens. Make a .gif The source emits photons all the time. The observer catches photons that where emitted some time ago. It is like the arrow of a hunter trying to catch a flying bird: the hunter has to shoot in a direction where the bird will be. In our case, the hunter (the source) ejects arrows (photons) in all directions all the time, so that the bird (the observer) is hit continuously. The photons travel in "straigt lines" (read geodesic).

Instead of "geocentric" you could use the word "relative". Every observer has its own present. This relative present is placed where the observer is. Anywhere else, it is not his present. Actually what an observer calls "the present" looking around him is in fact the sum of events he can observe at a simultanate time he calls "now'. Physically all these simultanate events belong to his past. The only simultanate event that is not in his past is the event of his own existence exactly where the observer is. So, to "us" (meaning by "us" an humanoid living on planet Earth in some 10.000 future years), the supernova will appear to explode then. For another observer anywhere else in the Universe, the supernova will appear to explode at another time depending on the distance. Only to an observer upon the supernova it appears to happen "now". So that's relative, that's not geocentric. You could call that "observocentric" .

IMHO the right question is: Where is the present ?

looks like Le Sage Theory.

Interesting indeed. There is no date on Petkov's paper. Isn't that a paradox for a paper about spacetime? ------------------- To the point: IMHO the Block Universe is a remain of the belief that something can exist in 3D space only. The Block Universe is the image of a collection of stacked 3Dspaces the one above the other (or the one after the other). I think this is a wrong conception. IMHO things exist in time first (that means vertically through the stacks) and then, eventually, horizontally (that is in 3d space). Existence means first displacement in time.

If Krauss is right, it is a good indication that he is wrong.

An object at the limit of our observable universe can be causally connected to another object outside of our observable universe.

(bolded mine) with all my respect, that is quite a bold statement. Maybe you should present yourself, the "who's talking" is important to me. My opinion: _In short, I agree, there were no ramps. _in long: I am architect. I have on my bookshelf a very interesting architectural book on the subject, with details, methods of construction, etc. The book is a french edition in black & white, from the 80's. External ramps are described and proposed as the way the pyramid were build. They should have been huge, representing more than 1/3 of the pyramid. I always disagrred with external ramps, considering that it would be insane to build something (pyramid + ramp) and then demolish 1/3 of the construction in order to obtain the pyramid. I strongly suspect that ancient egyptians had the same considerations than today about economy of means, rentability, etc. and were certainly not insane. So I always disagrred with external ramps. There are some theories about internal ramp, but I don't think they are correct. these theories require some difficult gymnastic to make the ramps coincide with the final scheme of a pyramid. Also, I believe we are looking at the pyramids in a wrong way today. We have those grandious monuments surrounded by desert and think that the builders had only sand, stones and ropes as building material. If we had a look at the pyramids 5.000 b.c., maybe (maybe) we'd look at monument surrounded by gardens, trees, maybe forest, instead of desert. IOW they had wood also as building material. Still today, wood is one the most basic material for construction. Wood was the only technical material for ages, remember all invention of Leonardo Da Vinci, all in wood. With wood you make cranes, chariots, ships, etc. So to me the slope of the pyramid is a function of the technical means of the times, it is the height at which one could elevate a stone with a kind of crane or other mean (with counterweight, no doubt) To be continued.