michel123456

Length discrepancies? Less important than time discrepancies? I don't see any length discrepancy in the following formula (about gravitational time shifts). from here

IIRC the main cause is the vertical position. (sorry, can't find any ref, it may be BS)

I think you are not far from Islam.

I agree and disagree. I am astonished that you state simultaneously "reason is the controlling force of the universe," and "Only by maintinaing a notion of God can we protect our liberty." I cannot follow how you filled the gap between the 2 sentences. I prefer reason. Alone. You can add to reason anything you please, even God. Simply, I won't. You have described how terrible situations occured due to a difference in religion. I don't want this to happen again.

I was not expecting such a capitalistic idea from Marat. "frontiers are scars on the visage of the planet" says a graffiti.

I understand. You must be right.

The Hafele-Keating experiment?

It is not the answer. Now the pupil must prove that a 4 nm thick layer of oxide is enough insulation for 220V electric current.

Interesting. I thought epigenetics do not act upon DNA.

It means that the displacement of light in spacetime is null.

I have no doubt. Why is this called a spacetime interval?

In any gravitational potential Relativity states that time dilation takes place. But Relativity states also that Speed Of Light is constant. So I presume that under gravitational potential, not only time is dilated, but space too, in order to preserve the relation c=d/t unchanged. So, when time contracts, distances contract, and when time expands, distances expand. Is that correct?

No it does not help much. Of course zero is invariant. Since light moves in straight line, we can always choose a XYZ system of axis so that X corresponds to the direction of light, obtaining the elementary equation [math] x=ct [math] or [math] c=x/t [math] which is the definition of speed. For any other random system of axis, you take Pythagore and you get the squared equation, what's the big deal? What we did is α=βγ, rearranging into α-βγ=0, stating then that zero is invariant. My question is how did we call zero a "spacetime interval"?

Nobody answered, no matter, that was not the main question. The question is the following: We have [math] r=\sqrt{x^2+y^2+z^2}=ct [/math] On which we all agree. By squaring, we obtain [math] r^2=x^2+y^2+z^2=(ct)^2 [/math] And thus [math] x^2+y^2+z^2-(ct)^2=0 [/math] How came the idea that [math] x^2+y^2+z^2-(ct)^2=S^2 [/math] ?

The described situation with rotting potatoes corresponds to a phenomena where the Moon continuously moves away from the Earth. When the distance increases, the gap in time increases too. The 3 sec become 60 sec, then 60 hours and so on, as in the potatoes analogy. Simply distance makes the work of time. In the potatoes analogy, the travel of Neil Armstrong 3 sec in the past has been negligated. Or if we had a crane to grasp the Moon and take it close to Earth, we would also make the Moon travel 3 sec in time. It is always true, even if the Moon was 3 billions light years away, in distance & in time.

I don't understand. At the moment there is a gap in time, there is what we call past, present, future, or do I miss something? The Moon is there in the sky at a gap that corresponds to about 3 light-seconds. From our point of vue, the Moon is in our past 3 sec ago. When an astronaut goes to the Moon, he walks on the Moon in his present, and in our past. I think that if one goes from the kitchen to the attic, it is the same than traveling from the Earth to Moon. Landing, you will not find the Moon 3 sec ago, and going to the attic, you will not find your potatoes older.

Food for thoughts. Thanks. Besides, who is that guy next to you?

There is a Variable Speed of Light Theory which is outside mainstream physics and others (look here) as the one proposed by Halton Arp. And you may find on the web some articles about alternative explanations of the cosmological redshift but you must be highly cautious about all of these. As much as I know, all alternative theories , except old ones, rely on Relativity.

You have to do the math to say that. Here an example of my thoughts without maths: Lets say you are in the kitchen, and you put your potatoes in place. After some time it is 6.00 o'clock in the kitchen, 7.00 o'clock in the attic, and 5.00 o'clock in the cellar (because time clicks slower in the cellar). As seen from the attic, kitchen & cellar are in the past. And the more time elapses, the more in the past they will be. So one could say that time acts exactly as if the distance between the attic, kitchen & cellar was increasing. The observational result is the same. And this result is comparable with what we are observing from Earth looking outside to the universe (instead of looking inside as seen from the attic). Do you agree?

I thought it was time dilation Also I strongly suggest to read again the gravitational redshift article of wikipedia, in which the role of acceleration is explained. But of course I am probably wrong.

divide by 100 first. 181,3 cm becomes 1,813 cm (approximatively 1,8 cm)

I believe the crucial point is always what we see, and never what happens. If you were in the cellar with your potatoes, would you notice anything? No, of course, because the effects of time upon your potatoes would be the same upon you. The question arises when the observator is not in the cellar, and it has all to do with observation, curvature of spacetime under strong gravitational potential, S.O.L. and all that kind of stuff. IMHO it is a wrong interpretation of Relativity. It does not take into count all the parameters, like the displacement & enormous acceleration of the potatoes when you placed them in the attic (with the help of a rocket) & the cellar, and when you took it back to the kitchen with a crane & much difficulty, remember the gravity well has been immensily exaggerated.

Maybe there were other "intelligent apes" around and we killed them all a long time ago to assure superiority. As to "why are we intelligent?" My opinion is that it is a mistake of mother nature. Our brain was, and is first designed to control a bunch of operations inside our own bodies. As a matter of survival it controls also the relation between our bodies and our environnement, through our senses. A small part of these relations has become conscient, and that part is what we call "intelligence". Maybe one day this function of the brain will tend to contract, and that will be the end of Homo Sapiens. Otherwise, if we ever find an insect or any other specie the same intelligent as we are, we will try to kill it at first sight.