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Charles 3781

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Posts posted by Charles 3781

  1. 20 hours ago, studiot said:

    FYI Professors of English (and other languages) study and comment on works of English that have not yet been published and in some cases not even finished.
    And that is, of course, apart from connections they discover between various works of 'literature' over the ages.

    It is interesting that great breakthroughs in Science often arise when someone spots a connection between already know material, that has previously been missed.

    Thanks studiot.  I admit the general validity of your first point.  About discovering connections between various works of literature, over the ages.  This was brought out to me, very strongly, by repeated reading of one of my all-time favourite books: Vladimir Nabokov's 2-volume "Commentary" on Pushkin's verse-novel: "Eugene Onegin".  

    Nabokov, in his Commentary, demonstrates connections between Pushkin, Byron, Swift,  old Virgil and many other authors over the ages. None of which might have occurred to me. If not pointed out by Nabokov.

    Also, as a further,  more modern example -  Orwell's "1984".  When Winston and Julia go to meet O'Brien, their meeting is conducted in a manner strongly resembling a Catholic Ritual.  With O'Brien as the Priest, administering the wine,  and the Host,  (in the form of tablets). And taking Confession (in secret when the telescreen's switched off) and so on. The parallels are clear.

    But despite have read the book so many times that it's practically engraved in my memory -  I only became aware of the parallels after reading "Brodie's Notes" on 1984.  These scholarly clarifications of allusions and connotations, certainly increased my literary understanding.  Can't say they increased my scientific understanding though!

    Which leads on to your second point - about breakthroughs in Science arising from spotting connections in already known material.  I think something like happened when scientists used known NASA data from Jupiter probes to spot some previously missed Jovian satellites.  Not a great breakthrough, though,  was it?

    Can you think of any examples where previously known scientific  data has been re-examined -  with the result of a great breakthrough in Science?


  2. On 10/25/2020 at 8:14 PM, Hans de Vries said:

    Occasionalism is the dominant metaphysical stance in Islam and has been for 800 years now.


    It states that God constantly destroys the world and creates it anew, therefore all causality observed in the world is an illusion. Hence, studying the outside world is useless (because God can change t at will) and only study of theology is worthwhile.

    Catholic Church choose a different doctrine that God is inherently rational and by studying the world we are studying God (because he created the world)



    Before reading your posts, I hadn't realised there was such a difference between Islam and Christianity, in their views about studying the world.

    As far as I can gather, it boils down to:

    1. Islam says: There's no point studying the physical world, because God constantly destroys it, and re-creates, it according to His will, which changes all the time, so you never know.

    2. Christianity says: There is a point in studying the world, because God created the world once only. So by studying it,  you can get to know what His will actually is.

    Is this too simplistic?


  3. 18 hours ago, swansont said:

    Yes, there is some overlap. Scientists comprise some of academics. Academics comprise some of scientists.

     In the US, in my field (physics), 10-20% of PhD students end up with permanent positions in academia. IOW the vast majority are not academics.

    Don't you think the term "academic" is rather too vague.  It could encompass all persons who have attended an institute of learning. Whatever the learning was about.

    Thus,  a Professor of English Literature, and a Professor of Nuclear Physics, could both be described, simplistically, as "academics".  That's to say, they've learned things that most people don't know about.

    But  the distinction between them is this:  The  Physics professor gets his knowledge from following new experiments in modern science. Whereas the Literature professor gets it only by studying old books.  Therefore, I would classify the Literary bloke as a "Scholar". Not a "Scientist" at all.  Even though he's an "Academic". 

    Isn't there a huge difference between being a "Scholar", and being a "Scientist"?


  4. 9 hours ago, Sensei said:

    Yesterday, it was too late. OK. Now, I made program in C/C++:

    #include <stdio.h>
    //int primes[] = { 2, 3, 5, -1 };
    int primes[] = { 2, 3, 5, 7, 11, 13, 17, 19, 23, -1 };
    bool check(int a, int b) {
    	for (int i = 0; primes[i] > 0; i++) {
    		if ((a % primes[i]) == 0) return(false);
    		if ((b % primes[i]) == 0) return(false);
    int main(int argc, int *argv[]) {
    	int count = 0;
    	int end = 1;
    	printf("Primes: ");
    	for (int i = 0; primes[i] > 0; i++) {
    		printf("%d ", primes[i]);
    		end *= primes[i];
    	printf("End %d\n", end);
    	int half = end / 2;
    	for (int i = 0; i < half; i++) {
    		int a = i;
    		int b = end - a;
    		if (check(a, b)) {
    			//printf("Found %d %d\n", a, b);
    	printf("Count %d\n", count);

    For test case with 3 primes it gave:

    Which looks good.

    For OP problem with 9 primes it gave too many results to show them all (so had to disable printf()):

    18 mln is over twice more than OP value.

    Could you translate your program into BASIC, please, as that's the only programming language I understand?

  5. 22 hours ago, John Cuthber said:

    Only at depths where it could navigate by the stars in the way that sailing ships did.
    Attenuation of 1.5GHz GPS signals by water  will be worse than attenuation of light.

    Just wondering why water should impede radio-waves.  Water is composed of Hydrogen and Oxygen. 

    Neither of these two elements, by themselves, seem to offer much resistance to radio-waves.  For example, the Oxygen in the Earth's atmosphere doesn't prevent terrestrial radio stations from receiving  broadcasts over long distances.   And Hydrogen gas, which is present in large quantities on the planet Jupiter, doesn't prevent random radio-noise from that planet, being received over even longer distances by our radio-telescopes on Earth.

    This demonstrates that both elements are transparent to radio-waves.

    So why do Oxygen and Hydrogen when combined together in the form  of water,  block radio waves so strongly?

  6. 4 minutes ago, CharonY said:

    Absolutely and it depends on the complexity of the system. Simple and well controlled systems allow for precise predictions. Complex systems come with uncertainties attached. You cannot predict precisely, for example what is going to happen if you get exposed to a pathogen. However, we can tell a range of likelihoods of what to expect. 

    Well that's not Science.  Science means you can make precise predictions.  Otherwise, it's just well=informed guess-work.  Like, when you mention pathogens, such as the Covid-19 virus, there is no science in predictions of how the virus will affect people.

    Just now, swansont said:

    Not even that. Under the scenario offered by Charles, Einstein would not have become a scientist until Eddington confirmed GR. Which is ridiculous.

    Haven't Eddington's so-called "photographic" proofs of star-displacements caused by Einsteinian effects, long been called into question and discredited?



  7. 2 minutes ago, CharonY said:

    Oh you would be surprised. There are a number of tests and measures that result in fairly reproducible results (or at least similarly reproducible as other measures with uncertainties). 

    Uhm.  When you say "fairly reproducible results"... "with uncertainties",  does that sound like Science in its true sense?  

    I mean, couldn't Scientists such as Physicists and Chemists, provide exact answers to questions?


  8. 2 minutes ago, swansont said:

    Doing experiments is part of science. So is developing models, which are tested by those experiments.

    Yes, but haven't theoretical physicists developed models such as "String Theory".  A theory which apparently cannot be tested by any practical experiments.

    If so,  is "String Theory" science?  Or just philosophical speculation.

  9. Navigation of the supersonic sub will also present difficulties to the captain.  Travelling sub-surface at a dash-speed of 850+ mph,  he/she will be essentially operating blind.  

    Sonar will be of little help - aquatic shock-wave effects will delay and distort  echo-returns from enemy vessels.  Thus rendering precise torpedo launches hopeless.

    Probably, the best military tactic for the supersonic sub,  will be to come up to periscope-depth near an enemy ship, and get a  directional bearing through the scope,.  Then submerge, accelerate up to supersonic speed, and execute a ramming attack - Jules Verne "Nautilus" style - to slice the bottom off the enemy vessel by sheer kinetic energy.

    This will not damage the super sub, as its hull will, of course, be built of titanium/depleted-uranium alloy.

    What could possibly go wrong?


  10. On 10/26/2020 at 10:10 AM, swansont said:

    The shock wave in water would be an interesting phenomenon.

    A problem with streamlining a submarine hull is that it's not the best shape for a pressure hull. Keeping out pressures above atmosphere are a priority for submarines, whereas planes never have to deal with a static difference greater than 1 atm, usually it's even less, and when it's an issue it's about keeping air in rather than being crushed. An autonomous or remotely-piloted vehicle would be required.

    Swansont,  after pondering about the interesting  point you mentioned, "shock waves in water",  I've come to the conclusion that  supersonic submarines can't be compared to supersonic aircraft.  For this reason:

    Aircraft fly through the Earth's atmosphere - ie,  through a mixture of gasses.  And  gasses can be readily compressed, and pushed aside. Thus generating a Mach "shock-wave" in the atmosphere.  The atmosphere absorbs and dissipates the shockwave, turning it into a "sonic-boom".  Which may annoy remote ground-based residents.  But doesn't molest the aircraft.

    However - water is a different matter.  Water absolutely  cannot be compressed.  It retains its volume no matter how much it's squeezed.  This is indeed, why hydraulic machines work.    

    Therefore, it seems to me, that if a submarine accelerated underwater at ultra-high speed,  then when it reached under-water Mach -1,  the outcome would be crushing disaster for the sub.   

    Can you fault my reasoning?

  11. 34 minutes ago, swansont said:

    What is “derivative” here? What is “take the instantaneous vibration of the right area location”?

    A boat bobbing up and down is not stationary.


    From the viewpoint of someone aboard a boat, surely it is stationary. It's the sea outside which is going up and down.  This is elementary Galilean relativity. Which applies to us all.

    For example, from the point of view of the Earth, the Sun is going round it. When the the Sun rises in the east, goes across the sky, then sets in the west,  no-one on Earth experiences any sense of motion.  We stay still.  We don't experience any "whirling" movement.

    How can you confute this?  Without offending both Special and General  Relativity?

  12. 11 minutes ago, noquacks said:

    I agree, except that it was considered reasonable based on what man knew about biology, earth science, astronomy and chemistry 3000 years ago. It is not considered reasonable today. 

    Yes, but it was a decent first start.  For that, surely it deserves some respect.  I mean, you have to start from somewhere. Religion was a first attempt to organise our way of thinking about the Universe.  Later, we got into Science, which is much better and far more productive.  But the earlier religious ideas should not be despised, or so it seems to me.

  13. 20 hours ago, joigus said:

    Bear in mind, the rebound, if you prefer that term, goes to about a billion K degrees. Never mind collapse is not reached. What nucleotide can survive that? EM signals? Radiation in the universe doesn't hold information. In fact, in cosmological calculations, the entropy of the universe (the disorder) is about the number of photons.


    That is a very good point.  If the collapsing Universe reaches a temperature of a billion K degrees, as joigus plausibly suggests, no presently  living matter could survive such intense heat.

    Even atoms couldn't survive it, and certainly not organic molecules.  Only photons could survive.  Do you think that in the far future,  humans could evolve into photons?

  14. 16 hours ago, VenusPrincess said:

    If you told me the average temperature on the Martian surface was -60 °C that would be utterly useless for our efforts to engineer a rover to survive on Mars. A useful understanding of the thermodynamics of planet's atmosphere simply cannot be summarized in a single number. It contains very little useful information.

    Surely, you are going too far.  If we know that the average temperature of the Martian surface is -60C, how can that be "utterly useless" in our efforts to engineer a rover capable of surviving on Mars?  On the contrary, it has enabled us to engineer numerous recent examples of rovers capable of operating in this low-temperature Martian environment.  


  15. 28 minutes ago, John Cuthber said:

    Let me know if you find any "rational foundations of Religion".

    Don't you think that that Religion does have a rational foundation?  Which is this - it's an attempt to explain why things happen.

    Why things don't just happen at random.  Why, for example, the Moon doesn't just exhibit itself in the sky, in a random unpredictable way.  But follows definite rules, which involve a 27 day cycle between the first appearance of a slender crescent "New Moon".  Then its gradual "waxing", through the phases of "Half Moon" to a "Full Moon".  Then the "waning" phases of "Full" to "Half", and fading crescent.

    These nightly exhibitions of regular phase-behaviour, must induce a sense of "rationality" in the Universe, don't you think?  Which is what Religion attempts to do  - to provide a reasonable explanation for why some things happen.

  16. 4 hours ago, swansont said:

    IIRC it was burning/oxidation in metals, not the burning of wood, where mass increase was observed. Right concept, wrong target.

    Specifically I think it was a detailed analysis of magnesium.



    “Eventually, quantitative experiments revealed problems, including the fact that some metals gained mass when they burned, even though they were supposed to have lost phlogiston. Some[who?] phlogiston proponents explained this by concluding that phlogiston had negative weight; others, such as Louis-Bernard Guyton de Morveau, gave the more conventional argument that it was lighter than air. However, a more detailed analysis based on Archimedes' principle, the densities of magnesium and its combustion product showed that just being lighter than air could not account for the increase in mass”

    Swansont,  I stand corrected.  You are right that the phlogiston theory wasn't exploded by experiments which involved  the burning of wood.  Wood is too light and variable a substance to display convincing weight differences, on a 18th-century chemical balance,  between raw wood and its combusted ash.  

    However,  I do regard with deep suspicion,  your suggestion that phlogiston was debunked by experiments involving magnesium.  Can you offer any evidence for it?

  17. humilty's post mentions "tidal power".  This is sometimes cited, nowadays, as a potential source of "Green Energy".  That's to say, harnessing the ebb and flow of the tides in the oceans, to drive turbines, thereby generating electricity.

    As long as this electricity is employed for purely terrestrial purposes, I can't see that it would do any harm.  After all, the tides are created by the gravitational influence of the Moon, as it orbits the Earth.

    And the Moon doesn't care how its gravitational influence is employed on Earth.  Whether by making the Earth's oceans  just rise up and fall down again, creating pure kinetic energy.  Or by having part of this kinetic energy, converted , via turbines,  into terrestrial electrical energy.

    Either way, the Moon's energy "expenditure" would seem to be the same. So the Moon  would keep orbiting the Earth at the same distance and speed.  

    The turbines on Earth, couldn't affect the Moon, could they?

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