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  1. 5 points
    Because the electron is not a classical particle (“little ball of mass and charge”), but a quantum object. As a first approximation, you can picture an electron as a 3D standing wave around the nucleus - you can only get standing waves of a given wavelength in specific places, which is why orbitals come in discrete levels. Crucially, there is a lowest energy level, which corresponds to the minimum distance an electron can be with respect to the nucleus (let’s assume here there is only one electron) - and that lowest energy level is not zero. Therefore the electron cannot fall all the way to the nucleus, it can only fall into its lowest energy level, which corresponds to an orbital that is still some distance outside the nucleus. This is a direct consequence of the laws of quantum mechanics, and coincidentally one of the questions that motivated the development of quantum mechanics in the first place.
  2. 4 points
    If only it was as simplistic as you think it is First of all, quantum physics is both completely deterministic and stochastic. What is deterministic is the evolution of the wave function - given any initial wave function, you can predict with certainty how that wave function will evolve over time (assuming you know the respective boundary conditions etc). However, what is stochastic is the relationship between the wave function, and physical observables - observables are represented by hermitian operators, and which of their eigenvalues you actually measure is - in general - purely probabilistic. For example - you send a stream of photons through a double slit. Given knowledge about the initial conditions (slit separation, photon frequencies, etc) you can predict with certainty what kind of an interference pattern you are going to get on your screen at the end of the experiment. However, you can not predict precisely where each individual photon will hit the screen, that is purely probabilistic. And we’re not even talking about the question which slit each photon goes through. So this is your third possibility - it’s come to be called “determined probabilities”. That’s the first thing. The other thing then is that determinism does not imply an absence of free will, and conversely, indeterminism does not imply that free will is necessarily possible. There are four different philosophical positions that encompass the four possibilities here: hard determinism, compatibilism, hard incompatibilism, and libertarianism. You can look these up yourself. The main point here is that this an ongoing debate, and there is no consensus about which is the correct one. And just to top things off - the human brain is a macroscopic system, and as such classical. So one would expect it to be deterministic. In reality however, in spite of its classicality, it is an example of a complex non-isolated, non-linear, chaotic system. So even if it were completely classical (which actually it isn’t anyway, since it’s fundamental building blocks are quantum mechanical), you still couldn’t predict its precise state very far into the future, because it is extremely sensitive to initial and boundary conditions, never even mind way too complex to mathematically model with currently available technology. It’s also an open feedback system, since it continuously receives external inputs, and generates responses that can modify those very inputs. So is the brain deterministic? You decide yourself, based on the above. Whatever your conclusion, what does that imply for free will? Again, you decide yourself, based on the philosophical positions on this subject matter. I think it is safe to say that there are no straightforward answers either way here.
  3. 3 points
    ! Moderator Note Posting to try and get others to do your work is getting rather tiresome. You have a question about a website, you go to THEIR help page and look for an answer. You want to know where to find information, use a search engine to find it. Stop posting crap like this here.
  4. 3 points
    I asked a sincere question and I’m here to learn. I assumed you being the forum chemistry expert you could lend a hand. And yes, since you’re the chemistry expert - it is your job John.
  5. 3 points
    Agreed. BUT THAT IS NOT WHAT THIS THREAD IS ABOUT. (It's your thread, so you should know this.) Obviously, there are people who don't believe the theory of evolution, or the Big Bang, or that the large scale structure of the universe is formed by gravity or that the Earth is round. So what? That is totally irrelevant. Your question was whether you can be religious and still believe in theories of evolution. And the answer is obviously "yes". Pointing out the blindingly obvious fact that some people don't doesn't change that fact. It is like I asked if you can have two legs and believe the Earth is round. Then, when someone points out that there are people with two legs who believe the Earth is round, you say "but some people with two legs don't believe that". Can you not see how unbelievably, monumentally irrelevant that comment is? Sheesh.
  6. 3 points
    If I may comment on just this bit here, your comment appears to show how little you may understand science. Science attempts to provide a clear, cogent, and reliable methodology whereby evidence may be investigated or found for the ideas we espouse. Science isn't discouraged from investigating the supernatural, it has investigated and have found clear, cogent, and reliable evidence lacking.
  7. 3 points
    I'd hate to think how mortifying it would be to get an award from the same people who thought Mother Teresa deserved one...
  8. 3 points
    The problem is that in your original post you said "clock". Which can be taken to mean any general time keeping device and not one based on an y particular mechanism. In fact, in such discussions, the term "clock" is assumed to mean an "ideal clock" (one that does not lose or gain time due to local conditions.) It isn't until much later that you mention a light clock. And even then you restrict yourself to just a single type of light clock. So lets take your latest example. You have two light (or sound) clocks, one is moving, and one is at "rest" : The red numbers keep track of the ticks for each clock. The white dots are the light/sound pulses and the expanding circles show how the light travels at a set speed relative to our chosen frame. In this example, it does appear that Relativity and Newtonian physics will give the same answer as to how fast the moving clock ticks with respect to the stationary clock. However, what if we add another set of mirrors/sound reflectors, laid out left to right? Then if we use sound or a Newtonian fixed speed for light we get this: With the stationary clock, the two pulses keep time with each other. But with the moving clock, the up and down pulse makes one complete round trip before the left-right pulse has even made one leg of the round trip. In Relativity there is length contraction so you get this: The distance between the left and right mirrors is length contracted as measured from our rest frame, and this causes the two pulses to stay in sync in terms of round trip time. So right here we have a fundamental difference between Newtonian and Relativistic predictions. Or let's go further. Let's enclose the sound clock so that it carries it air with it, and design or light clock to use fiber optic cables to carry the pulses rather than free space. In both these cases, Newtonian physics says that the speed of sound for the sound clock or the speed of light in the light clock is a constant relative to the medium it is traveling through and is completely independent of any motion these clocks may have. So two self-enclosed sound clocks would measure no difference in tick rate between each other no matter which one was moving relative to the outside air, and two light fiber clocks would tick at the same rate regardless of their relative motion. This gets back to what strange was saying with your sound clock example. Someone riding along with the moving sound clock would agree with the stationary observer that his sound clock was ticking slow. Which is in contrast to what Relativity says about moving clocks, in that each will say that it is the other clock ticking slow and their clock is ticking at normal rate. You took one particular set up, measured by one particular frame, and when you got an answer you liked, you stopped and didn't think it all the way through. You failed to consider whether or not the relationship held for more general cases or not. This also means that with the sound clock example the person riding along with the moving light clock would measure a stationary light clock as ticking at the "normal" rate, and the only difference he would visually perceive in its tick rate would be due to Doppler shift. Basically what this mean is that in Newtonian physics, the Doppler shift measured between two receding sources will be different when measured by the Moving source and when measured by the stationary source, While in Relativity all that matter is the relative velocity and they both measure the same Doppler shift. This has practical consequences. when we send space probes to other planets, their velocity has to be planned out very carefully, if they are moving too fast or too slow by just a small amount, not only will they arrive at the target planet's orbit too soon or too late, their actual trajectory will be changed so that they will arrive at the wrong point of the orbit. In other words, it wouldn't take much to make the probe miss the target planet by a wide margin. Once the craft is in space, the only real way NASA has to measure its speed is by Doppler shift. They know the base frequency of the craft and they can check for a Doppler shift to get the relative speed with respect to the Earth. If you use a Newtonian Doppler shift model, both the Earth and Probe are moving objects (the whole solar system for that matter, unless you are proposing a heliocentric universe) And thus all these various motions would have an effect on the Doppler shift measured from the probe, even what time of the year the measurement was made would make a difference. with the Relativistic model, all that counts is the relative velocity between probe and Earth. The two models would lead to different conclusions as to the probes velocity with respect to the Sun when measuring the same Doppler shift. Thus If NASA used the relativistic model to work out what the craft's velocity was, and the Newtonian model was what the universe worked by, then NASA could measure the Doppler shift, conclude that the craft had the right velocity, and have it go on to miss the target planet. ( or conversely, they would conclude that the craft somehow missed its target velocity and that they had screwed up somewhere, only to have it make a perfect meet-up)
  9. 3 points
    He has pointed out that there is no real basis for myths, that you have little knowledge of the Big Bang theory (an objective fact) and commented on your behaviour (coming to a science forum and making emotional accusations about the inadequacy of science). Nowhere did he say, or even suggest, that you are an idiot. For someone who has come here to attack scientists, atheists and materialists, you are remarkably sensitive to perceived but non-existent insults.
  10. 3 points
    I hope you have references for this story. Just speculating a bit in advance: I've been practicing Aikido for many years. One of the exercises was 'reading the intentions' of your opponent, so you can react correctly in time. I can assure you, there are many bodily but subtle signals when somebody starts a movement. So a samurai might be able to react even before the gun was shot. It is not magic, it is practice (and talent, I suppose, I never made it to the black belt... ). Seems so. But because you corrected me elsewhere, now I correct you . The Chinese Room is from John Searle. But it is the case, that many people believe he has a point with it, and recently I saw an interview with him on Swiss Television, and Searle still adheres to it, even that I also think that it was definitely debunked by e.g. Hofstadter and Dennett in 'The mind's I'. Dennett therefore calls it a false 'intuition pump'. BTW, I once hat a chance to have a small chat with Penrose, and he is really a very nice, bit excentric (in the positive sense) guy. And he is not very dogmatic. He clearly saw that his and Hammeroff's 'Orch-OR' theory is still a hypothesis, and definitely not a full blown picture of reality. He did not become angry when I confessed I did not so much believe in his theory. Edit: Now I got a +1. But it was there before my remark on Searle and Penrose was merged with my comment on the samurai. So whoever gave me the point, read if you still agree with the new part. Otherwise you can remove it again. (no please don't... ).
  11. 3 points
    would I say all my questions were answered? Not entirely but I can say I can walk away content with the answers I got knowing I still have a lot to learn
  12. 3 points
    A couple of issues that I have with this video: It ignores length contraction and thus gives a misleading picture of what is happening. In the part of the video where the light from each flash is shown expanding from the train's frame, they just show each individual expanding sphere in sequence and never together. Showing them together would show where they would meet on the platform according to the Train frame. Here's my own animation of the train experiment. Not as stylish as the above video, but I think it is more instructive. First, how things are viewed from the embankment. Here the red dots show where the lightning strikes the embankment, which happens when the ends of the train reaches them. The expanding flashes of light meet at the embankment observer. The leading flash reaches the train observer first and then the trailing flash reaches them. Now the same events from the frame of the train. First, I need to make a point about the above animation. In it, the train is motion with respect to our chosen frame, which means that the train undergoes length contraction as measured from the embankment. The embankment measures the length of the train as being shorter than what the train would measure itself as being. So in the next animation, shows events according to the frame of the train, we must show the train as being its "proper" length ( the length it would measure itself as being). In addition, it is now the embankment the is in motion with respect to our chosen frame, so it is the embankment that undergoes length contraction: As we can see in the animation, the red dots are closer together and the train is longer in the train frame, and the train no longer fits between the red dots. As a result, the front of the train reaches the left red dot before the rear of the train reaches the right red dot. Since the lightning strikes hit when the end of the the train and red dot align, the strikes have to occur at different times. But you will note that even though they occur at different times, they still meet at the embankment observer. Also compare where the train observer is relative to the tracks when each flash reaches them in each animation. In both the lead flash reaches them when they are at around three railway ties past the embankment observer, and the trailing flash reaches him when he is about even with the right red dot. In addition, the two flashes meet at the embankment observer when he is adjacent to the same railway car in both animations. If we were to put clocks with each observer, at the red dots, and at the ends of the trains so that, so that all the clocks on the train were synchronized according to the train, and the clocks on the embankments were synchronized according to the embankment then these clocks would all record events just as shown in the animations. The clocks at red dots would record exactly the same times when the lightning strikes hit, and the clocks at the ends of the train would record different times fro the lightning strikes. This will also leads to the conclusion that according to the embankment frame, the clocks on the train are not synchronized to each other, and the according to the train frame, the embankment frame clocks are not synchronized to each other. Also, if we were to show the clocks in the animations, we would also have to account for time dilation. To demonstrate how all three effects come together, let's consider the following scenario: In it we have two rows of clocks moving relative to each other but have arrange things such that in one frame, (that of the lower row of clocks) all the the clock in both rows are synchronized to each other, and are spaced equally. Thus, if you are at rest with respect to the lower row of clocks, this is what happens as the lower row clocks run from 12 to 2 o'clock. note that, as any two clocks in the top and bottom row pass each other they read the same time. But if we switch to the frame of the upper row, we get this: The clocks in the lower row are closer together than those in the top row, they run slower, and the clocks in neither row are synchronized to each other. However, whenever any two clocks in the top and bottom row pass each other, they still read the same time. Thus while the two frames do not agree on the distance between the clocks, the rate at which they tick, or the synchronization of the clocks, they do share common events (such as two given clocks in the upper and lower row both reading 3:00 when they pass each other.) With the train example there are also common events that both frames agree upon, such as the reading on a clock at a red dot and the reading on the train clock as they pass each other and lightning strikes them at that moment. It is the reconciliation between these common events and the invariant nature for the speed of light that leads to the disagreement in simultaneity between the two frames.
  13. 3 points
    You do realise that is just a bit of journalistic sensationalism, not a real thing. And what if it is clockwork or powered by wet string (both equally well supported) And where does that 20 millihertz come from? Entanglement happens between individual particles. It is a bit bizarre to use the rule that says it involves pairs of particles to claim it applies to entire “computers” Check out the concept of “evidence” 1. Argument from authority 2. Penrose’s stature is as a mathematician and physicist 3. There are plenty of people of similar stature in the relevant fields 4. Pseudoscience is still pseudoscience even if done by scientists (there are lots of presedenti for this) ALL chemistry is due to quantum processes
  14. 3 points
    Hello, I live in Muslim country and i have to say something about that. Actually, in educated side of our country, people are informed about birth control methods . However, in uneducated side , it is beyond women's power. Womens doesn't have right to speak, so that all control is belonged to men. Our goverment is handing out preservatives to prevent this problem , but I think nobody use them. Even,a few years ago, I heard some news about that. Some kids were using preservatives like balloon. On the other hand, even if they were educated, probably they don't do something. They aims to having much kids, they use them like soliders. they protect themselves and make money through their kids. Nobody doesn't care life standards of kids, especially girls. These people do that to live. Goverment, police or any defensive force can't prevent them, because they are not enough to stop hunger , terror and unemployment. In my opinion, education can be part of the solution , but this is not enough. It is releated with economy and politic situation of country. Solution is being social democracy. As for me, this is not about religion. In our country, nobody against abortion, it is totally about management.
  15. 2 points
    I don't think so. You can easily check this with your current configuration (without the tube blocked/sealed) if you put something that creates smoke (a cigar maybe) instead of that paper. The smoke would enter the tube in the center, along the rotation axis, where the air has a low presure, and exit near the walls, were the air/smoke is pushed by the centrifugal force (the rotation creates a vortex). Still, I recommend the wooden board I mentioned above, in order to block both air and electrostatic forces (if any). Gravity is not blocked by wood.
  16. 2 points
    Look man, I’m assuming you’re not some nutcase trying to hoax people on youtube and you’re genuinely interested in finding things out. Am I right assuming that? If that is the case, 1. Ground the pipe (if its metal, if its PVC you wont be able to) Tape a bare wire to the pipe and the other end connect to the ground (your vice or some other big chunk of metal should be enough for this purpose) You can also use an ESD set if you have one around the shop. 2. Use your multimeter to check for presence of static charge. Set it to measure „amperes” and be sure your meter has an option to retain a reading as the neasured discharge will take a microsecond or so only. Use tape to attach the myltimeter probes to the pipe. If the pioe is PVC it probably won’t work. Practise by rubbing a sweater or your bare feet on a carpet and measure that with your multimeter to get a readout by using the probes on your hands. 3. Use a feather instead of the paper to get a better idea of where and how much of air movement occurs. There might actually be both factors playing a role here at the same time - electromagnetism and air movement. 4. Read the wikipedia article I linked you to on gravity. Come up with questions and post them here, there are PHD physicists in this very thread who will answer all the questions you have, you can learn a lot from them. 5. Forget about hope you discovered how to „generate gravity” There is no way that could have happened, learn the basics of gravity what it is and how it interacts and you will laugh yourself a year later at this whole thing. I think its cool youre doing the experiments and I fully support you in this. Providing you’re not a nutcase or deliberately trying to find out how to hoax people.
  17. 2 points
    Do you know how CaO is produced? Mostly from CaCO3... CaCO3 + heat -> CaO + CO2..
  18. 2 points
    Distribution is still restricted there, from what I understand. Nonetheless I think part of the discussion seems to be based on the assumption that certain drugs are fundamentally (biologically) harmful than others. Thus, legislation is or should address that as a means to protect public health. The counter-argument do this are that evidence point to criminalizing drug abuse does not ameliorate the situation. Moreover, as the discussion with soft and hard drugs has been shown, it is not based on medical effects, either. Specifically alcohol seems to be seen as harmless (and ironically is a prime example how abolitionist movements did not work). Yet if scaled systematically it is on par with lots of other drugs typically seen as "hard" in common parlance. This does not come to a surprise to folks who work on physiological effects on drugs. Likewise, the dangers of tobacco are vastly underestimated, simply because we are used to it.' There have been efforts to use multiple criteria (which include harm to individual and harm to society) and according to one of the most cited study in the UK (Nutt et al. 2010 Lancet). The most damaging drug overall was alcohol, scoring higher than heroin or Crack cocaine. Of course one could surmise that the societal effects were driven by availability, but even on the harm to the individual user scale alcohol scores just behind Heroin, Crack Cocaine and metaphetamine. Drugs scoring lower than alcohol on the individual scale included cocaine and amphetamine. Tobacco scored close to cocaine and amphetamines. Tobaccos is a special case as it is generally not associated with overdose situations. However, if we include the increase in lung cancer, it suddenly becomes on of the deadlier drugs. Sure, it is less dramatic but lethal nonetheless. If we look deeper into the type of harm, alcohol and tobacco are drugs with some of the highest drug specific damages. When we look into drug specific mortality (which excludes e.g. violence), alcohol scores lower than heroin but higher than (crack) cocaine, methamphetamine etc. Especially the comparison between crack cocaine and cocaine is interesting. On the biological side, there is little difference in the damage they do bodily (mortality and damage are very similar). But on the overall damage scale crack cocaine causes more damage on the individual as well as societal level. A part of these different outcomes is based on the different policies surrounding those drugs, which, in my mind indicates that the additional punishment for crack cocaine is net harmful.In other words, the perception of what is considered a relatively safe drug (tobacco, alcohol) with actual medical data is quite different. Pretty much the only clear overlap are probably mushrooms. Of course, one could weigh different parts of the equation differently. E.g. focusing more on withdrawal, or availability of treatment options and so on. However, it does show our given perception not data driven but based on certain narratives that we built ourselves surrounding certain drugs. I found this argument, as well as your earlier approach to playing devil's advocate highly problematic as you tend to leave out so much nuance as to make the argument worthless. I have addressed what the difference between "feel good" and addiction or compulsive behaviour and that those require different approaches. Heroin itself was, for several reasons perhaps not the best example John could have picked. But what is clear is that alcohol is far from a safe drug. Yet we deal with it in a certain way that we find acceptable. It is certainly not based on the objective harm done to the individual. However, as a parent the answer should clearly be: don't give alcohol to them or any other drugs. If that is not possible than disapprove of dosages that can cause short or long-term damage. Clearly we do that for certain drugs. But for others we seem to be fine(ish) with the toll on public health. What you are advocating here, MigL is a full-on emotional response and I do not consider that a good foundation for policy-making. While I am far from being an expert in this area, it seems pretty clear to me that punishing users has almost only negative effects. The Portugal model (personal use is allowed, there is support to kick addiction, distribution and production is still prohibited) is not perfect and does not really eliminate drug abuse. However, it has also not lead to a surge of addiction. More importantly, indicators associated with drug addiction have improved. While certainly not perfect, it certainly seems a bit better than the decade old punishment route, which just made matters worse. @Koti, some of the references regarding cannabis and tobacco: Budney et al. 2008, Journal of Substance Abuse Treatment; Vandrey et al. 2008 Drug and Alcohol Dependence. Also note as per your earlier comment: there are no perfect policies. Every policy ever made is an empirical experiment. However, holding fast on wrong assumptions or not implementing changes once it becomes evident that they do more harm then good makes bad policies.
  19. 2 points
    The question was not about using computers to solve calculus problems anyway. Since computer science is mainly about proving asymptotic behavior of the maximal running time of algorithms, there are lots of results in computer science that cannot or only with some extra difficulty be proved without calculus, e.g. typically using that the limit behavior is given by a suitable Riemann integral. Generally you cannot escape using limits to get general bounds on running time.
  20. 2 points
    Considering a wasted education in my youth and the limited ability to remember that seems to come with my age. I like SFN, and several YouTube host, I also have an app that lets my download k12 textbooks, and I am not ashamed to download the lowest grade text I can find to try and get a feel for the basics. I'm not afraid of getting it wrong because SFN members are gratefuly quick to set me straight when needs be. Though at times I feel puzzled especially when I ask a question about spacial density and it seems I'm sent on a snipe hunt. I can only guess that my question was so far off the mark that they were trying to help me along by making it sound like I had asked an intelligent question. I read those articles over and over to the point that I should know them verbatim, Sadly the only thing I can remember about them is that I never did figure out what they had to do with my question. Pretty much everything is new to me. Sometimes even the answers I thought I knew, are new to me, like the conversation about why electrons don't fall into the nucleus. An amazing question followed by an amazing conversation. I wanted to upvote the whole conversation, and I'm glad you Achilles thought to ask the question, cause I was apparently clueless.
  21. 2 points
    Your imagination is irrelevant. There are people who use heroin (under it's more respectable name of diamorphine) regularly for years. In terms of toxic damage done to the body, alcohol is worse- simply because the doses (ounces rather than milligrams)are so much bigger. Of course there is. Several countries have relaxed the legislation on drugs- notably Holland and Portugal. There is typically a small increase in the number of users of pot (and a slight drop in alcohol use). There's a huge saving on police time etc. The problem isn't people using drugs. There is a problem with people how use them too much, or too often. But there's a huge problem with people who are injured- not by the drug use, but by the illegality of that use. The people killed in gang wars over drug territories are killed by the fact that the drugs are illegal. The people who die of overdoses from drugs that were sold with uncontrolled strength and make-up were killed by the fact that the drugs are illegal. The people who die from infections from sharing needles are killed by the fact that the drugs are illegal. We could save most of those people. Why are we not donig so?
  22. 2 points
    Actually, this is not correct. The charge that is associated with the weak interaction is a quantum number called “weak isospin”. All particles possess this, and it is conserved in all types of interactions - unlike flavour, which is carried only be quarks, and is not conserved anyway. Thus, the weak interaction concerns more (elementary) particles than just quarks. To be honest, I don’t think there is an intuitive way to really understand the weak interaction. It’s really quite a complicated mechanism, and requires quite a bit of background knowledge in quantum field theory to fully understand.
  23. 2 points
    Most scientists do accept that we are probably not alone in this universe. Many reasons for that starting with the fact that Earth does not hold any privileged position. Along with the facts that the "near infinite" extent and content of the universe, and the stuff of life being everywhere we look, leads reasonable opinion to conclude that we are not alone. Still the fact remains that so far we do not have any convincing evidence of any life off this Earth, let alone any Alien visitations and anal probing on Earth. Those are the facts at this time, not withstanding the sensational claims of impressionable gullible folk who are so fascinated and in awe of mystique in the world around them, that it clouds any logical judgement on their part.
  24. 2 points
    Wow! What a remarkably obtuse answer! From a quick glance, this looks like a meta-analysis of 76 published studies (all of which are likely to have been peer-reviewed). The opinion reached by at maximum 76 teams of researchers who use the scientific method are likely to be better than you sitting at your computer and trying to rubbish their work. Don't talk complete garbage. Also, if you are a troll, you are likely to get caught early with your stubborn and near-sighted nonsense.
  25. 2 points
    I would argue that you do not know what might be round the corner. You have 1 chance at life. It is an incredible opportunity just to even exist and be aware of it, whatever the pain you have to go through. I would urge them to try something new - they say 'time heals all wounds'.... although it might not be true you can only hope. If someone makes that decision to end themselves I think it is a shame and a waste of the chance for future joy/pleasure/whatever or the chance to pass on your wisdom to someone else. Look to what you can do for the world rather than what it can do for you. Be a part of something greater than your self. Anyway - what do I know? - just my opinion... It is very sad that people hit the lows that make them feel this way imo. We need more unconditional agape love in the world. If I had a prayer for the world - more Agape in all our hearts please.
  26. 2 points
    https://phys.org/news/2018-08-quiet-sunday-night-supermassive-black.html Earlier this year, on a quiet Sunday night, my colleague Jack and I found the fastest-growing supermassive black hole in the known universe. We were fortunate to be part of the team that made one of the greatest discoveries in astronomy this year. This supermassive black hole, or quasar, is 20 billion times the mass of our Sun and is 12.5 billion light years away from Earth. It expands 1 per cent every million years and it devours a mass equivalent to our Sun every two days. Officially, it is called SMSS J215728.21-360215.1, but we call it the hungry monster. The 'we' that made the discovery was a small team led by Australian National University astronomer Dr. Christian Wolf and his team, and included two postgraduate students from the University of Melbourne, Jack Hon and myself. Read more at: https://phys.org/news/2018-08-quiet-sunday-night-supermassive-black.html#jCp
  27. 2 points
    Nope, hence the impasse and suggestion of moved goalposts / evasion / willful ignorance
  28. 2 points
    There There are two related but different definitions of "dense," and completeness has NOTHING TO DO WITH EITHER. * A set is dense if there's a third (distinct) point between any two points. So the rationals are a dense set and so are the reals. * A set X is dense in a set Y if every element of Y has elements of X arbitrarily close to it. For example the rationals are dense in the reals. * A Cauchy sequence is a sequence that should "morally" converge. For example the sequence 1/2, 1/3, 1/4, 1/5, ... should converge, and in the real numbers it does, to 0. But in the open unit interval (0,1), it does NOT converge, because there's nothing for it to converge to. Its limit, namely 0, isn't in the set. * A set is complete if every Cauchy sequence converges. The real numbers are complete, the unit interval [0,1] is complete, and the half-open unit interval (0,1] isn't. Note that completeness is a metric property and not a topological one. The open unit interval (0,1) and the real numbers are homeomorphic, that means they are identical topologically. But the reals are complete and (0,1) isn't. These are all perfectly standard definitions and any book on real analysis will define them the same way. Your posted proof is a train wreck full of misunderstandings and logic errors. Also, I'll assume you meant to say, "Thank you wtf for putting some effort into this to help me when nobody else in the world did" but simply forgot because you're so busy with other important things. ps -- Your approach is hopeless, by the way. Well-ordering has NOTHING to do with denseness or completeness. A well-ordered set looks discrete. It's got a first element, a second, a third, etc. A well-order can't be dense, because for example there are no integers between 2 and 3. In a well-ordered set, given any element there's a successor, with no other element between them. So your approach simply can't work. Likewise, completeness can't work either, since it's based on a metric, and most well-ordered sets have no metric defined on them. For example any transfinite ordinal number is well-ordered, but there's no metric defined on it. So the concepts you're using to attack the problem are the wrong tools. I do encourage you to learn more real analysis, it's a wonderfully interesting subject that will forever clarify your understanding of the real numbers. But flailing away with half-understood and misunderstood concepts, in order to disprove a standard theorem that's already been proven and accepted as true for well over a century, is not the most productive way to go about learning.
  29. 2 points
    I am an open water certified diver, the pressure increases by one bar every 33 feet you go down. Looking at it from that perspective then at 33 feet you would be under 2 bars of pressure but one bar more than at the surface... I am going to say from the perspective of decompression tables you do not consider the surface pressure to be 0 bar. Traveling in an airplane after a deep dive can be fatal even though you are fine at the surface...
  30. 2 points
    No offense, Brett, but you really should read the forum rules before posting anything else on this site. It is required that you back up your claims instead of just making stuff up. Whenever I see your name pop up, unsupported nonsense follows. Please at least do a Google search to check your "facts" in the future. You are of course welcome to ask questions to learn.
  31. 2 points
    Have you seen the program - The Big Bang Theory? The song at the start suggests - "the whole universe was in a hot dense state...." Before the big bang the universe was in a hot dense state - this is not nothing and it is not claimed that it was nothing. What was before the hot dense state? I don't know and nobody does - many may 'speculate' that it came from nothing, but that is nothing to do with the big bang theory and is pure speculation. Your question was regarding the big bang theory - not 'the creation of the universe' - which is why people are asking you if you really understand what TBBT says - which clearly you don't. As I said - I am not an expert - I only have a degree in Physics and chemistry - I never covered it at uni so I will let others that are more knowledgeable explain it to you - but if you don't accept what they say then why would they bother taslking to you - you seem hung up on this 'something from nothing' nonsense - it sounds like something your pastor might claim. What about these newly discovered particles that appear and disappear out of 'nowhere' in a vacuum.... I'm sure they don't come from 'nothing'... they must come from somewhere - no-one knows. You are clearly not listening... bye. Just repeating the question isn't going to help you understand it when you have been told you are already barking up the wrong tree. Sorry - your question doesn't prove or disprove anything. God is a myth - get over it.
  32. 2 points
    Obviously it goes without saying, that if we were to find signs of basic bacterial/microbial life in our own solar system, that chances of life even beyond and at all stages, would be significantly increased.
  33. 2 points
  34. 2 points
    Why not learn what physicists have learnt by experiment instead of making it up?
  35. 2 points
    It is hard to come up with any generally applicable definition by which zero should not be finite. Dedekind: 0 (understood as the empty set, so that the definition applies) does not allow an injection into a proper subset. Hence 0 is finite. Russell: 0 has a bijection to a set {1,2,...,n} for a natural number n, namely for n = 0 and empty bijection. Hence 0 is finite. All well-orderings of 0 are isomorphic. This implies 0 is finite. Every non-empty family of subsets of 0 has an inclusionwise minimal element (Tarski). Etc. There are strange sets that are Dedekind-finite but Kuratowski-infinite. 0 is not one of them, since 0 is Kuratowski-finite by definition. I prefer Russell myself, probably because I come from Combinatorics. For us it is important not only to know whether some things exists or not, but also to count the number of them. An expression like n^m for natural numbers n and m means, by definition, the number of different functions from a set of m elements to a set of n elements. In particular you are quite aware that 0^0 = 1 means that there is the unique function \( \emptyset \) from the empty set to the empty set, so Russell's definition applies nicely.
  36. 2 points
    No. It is a practical concept in daily use. Like 'here'. Both have no meaning without any context. Both are called 'indexicals' in linguistics and philosophy. And, alas, there is nothing that corresponds with it in physics. The idea of 'universal here' does not make sense already in classical physics. The idea of a a 'universal now' would mean that all watches in the universe agree on the time, and have the same pace. Since special relativity we know this idea does not make sense either.
  37. 2 points
    If I have three objects, for example a red ball, a blue ball and a green ball, there are 3! ways I can arrange them. RGB RBG BRG BGR GBR GRB With just two objects there are 2! ways RG GR And with 1 object there's only 1! way to arrange it G There's only 1 way to arrange zero objects And that's why 0! =1 It's adopted as a convention so the maths gives sensible answers for things like probability.
  38. 2 points
    Thank you, I will await with interest. I assume the rest of your post referred to your 'discussion' with Strange. Perhaps I can pour some oil here because I think you two are talking at cross purposes. The reason is simple. One way of looking at simultaneity in the four dimensional continuum you mention is to plot isolines (contours) of constant time coordinate. The problem is that these contours are different when viewed from every point in the continuum. That is you have as many different statements of 'now' as the are points in the continuum. Worse you have no reason to accept any one of these as 'the rightone' or 'the best'. This is the same chain of reasoning that leads to the idea that there is no absolute frame of reference.
  39. 2 points
    Found it. It is on youtube.
  40. 2 points
    Hmm, so you chose emotional, ignorant, and unsupported beliefs over evidenced based science? Do you have any evidence at all supporting any of these religions and or any soul? Whatever "evidence" there is that in anyway supports what you claim, it pales into insignificance to the evidence totally supporting such beliefs to be all scientific woo, myth and nonsense. Perhaps it is just patently obvious that evidence for any supernatural/paranormal myth is lacking, and that alternatively, the evidence for the BB, evolution of life and universal Abiogenesis is overwhelming. Irrespective there are intelligent people who are also religious but phycologically speaking their desire for some warm inner comforting feeling over rides their logic, and of course science as yet does not have all the answers, such as why the BB banged, but it continues to search, for answers, rather then short circuiting it with unsupported myth. No, you don't just get the BB theory. The BB theory as first proposed by a Catholic priest, was based on observational evidence. That evidence over the last 100 years has grown so that it is by far the most accepted theory on how the universe/space/time came to be...Yes, an accident, speculatively explained by a fluctuation in the quantum foam. Richard describes it adequately and well...a happy little accident. The chances of the universe arising is quite real, considering that we are here. More to the point, https://www.youtube.com/watch?v=G4a7F6dOdlc So as Carl said try being couragious, and honest...It's not hard. Well again, it is you that has ventured into a science forum, on your white charger conducting some crusade against science. Is it not you with this weird mind set?? I also have plenty to say about the wonders and awe and answers that science and the scientific methodology has given us. But I will express them on forums such as this, and not venture into church next Sunday, expressing what a lot of gullible fools they are. Perhaps you and I actually swung in the same tree before science evolved?
  41. 2 points
    You have now Nickel's worth of free advice? You'll get along much better here if you remove that giant chip from your shoulder and approach posters as individuals, not stereotypes and labels.
  42. 2 points
    I’m in my forties and still have insomnia (now just habit) that stems from 5 years of age due to fear of death. Trying to get your head around the self not existing anymore ever again was too much to bear and I struggled with life because of this. At some point I was able to control my thoughts from this slippery slope and it’s not a problem these days. I hope the same will happen for you. in Buddhism there’s a saying; ‘If you can do something about it, you don’t need to worry. If you can’t do something about it, you don’t need to worry ‘. Simple but true. And anyway - there’s always hope Why must this be clarified? My feeling is that most people don’t need to label or call themselves an atheist. Rather they are just indifferent to religion as it simply doesn’t concern them. At least, that’s how I see it anyway.
  43. 2 points
    Yes. Precision matters (which is why a lot of discussions are mathematical, because language is often imprecise). Welcome to science.
  44. 2 points
    Is it? What do you base that on? I know plenty of atheists who are thoughtful, kind, modest, ... I don't find that at all surprising. There might be a tendency for conservatism to be associated with religiosity, particularly in the USA perhaps, but it is not an absolute rule. I'm sure there are left-leaning fundamentalist religious types as well. There are many atheists where the "a" seems to stand for "anti"; they can be very strongly anti-religious. Richard Dawkins is one, and I despise him for it. There are also several on this forum (who I occasionally get into arguments with because of it!). My attitude to religious belief is similar to my attitude to golf: it is incomprehensible and of little interest to me. I don't disapprove of people who have faith and I certainly don't despise them. Faith has prompted great acts of human kindness, the creation of beautiful music, etc. (And, obviously as the anti-theists will rush point out in their usual whataboutism, has also been used to justify inhuman acts.) What I will argue with is people trying to use evidence or logic to justify their belief (or lack of belief), or saying that science/evidence must be wrong because some book says so, etc. Hello. Nice to meet you.
  45. 2 points
    Not quite a room... This is currently done by NASA using an empty passenger plane to approximate weightlessness for training purposes The effect won't last as long, but buying and modifying a plane for such a purpose is immensely cheaper than your scheme..
  46. 2 points
    I think you would be on far better ground if you said "Religious people exhibit a higher birth rate", which doesn't have to be associated with fertility.
  47. 2 points
    20 mHz? 0.02 Hz? That means you are aware only 1 time in 50 seconds? (1/50 = 0.02). I assume you mean 20 MHz, 20,000,000 Hz. But neurons cannot fire that fast. The individual components of the brain are, e.g. in comparison to computers, very slow (a neuron fires at a rate of about 6 Hz, computers are at a few GHz now). It is only due to the massive parallel processing in the brain, that it still can fulfill certain complex tasks in fractions of a second. But it is interesting to note that the fastest reactions people are capable of, are not aware immediately, but often only afterwards (this is one of the aspects of sport training: to learn to react automatically on situations, because first becoming aware is just too slow). Of all the process in the brain, awareness is one of the slower ones.
  48. 2 points
    Well, at least your specific existence is an accident. When you were conceived, the sperm that made it was one of about 1 Billion. If another one had made it, you would not have existed. Is that depressing? If not why would it be depressing for the universe as a whole? I think panpsychism is nothing more than the statement that 'all matter is also conscious'. I have no idea how you can make science of that. If you accept that the more complex a system is, the chances increase that the system can be conscious (our brain is a very complex structure), what does the addition that 'all matter is conscious to some degree' helps? Or do you think every corn of sand is just as conscious as we are? On what would such a belief be based? Consciousness is not a thing, it is a process, and it is normal for processes that they can stop. Where is the wave, when it has broken on the shore? Where is the clock, if you hammer it to pieces? Where is your proof of the law of conservation of consciousness? 'I cannot imagine', or 'it does not make sense to me' are not very strong arguments. Spirituality is not some kind of (meta)physics, i.e. there are no spiritual entities. 'Spirituality' is a way to relate to the world, whatever this world really is like. So there is no contradiction between leading a spiritual life, and having a materialistic world view. As a counter-example: take the big religions. Most believers have no spiritual attitude at all. They just have a set of beliefs. But it is interesting to see that nearly every religion, has its spiritual corners, i.e. those people that want to experience what they take as true as intense as possible. Same is true for a materialistic world view. You can just believe it (in contrast with religions however there are very good grounds to believe in the results of science), which I think the majority of science minded people does, but you can also try to deeply feel this, and stand in awe for what science discovers: the working of the universe at the grand or micro scale. Let me just add that many mystics, if you look at their life stories, went through a crisis, before they could accept what they took for true, and found a way to live a happy life with what they accepted as truths. Bending the truth, based on how the universe needs to be so that you feel comforted ('it does not make sense to me') is wagging the dog, and means you have left the spiritual path.
  49. 2 points
    So the Article 4 states that Islam is the official religion (and the sanctity of other heavenly religions shall be maintained. Two things of note. First, there are other countries which have state religions (including some nordic states, England etc.). In itself one could argue for or against it, but it is not quite the same as what is proposed in the bill (which one probably should read). Before I continue with it, I should mention that even if the Palestinian constitution had questionable provisions (I'd have to read the whole thing, for which I do not have the time right now) one would hope that Israel would provide a better example (after all, it is supposed to be the beacon of democracy in the middle East. Also I want to re-iterate that while there are little practical provisions in terms of shifting to more autocratic system, it does show a certain political shift. Similar to the rise of right wing groups in Europe, which could lead to constitutional issues (as seen in Poland). Among the problematic provisions are the following and to make sure, I do not have any expertise in that area, so my interpretation could be way off but: This seems to imply that non-Jews (regardless of citizenship) should have less influence on the State of Israel. In contrast to setting a state religion (and assuming there are no further provision to diminish others) this implies an exclusion of a certain citizens just based on their cultural background. In most Western countries this would be clearly unconstitutional and in certainly seems undemocratic. I do not know enough on how current and future treatment of Arabic is going to shift. I will just note that if one traditionally had two accepted languages and removes one (if that is what is happening) then it is quite a different thing if one was always only used in official capacity. I think that is kind of self-explanatory. Then there is the baffling issue that it does not mention equality of its citizens anywhere, which is found in virtually all democratic constitutions (and is also included in the Palestinian constitution). Perhaps even more so, as it has been in the declaration of independence in 48. Note that the bill is also controversial among Israelis, including President Rivlin. Now there are several layers in which this bill can be considered problematic. One is the general tone for further legislation, second is its possible consequence for the conflict with the Palestinian people (partially due to the ongoing conflict over Jerusalem, part due to the explicit mentioning of settlement expansion in a basic law) and third is of course as it could be seen as an indicator of how Israel sees its future in relationship the contentious situation they have with their Arabic citizens and neighbours/rivals. Western countries see it as Israel moving away from a two-state solution.
  50. 2 points
    It's a classic slut versus virgin dichotomy and is not rooted in fact. It's much more rooted in stereotypes and objectification, desire to use broad labels to justify broad mistreatment. It ignores individual differences and suggests no books need reading, that all information needed can be found on their cover.