11–20 of 193 posts
Why don't they ever fix that?
> "If Newtonian physics can’t predict the fixed curves, perhaps we should fix Newton, instead of making up a whole new class of matter just to fit our measurements." I've always felt this way about dark matter, but as a lay person with no background in physics, it's an opinion I'm hesitant to express. if you have a model that predicts something, but the prediction is off by several orders of magnitude, the model is w…
Ok, but physics has had a long and fruitful history of inventing invisible stuff when theory and results disagree. I mean, have you ever seen an atom? A proton? A neutrino? Scientific theories are generally not just amalgamations of tweaks. General relativity is internally consistent, explains so much , and just got a huge boost last year with the first detection of gravity waves... which BTW are invisible stuff that…
Physics also has an unfruitful history of invisible stuff: ether, strings (string theory), etc.
Personally I'm glad something other than dark matter is being considered. I was only told that the rotational velocities of galaxies did not match the predictions. IME simple explanations tend to work better for mechanics in physics (until quantum mechanics...)
> "If Newtonian physics can’t predict the fixed curves, perhaps we should fix Newton, instead of making up a whole new class of matter just to fit our measurements." I've always felt this way about dark matter, but as a lay person with no background in physics, it's an opinion I'm hesitant to express. if you have a model that predicts something, but the prediction is off by several orders of magnitude, the model is w…
But that's not the case. We have petabytes of data from space (if not more). Your theory needs to match all of them, give or take noise. The common example of the Bullet Cluster [1] comes up a lot, but it's just one particularly exciting example of the problem. I've seen people create variants of MOND that try to address the Bullet Cluster problem, but you start having to have some sort of really weird gravity memory effect in space or something, where space itself "remembers" that it used to have a lot of matter in it and still has a small amount of gravitation in it despite no longer containing the corresponding mass. Which I suppose isn't necessarily out of the question given that we're intrinsically discussing a non-linearity in gravity, but it's still a bit strange.
By the time you work out what MOND is going to need to look like in order to explain everything we see in space, it ends up losing its "Oh, it's just one more simple term on gravity" nature and starts looking pretty weird itself. It's constrained by the real data to be at least as weird as dark matter itself, because the data itself is weird. Given the history physics has had with "calling its shots" and identifying the necessity of particles years or decades before they are detected, dark matter is something that I consider at least not out of the question.
I also am sympathetic to MOND solutions as well. After all, "the math looked awfully weird by the time we finished working out the theory" also has a long and illustrious history in physics too! What's true is true, regardless of how we feel about how beautiful it is. We also have a Standard Model of particle physics that, whatever its known flaws may be, doesn't immediately obviously have a hole for dark matter in it, so perhaps the "we've called our shots before" argument doesn't apply so well here. There is something to be said for not trying to push a new particle in there. But if MOND is the answer, you're likely to find the final result to have non-trivial weirdness in it, too.
[1]: https://en.wikipedia.org/wiki/Bullet_Cluster#Significance_to...
> "If Newtonian physics can’t predict the fixed curves, perhaps we should fix Newton, instead of making up a whole new class of matter just to fit our measurements." I've always felt this way about dark matter, but as a lay person with no background in physics, it's an opinion I'm hesitant to express. if you have a model that predicts something, but the prediction is off by several orders of magnitude, the model is w…
Same feelings here. I genuinely do not understand how adding unobservable objects would be the right approach instead of just fixing the equations.
As other commenters said, physics has a history of "adding unobservable objects", and then finding a way to observe them.
Electric force is many orders of magnitude stronger than gravity. So, if the objects in the universe are charged, the repelling force between them could account for the expansion acceleration in a very simple way.
> "If Newtonian physics can’t predict the fixed curves, perhaps we should fix Newton, instead of making up a whole new class of matter just to fit our measurements." I've always felt this way about dark matter, but as a lay person with no background in physics, it's an opinion I'm hesitant to express. if you have a model that predicts something, but the prediction is off by several orders of magnitude, the model is w…
Today of course, this sounds ridiculous. But my physics teacher was always keen to point out that the people involved weren't stupid and that it was an important theory because it was a good starting mental model of how things actually worked and led to our better understanding today.
I wonder if dark matter is similar. It's not flat wrong, it's the best explanation that we have so far and in it will lead us into another breakthrough of understanding.
Earlier quoted context omitted.
Ok, but physics has had a long and fruitful history of inventing invisible stuff when theory and results disagree. I mean, have you ever seen an atom? A proton? A neutrino? Scientific theories are generally not just amalgamations of tweaks. General relativity is internally consistent, explains so much , and just got a huge boost last year with the first detection of gravity waves... which BTW are invisible stuff that…
It's also worth pointing out that several similar 'holes' in theories have turned out to be correct. Things like missing elements in the periodic table, and fundamental particles like the Ω− baryon or the Higgs boson, where all things that seemed like holes in a theory, but were later discovered to exist.
Earlier quoted context omitted.
Same feelings here. I genuinely do not understand how adding unobservable objects would be the right approach instead of just fixing the equations.
You don't comprehend the magnitude of "just fixing the equations". As other commenters said, physics has a history of "adding unobservable objects", and then finding a way to observe them.
> "If Newtonian physics can’t predict the fixed curves, perhaps we should fix Newton, instead of making up a whole new class of matter just to fit our measurements." I've always felt this way about dark matter, but as a lay person with no background in physics, it's an opinion I'm hesitant to express. if you have a model that predicts something, but the prediction is off by several orders of magnitude, the model is w…
Ok, but physics has had a long and fruitful history of inventing invisible stuff when theory and results disagree. I mean, have you ever seen an atom? A proton? A neutrino? Scientific theories are generally not just amalgamations of tweaks. General relativity is internally consistent, explains so much , and just got a huge boost last year with the first detection of gravity waves... which BTW are invisible stuff that…
Inventing and then testing, though. As you said, GR got a huge boost last year, still being tested a century after being proposed. That's how science should be!
We know the darkX behaviour and we have some ideas as to explanation, but far from being proved in the way GR has been.
Dark energy, dark matter, string theory. Lots of IQ being poured into them, with a reasonable chance they're not the answer.