michel123456

Yes.

I am extremely interested in scaling too. _ fractals are very interesting too because they show that scaling can happen indefinitely, IOW scaling is relative. The fractal shapes are the same when zooming in or zooming out. _Some other interesting geometric feature of scaling occurs if you use a CAD program: make a simple diagram with 2 intersecting lines (say axis X and Y orthogonal), then zoom at the intersection point. What happens? exactly nothing. Now, instead of zooming, make a scaling of the axis: it happens exactly nothing. The image you get is exactly the same independently of the scale factor. So from this POV you can't tell if scaling occurs in one or another direction (scaling in or out, zoom in or zoom out). Once you introduce a metric (a distance upon one of the axis) then only you can tell what is happening. A scale in corresponds to a zoom out, and a scale out corresponds to a zoom in. And indeed then scaling has a "direction". _Another interesting feature of scaling is that scaling is linked to acceleration: with the same scaling factor the closer objects are scaled less than the farther objects. For example with Sc.factor 2, an object at 1 metre of distance is scaled at 2 metres, while an object at 100 metres is scaled at 200 metres. The increase is proportional to the distance (the Hubble Law comes immediately to mind). see also this outstanding post from highly valuable member Iggy on this Forum. _Julian Barbour and his collaborators have made a wonderful research in this domain. See here for more info. Have a look at the whole site, especially under Shape Dynamics. Outstanding job IMHO. _I also have my pet theory you can evaluate from this thread. Not much different from your idea I suppose. ------------- (edit) note on my pet theory: I am convinced that the scale factor is that feature which introduces the arrow of time, the direction you are talking about. No matter whether the scaling is in or out, it cannot be in and out, the 2 states are mutually exclusive.

I agree. The member receiving the neg rep should know where the hit came from, and the one giving the neg rep should wear responsibility for this. I have another crazy proposal: The neg rep that you give could come from the reservoir of pos rep of the giving member. You positive reputation is then like a bank account from which you can spend neg rep as payment. Rep point becomes an exchange unit (like money). only members with lot of "money" would dare to spend their "money": only valuable members would spend their rep points. What do you think?

Sort of. Have a look at the 3rd diagram on the link below. Beware to understand the first ones also. http://www.phy.syr.edu/courses/modules/LIGHTCONE/schwarzschild.html

In a BH light is not sucked, it is spacetime that is so much curved that a ray of light following the geodesic will enter again the BH.

Why do you say that scale is not relative?

I intended to say that K is a factor, a ratio, an angle. Put tachys on x axis, put seconds on the Y axis: the result is a surface rectangle representing distance in metres. The angle of the diagonal of the obtained rectangle represents K. The pizza has just arrived. Coming back in a while. Back. yes and no. Yes to your first 2 sentences. No to the rest because tachys is supposedly more fundamental than meters. You are dividing meters in order to obtain tachys.

meters are rods, seconds are clocks. radian and degrees are angles. It can be considered that C is the conversion factor of rods into clocks. but it should be evident that a number without unit cannot convert rods into clocks (convert meters into seconds). Indeed, C has unit meter/sec, which is a tautology. Once you put a name to something suddenly it exists. Once you put a name to the unit of velocity (I don't like my 2 first proposals, lets call it "tachys" for the moment ), here we are, tachys exist. Then one can say that a metre is a tachys multiplied by K seconds. (where K is unitless) So, a distance, a metre is something complex (not fundamental) made up of 2 things: velocity and time.

After reading this outstanding pdf arxiv first provided on this forum by DH in this thread post #11: It is stated and commonly accepted that C is a fundamental quantity. (Trialogue on the number of fundamental constants Authors: M. J. Duff, L. B. Okun, G. Veneziano, 3.1, page 4) Why then C has no "fundamental unit" (a unit of velocity, call it for example "velocimetre" or "velociconds") and is paradoxically exprimed as a ratio of 2 other units, metres and seconds? How come that the metre or the second is a part of something fundamental? or Ultimately, is it possible to have something that is a part of something fundamental ? In the third part of the same paper: (Trialogue on the number of fundamental constants Authors: M. J. Duff, L. B. Okun, G. Veneziano, 4, page 25) And further: (Trialogue on the number of fundamental constants Authors: M. J. Duff, L. B. Okun, G. Veneziano, 5, page 26) bolded mine. Wich is a statement that presupposes that there are more than one unit necessary in order to define something fundamental. Isn't that a wrong concept?

Doesn't that mean that a dimensionless number (as a result of unit cancelation) keeps a "meaning", although unitless?

from wiki http://en.wikipedia.org/wiki/Category:Units_of_angle Bolded mine And under Wiki's page Slope Bolded mine.

Fantastic DH. +10 if I could. -------------------- Commenting the arxiv: http://arxiv.org/abs/physics/0110060 It is stated that in some practical unit system, C =1 (dimensionless number) It is also stated that (bolded mine) But a "conversion factor" (a ratio) is a way to convert some unit into some other unit (usually C converts metres in seconds and vice-versa). It may be a dimensionless number but it applies to some unit. Whithout any unit in the first place you cannot obtain a second one. IOW I miss the supporters of the Single Constant Party (paraphrasing Michael J. Duff).

Right. But no smiley. Different numbers representing different physical things ought to have different units. Imagine you make unit cancelation in some weird new Theory, you may obtain totally unphysical results.

Great reply! Thanks But in the long list of this article: No Angle (because angles do have units) although angles are treated in the text. No Percentage (which is a ratio, treated several times in the right column of the list----after some thinking any number is a ratio, isn't it?) Maybe I am looking too far, but I find it very amazing that a ratio (no unit) is the same thing as an angle (or is it not?) -------------- (cross edited -the + rep was for the unedited part above, thank you) Bolded mine. O.K. that is 5% volume of alcohol by volume of beer. These are 2 measurements of 2 different things. And that's maybe the answer to my question: when measuring a slope, it is a ratio of vertical measurement by horizontal measurement, again 2 different things.

An angle represents something physical too. and has several units. See Wiki. And any unitless number is not necessary an angle.

This thread paraphrasing an old interesting one in this same forum. As always fascinated by the power of units and after a post of dear Swansont, here are some thoughts: _as an Architect, I use quite commonly a method to measure the slope of a piece of land, or the slope of a ramp, expressed as a percentage. For example say you have a ramp 10 meters long going one meter up, that gives a slope of 10% What did you do? You took the eight divided by the length (the horizontal projection), that is: 1m/10m=0,10 or 10% In fact you divided meters by meters and ended up with a unitless number. This unitless number represents something physical though: it is a slope or if you prefer it is an angle. An angle of 10% that can be translated in degrees.(arctangent 0,10=5,71degrees approx) And degrees are a kind of unit. So, dividing meters by meters you did not end up with something unitless. Or do I miss something?

It works fine for me. No problem.

If a is a unitless constant, it can arise from geometry (like number Π ).proportionality is maintained.

(bolded mine) exactly, proportionality.

from http://www.bigfootlunchclub.com/2012/01/robert-lindsay-bigfoot-dna-news-updates.html ----------------- From the story I understand that a dog, a deer, a squirrel, a bear and a human female licked the camera (I didn't knew that there were Clinton's scheme cameras in the U.S.).

There must have been attempts to derive the physical constants from pure geometry.

I agree I suspect that the Universe must be extraordinary simple, while the Observable Universe might be extremely complicated.

(hidden line mine) I agree on all that is written above the line. I don't understand the connection with what is beneath the line. To me the fact that constants do exist with that specific value is indeed an amazing feature of the universe. But I don't think the solution to the mystery (if any) is "programmed simulation". ------------- edit On the other hand it would be interesting to discover (or invent) a universe without any physical constant.

the negative of this region is a bottom. . . . . Sorry I couldn't resist.

mmm. That's not about rating SFN. That's about why posting once and then leaving. I myself may have done this in the past. I can't recall exactly, it was on some newspaper site. This Leerdamer is striking again. (edit) Alzheimer. ------------ If I remember well, it was after googling for info, reading some BS and wanting instinctively to say something fabulous, then becoming totally uninterested in what I wrote. Something like that.