6 ms·

Nobody pointed to a source of energy for this "expansion" of "space". Usually, coordinate system doesn't expand with time. An extraordinary claim requires extra

Nobody pointed to a source of energy for this "expansion" of "space". Usually, coordinate system doesn't expand with time. An extraordinary claim requires extraordinary evidence. Yes, CMB emitters are much further away, at a distance of about 4Tly, while BB claimed to be just 14By ago. Your claim, that CMB is produced by BB, requires a lot of stretching.

ben_w 3y ago
> Nobody pointed to a source of energy for this "expansion" of "space". Several have been made, the suggestions have issues. > Usually, coordinate system doesn't expand with time. Define "usually". Do you have experience of other universes? > An extraordinary claim requires extraordinary evidence. Indeed, but this comment box is too small to do the evidence justice. Edit: that's unhelpful in retrospect, so I suggest the Youtube channel "PBS Space Time". The videos build on each other, so start at the beginning and work through the back catalogue. > Yes, CMB emitters are much further away, at a distance of about 4Tly, I have no idea where you got this belief from.
- oneshtein 3y ago
  > Define "usually". Do you have experience of other universes? I have experience with coordinate systems. I can bend or expand space-time on my computer all day long, to simulate reality, but I cannot do that in the real world at all. > Indeed, but this comment box is too small to do the evidence justice. Looking for the paper or a blog post! However, I suspect that you will just stretch evidence until it will match your model. > I have no idea where you got this belief from. Just by looking in the window, I see that some object are close, other are far away, then even further away, and so on, up to 4Tly. Nothing extraordinary. No Big Bangs, no FTL speeds, no hidden sources of energy of epic size, just ordinary physics.
  - ben_w 3y ago
    > I cannot do that in the real world at all Sure you do, just by sitting there. Reminds me a bit of my dad; he did radar simulation for military IFF and one of his work anecdotes was about increasing the number of decimal(!) digits of pi the software used. He stopped boasting about that when I pointed out the extra digits were less relevant than the curvature of spacetime caused by Earth itself. > Just by looking in the window, I see that some object are close, other are far away, then even further away, and so on, up to 4Tly I had dreams like that once. Woke up to find I was suffering from testicular torsion. If you seriously believe you can see 4e12 light years through your window, that's probably hallucinogens of some kind (not necessarily intentional).
    - oneshtein 3y ago
      > Sure you do, just by sitting there. I 100% sure that I cannot bend or stretch imaginary coordinate system outside of my imagination. Can you point to real physical process which causes stretching or bending of the mathematical abstraction? > If you seriously believe you can see 4e12 light years through your window, that's probably hallucinogens of some kind (not necessarily intentional). I cannot see objects smaller than a star or galaxy with naked eye. However, we can see light stretched to the microwave range.
      - ben_w 3y ago
        > Can you point to real physical process which causes stretching or bending of the mathematical abstraction? "General relativity" as we keep telling you. > I cannot see objects smaller than a star or galaxy with naked eye. Only a factor of about a trillion in the size of those two things. > However, we can see light stretched to the microwave range. With your eyes? No. And certainly not through your window, whose own thermal emissions relative to the CMB makes your previous claim roughly as unphysical as saying you can look through the sun's photosphere to see Jupiter during an occultation.
        oneshtein 3y ago
        General Relativity is a mathematical model. Model needs mapping between physical world and model.
        ben_w 3y ago
        My phone's GPS only works because that mapping keeps being better than anything else we've tested on that scale. The atomic clocks (as I mentioned in another comment) demonstrating gravitational time dilation within a building is another fun example.
        oneshtein 3y ago
        Your phone works because engineers did it. I see strong annual signal in GPS: https://link.springer.com/article/10.1007/s10291-017-0686-6 https://link.springer.com/article/10.1007/s10291-017-0686-6 . Why it there?
DiogenesKynikos 3y ago
There's no point in arguing about this here. There's a very well defined, mathematical theory called General Relativity, which explains gravitational phenomena from Mercury's precession all the way to the expansion of the Universe. If you take the time to learn General Relativity, and to learn how to apply it to cosmology, you will see that there are rigorous mathematical answers to the various questions you're raising. I want to point out that this isn't esoteric stuff that only a few people understand. General Relativity and cosmology are part of a standard undergraduate physics curriculum. It only takes a few years of study, starting from Physics 101, to get to the point where you can derive the answers to all your questions from scratch.
- oneshtein 3y ago
  How GR explains claimed FTL speed of GLASS-z12? (20Bly travelled in 13By, 1.5c). I'm listening with both ears.
  - ben_w 3y ago
    You've already got the answer: space expanded. Spacetime being dynamic is kinda the point of GR. "How" this specific expansion happens is an open question — not because nobody has any idea, but because we can't distinguish between three of them and a forth leads directly to the unsolved challenge of combining GR with quantum mechanics.
    - oneshtein 3y ago
      No, this is not an answer, because it breaks number of laws of physics, such conservation of energy. It looks like an excuse that an answer. It's just heavy stretching of the evidence until it fits the BB model of evolution of Universe. Static Universe model of evolution doesn't requires such stretching: CMB is just light of distant galaxies. End of story.
      - ben_w 3y ago
        > this is not an answer, because it breaks number of laws of physics, such conservation of energy GR doesn't conserve energy. What follows is a bit beyond my level so I may be misremembering, but IIRC Noether's theorem is that conservation laws are always identical to some symmetries, and the symmetry for energy (time?) just isn't true in GR. (I don't think it's even true in SR because space and time are observer dependent, but at least in SR you can get a different conserved quantity because all observers agree on a space-time interval; but as I implied in a different comment where I mentioned brilliant, this is my hobby not my profession).

ben_w 3y ago

> Nobody pointed to a source of energy for this "expansion" of "space". Several have been made, the suggestions have issues. > Usually, coordinate system doesn't expand with time. Define "usually". Do you have experience of other universes? > An extraordinary claim requires extraordinary evidence. Indeed, but this comment box is too small to do the evidence justice. Edit: that's unhelpful in retrospect, so I suggest the Youtube channel "PBS Space Time". The videos build on each other, so start at the beginning and work through the back catalogue. > Yes, CMB emitters are much further away, at a distance of about 4Tly, I have no idea where you got this belief from.

oneshtein 3y ago
> Define "usually". Do you have experience of other universes? I have experience with coordinate systems. I can bend or expand space-time on my computer all day long, to simulate reality, but I cannot do that in the real world at all. > Indeed, but this comment box is too small to do the evidence justice. Looking for the paper or a blog post! However, I suspect that you will just stretch evidence until it will match your model. > I have no idea where you got this belief from. Just by looking in the window, I see that some object are close, other are far away, then even further away, and so on, up to 4Tly. Nothing extraordinary. No Big Bangs, no FTL speeds, no hidden sources of energy of epic size, just ordinary physics.
- ben_w 3y ago
  > I cannot do that in the real world at all Sure you do, just by sitting there. Reminds me a bit of my dad; he did radar simulation for military IFF and one of his work anecdotes was about increasing the number of decimal(!) digits of pi the software used. He stopped boasting about that when I pointed out the extra digits were less relevant than the curvature of spacetime caused by Earth itself. > Just by looking in the window, I see that some object are close, other are far away, then even further away, and so on, up to 4Tly I had dreams like that once. Woke up to find I was suffering from testicular torsion. If you seriously believe you can see 4e12 light years through your window, that's probably hallucinogens of some kind (not necessarily intentional).
  - oneshtein 3y ago
    > Sure you do, just by sitting there. I 100% sure that I cannot bend or stretch imaginary coordinate system outside of my imagination. Can you point to real physical process which causes stretching or bending of the mathematical abstraction? > If you seriously believe you can see 4e12 light years through your window, that's probably hallucinogens of some kind (not necessarily intentional). I cannot see objects smaller than a star or galaxy with naked eye. However, we can see light stretched to the microwave range.
    - ben_w 3y ago
      > Can you point to real physical process which causes stretching or bending of the mathematical abstraction? "General relativity" as we keep telling you. > I cannot see objects smaller than a star or galaxy with naked eye. Only a factor of about a trillion in the size of those two things. > However, we can see light stretched to the microwave range. With your eyes? No. And certainly not through your window, whose own thermal emissions relative to the CMB makes your previous claim roughly as unphysical as saying you can look through the sun's photosphere to see Jupiter during an occultation.
      - oneshtein 3y ago
        General Relativity is a mathematical model. Model needs mapping between physical world and model.
        ben_w 3y ago
        My phone's GPS only works because that mapping keeps being better than anything else we've tested on that scale. The atomic clocks (as I mentioned in another comment) demonstrating gravitational time dilation within a building is another fun example.
        oneshtein 3y ago
        Your phone works because engineers did it. I see strong annual signal in GPS: https://link.springer.com/article/10.1007/s10291-017-0686-6 https://link.springer.com/article/10.1007/s10291-017-0686-6 . Why it there?

DiogenesKynikos 3y ago

There's no point in arguing about this here. There's a very well defined, mathematical theory called General Relativity, which explains gravitational phenomena from Mercury's precession all the way to the expansion of the Universe. If you take the time to learn General Relativity, and to learn how to apply it to cosmology, you will see that there are rigorous mathematical answers to the various questions you're raising. I want to point out that this isn't esoteric stuff that only a few people understand. General Relativity and cosmology are part of a standard undergraduate physics curriculum. It only takes a few years of study, starting from Physics 101, to get to the point where you can derive the answers to all your questions from scratch.

oneshtein 3y ago
How GR explains claimed FTL speed of GLASS-z12? (20Bly travelled in 13By, 1.5c). I'm listening with both ears.
- ben_w 3y ago
  You've already got the answer: space expanded. Spacetime being dynamic is kinda the point of GR. "How" this specific expansion happens is an open question — not because nobody has any idea, but because we can't distinguish between three of them and a forth leads directly to the unsolved challenge of combining GR with quantum mechanics.
  - oneshtein 3y ago
    No, this is not an answer, because it breaks number of laws of physics, such conservation of energy. It looks like an excuse that an answer. It's just heavy stretching of the evidence until it fits the BB model of evolution of Universe. Static Universe model of evolution doesn't requires such stretching: CMB is just light of distant galaxies. End of story.
    - ben_w 3y ago
      > this is not an answer, because it breaks number of laws of physics, such conservation of energy GR doesn't conserve energy. What follows is a bit beyond my level so I may be misremembering, but IIRC Noether's theorem is that conservation laws are always identical to some symmetries, and the symmetry for energy (time?) just isn't true in GR. (I don't think it's even true in SR because space and time are observer dependent, but at least in SR you can get a different conserved quantity because all observers agree on a space-time interval; but as I implied in a different comment where I mentioned brilliant, this is my hobby not my profession).