studiot

Thank you for your answer, now we are actually getting somewhere. Since this is a speculation, not established Physics, you are entitled to posit a statement similar to A body requires to be acted on by a force in order to move. Of course as a speculation you will need to demonstrate predictions that result from applying this statement that can be checked by direct observation. I will tell you now that this was the belief held for thousands of years before Newton. Newton's great insight was to show that a body only requires an acting force to change its state of motion.

In response to the last superlarge dish of word salad I offer a simple analysis, I offered on a maths site to someone who thinks they have discovered a 'pattern' in the occurrence of primes. Since there are a very large number of primes (the ancient Greeks proved this large number to be transfinite) it is not only not suprising to be able to find not only a pattern but any finite pattern inclusded in that infinity.

Perhaps it is philosophic, but it is not a trick question. You talked about "fundamental grounds". So I am trying to establish what are your fundamental grounds. If by saying motion is the property by which it demonstrates its relativity (I have shortened this to the important part) I think in English we would say All motion is relative to something other than the moving object. I would agree with you. That leaves my second question unanswered. Are you aware of Newton's Laws of Motion ? The first one says N1 : A body will continue in its state of motion in a straight line, or of rest, unless acted upon by a force. So once again please state whether you agree or disagree with this. ?

So do you disagree with Newton's First Law ? What is your definition of motion please ?

Fair enough, but you wrote that , not I. and it was in the quote of your post that I responded to. So what about my request ?

I am not a cosmologist, and certainly give way on the formal detail to Markus (+1) although over the years I have seen cosmological theories come and go. Here is a less formal 2022 summary of Dark Matter and Dark Energy from someone I respect greatly, Frank Wilczek.

Really ? How does a meteorite impact show that "the distance from the planet's centre is constant " ? And if I was standing at the North Pole ? Apparantly not. Repetition does not improve understanding or veracity. Actually responding to the points of others migh go some way to achieving this. No, in my day (the 1970s) we did gravimetric surveys the hard way from on board ship or sometimes aircraft.

Well part of g depends on G, but as I said, G is a scalar constant. This means it is the same everywhere in the universe. g is a vector so how exactly do you derive the direction part of this vector from a universal scalar constant ? Your equations only tell part of the story, but omit the all important direction part. You also have yet to answer my comment that for the Earth it is just not true that Nor, for that matter have you defined 'the surface of the planet'.

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 ?