studiot

Old saying "Don't count your chickens before they are hatched." I have one broody hen sitting on four eggs. How many chickens have I got ? When counting we can generally agree if 1) The numbers are small eg I have 5 apples in this bag. 2) The objects being counted are well defined (eg 5 apples) 3) The counts are not averaged. So 1) Large numbers. I doubt that anyone has ever enumerated all 23 digits of Avogadro's number, although it is an exact number . 2) How many rivers are there in the United states ? It depends on your definition of river? 3) Many objects eg insect populations are measured by counting per square cm for lots of square centimetres and averaging. This will not in general result in a whole number. Sensei's example of a geiger counter is also an averaged result.

Counting is often (but not always) an exact science. Don't forget the counting numbers. +1

So you 100% agree with me . . ... . I can't tell what you mean by 100%, but yes I agree that Science is built on perceived data. But I did not claim that is the whole story, whoever. Science is much more than that. Science is also about the systematic recording, collating and organising that data and comparing it with previously perceived recorded, collated and organised data, and also using it to suggest new interactions. This may well be the reason Science proceeds in bursts of activity, followed by periods of 'filling in' and structural optimisation. It is also the reason formal treatise textbooks like Euclid etc are more difficult than tests written for instruction.

Markus especially for you https://www.bbc.co.uk/news/uk-england-somerset-56427251

Well yes, this is where the Ancient Greeks went wrong. Science studies whatever you can interact with. If you can't interact with it is there any point studying it since it can never affect you, by definition. Abstractions are useful if applied to sunsequent interactions, otherwise they are just guesswork and dreaming. And yes there are some very beautiful dreams about, but I prefer to carefully distinguish between the pure fiction of what I can imagine might be and whatever my interactions suggest reality might be.

Thank you again for more useful information +1. It may be worth noting that no one outside the contract process knows exactly what went on and what short cuts, if any, were taken by various organisations. The US seems to have had a robust approach (even under Trump) which echoes the UK one of spreading the risk over many types of vaccine. I don't know how many here have participated in government procurement programmes on either side of the 'contract', but the UK government is currently being criticised for over short cutting the normal rules. I think the EU was a great deal more circumspect about this. I have personal experience of writing and administering contracts under both UK and EU rules and can confirm that there are many 'stages' to go through before commitment and even then the client can often pull out after this. Was it the EU politicians or the unelected beaurocrats ?

This thread is somehow about the difference between time itself and the human perception of it. I would question the thesis that human time perception is incapable of investigation by Science. In support I offer the following. Human time perception is governed by the rate of (chemical) processes within the body. We know that if all is tranquil about us so that we are bored and soporific, time seems to 'drag'. ie run slowly. If suddenly something happens to alert us, stimulating chemicals are dumped into our system and time seems to speed up. Whatever else the human may be, it includes a body which is a bag of multiple chemical reactions proceeding at once and interlinking. Such a system is not unknown is Chemistry - though of course we cannot at present compass anything as complex as a human - and each reaction has its own natural rate constant, some combination of these will be dominant according to ordinary chemical kinetics.

You need to factor in the rest of my post that you referred to. Thank you also for your replies (Zapatos beat you to it) Here is an interesting article from the BBC covid correspondent on the nonsense about vaccine side effects.

That surely is up to the citizens and consituent governments of the EU, who notably did not pull together during 2020, setting up physical borders between each other. In the UK the inquest into who messed up what and when has already started we will see if that is a whitewash or not but serious accusations by influential people have been made. As to the vaccine companies; note the difference between intent to order UK "we will pay for them whether they work or not" EU "we will only order and pay when they are proven to work." Up to Jan1st 2021 they had not placed any firm orders. How can any firm in any business guarantee to supply "whatever the client, in any quantity they want, with as little notice as the client sees fit to give" ? The best they can do is to say "we will do our best at the time madam", which is what they did actually say. https://www.cnbc.com/2021/03/12/us-tops-100-million-covid-vaccine-doses-administered-13percent-of-adults-now-fully-vaccinated.html Thank you, they are getting on pretty fast then. As swansont said Where did they come from ?

My own reading of the situation is somewhat different. I think that the EU leadership is manufacturing a dispute where none should exist to try to divert attention from their own abysmal failings. The UK placed firm orders at least three months before the end of 2020 and announced 'intent to buy orders three months before that'. The EU still had not placed firm orders at the beginning of January 2021, and indeed could not do so because it has still not licenced the vaccine.

That sounds a lot, citation required please. How is this number consistent with the fact we are just in week 10/11 of vaccinations ? By comparison the UK should just exceed 25 million vaccinations today.

So you are studying applications of partial differential equations. So what have you done so far ? What happens if you substitute for v and v' in the density equation ? Do you understand that the 'flux' q, will be the integral of the density over some region defined by x and t ?

Thank you Markus, for yet another big word. +1 Hiatus means pause or interruption not permanent cessation so I am pleased you have found something worthwhile to move onto and add to you list of accomplishments. I look forward to welcoming you back someday. 🙂

A radical view might be that it is amazing how long a time the covid vaccine took, not how short a time. Think back to the spring of 2020. Political leaders in the UK, America and Europe were all promising (hoping for) a vaccine ' in use by the autumn and before the 20/21 winter'. It was only the scientists who were saying "we would be lucky to have a working vaccine by 2021" Now we have the press and media whipping up antagonism to the Asta vaccine, using any excuse generated. Specifically those by the same crank lobbies that seem to oppose any modern medicine. They have too much media exposure. The media loves a controversy. Congratulatory reports are few and far between, over too quickly and soon forgotton in the welter of bad news.

I should also add that these books were selected as beings suitable for self study and for those who are not following a formal course.

Why or in what way is it a point worth discussing ?

Hello again Alex, I thought you had abandoned this thread. I didn't suggest Aline was looking for the same thing as yourself, just that there were some ideas and information there that would be relevent and useful to your question. So back to your question. I am sorry to tell you that not only does it not exist but it is impossible for it to exist. Just a little bit of history, then some references to what can be obtained (and appreciated) by someone with your stated mathematical background. As the 19th century turned into the 20th four of the top mathematicians in the world tried to do exaxactly what you are asking. All four failed for different reasons. The first two worked together to try to produce a book which took its inspiration from Newton's famous Principia for Physics and was to be the equivalent for Mathematics, So they called it Principia Mathematica. Their book was produced and was indeed a massive effort and success, it was not comprehensive. But by this time the scope and depth of Mathematics had grown so much that it was well beyond two people to comprehend it all, let alone one. And Mathematics was, and still is, growing at an ever accelerating pace. The two were Russell and Whitehead. Meanwhile Klein had introduced the Erlangen Program which married geometry and algebra in an axiomatic way updating Euclid. https://en.wikipedia.org/wiki/Erlangen_program And Hilbert attempted to build on this to provide an axiomatic basis for all of Mathematics. https://en.wikipedia.org/wiki/Hilbert's_program Then along came Godel in 1931 who published (over a period of time) his completeness and incompleteness theorems. He had proved that questions could be posed for all system of axioms as complicated or more complicated than simple arithmetic, questions that could not be answered within the system. https://en.wikipedia.org/wiki/Gödel's_incompleteness_theorems With reagrd to you desired book list I would recommend the following What is Mathematics, and elementary approach to ideas and methods By Courant and Robbins Principles of Mathematics By Allendoerfer and Oakley Unknown Quantity By John Derbyshire Discovering Modern Algebra By Gardner A survey of Modern Algebra By Birkhoff and MacLane From Geometry to Topology By Graham Flegg Introduction to Topology and Modern Analysis By Simmons Beginning Logic Lemmon Elementary Geometry By Roe Note this selection is far from comprehnsive, huge areas of maths are omitted entirely eg statistics and numerical methods theory. But they will take you from the classical high school notation to modern notation, without which knowledge you would be struggling. They would also lay a foundation for further studies at higher level.

The correct term for 3D is a ball not a disk. Disks are 2D. What you then describe doesn't actually work and all you have done by moving from 2D to 3D is make it a bit more complicated. Essentially you talking about a 3D ball travelling along a fourth axis. Yes this could be a valid picture, but that fourth axis cannot be time if the ball is 'travelling' since the act of travelling involves change of space with respect to another quantity called time. Just the same as if we consider a disk strung on a necklace and travelling along it. You will always need that extra different axis to describe the universe we live in and experience. Just as beecee sort of indicated. So if you want 4 space axes for some reason, you must still have another one called time.

Then I would say you don't fully understand probability.

I'd just like to point out the Heisenberg's Quantum mechanics is a matrix - energy formulation, not a wavelike differential equation. This thread is about Heisenberg QM. https://en.wikipedia.org/wiki/Matrix_mechanics

That's an unusual combination and spread of subjects. Alligation is used in Pharmacy for instance. Thre will be lots of 'word problems' where you have to extract the relevent information from the text to peform some calculation or deduction.

Wherever the water originally came from, fossils of marine life in the Himalayas etc are not evidence of total submergence, just of earth movements. The "land" as you call it ie dry land is technically called continental crust. There are two types of crust, continental crust and oceanic crust (which is the sea bed rock at the bottom of the sea) The oceanic crust is densier ('heavier') and the continental crust is lighter so 'floats' on top. It has been piled up by successive earth movements to heights that would not be all submerged by all the water on Earth. A simple test would be to estimate the rise in sea level if all the water from ice and the air were to be dumped on the ground. This would be less than 100 metres, yet there are mountain ranges many thousands of metres high. Clearly these would not be submerged.

Clearly the answer is no, time is not linear. I liked both the answers given so far, +1 to dimreeper and bufofrog. Just to add that perhaps linear is the wrong word for what I think mean. I think you mean homogeneous, which is the posh scientifc way of saying that every second of time is the same as every other second. Scientifically linear means something other than lined up or in a line. It refers to some very specific mathematical properties. So specific that even most straight line graphs are not linear!

It is a question of mathematics, not physics. Or more exactly it is a question to the application(s) of Mathematics in Physics. It occurs because of the dfference between addition and multiplication in mathematics. In Physics, if you take two quantities say length and width and add them together you still have the same physical quantity, viz a longer length. But if you multiply them together you generate a new quantity viz area. It may be that the two quantities have different physical significance, for example 10 miles per hour and 3 hours. Mathematically you can add 10 and 3 without a problem. But you cannot add 10mph to 3hours in Physics and obtain anything sensible. But you can multiply them, and obtain a new quantity 30 miles, which is different from either of the original quantities. An uncertainty principle applies when the two quantities are distributed or spread out to some extent along their scale. To go back to my area example it does not matter which order you multiply the pair of quantities you will arrive at the same answer. So length x width = width x length = the area and the uncertainty is zero. Or there is no difference between A x B and B x A or (BA - AB) = 0 (BA - AB) is called the commutator of this product AB If one of the quantities being multiplied has an extent in terms of the other quantity this commutator will not in general be zero. It's easier to understand this last sentence in Heisenberg's original pair viz position and momentum. In order to answer the question "what is the momentum of a particle when it passes point x?" you have to answer first the question "Which part of the particle passes x ?", since it does not all appear at x at once. Does this help ?

Timo is correct, (+1) to ask where the water would come from. There is not enough water on the planet, even if all the ice melted and all the atmospheric water fell out of the sky, to cover the entire surface.