studiot

So why did you not address the question I asked you ? G is a universal scalar constant. g is a vector which is not proportional to G and is the variable that measures the Earth's gravity field. They do not have the same units or dimensions. I quoted exactly which of your many points I was objecting to. Here it is again. And here is what I asked you. I should like to point out that there is a whole branch of Science called Geodesy, which I studied for postgrad, devoted to measuring and studying the fact that the Earth's gravity field does not follow these predictions.

That wasn't what I asked you. Do you know and understand the difference between g and G ?

I went to the time and trouble of carefully reading and analysing you longish initial posting. Then I asked you only 4 very clear questions about It has taken you two weeks to not answer even one of them. The above short reply was a repetition of what you already wrote and not a response to my question about that particular point. I'm sorry I wasted my time.

Why does the gravity field of the Earth not follow these predictions ?

Peter, if you don't tell us more we can't help you properly. I gather that English is not your first language, but the more you use it the better and easier it will become. Letters are symbols and so is infinity, although it is not a letter of any alphabet it comes from ancient Greek. In mathematics limits are not part of Calculus, although they are often taught just before calculus. The letters you refer to in the limit expressions are called dummy indices, which means they stand for integers and that you can use any letter, although, l,m,n i,j,k are the most common. Infinity itself does not correspond to or replace any integer, and only appears at the end of the limit arrow. This should be read that n 'tends to infinity' whcih means the process of getting larger larger for ever, but never actually becoming infinity so you don't replace n by infinity.

That's rather like saying to me "You have one penny in your pocket, I have two so I am very much richer than you are !" We could only just measure the difference two hundred years after Newton's death. So he was not very much wrong.

The point of Newtonian (gravity) and Maxwellian (electromagnetic) treatments is that they are couched in terms of mechanical forces. Mechanical forces are vectors that can be added in vector fashion to produce a vector resultant to work with. So when applied to field theory you have a vector field of forces for each source contributing to the overall result.

Somewhat depends upon what you mean by a Concept. Some would say that all numbers are concepts. It also depends what you mean by a number. Any number is of no use on its own. They are all part of some system of numbers or another. We distinguish many different number systems. There is no number system that contains every individual number. When others are telling you that infinity is not a number, what they mean is that infinity is not a 'real' number, or a number in one of the many simpler systems of numbers. If you would like to indicate where you want to go with this and also give us some idea of your level of mathematical knowledge we can give you are more detailed answer.

+1

+1

That's a good way to conduct a discussion. + Differentiation in the materials sense has almost nothing to do with calculus. In a materials sense (as being used here) it means a physical 'separating out' of different physical or chemical constituents, phases, mechanical grading of grain size, and all similar processes. Other technical disciplines such as medicine have yet other uses, doctors consider a 'differential diagnosis' which is a listing of (all) possible causes of a patient's symptoms. Mechanical engineer's refer to the 'differential' in a vehicle which is mechanical gearbox that allows various wheels to turn at different speeds when driven by a common drive shaft. The differential calculus is a mathematical technique that allows calculation of various important properties of all these systems. Does this help ?

I think the time has come to add another book to this thread. Frank Wilczek has asked the same question. In fact he has written a book about it "A Beautiful Question" There are many exquisite colour plates, here are a couple of samples, relating to Physics, the the ambit is very wide from sweet stalls in Barcelona to quark containment to mosque decoration.

I think you are just trolling here. Instead of solid answers to simple questions, excuses like when you are playing with words, again and again, as here You did not introduce two notions of time in your OP but suddenly you have Time and time - Why is this ? Equally there is less wrong with your Physics skills than you make out. You have introduced several advanced physics concepts, that you would not meet in everyday (non physics) life, in apparent answers to the points of others.

@Sensei and @exchemist Whilst both of you have vailid points, I think you are being a little hard on the OP. Concentrators (I prefer concentrators to compounders) are in use today in respect of solar energy. However these are mostly reflective collectors rather than refractive concentrators as suggested by the OP. Nevertheless whatever means of collection is employed it is necessary to collect solar energy over a wider area than where it is applied and a reasonable estimate of the area required is given in my calculation above. I think this idea is indicated in the posted diagram, although the OP may not have fully realised thes size of the area required at the top of his 'funnel'. So he would need a 260m2 magnifying glass to 'compound' (=focus ?) enough energy to recharge my brother's car in a day. This would mean a 10 metre radius glass.

My brother's Kia has a 64kw-hr battery. He lives in London, where the average total daily solar energy available is 2.5 kw-hrs per square metre. It follows that the total output of 64/ 2.5 ~ 26 square metres of collector for 1 day or the output of 1 square metre for 26 days would be required to recharge his battery, assuming all the sunlight is converted. I reality, solar cells average no better than 10% efficiency so realistic figures of 260 square metres or 260 days would be required. Our cousin in Alice Springs would fare better as the total insolation there is 3 times that of London. These are the true figures of 'compounding'.

Are you taking the piss ? I thought at first you had a serious question, but then you reject your own question. The short answer is, yes there is UV around and it's not all direct sunlight, it's not even all sunlight. And yes the subject has received intensive study from many different points of view. So would you like to restate your question unequivocally so we know what you really want ?

There is almost always more than 'a few bones' of evidence at a site. Not only that but H. Neanderthalis was abl to think and reason and will have chosen the best locations to live. Peoples that came later and displaced them will have ovelaid and mixed up with their own material. This is a double edged sword since on the one hand it damages the archeological record. But on the other hand it provides comparisons, especially for those things which stand out as 'different'. Skull shapes and sizes are one such example of a difference that was spotted long ago. Other records they left include cave paintings of thier world (as they saw it). And don't you think you are being less than complimentary about your cousins ?

Gosh so did we over here. I remember that. +1 Now we have the Tik Tok, Twitter and other well researched and corroborated media instead.

Whilst I don't see how any of your response is on topic, it isn't even self coherent. I wasn't aware that Claudia Kempfert worked for the BBC propaganda department. Do you have any evidence for this claim ?

Is the real reason for this thread to continue to deflect questions as to what this famous disaster of yours is ? Here is a quote from today's BBC News of something that may be similar.

Do you never blow jokes out of that trumpet (cornet I think, but I am no expert) of yours ?

We don't see evidence of time but see instead change which we assign a time factor. Aging is one of the things we see but can be reversed without any of the other signs changing. And I'm just another part of the physical world, as we all are, another 'node' as it were. You remind me of the Sunday preacher who starts with something innocuous, like 'as I was spreading the marmalade on my toast' and extrapolates directly to whatever brand of religion he peddles, hellfire and damnation / benevolence / whatever in your response to other folks. He inevitably ogneroe / dismisses any other opionions as though they did not exist and simple repeats his nonsense claims. I asked you who 'we' was and made it quite plain that I did not wish to be included in your 'we' - whoever they were and even offered a reasonable polite comment as to why I held that view. The first words of your response were to repeat the assertion 'we...'

What a good idea and example of lateral thinking. +1 Take an immediate lateral flow test!

I think this nonsense thread has shown itself unworthy of General Philosophy and note that the door to speculations and lid of the trash can are wide open.

Interesting, although I would place the output of reasoning as a conclusion and say that logic is more concerned with 'truth values'. +1