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  2. Strange

    Sound waves in a vacuum

    No. https://www.bbc.com/bitesize/articles/z8mmb82
  3. DrP

    Sound waves in a vacuum

    Because they are pressure waves not electromagnetic. They propagate through the air... of which there is none in a vacuum.
  4. swansont

    Banned/Suspended Users

    Frank Sidebottom has been banned as a sockpuppet of Samantha Priss, The Operator and Taxonomist, et al.
  5. Bushranger

    Sound waves in a vacuum

    Sound waves are part of the electromagnetic spectrum as are light and radio waves. However, sound waves cannot pass through a vacuum. Why/how is it that they cannot?
  6. Today
  7. DrP

    Poliosis

    I do not know for sure... but I used to know a kid who had a white patch in his hair and his parents did not, so that would suggest so.
  8. This is an assertion, not a fact. Nature cares not a whit for "common reason" I think physicists are in a better position to decide whether they are doing real™ physics.
  9. tim86

    Poliosis

    My baby has a single white steak of hair (since birth) but neither of us as parents have had this. Can these things develop out of nowhere and not passed down? Could it be from our extended family and past generations of family? Or is it just a lack of pigmentation that has happened for a number of reasons?
  10. While there is no evidence for something coming from nothing, I don't think you can dismiss the concept based on "common reason and logic". Especially, as I guess that when you say "logic" you mean "something that makes sense to me, personally". Many things that were thought to be contrary to common sense and "logic" have turned out to be true.
  11. How are you defining nothing in this statement? A lot of the first page of this thread was talking about definition and context. What about the virtual particle pairs that pop into and out of existence? (although they obviously do not come from 'nothing'.. they do appear to. Matter moving through dimensions not bound by our 4?) What was Einstein's E=mC2 if it wasn't physics? It was very much maths. I am certain that there are many natural things that seem to defy common sense and logic that we do not understand. Only viewing the universe with eyes and minds that can see and think in 4 dimensions might limit us as to what we can ever know about a multi dimensional universe.
  12. swansont

    Fire in Notre Dame in Paris

    Perhaps an odd structure here an there, built by the native Americans, but nothing by European settlers. To us, "old" means "colonial" (250-300 years old). It's a culture shock to go to Europe, where you are regularly seeing buildings and walls that are 3 times as old, and a few things that are much older.
  13. seriously disabled

    Why is there something rather than nothing?

    Something cannot come from nothing. To believe otherwise is to go against common reason and logic. Also mathematics isn't physics. Scientists believe that by being able to solve highly complicated mathematical equations that they are doing real physics but fact is what they are doing isn't physics.
  14. DrP

    Fire in Notre Dame in Paris

    ha ha - yea - I've just realised, lol. ARE there any buildings older than 500 years old in your country even?
  15. swansont

    Fire in Notre Dame in Paris

    By that metric, all buildings in the US are modern buildings. I was under the impression that (in the US) as building codes are modified, they are only applied to new construction, or when you remodel old construction.
  16. DrP

    Fire in Notre Dame in Paris

    OK thanks. I think they might be an USA thing then - I've not heard of them over here in the EU. I work in 'Passive' Fire protection, so wouldn't necessarily know about the system anyway as it is active, but would have thought I would know more about it if it was common here.
  17. Carrock

    Fire in Notre Dame in Paris

    Do old buildings in the US all have these fitted then or something? All the old US buildings have these fitted. They're not considered cost effective for modern buildings i.e. less than 500 years old.
  18. So nothing new to add to well-established physics, and idea based on misunderstandings. But misunderstandings and/or lack of knowledge is possible to fix, start by opening a new thread with some relevant question in the cosmology section! I vote "yes".
  19. Hello everyone! I was wondering if anyone could help me with a functional group formation and curly arrow mechanism. On the drug Ibrutinib there is what I think is a diphenyl ether. I know that the Williamson Synthesis can be used to form ether but I do not understand how to form a diphenyl ether at all. I tried looking up the Ullmann synthesis but I am not sure if that would be the correct way to form a diphenyl ether. Could anyone please show me how/ what reaction would occur that would form a diphenyl ether on Ibrutinib? Any help or suggestions would be very much appreciated. Thank you! http://www.chemspider.com/Chemical-Structure.26637187.html I have attached an image of Ibrutinib in the URL above
  20. DrP

    Fire in Notre Dame in Paris

    Do old buildings in the US all have these fitted then or something?
  21. Eise

    Split from AI sentience

    'Emergent phenomenon' and 'epiphenomenon' are not the same. Emergent phenomena can have causal effects, epiphenomena can't, per definition. So if you see consciousness as an emergent phenomenon, then it can have causal impact, and to describe it as just a 'byproduct' does not suffice. You lost me there. I'm the last person you'll find arguing for existence of a soul, yet you claim I'm presupposing one to justify my position. I meant it in the negative: The kind that implies a type of ghost in the machine; some supraconscious self or soul beyond / untethered to the underlying neural substrate and activity. If you say 'free will is an illusion', you mean the kind of free will that needs a ghost in the machine. We agree here: that kind of free will really does not exist. Two things: First, it is a misunderstanding, as explained above. Second, if people were always clear about the basic assumptions of their thinking, there would not be any need for philosophy. To give an example, from 'new age trash': people defend that body and soul are one, and at the same time believe in personal reincarnation. Obviously, they do not see that an assumption for personal reincarnation is that the soul cannot be one with the body. So they do not understand their own thoughts. I want to point you to two things: When you deny the existence of free will, you only do this in the meaning described above: that there is no soul controlling the body/brain. But there are better definitions of free will that on one side are not touched by the fact that (for all practical purposes) we are determined, and on the other side fits to the way we experience free will without its ideological, metaphysical extensions. A sweeping generalisation 'free will does not exist' is therefore wrong. Consciousness has impact on what we do, but it can do it, not because it causally influences the brain, but because it is the functioning brain. (And no, this is not just semantics.)
  22. My thought too. But if they are not planetary nebulae, what are they?
  23. StringJunky

    How can bindweed be so persistent?

    It seems that there are bud sites at intervals along the roots. A piece an inch long can contain a bud and grow.
  24. Hello folks, newbie here, and I have a question for you. Bindweed is a common, invasive weed that can create new growth from tiny fragments of roots remaining after the main body of the plant has been dug out. Because it can regrow from tiny fragments, it's extremely persistent, and causes a lot of problems for farmers, gardeners, horticulture etc. This may seem like no big deal, but when you consider the growth can be a shoot 20-30cm long, yet come from a fragment of root less than 1cm, and in complete darkness - how can this be?
  25. Yesterday
  26. If you are interested, later today and tomorrow, can catch the broadcasting at ----> https://www3.nhk.or.jp/nhkworld/en/tv/medicalfrontiers/20190423/2050072/
  27. This is surely more a philosophy of meaning question. Now by definition one point cannot be regular (or irregular) Difficult to say if two points can be regular or irregular. It takes many points to show regularity. By definition an irregularity is that which is not regular, unless there are too few points to distinguish. So in order for there to be irregularity there must be many points of regularity to establish that regularity. If there are many more non regular points than regular, there is no pattern and therefore neither regularity nor irregularity. Yes
  28. The LMC is ~ 14,000 ly across, so even if we were viewing it along its longest dimension ( which I don't think is the case), 14,000 years is the most time separation we would see. Planetary Nebula last for 10's of thousands of years. That being said, I don't think those rings are planetary nebula.
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