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Showing content with the highest reputation on 07/23/20 in all areas

  1. 2 points
    Actually the most likely scenario are neutral mutations. In most species there is a large space where mutations happen, but nothing changes on the physiological level. In viruses and other condensed genomes mutations are more likely to have an effect. But due to the high production rates many deleterious mutations are not observed as they do not get transmitted or even out of host cells in the first place (e.g. if the particle is not fully formed). Those that have been monitored so far are, again, mostly neutral, though the latest research indicate a potential new mutation that could be more effective in transmission (though not validated yet). While this often happens, it is over a longer time. What basically happens is that if a less harmful strain emerges in parallel with a deadlier one, over time there is a certain likelihood that the deadlier version spreads slower (as its host keeps dying). After a certain while, the less harmful one may become dominant. However, especially in this case it may take much longer, as the death rate is not terribly high and especially among folks that are very good at spreading (i.e. younger folks) the symptoms are relatively mild. There is evidence that there are long-term damages to the lung, even among those that recover, but that is unlikely to be detrimental to its spread. Wait what? First time I have seen that. Is there an article about that that you could share? Edit: Looks like one of those viral social media thingies. I.e. more rumors than anything https://www.snopes.com/fact-check/people-collapsing-coronavirus/ Those things add confusion to the current situation which is not really ideal.
  2. 1 point
    This is not how I understand the original situation. I understand it to mean that The distance from Earth to planet 2 has already been measured (and will not change in the lifetime of Alice) by othe astronomical means. Similarly the spaceship has a 'cruise control so its velocity is predetermined at a fixed rate of 0.99c. No one measures this. Bob starts out from Earth when both his clock and Alice's clock read zero. So by Alice will know that when her clock reads 20.5 years Bob is just arriving at planet 2 with his clock. Bob's clock will be reading a value given by the Lorenz transform of this time.
  3. 1 point
    The star TYC 8998-760-1 (top center) was photographed with two giant exoplanets (arrows), the first time astronomers have directly imaged more than one planet orbiting a sunlike star. The bright spots above star TYC 8998-760-1 are other stars in the background. BOHN ET AL/ESO https://www.sciencenews.org/article/first-picture-sun-like-star-multiple-exoplanets-astronomy-planets
  4. 1 point
    All calculations of distance and time have to be done in the same frame. You use the transforms to get the values in the other frame. You have done the calculations in Alice’s frame. If you want the distance and/or time in Bob’s frame, you do the transform.
  5. 1 point
    Surely Alice just reads it off her clock ?
  6. 1 point
    Hello michel123456: As Studiot said, it depends on how you define change, and Markus is careful to initially put quotation marks around that word before he gives an example. And when you say "in your mind", you are offering nothing more than another definition. Strictly speaking, Markus never said anything about changing the spatial coordinates; he said the curvature changes with respect to different spatial coordinates.
  7. 1 point
    I my mind for change to appear you need a before/after relation. In the spatial tea cup example, how do you change spatial coordinates? Or how do you hover over the cup in order to notice the curve change? You can even say that the cup cannot have been created, it was always there. It is a mathematical cup-universe in which nothing can happen. I have even the gut feeling that mathematics have inherently time inside it. How can you make any calculation without time?
  8. 1 point
    Now that is an example of bad philosophy... And a pretty good example of my present disclaimer: With other words: what you say is a philosophical remark. E.g. it is based on the assumption that only empirical facts matter in life. But that itself is not an empirically verified position, so, according to you, it distracts from true knowledge. Your position is self-refuting. As to the question of the poll: of course there is good and bad philosophy. But we should keep Strange's distinction in mind: 'philosophy' as a 'philosophical theory', i.e. the contents of what a philosopher is saying about the subject at hand; and 'philosophy' as an activity. Which of course agrees more or less with the same distinction in science. Good philosophy, in modern times: Is well informed about relevant science, culture and politics Takes into account other viewpoints about the topic at hand Confirms or refutes other viewpoints with good arguments, i.e. arguments that are relevant and well supported by sciences and other well argued philosophical viewpoints Is extremely aware of the methods it uses to argue for a certain position. Bad philosophy: Only expresses opinions without arguing Uses arguments that are already refuted by others Confuses scientific speculations with philosophy The specialty with philosophy which distinguishes it from sciences is that in science the domain of knowledge it tries to gather differs from the (transcendental...) subject (i.e the one that observes, experiments, and expresses ideas about the object) of the domain. A physicist investigating certain phenomena does not investigate herself. As I said elsewhere here, the object of physics is not physics: it is the natural world as we observe it. As soon as physicists investigate physics, they are philosophising. Philosophy is essential reflective: it tries to understand our thinking with thinking, just as the physicist thinking about physics.
  9. 1 point
    ‘Satisfactoriness’ is not a property of scientific models; internal self-consistency, empirical testability (in the sense of making testable predictions), and falsifiability are. And QM does rather well in those regards, all of the debates around different interpretations of the formalism notwithstanding. The standard way of modelling ‘delayed choice’ type experiments may appear unsatisfactory to you only because you tacitly (and perhaps unconsciously) think of the world as classical, which is what we as human experience. More precisely, you tacitly assume locality. But embedding a quantum system such as a delayed-choice eraser setup into spacetime is non-trivial, and in particular not possible so long as one demands Einstein locality to hold. However, we know now for pretty much certain (ref Alain Aspect et al) that Bell’s inequalities are violated in quantum systems, so Einstein locality must be violated; when one takes this into account, a self-consistent and testable model of this experimental setup is easy enough to write down. However, such an explanation will always seem non-intuitive and ‘unsatisfactory’ to us, because it has no analogue in the classical domain.
  10. 1 point
    I thought I was wrong once, but I was mistaken. 😃
  11. 1 point
    ! Moderator Note OK. As you think testing of ideas is unnecessarily tedious, you are clearly not interested in science. Do not open another thread on this topic.
  12. 1 point
    QCD is a model which would explain how the particles interact. Dark matter is a class of matter that is cold and dark. Some axions could be cold, and thus comprise dark matter. QCD (or some other model) would have to explain why they are dark. But AFAIK, the potential role of the axion as dark matter is because they would have mass.
  13. 1 point
    Sure why not? Mathematically, instead of having quantities that change with respect to some time coordinate, you can always have quantities that change with respect to one another, without reference to any notion of time. ‘Change’ doesn’t imply time, and time doesn’t imply change. Derivatives (in the calculus sense) with respect to some quantity other than time are well defined and commonly used. For example, imagine you have a purely 3D universe, without time, that contains a tea cup. The handle of the cup has a certain curvature; the interior surface of the cup also has curvature, which is probably numerically different. So the surface curvature changes with respect to spatial coordinates, rather than time. So you have a universe that encompasses changes, but no time. This is perfectly consistent and valid, at least in my mind
  14. 1 point
    Yes, the 'Law of unintended consequences'. +1 https://en.wikipedia.org/wiki/Unintended_consequences
  15. -1 points
    If this is numerology, then so is the Periodic Table of Elements! The first two primes for example. and 2 + 3 = the 3th prime. Just 5 is sum of two consecutive primes. Have you a published paper for give lesson?
  16. -2 points
    Well if you found it on the internet it must be real, right? LOL have you bought back issues that are available on the net for free? https://nym.pcdfusion.com/pcd/ShoppingCart/store/210/Category/1080 Again I had this disease and it was the best thing ever as now I have no fear
  17. -3 points
    LOL I had covid so the expert is me....................... The common cold has worse symptoms If you want to live scared and believe the nonsense that the government puts out have fun, because when I had covid the government was telling people not to wear masks. LOL
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