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A Physicist Who Denies That Dark Matter Exists

cosmos.nautil.us

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Re: A Physicist Who Denies That Dark Matter Exists

#51

Post by roywiggins »

fuhrysteve wrote: post #4
roryisok wrote: post #3

> "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…

> 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. I have always had the same inclination. It seems like a classic candidate for using Occam's razor. Would love to hear someone who knows more about physics weigh in with a more nuanced viewpoint.

Adding in a single extra particle is a lot simpler than rejiggering the entirety of our theories of gravitation. It's also a lot easier to test, just go out and find the particle. This worked for neutrinos, antimatter, the Higgs boson...

The Higgs boson took a long time to be discovered, but people thought it would be there because the alternative was the Standard Model being wrong. And so they looked, and there it was. Perfectly compatible with the Standard Model.

Re: A Physicist Who Denies That Dark Matter Exists

#52

Post by mikeash »

fuhrysteve wrote: post #4
roryisok wrote: post #3

> "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…

> 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. I have always had the same inclination. It seems like a classic candidate for using Occam's razor. Would love to hear someone who knows more about physics weigh in with a more nuanced viewpoint.

If you're looking at the sky and there appears to be a lot more stuff there than just the bits that emit light, wouldn't Occam's Razor suggest that the presence of more stuff is the most natural explanation, rather than rejiggering the fundamental laws of physics?

Re: A Physicist Who Denies That Dark Matter Exists

#53

Post by blueprint »

jerf wrote: post #13
roryisok wrote: post #3

> "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…

One of the mental problems that I think people get in this area is that you can't help but mentally imagine that there's just these few points of data that we need to hit, and so we have a lot of freedom in how to construct formulae that match the observation, so why are scientists being so obstinate about the possibility that MOND may be true? But that's not the case. We have petabytes of data from space (if not mor…

> 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

That's honestly not so "weird" at all. There are TONS of examples of objects and substances having that kind of behavior in nature. If I crash my car into something, the metal "remembers" what happened to it. If I run electricity through an inductor, the magnetic field "remembers" that electricity was being run through that space and doesn't just disappear the moment the electricity is turned off. Momentum is the same thing. Humans remember what happened to them because consciousness records everything that happens to us. What prevents gravity from being something similar? Gravity itself may mean exactly the same thing as space having a kind of memory and operating fundamentally by the law of cause and effect. Things may seem weird only in the absence of such a clear principle.

Re: A Physicist Who Denies That Dark Matter Exists

#54

Post by gadders »

mirekrusin wrote: post #44

Dark matter is probably just practical joke where the rest of civilised universe is looking at us from behind their see-through shields.

I always thought that. I imagine a sci-fi story where someone manages to finally observe dark matter and when they flip the switch they realise that the earth is actually on the equivalent of a traffic island.

Re: A Physicist Who Denies That Dark Matter Exists

#55

Post by dhimes »

roryisok wrote: post #3

> "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…

Well, it seemed to work for neutrinos.

Re: A Physicist Who Denies That Dark Matter Exists

#56

Post by Avshalom »

jcranmer wrote: post #22
roryisok wrote: post #3

> "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…

I've also been in the same boat, preferring the intellectual idea of modified Newtonian dynamics, primarily based on the fact that the only real checks we have on gravity are based on relatively short distances cosmologically. AIUI, assuming that gravity tends to 1/r at galactic distances "solves" the dark matter problem, for galactic rotation at least. The problem is that there are other phenomena that involve invok…

Also assuming gravity tends to 1/r at galactic distances makes no god damned geometric sense and would require like extra dimensions with funny topology for gravity to be traveling though.

Re: A Physicist Who Denies That Dark Matter Exists

#57

Post by dhimes »

jerf wrote: post #13
roryisok wrote: post #3

> "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…

One of the mental problems that I think people get in this area is that you can't help but mentally imagine that there's just these few points of data that we need to hit, and so we have a lot of freedom in how to construct formulae that match the observation, so why are scientists being so obstinate about the possibility that MOND may be true? But that's not the case. We have petabytes of data from space (if not mor…

Cool- a relaxation time for spacetime.

Re: A Physicist Who Denies That Dark Matter Exists

#58

Post by waqf »

jerf wrote: post #13
roryisok wrote: post #3

> "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…

One of the mental problems that I think people get in this area is that you can't help but mentally imagine that there's just these few points of data that we need to hit, and so we have a lot of freedom in how to construct formulae that match the observation, so why are scientists being so obstinate about the possibility that MOND may be true? But that's not the case. We have petabytes of data from space (if not mor…

> What's true is true, regardless of how we feel about how beautiful it is.

I think that's, in a certain sense, not really correct. Without some form of Occam's Razor, you can't do science — or at least, you can't come to any definite conclusions, because there are always infinitely many models that would explain any observation.

Turning that around, it means that for any fixed amount N of data in support of your hypothesis, there's an ugliness/arbitrariness threshold H_0 such that if your hypothesis is more ugly/arbitrary/possessed of entia multiplicata than H_0 you shouldn't accept it yet.

Re: A Physicist Who Denies That Dark Matter Exists

#59

Post by quantumhobbit »

mikeash wrote: post #23
roryisok wrote: post #3

> "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…

Remember the discovery of Neptune? I mean, not directly, since everyone from that time is dead, but.... That's a nice example of a prediction being wrong, inventing an as-yet-unobserved chunk of matter to fix it, and that invention then being correct. Of course, there's a counter-example in the inner solar system in the form of Vulcan. It was invented to explain Mercury's orbit, but the solution ended up being Relati…

The same thing happened in particle physics with neutrinos. There were two ways to get explain beta decay: conservation of mass is wrong, or pretend that the extra mass is carried away by an impossible to detect particle. It took decades for neutrinos to be actually detected.

Re: A Physicist Who Denies That Dark Matter Exists

#60

Post by olavk »

fuhrysteve wrote: post #4
roryisok wrote: post #3

> "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…

> 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. I have always had the same inclination. It seems like a classic candidate for using Occam's razor. Would love to hear someone who knows more about physics weigh in with a more nuanced viewpoint.

Occam's Razor would only apply if the theories made the same prediction with and without the dark matter. You cannot use Occam's Razor to explain away a discrepancy between theory and observation.
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