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Showing content with the highest reputation since 08/08/19 in Posts

  1. 8 points
    Staff have decided to update the forum rules to include the following: This is in response to a number of threads and certain members who have made threads here under the premise of 'just asking a question,' only to reveal that they are in fact trying to peddle conspiratorial or otherwise nonsense ideas. While covered to some extent by pre-existing rules, we have decided to make it explicit that we will not be hosting these sorts of threads, if for no other reason than the fact that they are a waste of everyone's time.
  2. 8 points
    OK let's clarify something here. First consider the following definitions. Mass is resistance to inertia change Energy the ability to perform work. Spacetime a geometric model system with 3 spatial dimensions with 1 time dimension. In physics dimension is an independent variable or value that can change without affecting any other mathematical object. So how does mass curve spacetime. Well GR models bodies in free fall that is without any force applied. Time is given units of length and can be called an interval. This is done by setting c which is constant to all observers and adding a unit of time. So the time coordinate is given units of length by ct. [latex] (t,x,y,z)=(ct,x,y,z)=(x^1,x^2x^3x,x^4)[/latex] the last is in four momentum form for convenience as its useful to model a particle trajectory along the x axis. Now what is spacetime curvature. Well space is just volume... (Very important ) it isn't a stretchable bendable fabric... Those are just analogy descriptive. What spacetime truly means by curvature is the worldline paths for light it us the null geodesic. If you shoot two laser beams in flat spacetime those beams stay parallel. If spacetime is curved then the beams converge for positive curvature and spread apart for negative curvature. This is a consequence of how the mass term affects the time it takes for a particle to go from emitter to observer. That whole resistance to inertia. So let's drop two objects toward a planet. You have the usual Centre of mass. As the objects free fall they do not stay parallel. They will converge upon one another as they approach the center of mass. That what is really meant by curvature the free fall paths are curved. Not the volume of space.
  3. 7 points
    I am unsure why you would think that - you have never upset me in the slightest with anything you have said, so no apology is necessary at all. But just to set the record straight anyway: it is highly unlikely that I know more about GR than you do I am merely an interested amateur, and everything I post here - without exception - is entirely self-taught. Unlike Mordred, I have no academic credentials in any area of science; truth be told, I never even went to university at all. My understanding of GR and physics in general is cobbled together from a variety of textbooks over the years. I am on the autism spectrum, and one of the defining characteristics of people on the spectrum is that we tend to get totally absorbed by narrow areas of interest (this is called monotropism) - for me that just happened to be physics, specifically GR, at least in the beginning; so I did a lot of reading and self-study in that area. In recent years my interests have diversified somewhat, and I also got involved with certain areas of philosophy and spirituality. Also, understanding GR is natural and intuitive to me, in a way that does not seem to be the case for most neurotypical people; perhaps people on the spectrum find it easier to step outside established paradigms (in this case Newtonian physics) and look at things from a different angle. We tend to have difficulties with other aspects of life, though. I can only speak for myself here. I have no interest whatsoever in anything to do with politics; I stay as far away from it as I can. Anytime in the past when I needed to get involved in politics (workplace, family, etc) it ended badly for me in some way or another. The main reason would be that, as being on the autism spectrum, I am unable to read social cues and guess at peoples’ social intentions. Social interactions between neurotypical people are a complete mystery to me, I cannot understand them. I function reasonably well in daily life, but that is only because I have learned to mask a lot; it’s not the same thing. To me, politics is a bunch of people with strong opinions, who do not recognise them as being opinions, and mistake them for some kind of reality. So they get terribly agitated when others don’t share them; there is a lot of suffering it it, really, and no one seems to even see that. I have plenty of views and opinions as well, but I tend to be able to recognise them as such (or so I hope), and see how they are changing with time, so I don’t try to push them on other people. They are just constructs of my mind, so ultimately they say more about my mind than they do about the world at large. As for religion and ethics, they are areas of interest to me - but I personally don’t see them as something to be debated or discussed on social media, which is why I don’t participate in those threads. Religion - or rather: spirituality - in particular is something you do, not just some passive view on the world. I see lots of people who call themselves “Christian” or “Muslim” or “Buddhist”, but these are just labels - those same people may speak and act in ways that reveal complete ignorance of the nature of human suffering. And conversely, some of those people I have met who were most at peace with themselves and the world did not label themselves in any way; they just lived a truth that existed within them on a visceral, intuitive level. So religion and spirituality are never external things, they come from the inside; they are lived, not debated. That’s all I can really share with regards to this. Ethics, to me, is the art of finding the path of least suffering, for myself and everyone else who is involved, in any given situation. There is no such thing as “right” or “wrong”, there is only cause and effect. One can write down general principles for this that may hold true in most cultural backgrounds, but ultimately it is again something intuitive and visceral, something that happens inside. Intention has a lot to do with it - if we act from a place that understands the suffering inherent in all sentient life, and consciously choose to act in ways that minimises it to the best of our limited abilities, then the seeds of our actions will generally be wholesome ones. Again, I think it has a lot to do with one’s reasons for being here. I am on this forum for two reasons only - to expand my own knowledge and understanding, and to help others do the same; and very often, these two things are mutually co-dependent, and happen simultaneously. It is no longer about getting anyone else to adopt my own views on things. Ultimately you cannot force someone to understand something; you can only offer them the tools that might enable them to put the causes and conditions in place for such understanding to arise eventually. But different people come from different backgrounds, and they are at different stages of their own journeys when they arrive here on this forum; it does happen that someone just isn’t ready to listen, and then it won’t matter what you say to them, regardless of how rational and scientific it is. They will be unable to see the merit in it. It’s not even their “fault” really, it’s just that the conditions are not right yet for understanding to arise. Getting upset or offended will never help in these situations - most often it is best to simply disengage and walk away. After all, it is their journey, so I don’t need to loose my own balance over it.
  4. 6 points
    A question about a sign convention that leads to a lot of confusion. This is not the only instance multiple sign conventions in Science. In this case it is a result of History. Thermodynamics was originally developed by physical scientists and engineers. They were concerned with making machines (steam engines) for the industrial revolution. Steam engines are heat engines. That is they thought in terms of input (heat in the form of fuel) and output (work). Both of these were thought of as 'naturally being' positive quantities. So they wrote their version of the Law of Conservation of Energy (The First Law of Thermodynamics) as ΔU = q - w. Chemists came to the scene from a different point of view. They wanted all forms of energy to have the same sign, whichever side of the conservation appearance they appeared so they could present the equation as a sum on both sides of the equation. So they wrote their equation as ΔU = q + w. By then it was also realised that, although all the terms are energies, there is a difference between ΔU , which is a state variable of the system, and q and w which are exchange variables of the energies crossing the system boundary. So they tidied up by stating that all energies crossing the boundary from the system to the surroundings are negative and all energies passing from the surroundings to the system are positive. Now they could add them up, move them about in equations and between equations in other parts of Science in a consistent manner. It is an improved system But it shows the importance of knowing the sign convention in use and the equations that go with it. This last remark also applies to other such instances of multiple conventions such as those in Electricity, Elasticity and elsewhere.
  5. 6 points
    This is my 1000th post! Time to celebrate, This is a fine moment to open the Islay Single Malt I got for Christmas. Cheers from Ghideon, to all new and old form members!
  6. 6 points
    It might help, if you @Angelo would first, in an objective tone, lay out exactly what you believe Tyson's argument to be, and the steps in his reasoning (as far as they are provided and assuming they are truthful). As far as I understand the simulation hypothesis, is that it is based on chance and likelihoods coupled with some very specific assumptions; however the things you say, and the way you ask your questions and/or comment on other peoples posts, to me seems to indicate that you (at best) don't know the full reasoning behind the simulation hypothesis (or you do understand it, but are wilfully creating strawmens). Additionally, it would be great to present the strongest argument(s) for the simulation hypothesis, and not immediately assume that Tyson and other people agree on everything. If he has some illogical reasoning or assumptions you don't agree with, then it may be good to find a better version of the argument, instead of immediately disregarding the entire hypothesis. If you are really interested in understanding Tyson's and other people's point of view on this, it would help to start with a detailed summary/explanation of the hypothesis, because I could explain it (as far as I understand it), but I doubt the explanation is similar to what you think it is. And if you aren't sure on WHAT people belief, then it is very strange to already think of it as nonsense, therefore (assuming you have good reason to think of it as nonsense) it should be easy for you to explain it (in your own words, please don't just link something, that doesn't test your current understanding). Kind regards, Dagl
  7. 6 points
    My son holding my grand daughter!
  8. 5 points
    The 'bowling ball on a rubber sheet' is a two dimensional reduction of a 4 dimensional configuration. It has multiple problems, one of which is that you can observe it from an embedding third dimension. Space-time has no embedding dimension; both the bowling ball and you, the observer, would need to be intrinsic to the rubber sheet ( i.e. also two dimensional ). A three dimensional representation would already get rid of some problems, but not all. Picture a three dimensional grid, where x, y, and z axis divide up the space into cubic elements. A mass placed in this space would curve the x, y, and z lines such that the elements are moreskewed, and smaller, as you get closer to the mass. That is 'space' curvature, and one aspect of gravity, but already much harder to visualize than the two dimensional example of the bowling ball/rubber sheet. Actual gravity is four dimensional 'curvature' of space-time, and I can't help you visualize that as it is impossible. Some problems are just not suited to visualization, but understanding even just the basics of the math goes a long way to clarifying things.
  9. 5 points
    At which point, I have to post this: https://what-if.xkcd.com/1/ Spoiler: it doesn't end well
  10. 5 points
    The 'economy' is not just a money making mechanism for the wealthy, Phi. It is the means by which most of us feed, clothe, house ourselves and our families; it's how we survive. I have no problem with the economy 'going for a sh*t' as long as it saves lives. But if it 'goes for a sh*t' for too long, people start losing their life for reasons other than the pandemic. That is the balance that has to be struck; dying by starvation is just as bad as dying by Covid-19. I believe that is what Danijel Gorupec meant.
  11. 5 points
    Today I learned that skills improved by participating here on scienceforums can, at least in some minor way, be helpful in the current virus situation. I joined a local initiative where students studying from home can ask about math and physics. Debating science here has made me more confident regarding mainstream science and how to respond with useful hints (instead of solutions) to homework questions.
  12. 5 points
    Element 115 (moscovium) has a half life of about half a second, so is not very practical as a target. https://en.wikipedia.org/wiki/Moscovium (And I doubt that element 116 can be produced by firing protons at the nucleus.) "Immediately decays"? It is true that the half life of livermorium is less than that of mosocvium; but it is not immediate. Livermorium decays via alpha decay. In other words, it emits a helium nucleus (a pair of protons and a pair of neutrons bound together). https://en.wikipedia.org/wiki/Livermorium It does not emit anti-protons. That would violate all sorts of conservation laws. https://en.wikipedia.org/wiki/Conservation_law And anyway, what would be the point? This can only be of interest to people who think that antimatter=magic. What are you going to do with these anti-protons? Presumably combine them with some protons to generate energy. But you can't get any more energy out of that than you put in. So the whole process of accelerating some protons, transmuting 115 to 116, then capturing the anti-protons and then generating some protons for them to interact with, then controlling their interaction and directing the energy ... all takes energy. And must run at less than 100% efficiency. https://en.wikipedia.org/wiki/Laws_of_thermodynamics So you are going to get less energy out than just using shooting the original protons out the back of the rocket. Or using the heat from the rapid decay of the moscovium (you will be left with no useful fuel after a few minutes, anyway). There is nothing to critique here. This is just meaningless word-salad from a bad SF book. No references here because there is no such thing as "Gravity-A waves", "Gravity B waves" or "Gravity Amplifiers". Also, gravitational waves (which do exist) are not directly related to gravity. Gravitational attraction is not a wave phenomenon. Also, gravity is only attractive; there is no practical or theoretical reason to think that somehow causing gravitational waves (if that is what the ignorant author means) to interfere would cause any gravitational effect (either pull or push). Gravitational waves cause stress (stretching and shrinking) in directions orthogonal to their direction of travel. This effect is too small to be significant, unless you are a few miles from two merging back holes. https://en.wikipedia.org/wiki/Gravitational_wave Gravity waves are something completely different. They are a phenomenon in fluid dynamics and have nothing to do with gravity (in the sense implied here; they are caused by gravity, not a cause of gravity). https://en.wikipedia.org/wiki/Gravity_wave It is almost as if the author doesn't know what they are talking about. And are just stringing together a bunch of words they don't understand. See anyone can do it.
  13. 5 points
    Thank you all for your insightful comments and helpful links, and sorry I didn't reply earlier but I just joined and hit the five reply limit. You've helped me see the flaws in my thinking and weak areas of understanding, especially misunderstanding space/time to have elastic potential energy (as this was just a misunderstanding of how the models are visually represented), not using accepted vernacular, and uniform expansion. In retrospect, I should've just left out the Quantum Field explanation as I'm sure most of you understand more of it than I do already and it's already discussed on these forums. It's all forced me into the frightening conclusion that if my thoughts in this area are to have any value I'm going to have to move from being interested to being dedicated and learn some math. Darn it.
  14. 5 points
    A better question is why [math] 10^{-43}[/math]. Would it help to recognize that number is one unit of Planck time with our current observable universe to the volume of 1 Planck length. The temperature being equivalent to Planck temperature. The Planck units are in essence boundary conditions on which our ability to mathematically describe in essence breaks down into Infinities and nonsensical results. You often only hear the space and time axis in essence flipping roles for the GR descriptive but cosmology must also include both macro and quantum effects. So its good to understand how the limits of the macro and quantum theories apply. (String theory also recognizes these limits) One detail as mentioned in this thread is were describing our Observable portion in essence the limits of shared observable causality with our current universe. Time being a measure of rate of change or duration you in essence need a dimension in order to have something to measure or even something that must be able to change. However one must also realize that the t=0 represents the collective worldlines of all particles in our observable portion extrapolated from the closest we can mathematically describe and potentially measure. In the closest to pointlike we can describe. It does not represent any time outside our region of shared causality. In essence [math]10^{-43}[/math] is the origin of time for all potential worldlines in our observable universe that are extrapolated to the beginning of our observable universe (as the emitter event).
  15. 5 points
    Thank you for all your feedback. I’m currently working on some mental health issues and cannot reply on give the answers the time that I would like to in regards to research and time and I struggle to express the concept fully and accurately, more to come but I have to work on my stability at this time kind regards David Wavish
  16. 5 points
    As swansont has already stated, dark matter is matter that is hypothesized to exist due to the apparent gravitational effects we see, but which doesn't interact electromagnetically like the regular matter we are used to dealing with. This means it does not emit, reflect, or absorb light either, thus the description "dark". And as he said, we don't really know just what it is made up of yet. There are a couple of possibilities. Massive Compact Halo Objects (MACHOs) would be objects like neutron stars and black holes. These are object formed from "normal" matter (or at least a far as black holes go initially from it), but compact so much mass into a small area that they are just to small and dim to see individually. However, we need quite a bit of dark matter to explain observations, and there are reasons why we don't think the universe could have this much mass in the form of MACHOs, as it would have effected how the universe evolved, resulting in one that looks a bit different from what we see. Another possibility is Weakly Interacting Massive Particles (WIMPs) These are sub-atomic particles that have a rest mass, but just don't interact via the electromagnetic interaction. (And pretty much everything having to do with how we interact with regular matter, from touching it or seeing it, to chemical reactions involves electromagnetic interaction) These "ghost-like" particles would pass right through you like you weren't even there. While this this seems bizarre, we actually already know of a particle that behaves like this, the neutrino; Billions of them pass through you every day with your ever noticing it. Neutrinos ( or at least the type we know of) don't work for dark matter for various reasons, so the WIMPs of dark matter would be something like, but not identical to neutrinos. It is also possible that both of the above play a role in making up the total effect we see. swansont also mentioned attempts to explain things by a modified theory of gravity. The problem with this is that a number of observations are not compatible with such an explanation. An example would be galaxies that appear to be identical but exhibit different gravity profiles. Even if the rule of gravity were different than what we presently think they are, they would still need to be consistent from galaxy to galaxy. So while its perfectly possible for different galaxies to contain different amounts of dark matter and thus as a whole act differently in terms of gravity, it is hard to explain why the actual rules governing gravity would change between galaxies. Having said this, it is still possible for a modified gravity theory to play some role, if combined with dark matter. A new theory of gravity which also incorporates a mix of MACHOs and WIMPs could end up being the final answer. Right now we are at the stage of continuing to make observations in order to narrow the playing field. We have eliminated some possibilities, but there are more to explore.
  17. 5 points
    Fake news! It was a perfect renewal! Absolutely perfect. In a world where even my fridge can give me reminders, I still managed to forget. Luckily Capn was able to social engineer his way through my answering service who sent a page out to me stating "CAPN REFSMMAT - RE: WEBSITE". They even listed a hospital he was calling from 😂. I wasn't on call today so when I heard my answering service text me I about lost my mind until I saw who it was.
  18. 4 points
    Disclaimer: Black hole not visible, southern hemisphere required. https://www.theregister.com/2020/05/06/nearest_black_hole_earth/
  19. 4 points
    My little bother just ate all the Scrabble tiles and his poop made more sense than you do.
  20. 4 points
    Why is it apparent that small things determine how big things work and not vice versa? Why is cause and effect noncommutative with respect to "size". In the sense that CAUSE is due to some physical laws: Quantum fluctuations CAUSE real and virtual particles. Real particles cause leptons, quarks, bosons. Leptons and quarks cause protons, neutrons and electrons. Protons neutrons electrons cause hydrogen helium and carbon atoms. Hydrogen, iron and oxygen cause stars, planets, and water. Stars, planets and water cause galaxies, solar systems, and oceans. Galaxies do not cause stars. Stars do not cause hydrogen. Hydrogen does not cause protons. Protons do not cause quarks. Quarks do not cause real particles. Real particles do not cause quantum fluctuations. The direction of time is forwards? The direction of cause is bigwards?
  21. 4 points
  22. 4 points
    Citation needed. Maybe it is just compensation for the Flynn effect. I would guess the lack of a good definition of IQ and the corresponding arbitrariness of the tests accounts for a large part of it. Maybe modern communication technology and social media means that cultural change is happening faster and the tests can no longer be fudged quickly enough to compensate.
  23. 4 points
    I think you'd better take a good look around, Dim, and not how you imagine things. You might not like what you see.
  24. 4 points
    After 8 seconds it said "This film is not presented as fact." So I did not watch the rest. Correct. I am not interested. But if anyone provides reliable scientific evidence about progress in our understanding of gravity (and/or anti gravity) I would be very interested. Warning: Straw man ahead: *) Replace alien technology with "magic", "psychic powers", "spirits", "life after death". The scientific content would be the same (zero).
  25. 4 points
  26. 4 points
    Note that the spread was predominantly along trade routes. While there is decent evidence supporting the use of (black plague) bodies (which, btw. were already spreading in Asia and the Middle East), the entry of the plague was likely independent of that (or it may have contributed it, but was not the major driver). The narrative of the use of cadavers and the spread of the bubonic plague to Europe following the the siege of Caffa was strongly based on the account by Gabriele de' Mussi. Historians disagree whether he was actually physically present during the siege, but it appears that they think it is at least plausible that cadavers were hurled into the city. There is also the possibility that the plague arrived with the army and was subsequent transmitted by rodents, but despite overall uncertainties it is (from what I have read) not the favoured explanation. In the accounts de' Mussi also said that those escaped from Caffa were bound to Genoa Venice and so on and thereby spread the disease. However that clashes with what I think is now fairly well established understanding how the plague spread into Europe. It is well established that the plague spread over the Crimea, but cases in Genoa and Venice appeared well over 2 years after the siege of Caffa. Since even under unfavourable conditions the voyage should have not taken more than a few months, the timeline does not line up well. Another aspect that even if that timeline would have worked out, the time required would still have resulted in a substantial outbreak on the ships themselves. But again, around that time, there were no records of something that must have been considered to be a significant event. There are also folks who dispute that corpses were used in the first place (as there are no reports from folks fleeing from Caffa describing it aside from de' Mussi's account) or that there is no indication that it was knowingly used as a bioweapon (some dispute that bodies would be effective, they should have flung rats instead...). There is for example the speculation that the plague may have entered Caffa via the waterways. The Mongols were not able to fully block those and this where Caffa was getting resupplied. Also historians report that a step-wise entry of the plague into Europe is more likely which makes a spread over trade routes via Crimean ports even more likely. Well established reports pinpoint spring 1347 as the start of the plague in Constantinople, for example. I.e. there are quite a few reports that contradict the strong narrative of warfare-mediated spread, which is quite fascinating actually as not only historians have been working on it, but also epidemiologists and microbiologist, who use the documents to establish timelines and spread, not dissimilar to modern epi-studies (just with scarcer data). What is rather neat is that a fairly recent PNAS paper actually described genome evolution in Yersinia pestis which is consistent with repeated introduction via migratory and trading routes.
  27. 4 points
    The plot revolves around a group of highly trained professionals who break into homes of elderly folks and aggressively cough into their faces for a few minutes. In a heartwarming twist one of their presumptuous victims confuses the terrorist with their grandchild to whom she had lost contact. After a furious intermezzo consisting of baking and copious amount tea the terrorist realizes that deep inside he is just longing for the love of a family. Meanwhile the grandparent realizes that the nightly visitor in stealth suit is indeed not her grandchild (the climbing hook on the balcony being a crucial hint- as well as a flashback highlight that the real grandchild had a fear of heights). But she enjoys the moment too much to care.Tragically, this human moment is also what ultimately resulted in successful infection. The terrorist becomes guilt-ridden when it becomes clear that the lonely grandma is not long for this world and he tries to reach her a last time to say his farewells. Meanwhile, his terrorist buddies consider him a traitor and try to stop him resulting in a highly choreographed fight scene involving lots of offensive coughing and running noses in slow-mo (the filmmakers did not consult experts as per usual and did not realize that this is not part of the symptoms). Finally, he survives all these ordeals and reaches the grandma, who turns out to be a special CDC/Homeland security agent in disguise (Jason Stratham) who have been delaying a rollout of coronavirus testing in favour of sting operations to catch corona-terrorists. PS: can anyone tell that I really, really do not want to read those student reports?
  28. 4 points
    The autism connection has been peer reviewed and the author of that has been discredited and struck off. He, to cut a long story short, had a financial interest in pursuing this position. Unfortunately, this myth has persisted and been magnified by the internet. Google 'andrew wakefield autism'
  29. 4 points
    What up! I know I am about 16 years late but, I just wanted to point out that (like others have) @Tesseract was incorrect in saying that salt and vinegar makes hydrochloric acid. I dislike the spread of misinformation. Next time make sure something is correct before you post it to the internet. Also I made this account to post this. But I'm sure nobody will ever see this. I put so much time and effort into doing something so utterly pointless.
  30. 4 points
    Your only questions are sarcastic and unhelpful. Your assertions have mostly been wrong, and have been pointed out to you, but you've chosen to ignore them. You're rejecting explanations without reason, simply because they don't seem intuitive to you. This isn't personal, it isn't about you. It's your approach to learning that's causing a problem in discussions. I have to ask, is there any way to reason with you on this subject, or is your incredulity always going to be an impassable obstacle? How can we turn this discussion into a meaningful one? Several people have tried explaining what mainstream science says on this subject, but it's hard to have a conversation with you when half the effort is spent trying to get your fingers out of your ears.
  31. 4 points
    The plane crash involved a Boeing 737-800NG, not the MAX but a previous version with stable aerodynamics and no computer override. The plane was 3 years old and had been in for maintenance on Monday. And Ukraine has suspended all flights into the area, but hasn't grounded similar 737-800NGs. I personally haven't seen it, but there are reports of a video showing the plane coming down engulfed in a fireball, and wreckage photos show puncture damage from either engine failure and breach of blades, or shrapnel. The plane was at 8000 ft when contact was lost and it disappeared from radar, but the ground elevation in the area is over 3000 ft, and it had made a sharp left turn as it climbed out at less than 5000 ft relative to ground elevation. At this point it would have been close to the Malard missile launch site. Given the circumstances, this does not seem to be a technical issue, even if there had been enough time to do an investigation ( usually takes months ), and engine failiures do not result in that type of a crash. I would assume, until evidence proves me wrong,, that the plane was warned not to overfly the missile launch site, but was mistaken by Iranian air defenses as incoming cruise missile or possibly even MANPAD launched in error at a low flying target. I have also seen reports of the 63 Canadians being mostly students from the Toronto area. Seems Iran's 'insignificant' response may have led to some very serious consequences, and the 'fog' of war has shown up again. May all 180 passengers RIP.
  32. 4 points
    It is very disingenuous to ask a question then assert the answers are wrong.
  33. 4 points
    A clock near a black hole ticks at “1 second per second”, a ruler near a black hole is “one meter per meter” long. A clock on Earth ticks at “1 second per second”, a ruler near Earth is “one meter per meter” long. Locally in their own small enough neighbourhoods, neither observer determines anything special to be happing. As the name already implies, relativistic effects become apparent only when you compare clocks and rulers in different frames - they are relationships between frames, not things in and of themselves that somehow happen to clocks and rulers. No clock will ever tick at anything other than “1 second per second”, and no ruler will ever measure anything other than “1 meter per meter”, within their own local frames. Time does not “slow”, space is not “stretched”, they merely become local concepts. It is crucially important to understand this point. So, in order to determine the geometry of spacetime, you need to either compare clocks and rulers at different events, or (equivalently) observe what happens when they traverse extended regions of spacetime. What you find then is that different observers may disagree on specific measurements of space and time, but they will always agree on how those measurements are related to one another. In other words - all observers agree on the geometry of spacetime. Mathematically speaking, the object that quantifies relevant aspects of the geometry of spacetime (in GR that is the Einstein tensor) is something that all observers agree on, regardless of where and when they are, or how they measure and determine it. The components of the tensor vary as you go from one observer to another, but they vary in such a way that the overall tensor remains the same one - that is the meaning of “covariance”.
  34. 4 points
    I think there are certain parallels between people believing in conspiracy and religious belief (religion being, from a certain point of view, the ultimate conspiracy) As folks have pointed out from time to time, when people do not use reason to arrive at a position, you will not be able to use reason to talk them out if it. Studies have shown that presenting such people with contrary evidence only tends to harden their resolve.
  35. 4 points
    As a silent reader not actively involved in this thread, allow me to offer an observation. Your initial post had one or two points in it that are relevant and worthwhile, but unfortunately your tone and general presence here comes across as arrogant and condescending, You made at least one good point (and some not so good ones), but you failed to communicate them in a proper manner. Please take this as constructive criticism, i.e. an opportunity for growth.
  36. 4 points
    This might be possible, if I may offer an opinion, for any number of reasons not apparent form the perspective of an 8-9 year old 20 years in retrospect. It's possible that your vivid recollection of what occurred 20 years ago isn't quite what happen. Time alters our memories and can create false ones that merges imagined experiences with those that are real. If your experience was real and you actually sustained "3 deep knife marks", scars of that experience would likely be visible somewhere on your body today, 20 years later, if they were truly as "deep" as you say. However, you've made no mention of such scars, which could suggest that the sleep injury you sustained was likely not as severe as you might have then perceived 20 years ago, which was likely precipitated and enhanced by the persisting fear an 8-9 year old could have experienced after a night of watching "scary movies". 20 years hence, your memory of the experience was embellished by time. Although, there's strong scientific evidence for the psychosomatic connection between mind and body, which can produce real physical injury, I do not believe this was likely your experience as a 9 year old child particularly without evidence of lingering scarification. I hope this helps.
  37. 4 points
    Artificial selection is not necessarily quicker than evolution, but using CRISPR Cas9 approaches, it is simple enough to produce antibiotic susceptible strains. Aseptic technique is still the most valuable tool in the prevention of nosocomical infection. Spreading pathogenic bacteria about an OR - drug susceptible or not, would have significant detrimental effects. So a few things 1) Often antibiotic resistance (AR) genes come with negligible costs to the bacteria, so do not suffer from negative selection. 2) They are often encoded on extrachromosomal transposable genetic elements (e.g. plasmids) or like the MecA gene in Staphylococcus aureus can be transferred by viruses - so you cannot prevent the spread of AR genes between your susceptible and resistant strains. 3) AR genes often, through selfish gene mechanisms, get crowded onto plasmids or prophage with other genes that confer a net benefit, such that they can piggyback on the positive selection of other genes to proliferate. 4) Resistance mechanisms like multi-drug efflux pumps, efflux many many other cytoplasmic contaminants, such they provided a benefit to bacteria in a wide array of environments. 5) Over 80% of antibiotics produced in the developed world are used as growth promoters in agriculture, rather than therapeutics. Therefore most of the interaction between bacteria and antibiotics is happening in the broader environment, not in the clinic. 6) Continuing from above, most of your patients present to the clinic having already acquired the resistant infection in the broader environment, so bacteria in the clinic are unlikely to have a positive impact. Dusting yourself with Staph/Klebsiella/Salmonella/Cholera etc, resistant or not is a terrible idea. You would wind up with far higher rates of infection and subsequent morbidity as a result, with a net negative public health outcome.
  38. 4 points
    This is the kind of problem that is more easily solved if you step back before turning the math crank. Look at y = x^2 and y = 16&x. y = X^2 is a parabola that passes through the origin. y = 16^x is an exponential function, and on the positive x side it rises faster than the parabola-- so it is obvious that there will be no solution for x > 0. On the negative side of the graph, 16^x approaches zero asymptotically, and is already 1/16 when x = -1 (while at x = -1 the parabola is at y = 1). Thus, it becomes obvious that the solution must lie in the region -1 < x < 0. I did a quick sketch of the two functions and it was equally obvious the crossing point had to be somewhere close to -0.5, as stated by Studiot. Understanding the shapes of functions makes trial and error, and heavy math, both unnecessary.
  39. 4 points
    Physical laws have certain properties, and you can have maths that have the same properties, but you can also have other maths that don't, including abstract mathematics that aren't based on physical things. For example, you can mathematically take apart an orange and rearrange it into two oranges identical to the original. https://en.wikipedia.org/wiki/Banach–Tarski_paradox The maths aren't restricted by the physical law of conservation of mass.
  40. 4 points
    Apparently, Marcus Aurelius commented on Pascal's wager about 2,000 years ago:
  41. 4 points
    I am more than likely wrong on all accounts but the Idea simply made sense to my current understanding. It seems apparent my current understanding is quite misleading. I appreciate your patience with me in your explanations. This stuff is fascinating the hell out of me though. Could you possibly recommend some entry level physics/calculus books I could begin with increasing my understanding of how all this works?
  42. 3 points
  43. 3 points
    In the absence of any science, I'm left to focus on the constant mention of other forums and other discussions and other people. I find it profoundly uninteresting, since the science behind your idea is the topic of this thread. Sorry, but screw Phil. We don't know Phil, he's not a member, he's not part of this conversation. You need to stop trying to massage your audience before the actual discussion takes place. We're only interested in the science. If you want anyone to discuss this with you, the idea should be sound enough on its own without you having to "sell" it. Please don't let this go to multiple pages without actually presenting your concept.
  44. 3 points
    For those of us ( like me ) who are not up to speed on Virology, this thread, from another forum I frequent, seems t be a good beginner tutorial... https://www.airliners.net/forum/viewtopic.php?f=11&t=1443947 Perhaps CharonY can have a look at it, and answer any questions we noobs might have. ( or make any corrections as needed )
  45. 3 points
    Observers not in line with the laser will not see the photons, unless the photons scatter off of something (e.g. dust). The number of photons in the beam is large but not infinite (and can be found knowing the wavelength and power)
  46. 3 points
    Do not forget that also in the physical 4D-world, the time dimension does not stand on equal footing with the space dimensions. Pythagoras in spacetime is: x2 + y2 + z2 - (ct)2 = d2 Note the minus-sign. So in some sense we experience a 4D world: we need 4 coordinates to define the spacetime location of events. But time- and space dimensions do not behave exactly the same.
  47. 3 points
    I should point out to you that you don’t seem to be following the scientific method, which is a big red flag. You appear to have arrived at a conclusion (electron is composed of photons), and now you are working at making everything fit that conclusion. That is not how science is done. In the scientific method, you start with the data - in this case the known dynamics and properties of electrons -, develop a model to describe that data, and then test that model. If the model does not work, you either amend or abandon it. Crucially, any new model must fit in with all the rest of what we know about physics. If you come up with an idea, and then find yourself unable to abandon that idea even in the face of overwhelming evidence that it doesn’t work and cannot work, then you have a problem. I think you should stop wasting your time with this, and reinvest your resources into learning what we already know about the physics of particles. Only when you are familiar with what we already know, can you make meaningful inroads into what we don’t know yet. Just some friendly advice.
  48. 3 points
    I know I'm often guilty of the same thing, but if INow and Zap on one side, and YJ02 and JC on the other, would pause before re-posting and ask for clarification of a comment made by the other side, instead of assuming and bringing their own biases into play ( yes, we all have them ) this conversation/discussion would be a lot more congenial. I think we all agree that D Trump is bad for the country ( and the rest of the world ), we just have a different perspective on which method/process for removal would do the least damage to the country and its government.
  49. 3 points
    They said that about calling ll Mexicans rapists, and the Access Hollywood tape, and about saying John McCain wasn't a war hero b/c he got captured, and about calling predominantly black locations shithole countries, and for disowning our allies, and for having secret service rent golf carts from his properties every time he travels, and for golfing more than the last several presidents combined for hundreds of millions of dollars in tax payer money, and for tweeting classified satellite images of Iran, and for telling his team to fire Mueller, and for not releasing his tax returns, and for saying he had no reason to believe our intelligence community or disbelieve Putin, or for raising our cost of goods through tariffs with China, or for asking again for foreign aid in our elections, or for having the military book and pay for vacant rooms at his properties even though they weren't staying there, or for having the VP fly across Ireland to stay at his properties when his meetings were 3 hours away, or for robbing his charity for kids with cancer, or for calling senators unamerican for being black or muslim, or for saying there are very fine people of both sides of a white supremacist rally, or.... or again... and or some more...
  50. 3 points
    That's kind of the definition of UFO.
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