studiot

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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

Examples are always good, though I'm not sure about the first ones as you can make a fictional character do anything. But thank you for reminding me of Godel's story. +1 Well since fiction can be logical, why not ?

How does that work and why is it compatible with what you said before ? Do you think the only purpose/use of logic is validation ? Otherwise that's pretty close to my own view, except that I would add in the following. In logical thinking you are comparing with some external (logicians claim universal) standards. In rational thinking you are comparing the internal relationships/standards of whatever is under scrutiny. External standards are unneccessary. Both these these forms of thought can be used together. Sometimes it is difficult to separate them.

That would suggest you don't accept that you can apply any of these thought processes to non real or abstract things (like Harry Potter). ??

I don't think we know enough about the composition of the minor elements deepr down (the mantle) laet alone in the core. Here is the currently the mostl reliable information for the crust fromthe lates edition of Greenwood and Earnshaw "Chemistry of the Elements" I have highlighted gold whose symbol is is Au

Folks often throw in as justification It's logical that It's rational that It's reasonable that It's sensible that And other terms I haven't thought of Well most of the topic is in the title. But there are a few other words that are also used so they should be included in the discussion.

To the best of our knowledge (source Cambridge Handbook of Earth Science Data) For every silicon (ie rocky) atom in our solar system there are 25,000 hydrogen atoms (mostly in the Sun) and 0.0000002 gold atoms.

https://en.wikipedia.org/wiki/London_Bridge_(Lake_Havasu_City) Unless they rebuilt it. Funny that you should choose this example, of all the possibilities. But swansont and I have pointed out more fundamental problems with your proposition, to which we would be grateful for answers.

I posted this reference in another thread, to recent information about the New Horizons results.