Jump to content

exchemist

Senior Members
  • Posts

    1201
  • Joined

  • Last visited

  • Days Won

    16

Posts posted by exchemist

  1. 10 hours ago, Some dude said:

     If you were to have a circular magnet(s) facing south inwards, and in the middle have a spindel with a bar that has perches with a magnet facing south on each side toward the other magnets, would that generate a spin?

    I am (probably obviously) not very knowledgeable with the forces, and don’t know much what I am talking about hence the lack of evidence, but my theory is the energy would come from the bar holding the magnets together. This however, would suggest some theoretical energy from material just existing.

    Another glaring issue is the whole forces not being energy problem, but it’s just speculation, and speculation is no more than that.

    Once again, I am 99% sure I am wrong, but since I am pretty new, I don’t know exactly why.

    If you had a South pole facing inward all the way round, then there would be no reason for a force to be produced that was not purely radial. So there would be no rotation.  

  2. 8 hours ago, Some dude said:

    This is not my idea, but one of my friend thought of it, and it sounds like it would work.

    The idea is you have some massive metal tube stretching from the sea floor. A metal pole would be inside the tube, and the pole would be strapped to a buoyant object. As the tide rises/lowers, it would move the pole like a piston.

     

    The friend didn’t suggest how exactly the energy would be created, and I’m too dim witted to figure that out... but yeah. 

    It would generate energy, yes, but very little. What this device would do is displace a volume of water equal to the area of the pipe x the tidal range, once every 12hrs, so it would be a sort of very slow pump.

    To extract energy from the tides, you are far better off to use a place where a natural restriction, say the entrance to a bay, causes a significant tidal current and then use a turbine of some kind. That way, you exploit the tidal displacement of an entire bay's worth of water volume every cycle. 

  3. 33 minutes ago, SergUpstart said:

    And whether such measurements were carried out?

    No, I'm not confusing you. I propose to look at the problem of hyperinflation of the universe immediately after BB. As cosmological models show, in the early universe, individual parts of it scattered faster than the speed of light. Alternative physicist from Russia V. Yanchilin explains this by the fact that in the early Universe the speed of light was higher. Official cosmology says that space itself was expanding, which does not contradict the theory of relativity. But if you think about it, both of these explanations are equivalent. Yanchilin operates in absolute Galilean space, in which the meter and the second are constant, and therefore the speed of light must be variable. But a decrease in the speed of light in the absolute space of Galileo means an expansion of the relative space of Einstein. (If the object is removed at a distance of a million light-years, and the speed of light suddenly halves, then this object will be removed by two million light-years).

    OK, I see what you are saying, but if that were a valid explanation for the cosmological red shift, then presumably GR would be false and would predict results contrary to observation in other respects. Is that the case? Or can you somehow preserve GR AND this idea at the same time? 

  4. 59 minutes ago, SergUpstart said:

    I have already found an error in the GRT equation for about six months, but I still did not dare to share this idea here. If you look at the equation of Newton's law of universal gravitation and Einstein's equation of general relativity, you can see that they both include the gravitational constant G. But this constant is dimensional, and its SI dimension is m^3/kg*s^2. In Newton's theory, space and time are absolute, i.e. the scales along the axes of spatial coordinates and time are unchanged, so it is logical that in Newton's theory G is a constant. But in GRT, when approaching a massive body, time slows down, i.e. the value of the second increases, therefore the numerical value of G must change in accordance with the changes in the meter and second. And since the meter in the SI system is the distance that light travels in one second,the meter lengthens with each second. The dimension of G can be written as (m/kg)*(m^2/s^2), from which it can be seen that G must change inversely with the length of the meter or inversely with the deceleration of time. And the GRT equations should look like

    http://www.yuniverse.org/img/ngre.jpg

    Thus, when approaching a massive body, the gravitational constant should decrease and singularities and the event horizon should not occur.

     

    In addition, other basic physical constants, namely the dielectric and magnetic constants and Planck's constant, must also change their values depending on the time dilation. Therefore, such physical constants as the ratio of the Coulomb repulsion force of two electrons and two protons to the force of their gravitational attraction should not change their values.

    Here is a simple answer to the question, if even a photon cannot fly beyond the event horizon, then how did it happen that as a result of the BB, the entire Universe flew out of the singularity point.

    Re your last line, I think you may be confusing motion through space with expansion of the metric.

  5. 6 hours ago, gatewood said:

    Sure, but the question doesn't need it.

    Say we paused a black hole just after its schwarzschild radius gobbled all the core of the star that formed it, and, hypothetically, we could take a peek inside. What would we see? What would matter compressed down, further than neutron (or quark) degeneracy, would be like?

    I mean, the core of my question would be: all that fell inside a black hole... still exists in some form? And if so, what you think it that form is? A Bunch of elementary particles? Energy resulting from annihilated particles? A bunch of photons and neutrinos?

    As far as I'm aware, we  don't have a theory for that. As quarks are the most elementary unit of matter we know of, I doubt that we have anything on which to base any speculations as to  whether or not they might be decomposable into something "more" fundamental.  Though I'd be interested if any physicists have anything to add on that.

     

  6. 52 minutes ago, gatewood said:

    holy ppl... im merely asking, what might you think happens to matter, as it compresses, beyond neutron degeneracy. E.g. what state of matter could it be said it is in... if at any? (like the hypothetical quark stars).

    People theorise about "quark matter", I think, viz. a form of degenerate matter in which neutrons lose their identity and one has just quarks. But I know nothing about this. I gather we don't know enough about the strong force to model it very well.  

  7. 1 hour ago, gatewood said:

    ohhh... please, cut the chase, we all know gravitational singularities are basically a placeholder for where our understanding of physics breaks down.

    What I mean to say/ask: (fun question) what would you think we'll see if we could compress , say, 10 solar masses to the size of an atom (not an infinitesimally small volume)? Suppose there where no such thing as a schwartschild radius, but we could still compress stellar amounts of matter down to atomic/subatomic scales and also still observe it.

    You mean, what would we see if the laws of physics were not what they are? Surely that would depend on what they were instead, wouldn't it?  

  8. 1 hour ago, gatewood said:

    Just a fun question: what state of energy/matter, could it be argued, that a gravitational singularity is in?

    I would say that, it broke down to the most fundamental form of energy. Could it be said that, it is an extremely exotic form of atom?

    Energy is a property of a physical system of some sort. It is not "stuff": you can't have a jug of energy. So it becomes pretty hard to see how a singularity can have energy. It would have to be a system, and that would prevent it being a singularity. 

  9. 4 minutes ago, John Cuthber said:

    My actual post, part of which  you have snipped out of the whole, thereby altering its meaning, included this
     

     

    And that's probably not chromosomal.

    I have not altered the meaning of what you wrote in any way. Whereas your cutting the part of my sentence which actually already addresses the point you go on to make, does alter its meaning.  

     

  10. 5 hours ago, Duda Jarek said:

    Sure, as you mention, these ways have various costs based on physical limitations - market should stabilize on the cheapest ways up to profitability level, which grows with gold price.

    The problem is that potentially infinite number of various cryptocurrencies do not have such physical limitations - hence can grow to consume just all available resources ...

    ... unless being banned like https://www.cnbc.com/2021/05/26/iran-bans-bitcoin-mining-as-its-cities-suffer-blackouts.html

    Do you really think nobody would notice this "resource consumption" and take steps to limit it? 

  11. 11 hours ago, John Cuthber said:

    I wish I had been drinking milk.
    Whisky really stings.

    That depends on perspective.
    For example, Down Syndrome is more likely in the children of older mothers.
    Most people would say it's a health issue.

    It is absurd to ignore it .

    But there's also an increase in cardiovascular problems in children of older mothers.
    It may or may not be chromosomal but it's certainly an issue.
    https://physoc.onlinelibrary.wiley.com/doi/full/10.1113/JP275472
     

    My actual sentence, part of which you have snipped out of the whole, thereby altering its meaning, was : " If the foetus has the normal complement of chromosomes and the mother has no problems in the pregnancy, it would seem there are no issues for the child, once it is born. "

    Down's syndrome involves an extra copy of all or part of chromosome 21. 

  12. 4 hours ago, iNow said:

    Quoted info is summarized from the link which includes more:

    https://www.mayoclinic.org/healthy-lifestyle/getting-pregnant/in-depth/pregnancy/art-20045756#:~:text=Babies born to older mothers,conditions or fetal chromosomal abnormalities.

    There's also a higher risk of stillbirth, but it all really depends on the individual mother, her genetic profile, her lifestyle, general health, and quite a bit of luck regarding which egg happens to get fertilized in that specific coitus event. 

    All these issues seem to relate either to chromosomal abnormalities or to the process of pregnancy itself. If the foetus has the normal complement of chromosomes and the mother has no problems in the pregnancy, it would seem there are no issues for the child, once it is born.  

  13. 4 minutes ago, swansont said:

    But if it’s zero, are you considering a volume? How much mass do you have in zero volume, regardless of the density?

    Well yes, sure, if it is literally zero, but equally one can say density has no physical meaning if one has a zero-sized lump of material. What I suppose I mean is it that has physical meaning if instead one considers, let us say, an arbitrarily small volume of space close to the nucleus.

    What I'm rather more interested in, though, as I don't have the physics to know the answer to this, and I hope you might, is whether one can legitimately speak of an s-electron passing through the nucleus. I am not sure whether any of the interactions operating in the nucleus would prohibit this. Do you know? 

  14. 1 hour ago, swansont said:

    To the extent that “a sphere with zero volume” is meaningful, yes. But also that probability density lacks physical meaning if you ignore the volume you’re looking at.

    I'm not sure I agree. It seems to me that the concentration of a dissolved chemical substance, or the strength of a magnetic field - or indeed the density of a material -  has a physical meaning, regardless of what volume one considers.  

  15. 4 hours ago, Duda Jarek said:

    Population growth seems prevented by just children survivability, improved live quality - see e.g. some Hans Rosling talks like

     

    Exponentially growing additional waste makes fight with climate change even more hopeless ... 1 individual can easily exceed a million times required consumption here - it doesn't matter that 99% of population care and save resources, if 0.001-th percentile can saturate close to 100% of world resource usage.

    Yes, I've got Roslin's book.

    What you say is trivially true, if your 0.001th percentile does indeed generate waste exponentially. But that nicely illustrates how naive (a polite way of saying "wrong") it is to model just about anything on the basis of a pure exponential - a point Roslin makes repeatedly. Nothing works like that. In the case of resource consumption, it is obvious that as a resource becomes more scarce, it becomes more costly and the incentive to substitute it with something else - or to stop the activity entirely- grows. So very quickly you get a departure from exponential behaviour. In the case of fossil fuel consumption, we do not see anything like exponential growth. We are still seeing growth, true, but it is linear or plateauing. 

    So please put aside these exponential extrapolations. They almost invariably give wrong predictions. Just about their only use is to show people what would happen if nothing were done to prevent a runaway exponential.    

  16. 59 minutes ago, swansont said:

    There’s a mundane mathematical aspect to it.

    In a 1D system in cartesian coordinates, the square of the wave function gives us a probability. But going to 3D this is a density, so the probability is not just the square of the wave function. And we’ve moved to a spherical coordinate system. The volume element integral includes r^2dr, instead of the dx we had before.

    If you solved for a 1/x potential in cartesian coordinates, you’re going to get a wave function that looks something like xe^-x/a (for x>0), i.e. something that goes to zero at the origin

     

    Isn't that just tantamount to saying that a sphere of zero radius contains zero volume, so the chance of the electron being there is zero, the non-zero probability density function notwithstanding? 

  17. 1 hour ago, Duda Jarek said:

    What do you mean? People buy hardware and use energy just to get money (for otherwise meaningless activity) ... until reaching profitability level, like burning $99 worth resources to get $100 banknote.

     

    In contrast, mining other resources like gold is not otherwise meaningless ( https://www.mecmining.com.au/top-5-uses-of-gold-one-of-the-worlds-most-coveted-metals/ ).

    But most importantly it is limited - in contrast to unlimited number of cryptocurrencies they can create, it is impossible to maintain exponential growth of gold mining ... while cryptocurrencies can use literally all available resources, growing exponentially until saturating on 100% of world energy production cap.

    Bitcoin is just the latest IT fad, followed by a handful of nerdy and greedy people. It already looks doomed, because of its absurd energy consumption, cf. the recent reverse ferret by Elon Musk (now that he has made a tidy profit, no doubt). If Bitcoin doesn't fix this, it will get shut down. By governments. 

    Human society has lots of ways of preventing runaway exponentials. Population growth is another. All the indications are it will stabilise, because as people get more prosperous they delay having children and want to focus more attention on a small number of them. More and more countries are now worrying about ageing or even falling populations, China included.

    Climate change and pollution are far more pressing concerns than bloody bitcoin*.

     

    * Once memorably described by Warren Buffet as "rat poison, squared".  

  18. 11 hours ago, Arnav said:

    Please note that I mentioned electron probability density in my question, not radial electron probability distribution. What I want to convey is, why is graph(b) maximum at the nucleus?

    image.png.a5fe98030c761b55ac56b11d76d62cd7.png

    I understand how the actual probability is obtained by multiplying electron probability density at certain r by 4pir².dr

    What I want too understand is why the graph of Ψ² vs r peaks at r = 0. Does it have any physical significance?

    please bear with me if i missed something

    Ah, I may have misinterpreted what you were looking for in terms of physical significance. Let me try another angle. 

    You may have come across the problem with the original Rutherford-Bohr model of the atom that it can't account for why a supposedly orbiting electron does not emit radiation, lose kinetic energy  and fall into the nucleus. In a sense you can view the s-orbitals as the QM version of exactly that scenario. Electrons in s orbitals have zero angular momentum, so they can't be said, in any sense, to be "orbiting " the nucleus. Instead, it is as if they continually fall towards it - even through it perhaps -  and come out the other side. Being QM entities (Uncertainty Principle and all that), one cannot say they follow any defined trajectory of course, but the overall sense is of being able to touch  the nucleus, rather as if they fall into it. Whereas p, d, f, etc orbitals have 1,2, 3 etc units of angular momentum and, lo and behold, all have a node at the nucleus, which is more consistent with some kind of "orbiting" motion, even though again, being QM entities, they have no defined trajectory. 

    So I'be tempted to say the physical significance of non-zero ψ at the nucleus is a reflection of the absence of orbital angular momentum. 

  19. 1 hour ago, Duda Jarek said:

    Let me remind that this thread is not supposed to be about bitcoin, but about Fermi paradox:

    https://en.wikipedia.org/wiki/Fermi_paradox#It_is_the_nature_of_intelligent_life_to_destroy_itself

    Bitcoin was only example of such positive feedback mechanism leading to exponential growth - such that if continuing last 6 year trend to next 6 years, would reach half of world energy production, what some might find disturbing.

    There are already thousands of cryptocurrencies, and it is not that humans have to be smarter or more reasonable than such hypothetical civilizations, but we are not talking about a few years, but rather thousands.

    So on what percentage of world energy production cryptocurrencies should finally stabilize at - in a decade, century ... ?

    What other exponential growing positive feedback mechanisms of using resources on otherwise meaningless activities like hashing could you think of?

    Chip manufacturers, due to growing financial incentives, decide to produce bitcoin miners instead of standard electronics - couldn't it lead e.g. to shortages of electronics?

    Interesting, but how would it prevent from cryptomining simultaneously also in other places?

    Or couldn't such supercomputer search e.g. for cure for cancer etc. instead of calculating hashes?

    I don't believe there are any simple exponential processes that are relevant to this issue. Almost everything proves to be self-limiting in some way, eventually.

    (And actually, I've never understood the Fermi paradox. It seems to me that, given that in space travel all the numbers are awful, any intelligent race of aliens would work out that embarking on interstellar travel at all is a pointless exercise, and consequently signalling to the void is equally pointless.)  

     

  20. 2 hours ago, Arnav said:

    I was recently reading about atomic structure's journey, when i saw the electron probability distribution graphs for some orbitals.

    Why is the electron probability density maximum "at the nucleus" for s subshell ? does it have any physical significance? the confusing part for me is that the probability of finding an electron would be the least at nucleus, so how come probability density is maximum?

    P.S. I am a high school student, so it would be extremely good if someone could explain this to me in a simple way

    To build a bit on what @swansonthas said, yes it does have profound significance in chemistry.

    Because the s orbital wave function has no node at the nucleus, it implies that the electron spends some of its time up close to the nucleus. This means that, in multi-electron atoms, the s electrons are exposed to the full nuclear charge more than electrons in p , d or f orbitals, which are more "shielded" from the full nuclear charge by the electrons in shells closer in. S-orbitals are said to "penetrate" the cloud of electrons surrounding the nucleus more than the others.

    As one goes up* the Periodic Table, the increasing nuclear charge progressively pulls in the s orbitals and lowers their energy more than it does for the others. This is the reason why the Periodic Table has the shape it does. It results in s orbitals having lower energy than p, d or f orbitals of the same shell. This even happens to such a degree in the 4th row that at potassium, the 4s has lower energy than 3d. This is why the first row of the transition elements (d block) appears after K and Ca.  It is only then that the 3d has come down in energy enough to be filled, in preference to 4p.   

     

    *This concept of progressively filling subshells with electrons as the nuclear charge increases from one element to the next is known as the Aufbauprinzip (= building up principle). 

  21. 9 hours ago, Arete said:

    The point *should* be a pretty simple statistical point.

    In English, each set is comprised of a combination of 26 characters, of any length until a monkey pushes the space key -effectively meaning there are infinite sets. There are approximately 470,000 words in the English language, so that many sets are translatable, the rest are not. 

    In DNA, sets are a combination of 4 characters in lengths of three, meaning there are 64 possible sets. All are translatable to a suite of 21 meanings. 

    These two probability landscapes are incredibly different. One is like searching for a needle in a haystack, the other is like searching for a needle somewhere in the universe. 

    This point has to do with redundancy. The phrase "Call me Ishmael" has no redundancy - either all the letters are correct or the phrase is wrong. 

    The genetic code has lots of redundancy. All amino acids have at least two of the 64 codons that encode them. Seven have completely redundant third positions - if the first two letters encode the correct amino acid, the third base pair doesn't matter - theoretically a full third of the nucleotides in the gene/genome could be entirely different from the "right" sequence, but the encoded protein translation identical.  All of a sudden, there are a thousand needles in the haystack and you only need to find one. 

     

    Not quite - selection quickly fixes beneficial or "correct" sequences in the gene pool of a population. So, once a monkey gets a genetic "word" correct, it will tell all the other monkeys about it. In all subsequent iterations of the gene/genome the monkeys uniformly get that word right, iteratively shrinking the parameter space left to search. The monkeys are burning the straw as the search and the haystack iteratively shrinks. Not so for a random smashing of literary keys in search of a phrase in English.  

    While everything you have said is illuminating (to me, anyway), it presupposes an already high degree of order in living things, viz. a system of heredity, mediated by codes of bases on a long molecule. So it seems to me it can't address the fundamental argument in the (creationist) claim recited in the OP. Though I suppose it does address the issue of the probabilities involved in how more complex life arises from simple life through variation (and selection), once an RNA or DNA type replication system is up and running.   

  22. 10 hours ago, gatewood said:

     

    - Second paragraph (first half)

    But wouldn't the Ca++ actually compete with the O-- for the electrons to reduce themselves?

     

    That strikes me as a rather penetrating question. +1. 

    The answer, I think, must be that for Ca++ to pinch an electron from O-- would involve it getting a lot bigger, because the electron would have to go into the next shell (4s), which is at a greater distance from the nucleus than the 3s and 3p subshells, which are already full in Ca++. As I mentioned in an earlier post, Ca++ and O-- are of similar size and can pack efficiently. A larger Ca+ ion would pack less efficiently. The larger size would push the neighbouring ions apart, reducing the strength of the ionic bonding and leading to a higher energy state overall for the crystal. In other words, it would reduce the so-called "lattice energy". 

     

     

  23. 36 minutes ago, mardiyah said:

    What'd be the cheaper substitute and/or alternative to raw linseed oil functioning as a resin solvent?

    This question is too general to be answerable as it stands. There are plenty of solvents for resins of various sorts, depending on the resin. Raw linseed oil seems a rather peculiar choice in the first place.

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.