michel123456

I follow till there. And agree. After this point, please clarify. Thank you. Note: the Visible Universe is correctly represented in fig.1 as 2 (curved) lines. Those 2 lines represent Earth's past light cone. And the VU is the SURFACE of the cone. The inside part of the volume of this cone is not part of the Visible Universe.

Yes. The easy way is to forbid, then you don't have to educate.

Try Belgian beers. Chimay, Orval, Westmalle, Rochefort, Westvleteren, Achel, Leffe, Grimbergen, Affligem, Moinette, Mort Subite, Malheur, Bass, Aulne, Hoegaarden Blanche, Duvel, Liefmans, Maredsous, Floreffe, Saison, or other. There must be more than 700, you will find one (at least Stella Artois). Beer is an alcoholic beverage. It has the same age as civilization. It must have been invented in ancient Egypt or Mesopotamia. Agriculture founded sedentarism, & sedentarism founded the global civilization we know today. And at the same time agriculture produced bread and beer. Which have the same biblical simplicity: water and cereals. From wiki: "The invention of bread and beer has been argued to be responsible for humanity's ability to develop technology and build civilization." So from this point of vue I vote for alcohol. On the other hand, as you can hurt yourself with a car, you can hurt yourself with alcohol. It is a matter of good or wrong utilization of the poroduct. And you can hurt yourself with a horse or a camel too. And with water. From this second point of vue, I vote for education.

Alcohol is good and alcohol is poisonous. As said Paracelsus: "The dose makes the poison."

The problem you raise is about the concepts of inside and outside. When you make a closed boundary, a box, you are making a division of the Universe in 2 entities: inside of the box, and outside of the box. Simple observation makes us formulate 3 objective statements: 1. the inside part of the box (the content) is always smaller than the outside. 2. the inside part (the content) is finite. 3. the outside part is ...[insert here either "finite" or "infinite" following your convictions] IMHO the problem of point 3 is not the question of finite versus infinite, the problem is our "objective statements" under "simple observation". Mother Nature is tricky.

Replace the words "magnetic monopole" with the words "gravitational field", and it fits exactly. P.S. I'd like to vote for your post #7 at least 10 times, but I can't.

You are observing cats. All cats have 4 legs. So you are concluding that cats that you cannot see have 5 legs. Does that make sense? In other words, why should the unobservable universe be different from the one we are observing?

Hi Cap'n. I noticed when I reply using full editor, I cannot see the old posts numbers in Topic Summary. It makes difficult to write for example "in my post #32 I wrote ....blahblahblah", because the old post number vanishes from the right side of the blue band.

I know it is hard to swallow. My posts reflect my own ideas. I have a serious doubt you will find anything of it in any book. That's the reason why I have some difficulty to backup my claims. So you are free to consider all I say as complete crap. As you said, a gravitational field is used to be considered as something radiating, emanating from matter. But since we cannot find anything "emanating", I came to the idea that maybe something different happens. Beware of crap: My precedent post is slightly wrong. I should not have stated that a the grain of sand and his gravitational field are the one and the same thing. Since we know that a gravitational field extends both in Space and in Time, the corrected statement should have been : the gravitational field of a grain of sand was the same thing as the grain of sand. Which is even more difficult to swallow.

(emphasis mine) It is indeed a common conception. In this way of view, Space-time is a receptacle in which all things happen: when there is nothing Space-time is flat, when there is something Space-time is curved. I don't know what exactly is the standard accepted position on this but it seems all wrong to me. Look at things the following way: Take a planet, a rock, a pebble, even a grain of sand. You look at it, and it seems that any of those "things" are restricted in space. They occupy a certain amount of volume, you can measure it, and say it is blahblah cube meters. But we know that all these objects have a gravitational field around them. Even the grain of sand has a gravitational field that extents all around it till infinite. And we know that there is no way to dissociate the grain of sand from its gravitational field. In other words the grain of sand and the gravitational field are the one and the same thing. It means that when tou look at an object, a planet, or a pebble on the beach, what you see is only a tiny part of the object reality. So, the object and Space-time around it are the one and same thing. There is no immense Space-time receptacle in which objects are. There are only interacting immense objects (like the grain of sand).

I found Lemur's post quite sensitive. One could say that the definition of mass is gravity.

Your construction looks O.k. but it is not clear how does it come from. IMHO it is simpler to put the picture plane tangent to the back of the circle, and also choose a close distance so that the radius of the image becomes clearly larger than the original circle. The most peculiar in this construction is that the image-center of the green image-circle is not in its center.

If instead of a flash, I throw a stone from the elevator, the same phenomena will occur. That means that observation is relative, not that space-time is curved.

I don't understand.

Because Gravity, Time and Space are the one and same thing. Is that the kind of answer you are looking for?

Anamorphosis is something different. The precedent term, paramorphosis, is a common term in the Greek language meaning "deformation". It may not be the specific term designing the "deformation" you were discussing. I have some doubts about "without loss of definition". It goes out of my qualification. But you have to take into account _that this effect is due to the projection of the image on a plane surface.(if the projection was on a circular screen, no such effect would appear) _that the effect applies on object far away from the focus point.

I spent some time searching about sections of oblique cone, nothing. Then I made an Autocad drawing, which is very accurate : the graphic result is indeed an ellipse.

That was a joke. Belgian beer, with cherries instead of mushrooms.

Well, the maths are very persuasive. From the link "The conic sections in the plane are given as the locus, that is the set of all points (u,v) in E2 which satisfy a quadratic equation of the form (...) D = a c - b2 is negative, then the conic is a hyperbola, if D=0 the conic is a parabola and if D is positive the conic is an ellipse." The entire demonstration begins with the premise that we are examining a conic section. Correct. It is well known that there are 3 kinds of conic sections: hyperbola, parabola, ellipse. But here we have an unusual oblique cone, and I can currently not find any backup showing that all known equations of sections are still valid for an oblique cone. An oblique cone is a cone "in which the axis does not pass perpendicularly through the centre of the base" _see wiki Or to say it otherways, since only the ellipse is a closed curve (opposite to hyperbola & parabola), the supposition of a conic intersection points directly to the ellipse, and the whole demonstration is worthless.

Beer?

Great syllogism. I like it. Mr Dawkins is one of a kind. From the other kind there are plenty, so don't worry. You would have to worry in the unprobable case he was right. Einstein said that 100 scientists were not necessary to fight him: if he was wrong, only one would be enough. It is interesting that you find Mr Dawkins ennoying.

I have to admit I don't not fully understand your construction, better say where does it come from? and how do you insert it in a perspective view? You're welcome. Wonderful link. Thank you.

No. It is a kind of distortion. The sphere becomes an ellipse. In paintings & architectural drawings, there are 2 methods to avoid this effect: 1. avoiding to represent objects too far on the left or right (further than 45 degrees from the eye). 2. cheating. In photography, the same occurs. I found this showing what happen when the camera is too close (the angle is too wide), with rectification as the camera moves away. In real life, it is very difficult to observe. You have to close one eye, to focus on a point in front of you, and analyze in your head what you are viewing left & right. You need a lot of concentration to do that, usually you change your focus point, and you never take attention of the phenomena. It is a bit like looking in front of you and analyzing where does the picture ends, what is in the back of your head.

Correct. You know quite a bit in geometry. You must have been teaching.

Why not be true? IMHO the trick is when they show the artist working with bare hands. There are ways to use instruments, like the old-fashioned pantograph, and maybe others, based on the lever principle. With those instruments, a great movement is transformed in a small one, or the inverse. see also Nikolai Syadristy. and A.Schiller and Hagop Sandaldjian and & of Eduard Kazarian