studiot

All surfaces are 2D, by definition. They can be embedded in any number of dimensions of 2 or greater.

I am bemused by some of the jargon employed, but I tested it on a tinnitus sufferer quote A form of ASMR? https://en.wikipedia.org/wiki/Autonomous_sensory_meridian_response

Like it. +1

This is exactly what I have been trying to say about the simpler situation for the OP. And this is exactly my point When I asked how would you measure it?

Take Strange's example of a sphere. Pick any point on that sphere. Draw in a disk of tangents to the sphere at that point. (you do understand that there are an infinite number of tangents running radially round the disk don't you ?) If we now consider a sphere point an infinitesimal distance away from our base point the difference between the sphere point and the disk point is infinitesimal or the difference is effectively non existent. That disk can be extended to infinity in all directions, defining one of Swansont' planes. As you move further and further away from the sphere along the plane, the difference between the sphere and the plane becomes larger and larger. That is what is meant by locally flat. In terms of the Earth, surveyors usually use what is known as 'flat Earth theory' for a disk of radius less than 10 kilometers. This means that they can use plane trigonometry and straight lines to measure things to better than one second of arc and one tenth of one millimetre of distance.

When you were googling you should have found out that the universe is locally flat. This is a mathematical requirement of continuity which means there are no tears or gaps in it, As in a wiggly line that you can draw without taking your pen from the paper. It is this property that allows us to move from on point to the next.

Stating things without support/evidence doesn't make it so. Why for instance could your first occurrence not have happened many times over with many blind evolutionary alleys? Now you seem to have dispensed with the first two and narrowed the issue down to the emergence of humans, so which do you want just humans or all life? I think that both this and the first quote tries to impute too much from too little information. You should be aware that we know absolutely nothing about any life on the earlier techtonic configurations of the Earth since all that material has been recycled.

What evidence do you have that either such events only happened once or that they will (do you mean cannot or will not?) never happen again?

Yes indeed, I wanted to use this simple example to help the OP explore in some detail what he thinks is happening.

It is difficult to know how to reply to this question since I have not once mentioned aging. I did, however, address your expressed desire to come to an understanding of relativity and showed sympathy with your frustration at the difficulty in doing so. So it is a pity that you choose not to engage in that discussion since you need at least a qualitative conception of the idea. In other words you need to know what it actually says (in simple cases) before you can discuss the more difficult applications. So here is a simple answer to aging. When relativity was first proposed in 1905, applications to aging were not considered. It was not until 1940 that the first application to aging was confirmed in Colorado by Rossi and Hall. This was not the aging of a living system but the decay of certain comic radiation particles called muons. These muons lived longer than expected by classical physics, as they passed through the Earth's atmosphere. But their lifetime was correctly estimated by relativity. However you need to get straight how relativity goes about making such an estimation, before discussing that aspect further.

Ya, it is very easy to go wrong when describing relativity things in separated space and time. Consider the following. Suppose a traveller leaves a clock on a stationary table and takes another with him. He then travels, at high speed, along a gigantic tape measure that is stretched out from the table and stationary relative to it. At any point in his journey he can read the tape measure so he can see how far he has travelled. But he has no equivalent device for time Equally, without the table and tape measure he would not be able to determine how far he has travelled, only for how long by the clock he carries. 1) No problem, you did well to get the distinction. 2) You should look at four vectors and in particular four velocity. https://en.wikipedia.org/wiki/Four-velocity

I don't think you are catching my point. Say the stationary clock emits red light and the other blue light. The diagram you have shown refers to red light only, The pulse should be drawn as a wave front of the red light that intersects the path of the other clock and bounces off its upper mirror to achieve the diagonal path shown. As far as the blue light is concerned it always starts from the bottom of the travelling rod and bounces off the upper mirror of the travelling clock, travelling exactly the same distance as the red light in the stationary clock. Swansont was not asking questions, he was trying to answer them and note he specified spacetime not time or space separately. The interval is a spacetime invariant.

That is not an explanation as to why the second diagram shows a diagonal path. Perhaps that is why he doesn't want to engage my questions? He is using speed as in the conventional sense of the magnitude of a velocity in the title. He is confusing himself by talking about the 'speed of time', which is undefined in Physics and certainly not a velocity. At best I can say it is one of the ghosts of the absolute I referred to before, because it implies a comparison with some base 'absolute' speed.

The OP is using two entirely different definitions for the word speed. No wonder he is confused. I recommend you avoid this trap.

Yes you use the NET and NETSH commands, amongst others, once in the interface.

How can this be correct or otherwise? What does the speed of a clock mean?

What meaning do you ascribe to the emboldened statement?

Two different explanations; that is why I called it is confusing. This is incorrect, it has nothing to do with the motion of the clock. Yes that's it, well done. +1 It is not helped by the diagram which shows a distinct pulse of light.

This explanation could be very confusing, unless you explain why the light 'signal' travels vertically in the first clock and diagonally in the second.

Well you haven't said much about my posts, perhaps you missed them in the barrage. One of them was about observing this 'fixed' clock. The point being that the observation takes time and can't proceed faster than light. This simple fact needs to be taken into consideration on any accounting of what is seen (observed) by two observers in relative motion.

I do believe we are beginning to stray further and further from the topic, although as I said I found your information theory / modern concrete mathematics theory centered view interesting. I see that you have also replied in my uncertainty thread over the holidays. Both subjects and one other where I promised some views pertain to the difference between Maths and Physics. So I propose to collect them all together in a new thread about just that and leave Kip to his question entitled spin, though I am not sure as to his exact question.

Yes relativity is difficult to get your head around. I read somewhere (Berkson :- Fields of Force Routledge) that the main reason folks have difficulty is that we naturally cleave to the idea of an absolute time (and space) and struggle to leave this behind. So the ghost of the absolute lingers and interferes when we try to understand. Swansont said it all when he said "clocks measure elapsed time", not time. Perhaps you missed this. There are many quantites in Physics that appear in two guises which have the same units but are not quite the same. In each case one of these purports to be an absolute and the other relative. Voltage and voltage difference Gravitational potential and potential difference Distance and length Time and time difference or elapsed time and so on.

A very interesting point of view. Thank you +1

Relativity has a more complicated elephant-in-the-room surprise in store that no one has mentioned. Say you set a clock on a table and receded at an appreciable fraction of the speed of light. Just how would you read and continue to read that clock? Or if you prefer when could you read that clock? You need to invoke the relativity of simultaineity since there would be an increasing time lag.

https://en.wikipedia.org/wiki/Beta_decay