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I thought that Dark Matter and Dark Energy are simply placeholders for our lack of explanation of observed phenomenon? In which case these types of discoveries

I thought that Dark Matter and Dark Energy are simply placeholders for our lack of explanation of observed phenomenon? In which case these types of discoveries are to be expected as we fill in the missing blanks. If so then I am happy to see progress being made. If I am wrong about my assumptions about Dark Matter and Dark Energy I wouldn't mind some starters :) Thanks!

conistonwater 10y ago
My understanding is that the difference between observed and predicted galaxy rotation rates is real, and the thing that is thought to cause it is given the name of dark matter. But that doesn't make it a placeholder! Any more, for example, than when people detected the effects of Mercury or Neptune on the orbits of other planets in the solar system, before they could see those planets directly, they could give them a name without being able to see them: yet those weren't placeholders, rather their effects on orbits was evidence of their existence. OTOH, maybe everything in science is a kind of a placeholder, but that sort of thing can get unpleasantly philosophical.
- hanoz 10y ago
  It seems to me there's a big difference between an explanation of an expected/obsevered mismatch which says there must be another massive object involved - and here's where to point your telescopes to look for it, and one which says well there must be some other mass of some form somewhere.
  - conistonwater 10y ago
    For a pretty long time, for both those planets, they didn't know where to point their telescopes. This was also true for the outer planets, and Pluto too. A similar sort of thing, to a different/lesser extent, used to be the case with gravitational waves not having been directly observed despite other evidence. There were similar problems with the early discussions of atomic nuclei, electrons, neutrinos, neutrons, where all kinds of things were posited based on their effects only. I know it's quite a bit more difficult, and less direct, with dark matter, but still. (Really, I was objecting to the use of the word placeholder, because I found it unfair.)
- samatman 10y ago
  Mercury is visible to the naked eye. Consequently, its existence has been known since prehistory.
  - conistonwater 10y ago
    You're right. I think I must have misremembered something I read about https://en.wikipedia.org/wiki/Vulcan_(hypothetical_planet) https://en.wikipedia.org/wiki/Vulcan_(hypothetical_planet) But I think I got the example of Neptune right: https://en.wikipedia.org/wiki/Discovery_of_Neptune#Irregularities_in_Uranus.27s_orbit https://en.wikipedia.org/wiki/Discovery_of_Neptune#Irregular...
Avshalom 10y ago
Sort of, "dark matter" would just be matter that doesn't interact with photons. We're pretty dang sure dark matter isn't neutrinos but for reference neutrinos don't interact with photons either, so it's not like dark matter is actually all that exotic. We just can't constrain every thing about it. What it comes down to, and this paper doesn't change this at all, is that either there's a bunch of matter we can't see or force carrying particles don't obey basic geometry (or the universe has much weirder geometry than we think). Most of us are a lot more comfortable with basically invisible matter. https://en.wikipedia.org/wiki/Bullet_Cluster https://en.wikipedia.org/wiki/Bullet_Cluster https://en.wikipedia.org/wiki/MACS_J0025.4-1222 https://en.wikipedia.org/wiki/MACS_J0025.4-1222 https://en.wikipedia.org/wiki/Dragonfly_44 https://en.wikipedia.org/wiki/Dragonfly_44
- lisivka 10y ago
  It was called "Luminiferous aether". Sagnac effect shows that speed of light is not constant: http://www.conspiracyoflight.com/Sagnac/SagnacEarth.html http://www.conspiracyoflight.com/Sagnac/SagnacEarth.html . My understanding is that our Universe is endless in all 4 dimensions and in scale. Every point of Universe contains infinite number of small, even infinite small, particles. These particles are forming large objects, even infinite large objects. And these objects are oscillating endlessly: condensing and evaporating, so whole Universe cannot be sink into singularity, even in endless time. IMHO, we are in large bulb of plank-scale particles, which are called "physical vacuum", which are forming medium for all other particles and forces to travel. This medium is not regular: it denser in center (so it causes red shift), it denser around massive objects.
  - ifdefdebug 10y ago
    IMHO it's just turtles all the way down
    - Joof 10y ago
      At least that means it converges and we can estimate it to some useful degree.

conistonwater 10y ago

My understanding is that the difference between observed and predicted galaxy rotation rates is real, and the thing that is thought to cause it is given the name of dark matter. But that doesn't make it a placeholder! Any more, for example, than when people detected the effects of Mercury or Neptune on the orbits of other planets in the solar system, before they could see those planets directly, they could give them a name without being able to see them: yet those weren't placeholders, rather their effects on orbits was evidence of their existence. OTOH, maybe everything in science is a kind of a placeholder, but that sort of thing can get unpleasantly philosophical.

hanoz 10y ago
It seems to me there's a big difference between an explanation of an expected/obsevered mismatch which says there must be another massive object involved - and here's where to point your telescopes to look for it, and one which says well there must be some other mass of some form somewhere.
- conistonwater 10y ago
  For a pretty long time, for both those planets, they didn't know where to point their telescopes. This was also true for the outer planets, and Pluto too. A similar sort of thing, to a different/lesser extent, used to be the case with gravitational waves not having been directly observed despite other evidence. There were similar problems with the early discussions of atomic nuclei, electrons, neutrinos, neutrons, where all kinds of things were posited based on their effects only. I know it's quite a bit more difficult, and less direct, with dark matter, but still. (Really, I was objecting to the use of the word placeholder, because I found it unfair.)
samatman 10y ago
Mercury is visible to the naked eye. Consequently, its existence has been known since prehistory.
- conistonwater 10y ago
  You're right. I think I must have misremembered something I read about https://en.wikipedia.org/wiki/Vulcan_(hypothetical_planet) https://en.wikipedia.org/wiki/Vulcan_(hypothetical_planet) But I think I got the example of Neptune right: https://en.wikipedia.org/wiki/Discovery_of_Neptune#Irregularities_in_Uranus.27s_orbit https://en.wikipedia.org/wiki/Discovery_of_Neptune#Irregular...

Avshalom 10y ago

Sort of, "dark matter" would just be matter that doesn't interact with photons. We're pretty dang sure dark matter isn't neutrinos but for reference neutrinos don't interact with photons either, so it's not like dark matter is actually all that exotic. We just can't constrain every thing about it. What it comes down to, and this paper doesn't change this at all, is that either there's a bunch of matter we can't see or force carrying particles don't obey basic geometry (or the universe has much weirder geometry than we think). Most of us are a lot more comfortable with basically invisible matter. https://en.wikipedia.org/wiki/Bullet_Cluster https://en.wikipedia.org/wiki/Bullet_Cluster https://en.wikipedia.org/wiki/MACS_J0025.4-1222 https://en.wikipedia.org/wiki/MACS_J0025.4-1222 https://en.wikipedia.org/wiki/Dragonfly_44 https://en.wikipedia.org/wiki/Dragonfly_44

lisivka 10y ago
It was called "Luminiferous aether". Sagnac effect shows that speed of light is not constant: http://www.conspiracyoflight.com/Sagnac/SagnacEarth.html http://www.conspiracyoflight.com/Sagnac/SagnacEarth.html . My understanding is that our Universe is endless in all 4 dimensions and in scale. Every point of Universe contains infinite number of small, even infinite small, particles. These particles are forming large objects, even infinite large objects. And these objects are oscillating endlessly: condensing and evaporating, so whole Universe cannot be sink into singularity, even in endless time. IMHO, we are in large bulb of plank-scale particles, which are called "physical vacuum", which are forming medium for all other particles and forces to travel. This medium is not regular: it denser in center (so it causes red shift), it denser around massive objects.
- ifdefdebug 10y ago
  IMHO it's just turtles all the way down
  - Joof 10y ago
    At least that means it converges and we can estimate it to some useful degree.