michel123456

Maybe you looked early when I was editing. I posted: Interesting, I have never observed something like that. Usually I see the sunset at one side and (almost) black sky on the other side. Like in your fish eye picture. Editing again, I looked at your link where my display gives a better resolution of the fish eye. Again I have never observed anything like that. But we are not talking about the rays that do not reach the Earth. And the fact that the intensity drops down is irrelevant. However I understand that the square law is a result of geometry. (surprisingly because the geometry is plane, 2d, while the sphere is 3d). So intuitively it should be a cube law, contrarily to what is happening. (edited because irrelevant) Anyways I still hope that everybody (except 2 or 3 respected members of this Forum) consider that the sun rays that reach the Earth are parallel. As stated in Eise link: https://www.atoptics.co.uk/atoptics/anti1.htm

That requires an explanation.

Of course they don't radiate perpendicular to the Sun's surface, that's why I draw the orange ones in my sketch. The rays we receive are the ones between the orange triangle. My sketch is not wrong. I don't see we are disagreeing anywhere. The grey rays in my sketch are indicative. As I said, we are receiving rays from the entire surface of the Sun. Interesting, I have never observed something like that. Usually I see the sunset at one side and (almost) black sky on the other side. Like in your fish eye picture. Nonsense?? The discussion is about the direction of the rays, not about their intensity. And if you can draw "less than 1 pixel" be my guest.

The sun's intensity is irrelevant. The rays would be divergent if the Sun was a point but the Sun is huge compared to the Earth. Since the Earth receives rays from the entire surface of the sun (not only from its center) in fact the surface of the Earth receives converging rays (the orange ones on the sketch below). But because the Sun is so far away (much more than in the sketch), the rays are considered reaching the surface in a parallel way. The grey rays on the sketch are spread around the Sun through the universe and do not reach the Earth. If you compare the sketch with the picture, you will see that what we are observing is exactly the contrary of what is happening.

It has been closed. I was looking for a forum about Geometry. The meaning is to show that we are so deeply inserted into geometry to the point we don't even take notice of it.

I couldn't find a better place. Of course there is an answer. It is not a theory.

The rays of the sun that hit the planet Earth are parallel, we know that. Even ancient Greek Eratosthenes knew that because he used this particularity for measuring the Earth's radius. Then the question arises: why at the sunset do we see the sun rays converging towards the sun? (it is a sequel of an old thread I cannot find back)

The only photon you can directly observe is the one that hits your eye.

Replace the photon with a bullet. the bullet will look like accelerating, until it hits your retina (and you are dead). So with the photon it is likewise. Except you do not die, you see.

I am talking about observation, not about what "really" happens. Of course the passengers are not crushed. Exactly as in Relativity, the pilot of the spaceship is not crushed by length contraction. Both are an effect of geometry as observed. That was not my intention. The question about the observed state of motion is enough.

What video format is compatible to upload directly here? (not from Youtube) Look at the video again. First second, the bike is far away. At about sec 3 the bike is still away. At about sec 4 the bike suddenly appears and wizzzz. The same thing happens when you are in motion. I suggest to take attention the next time you will drive your car, and notice how the poles appear slowly in the background and look like accelerating when you pass them. Look at the poles & the bushes at the extreme right of the video. They disappear in a glimpse. At the center (the vanishing point at the horizon) the seem motionless. I know it is so usual that it is difficult to analyze. I understand your sarcastic comments. All the objects look like expanding as they approach. The distance between the objects looks like expanding too. But the time needed to go from one object to the other remains the same. An increased ratio of distance versus time is an acceleration. As observed because of geometry.

I like your argumentation.

Because it behaves like the bike (have you clicked the link?). The poles look like getting shorter yes. Due to geometry, yes. The poles are not accelerated, but an object going from one pole to the other looks like accelerating. At the horizon, the object motion will look null (zero motion). Next to you the motion will look maximum. In order to get from zero to maximum, acceleration must have taken place (as observed).

e are living in an accelerated world: have a look at the picture below We know that the distance between the poles is D. What appears to us is d4 larger than d3, larger than d2, larger than d1 etc If you are looking toward a motorcycle coming at you at constant velocity, what will you see? You will see the bike travelling d1 in say 1 sec, d2 in 1 sec, d3 in 1 sec, d4 in 1 sec. IOW you will see it coming slowly from far away, then progressively accelerating and suddenly wizzz in front of your eyes, then vanishing slowly to the horizon on the other direction. Like this: (link to a FB page with a Kawa at high speed) https://www.facebook.com/Kawasakicontact/videos/2728924687158606/UzpfSTEwMDAwMzIzNDE0NjE4NToyNjQwNjg1Mzk2MDQ5MjM5/?id=100003234146185&__tn__=%2CdlC-R-R&eid=ARBelMYfc-RJjAd_mXYlZx6caClxobLbN35at8MbKRlvdlHP8Er__IHh671LLBzYt5XUo6uQ7NtRryeG&hc_ref=ARSdLXkLSE5Ur04hkZaY8o5B1UndaVN0aNDCH7aAba-95_DHRFTDMStvEIKfKkQ23hQ It means that the effect of perspective transforms the constant motion into accelerated motion, for anything coming from far away in your direction. It means that even photons that reach your eyes must appear accelerated.

About tokamak, there is currently an international project under construction in southern France. see ITER https://www.iter.org/proj/inafewlines In Oxfordshire it is the private company Tokamak Energy working on it. https://www.theengineer.co.uk/tokamak-energy-15-million-fusion/

I don't understand clearly what you are trying to say. What I try to say is: To me Time is very fundamental. More fundamental than space. From my understanding, time is "inside" the spatial dimensions, it is not something you add after "creating" Space. The distance that separates you from the stars can be estimated with 2 values: the number of rods (or kilometers or yards) that you must put in between, or the time you need to get there (in practice the time light needs to get to you). The 2 measures are equivalent. IOW one could consider that time is the equivalent of distance, expressed in a different manner. Literally that time & distance are the same thing: that would explain naturally why space expands when time shortens, keeping c at the same value. However it is unconventional because time is defined by "what the clock measures" and not "what the tape-measurers measure". And one is used to observe a distant object as "far away" and not "time away".

Studiot wrote: And time is a physical process as much as I know. I wonder how you "include time implicitly" mathematically.

So I was wrong. The volume (& mass) will be different but it seems in the mathematical example, volume (&mass) does not matter.

"Two physical objects cannot occupy the same space" at the same time. They can occupy the same space at different times. And that makes me think that maybe (maybe) the duplication of the Banach-Torski paradox is the result of not including time in the equation.

Today I realized that the Apple inc. logo is not coming from Adam's apple (because it is eaten) but from Newton's apple falling from the tree. See the 1st logo of Apple on the left.

Nice argument. +1 So if I understand clearly the above, the reverse operation is mathematically doable. That is 1 orange + 1 orange = 1 orange. Isn't it? And in this case, doesn't it raise the question (again) of what is 1? Nice! The Galton board is exactly the kind of example that makes me think that it is not a coincidence that maths correspond to physics. It may be that maths are so abstract that they relate to the abstract background of the real world. Or it may be that maths have been created on the basis of the real physical world. IMHO the latter sounds more realistic. Could this be related to Mandelbrot's fractals?

I understand James Wheeler's One electron universe as showing that the concept of unit (the number 1) is directly linked to time. If a unique thing (unit) can be at different point of spaces at the same time it fails to be one. And if the concept of 1 is under scrunity, I suppose that maths should be under scrunity too. Maybe is that the reason of our difficulty to understand entanglement, when 2 particles separated by space behave as if it was the same and one particle (1 unit composed of 2 separated intervals on the number line).

This sounds like coming from ancient Greek philosophy.What are the arguments that support this statement? And I wonder, are there arguments against this? I mean, scientific arguments. Not philosophical ones. For sure arguments can not come out from physics because if so, it would be a counter-argument.

It may be a physical abstraction but IMHO it is wrong. For anything to "exist", even if this thing is an abstraction, you need time. What the mathematician describes as a point is in fact the section of an invisible line. Because if the point is described at the beginning of the concept and continues until the end of the explanation (standing as an abstraction on the black board), it means it "existed" a few seconds, or minutes. IOW what we see as a point on the blackboard is in fact a line (the translation of a point on the time line). Since it is physically impossible to "get out of time", we should always add inherently 1 dimension (the T dimension) to anything observed or described. And not add time as a 4th dimension, as if geometry could exist "out of time". It gives the false impression that space could somehow exist without time.

Very loosely, since space & time are transforming the one into the other it means they are "made up" of the same stuff. It also means that when you look at something in space you also look at that thing in time. It is evident for the stars: the farthest means also the oldest (in regard to us) and the youngest (in regard to the universe). It is less evident for things around you: the wall in your room is also at a distance in time. In fact, what you see at a distance is truly another image of time, different from the sensation given by the tic-tac of the clock.