5 ms·

Curious about conservation of charge - if all dark protons were to decay then there must be also an abundance of dark positrons?

ars 3y ago
You misread the article, it was not saying there are dark protons. It was using proton decay as an analogy. But to answer your question anyway, if a proton did decay then yes, it would be to a positron plus something else.
- ben_w 3y ago
  Along similar lines, I've been wondering (I am not a professional) about what would happen if charge wasn't always conserved. What would violating that symmetry do? If such a bias was in one direction, like the matter-antimatter near-symmetry appears to be, what would the universe look like if there was a small non-zero charge density everywhere that couldn't be fully cancelled out? Alas, my understanding of physics is only enough to look like a kook, which almost entirely prevents serious answers from people capable of providing them.
  - op00to 3y ago
    My lay opinion: Without symmetry, such as in conservation of momentum, you’d be able to create and destroy energy arbitrarily. Maybe like magic? Let’s say there were no proton/electron charge symmetry. That could mean atoms would be unstable. Maybe do some imagineering from this point!
    - regpertom 3y ago
      I’ve wondered what it would take to be able to create energy arbitrarily. Gravity and mass and light seem to be suss in that context. I’ve been having a laugh to myself about the aether, a comment in here mentions Hinduism also. But if there’s some big goo of stuff, then could it be that the ‘perfection of the universe’ (sorry I know that’s a loaded phrase but chill) is what can emerge into reality from that goo? If there wasn’t symmetry or whatever, then it couldn’t get to us. Kind of like the atoms that make us would have remained as mud instead of standing up and looking around? As someone else says encrypted vs plain space. Figure out some suss things like what’s going on with light and some kind of arbitrary infinity awaits? And those things are suss because they’re operating at the interface/affected by both ‘worlds’, like flying around in atmosphere; suddenly there’s sound barriers and what not. Which is why (I think) we scratch our heads and wonder like, what’s the deal with electrons?
      - eru 3y ago
        (Total) energy is not conserved in general relativity. So far all we know we are living in a universe without conservation of energy. See https://physics.stackexchange.com/questions/35431/is-the-law-of-conservation-of-energy-still-valid https://physics.stackexchange.com/questions/35431/is-the-law...
        op00to 3y ago
        In this house we obey the laws of thermodynamics! See https://youtu.be/tuxbMfKO9Pg?si=zyWt_miGeYcIfXQA https://youtu.be/tuxbMfKO9Pg?si=zyWt_miGeYcIfXQA :)
    - eru 3y ago
      Conservation of energy comes from continuous time symmetry. (See Noether's Theorem for an explanation.) So just violating conservation of charge or conservation of momentum alone would automatically break conservation of energy.
  - hoten 3y ago
    I'm not smart enough to say more than this, but it'd be interesting to see what Noethers theorm would imply about a universe with no conservation of charge. Wikipedia gives examples for other conservations https://en.wikipedia.org/wiki/Conservation_law?wprov=sfla1 https://en.wikipedia.org/wiki/Conservation_law?wprov=sfla1
    - leereeves 3y ago
      Wikipedia also has the answer you're lookng for: https://en.wikipedia.org/wiki/Charge_conservation#Connection_to_gauge_invariance https://en.wikipedia.org/wiki/Charge_conservation#Connection...
  - ars 3y ago
    > what would happen if charge wasn't always conserved Then conservation of energy would not be a thing, I suspect it would actually destroy all conservation laws, and the universe could not exist. > what would the universe look like if there was a small non-zero charge density everywhere that couldn't be fully cancelled out? Nothing. You would not be able to tell. You can only measure a difference in charge, you can not measure absolute charge. But it would have to be utterly uniform in all directions.
  - thaumasiotes 3y ago
    https://physics.stackexchange.com/questions/2721/what-is-the-symmetry-which-is-responsible-for-preservation-conservation-of-elect https://physics.stackexchange.com/questions/2721/what-is-the... > Remember that voltage is always expressed as a "potential difference." You can't measure the absolute value of voltage because everything is invariant when you add a constant voltage everywhere. That expresses a symmetry just like time translation invariance. > When you bring in the magnetic field this invariance or symmetry can be generalised to a bigger gauge invariance transforming the electromagnetic potential as a vector field. Charge particles are also described by fields such as Dirac spinors, which are multiplied by a phase factor under the action of this symmetry, making it a U(1) invariance. Electric charge is the conserved quantity that Noether's theorem gives for this symmetry. It sounds like violating this would mean that there was an observable difference between "zero electrical potential" and "nonzero electrical potential". Temperature is another quantity that is usually measured solely in terms of the difference between two states, but -- apparently unlike electrical gauge -- in that case there is an absolute zero point which is distinguishable from other points. It might be interesting to ask what would be conserved, but isn't now, if there were a temperature invariance analogous to gauge invariance.
- tanvach 3y ago
  > A special combination of physics led to a proton having roughly the same mass as a neutron; perhaps in the dark matter mirror, that combination of physics played out differently, causing the "dark proton" to evaporate and leave behind a sea of "dark neutrons" — what we identify as dark matter. I don't think I misread the article. Currently we expect dark matter to be neutral. So if we assume the statement is correct, what would then happen to the positrons and it's charge?

ars 3y ago

You misread the article, it was not saying there are dark protons. It was using proton decay as an analogy. But to answer your question anyway, if a proton did decay then yes, it would be to a positron plus something else.

ben_w 3y ago
Along similar lines, I've been wondering (I am not a professional) about what would happen if charge wasn't always conserved. What would violating that symmetry do? If such a bias was in one direction, like the matter-antimatter near-symmetry appears to be, what would the universe look like if there was a small non-zero charge density everywhere that couldn't be fully cancelled out? Alas, my understanding of physics is only enough to look like a kook, which almost entirely prevents serious answers from people capable of providing them.
- op00to 3y ago
  My lay opinion: Without symmetry, such as in conservation of momentum, you’d be able to create and destroy energy arbitrarily. Maybe like magic? Let’s say there were no proton/electron charge symmetry. That could mean atoms would be unstable. Maybe do some imagineering from this point!
  - regpertom 3y ago
    I’ve wondered what it would take to be able to create energy arbitrarily. Gravity and mass and light seem to be suss in that context. I’ve been having a laugh to myself about the aether, a comment in here mentions Hinduism also. But if there’s some big goo of stuff, then could it be that the ‘perfection of the universe’ (sorry I know that’s a loaded phrase but chill) is what can emerge into reality from that goo? If there wasn’t symmetry or whatever, then it couldn’t get to us. Kind of like the atoms that make us would have remained as mud instead of standing up and looking around? As someone else says encrypted vs plain space. Figure out some suss things like what’s going on with light and some kind of arbitrary infinity awaits? And those things are suss because they’re operating at the interface/affected by both ‘worlds’, like flying around in atmosphere; suddenly there’s sound barriers and what not. Which is why (I think) we scratch our heads and wonder like, what’s the deal with electrons?
    - eru 3y ago
      (Total) energy is not conserved in general relativity. So far all we know we are living in a universe without conservation of energy. See https://physics.stackexchange.com/questions/35431/is-the-law-of-conservation-of-energy-still-valid https://physics.stackexchange.com/questions/35431/is-the-law...
      - op00to 3y ago
        In this house we obey the laws of thermodynamics! See https://youtu.be/tuxbMfKO9Pg?si=zyWt_miGeYcIfXQA https://youtu.be/tuxbMfKO9Pg?si=zyWt_miGeYcIfXQA :)
  - eru 3y ago
    Conservation of energy comes from continuous time symmetry. (See Noether's Theorem for an explanation.) So just violating conservation of charge or conservation of momentum alone would automatically break conservation of energy.
- hoten 3y ago
  I'm not smart enough to say more than this, but it'd be interesting to see what Noethers theorm would imply about a universe with no conservation of charge. Wikipedia gives examples for other conservations https://en.wikipedia.org/wiki/Conservation_law?wprov=sfla1 https://en.wikipedia.org/wiki/Conservation_law?wprov=sfla1
  - leereeves 3y ago
    Wikipedia also has the answer you're lookng for: https://en.wikipedia.org/wiki/Charge_conservation#Connection_to_gauge_invariance https://en.wikipedia.org/wiki/Charge_conservation#Connection...
- ars 3y ago
  > what would happen if charge wasn't always conserved Then conservation of energy would not be a thing, I suspect it would actually destroy all conservation laws, and the universe could not exist. > what would the universe look like if there was a small non-zero charge density everywhere that couldn't be fully cancelled out? Nothing. You would not be able to tell. You can only measure a difference in charge, you can not measure absolute charge. But it would have to be utterly uniform in all directions.
- thaumasiotes 3y ago
  https://physics.stackexchange.com/questions/2721/what-is-the-symmetry-which-is-responsible-for-preservation-conservation-of-elect https://physics.stackexchange.com/questions/2721/what-is-the... > Remember that voltage is always expressed as a "potential difference." You can't measure the absolute value of voltage because everything is invariant when you add a constant voltage everywhere. That expresses a symmetry just like time translation invariance. > When you bring in the magnetic field this invariance or symmetry can be generalised to a bigger gauge invariance transforming the electromagnetic potential as a vector field. Charge particles are also described by fields such as Dirac spinors, which are multiplied by a phase factor under the action of this symmetry, making it a U(1) invariance. Electric charge is the conserved quantity that Noether's theorem gives for this symmetry. It sounds like violating this would mean that there was an observable difference between "zero electrical potential" and "nonzero electrical potential". Temperature is another quantity that is usually measured solely in terms of the difference between two states, but -- apparently unlike electrical gauge -- in that case there is an absolute zero point which is distinguishable from other points. It might be interesting to ask what would be conserved, but isn't now, if there were a temperature invariance analogous to gauge invariance.
tanvach 3y ago
> A special combination of physics led to a proton having roughly the same mass as a neutron; perhaps in the dark matter mirror, that combination of physics played out differently, causing the "dark proton" to evaporate and leave behind a sea of "dark neutrons" — what we identify as dark matter. I don't think I misread the article. Currently we expect dark matter to be neutral. So if we assume the statement is correct, what would then happen to the positrons and it's charge?