Strange

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Everything posted by Strange

  1. Parallax of the stars

    Show us how you work it out and maybe we can see where you went wrong.
  2. Parallax of the stars

    https://en.wikipedia.org/wiki/Cosmic_distance_ladder#Parallax
  3. Black holes and dark matter linked?

    I was just reading an article on direct collapse black holes (https://www.scientificamerican.com/article/the-puzzle-of-the-first-black-holes/). One of the problems with supermassive black holes is how they could form. The idea here is that they form directly from the collapse of large cloud of gas (rather than from supernovae). They are then absorbed by a nearby galaxy. The energy released when the black hole absorbs material could heat up gas and affect star formation throughout the galaxy. So there may well be effects beyond just the gravity.
  4. Correct. Yep. We absolutely don't need to worry abut that happening. It is just a nice example. Electric charge is the fundamental property. Individual particles (e.g. electrons) can have a charge. If that charged particle moves, this generates a magnetic field (this can be explained by special relativity, but we probably don't need to get into that). This all goes back to Faraday's experiments where he found that an electric current in a wire generates a magnetic field. And a changing magnetic field can generate an electric current in a wire. This was then turned into a mathematical description by Maxwell (and others) which is when it was realised that this described how changing electric and magnetic fields could generate a wave that travels through space. This turned out to be light. There is a big difference here. Friction will only oppose a force you apply. It isn't a force in itself. The force between two masses is, as swansont says, is equivalent to the force between two charges. You can think of them both as being caused by a "disturbance in the field" (in the first case the field is space-time, in the second it is the electromagnetic field). There are no particles involved in either case. (In quantum theory, the force is described in terms "virtual particles" but they are not really particles.) Getting out of your chair requires energy. But just sitting there doesn't. So energy is only expended when you lift yourself against gravity (i.e. add to your potential energy). The potential energy is given by m x g x h (mass of the rock times the acceleration due to gravity times the height you lift it). We are only ever concerned with differences in potential energy so if a hole opens up underneath you, that doesn't change the energy you have given it. There wouldn't be any! It would all cancel out. You would be close to a small amount of the shell on one side but there would be a larger amount of the shell on the other side pulling on you from further away. This all balances. Newton's Shell Theorem: https://en.wikipedia.org/wiki/Shell_theorem To be honest, I am not sure how electromagnetism works in curved space-time. So I will refrain from commenting further!
  5. God and the Big Bang

    Finite means it can be counted or measured. Infinity means beyond that which can be counted or measured. That doesn't mean anything. You won't find it. Of course it can't. However many times you repeat this idiotic statement it still won't be true. Of course it doesn't.
  6. God and the Big Bang

    This is a complete non-sequitur. It is impossible to have a coherent discussion with you. You just post random unconnected thoughts.
  7. Higher-ordered "quarks"?

    What evidence is there for this?
  8. Black holes and dark matter linked?

    Yes, pretty much. At a rage enough scale, you can treat the galaxy as a fairly homogeneous cloud of "stuff". Although, there are different "layers" - the central bulge is spherical and has a different density distribution that the disk, etc.
  9. Black holes and dark matter linked?

    That is true. But it is really just the total mass of the matter within a given orbital distance that matters. So, while it is true that the stars further out are held in place by the stars further in, the black hole doesn't really have a special role in this. Any distribution of the same mass would have the same effect.
  10. Black holes and dark matter linked?

    Not sure what you are thinking of. The orbit of a star (the Sun, for example) around the galaxy is determined (largely) by the total mass inside its orbit. It doesn't matter much where that mass is or what form it takes (assuming it is roughly evenly distributed). So the black hole contributes some tiny fraction of that mass. But it would be exactly the same as if that same mass were in multiple stars spread out through the galaxy.
  11. True Meaning of Life

    What does that have to do with religion?
  12. True Meaning of Life

    No. Evidence of what? Where consciousness arises from? I would have thought neurology (combined with psychology, perhaps) might be more fruitful, but I really don't know.
  13. True Meaning of Life

    Except, almost by definition, you can't know. Solipsism and free will / illusion of conscious agency / predeterminism are unprovable and unfalsifiable, almost by definition. How could you ever know if you had a choice to have tea or coffee or if it was determined in advance. So if you were certain about it, it would just be a belief not evidenced.
  14. True Meaning of Life

    It may be. And free will could be an illusion as well. Does it matter? Does it make any difference? To life, to the way you would live it, to the "meaning" of life? Taken to an extreme you end up with solipsism. Which still doesn't make any difference.
  15. True Meaning of Life

    I have no idea what you mean... It is a good article, though!
  16. I am always willing to help people learn (if they are interested) and overcome their misconceptions about the world and about science. (I don't think I am particularly brilliant. Not at all brilliant, in fact. And I'm usually posting here as a work-avoidance thing!)
  17. If you say so. Looks more like paddling in the shadows with a blindfold on.
  18. True Meaning of Life

    I just came across an article in Scientific American on the meaning of life. Interestingly, it came to exactly the opposite conclusion that a recently banned member claimed: https://www.scientificamerican.com/article/our-actions-dont-matter-in-a-cosmic-sense-but-that-doesnt-mean-they-dont-matter/
  19. I really think you should learn the basics of the subject before "speculating" in this way. There is a difference between the methodical approach of science and just making stuff up. If you can come up with a model, preferably mathematical, that makes testable predictions then you are doing science. If you are making stuff up and sticking some sciency-sounding words together ("the quantum continuum of processing bioperception") then you are not doing science. You are just wasting your time. So, where is the mathematical model for this? What predictions does it make that we could test? The Big Bang is not like an explosion. What is "quantum perception"? But if you just mean that as a result of the evolution of the universe from a hot dense state, it reached conditions where quantum phenomena, and then chemistry and then life could occur. Then, yes, rather obviously. I have no idea what that means. But, of course, the ongoing expansion of the universe (i.e. the Big Bang) is still perceivable. That is how we know it is happening. But it doesn't have much to do with chemistry (apart from the fact we are bags of chemicals, I suppose). There are many possible sources for gravitational waves. The ones that have been detected so far are from the merger of black holes and neutron stars. There was a claim that gravitational waves from the early universe had been (indirectly) detected. But that was later withdrawn: https://en.wikipedia.org/wiki/Gravitational_wave#Primordial Only in the sense that everything is. Life emerged about 13 billion years later.
  20. Black holes and dark matter linked?

    Also, worth noting that these black holes might be "supermassive" but they make up a minute proportion of the mass of the galaxy and so only have a direct effect on the few stars directly orbiting them. From: http://www.skyandtelescope.com/astronomy-news/milky-ways-central-monster-measured/
  21. Units (split from What is Time?)

    *Whispering so the mods won't notice* There is a bug in the software so that the votes don't appear immediately. If you come back to the thread, you should see it. And sometimes, there might appear to be a physical interpretation but it doesn't really mean anything. For example if you work out the fuel use of your car in, say, gallons per mile (for the Americans) the result has the same units as area. But I'm not sure what that area would mean.
  22. Black holes and dark matter linked?

    Most black holes are not consuming any significant amount of matter. We know this, because when they do, the matter falling in gets incredibly hot and generates a lot of radiation and even seeds jets of matter out at nearly the speed of light. We see this as the relatively small number of quasars and "active" galaxies. Also, galaxies are not, in general, expanding. They are pretty stable (apart from occasional collisions). Expansion only happens at very large scales. It is the space between galaxies that is increasing. Actually, it is the space between clusters of galaxies that is increasing. (Which is why galaxies in clusters can collide with one another!) There is no evidence that anything can come out of a black hole or that they can convert matter to dark matter. And no theoretical reason to think it might happen. Welcome to the forum!
  23. God and the Big Bang

    Obviously not. But if you are using "connection" in that vague sense, then your statement is so completely pointless that it becomes meaningless. On that basis my cat has a connection with science. The rocks in my garden have a connection with science. If, by your definition of the word, everything has a connection with science then saying that "religion has a connection with science" is pointless and meaningless. You have, once again, chosen to use words in a non-standard way that makes any discussion impossible.
  24. God and the Big Bang

    You are very confused. The fact that some (most?) religions accept science as a valid and worthwhile thing does not mean that religions have any connection with science. Many politicians think that science is a valid and worthwhile thing, but few of them have any connection with science. I think science is a valid and worthwhile thing. I have absolutely no connection with science
  25. mini-sun

    Probably doesn't require its own thread, but here is a story on China's work to build a fusion reactor: http://www.bbc.com/news/blogs-china-blog-43792655