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Frequently, at least in the past, when people raise speculation about dark matter/energy that somehow becomes deeply controversial. The controversy is a very no

Frequently, at least in the past, when people raise speculation about dark matter/energy that somehow becomes deeply controversial. The controversy is a very non-scientific position to take in the science of astronomy, which is both confusing and troubling. Science is meant to be challenged.

boxed 3y ago
Does it? I think it's more that we collectively try to tamp down on the breathless reporting of revolutions in media when there isn't any. As you say science should be challenged, but popular science reporting doesn't really do that...
proaralyst 3y ago
I tend to understand 'controversial' here as a shorthand for new theories not explaining some observations. There's lots of good evidence for the models that require dark matter and dark energy (which I also understand to be very different), so if you want to propose an alternative model it must do at least as well as those. My second belief is that popular science articles are not good at explaining nuance, and tend to focus on human factors. Both of these are fine for lay audiences but should probably not be used to judge the health of the scientific process itself
- candiodari 3y ago
  It's just that people just can't deal with existence proofs. In Math people seriously tried for ~180 years to prove that you don't need a single existence proof (which notably means you can't have real numbers, or calculus) For Dark Matter we have existence proofs. It MUST exist, in some form, we just don't know what it is. It will take another century before we're at 180 years ...
3abiton 3y ago
But in real life, there is a spillover of cultural norm into science communities, thus controversies in the sciences are born. In my university there used to be these 2 competing professor (and their respective teams) working on Dark Energy vs Modified Gravity, and their rivalry was very known on the campus. Whenever an external speaker invited by either one, you'd expect a presence from the other with very sharp round of questioning. It made physics fun for us.
chongli 3y ago
That’s because dark matter is frequently referred to as a theory. It’s not. Dark matter is a set of observations which we try to account for in our theories. New theories which account for some observations of dark matter but ignore others are rightfully considered suspect.
- willis936 3y ago
  This assumes that dark matter exists when there has been no direct evidence of it. The observations demand that the models change to fit the data. Some argue a light touch (dark matter).
  - chongli 3y ago
    Entirely on the contrary. Dark matter is the label given to a set of anomalous observations. The entire problem is that we called it “dark matter” when we should have called it “missing mass”, because that’s what it is. There would be no controversy with the latter name.
    - queuebert 3y ago
      Technically, "missing gravity". The mass is inferred, but not absolutely required. (Though it is by far the simplest explanation.)
- rcxdude 3y ago
  I'm not really sure that's a useful way of putting it. There are a set of observations which don't match expectations, one idea which explains most of them is that there is some matter present that we can't directly observe (and then there's a wide variety of more specific ideas of what the nature of this matter may be, some of which fit observations better than others). That's in contrast to the idea that our theory of gravity may be incorrect, which also explains some of the observations (including ones which dark matter does not), but less of them overall, and there's a wide variety of specific ideas of how we might modify gravity to fit the observations (and generally I think the difficulty is you can come up with modifications that explain one obversation well but it's hard to explain a lot of them at once). DM and MOND are referring to different ideas of matching the anomolous observations, not the observations themselves. And each is really a family of different theories, as opposed to one singular theory each.
ordu 3y ago
When I see people being yelled at for their non-standard theories in internet it mostly boils down to them ignoring (let's call it) the structure of a scientific knowledge, when they just pick from a textbooks statements they like, reject other statements they do not like, and then try to build something on top of a resulting mess. Scientific knowledge has a structure, similar to a structure of a math theory where axioms and definitions are used to prove theorems which in their turn are used to prove even more statements and so on. You can trace a path from any statement to axioms and definitions. But empirical sciences have structure more complex than that of math. They rely on empirical evidence which is limited by abilities of instruments, and they are subject to change when instruments become better. Sometimes they reject some hypotheses not due to contradicting evidence, but because there were several competing hypotheses and one of them had more supporting evidence. If you start asking questions why physics thinks that X is true, and ask a lot of them not accepting any statement without asking such question then you'll get a lot of answers (conditionally on a benevolent physicist willing to answer them all), and you'll get eventually the structure of physics. But then comes some freak and claims he proved Einstein wrong, while it is clear to physicists that he doesn't understand the structure of the theory. To get a simple example I can resort to a calculus and... Imagine a student that when asked to prove that sin(x)/x -> 1 when x->0, "proved" it with a help of L'Hôpital's rule by taking derivatives of nominator and denominator. L'Hôpital's rule doesn't forbid it explicitly, and it may seem to be ok, but the trouble is the derivative of sin is proved with reference to a limit of sin(x)/x when x->0. So it becomes a circular reasoning and if you see how student does it you know that the student doesn't understand a thing about calculus, his attempts to pretend to know calculus are pathetic. Similar mistakes one can make in any discipline, though in them the structure or reasoning behind the theory is more complex, in math you can rely on pure logic, you need no Occam's Razor or something like. In social sciences you need to know all the history of your chosen domain of knowledge, how it evolved and why so. In physics it is simpler but still you need to understand at least some decisions made in the past (or maybe all of them, I'm not a physicist, so I'm just speculating). One can propose any insane theory contradicting to Einstein, Newton or anyone else and not to be yelled at, but you need to state your starting position carefully with regard to a structure of a scientific knowledge. Like if you want to derive statement sin(x)/x->1 when x->0 by resorting to L'Hôpital's rule then you need first to build your own calculus with blackjack and hookers from scratch in a way that make it to be a non-circular reasoning. And probably you will need to explain your motivation why are you doing that, because people will be asking about it a lot.
mr_mitm 3y ago
The controversy is really only present in laymen circles. In scientific circles, DM proponents vastly outnumber MOND proponents. I agree that science is meant to be challenged, but a worthy challenger must produce a better theory. The consensus is that DM fits the available evidence best. The case about dark energy is way less settled and way less clear due to lack of evidence. The standard model (i.e. a cosmological constant) fits best while having the least number of parameters, but I'd say that most cosmologists agree that it is not the final answer. It is expected that another theory with more free parameters will prevail, but current observations are not precise enough to decide which ones can be ruled out.
yieldcrv 3y ago
faithful die with their beliefs, scientists let their beliefs die its a pretty easy rubric to tell what you're currently doing on any topic ask yourself what information would alter your belief, is reproducibility a factor in your belief at all, does your belief conveniently exempt itself from reproducibility in some way, such as a reward for maintaining your belief ... perhaps after you die?
Sysreq2 3y ago
I don’t know anything about physics at that level. Really just the pop science stuff. But I know how people work pretty damn well. I will tell you, right now, with 100% certainty: dark matter is modern witch craft. Bunch of nerds got together and convinced themselves of magical forces that can’t be seen, heard, felt, or touched because their models of the universe don’t work without it. Might be 200 years until we figure it out, but there is an error somewhere and scientists are too proud to admit that they ain’t got a clue. How’d the moon get in the sky? Well I guess someone had to put it up there. How do birds fly? I guess God made them float on account of their lack of sin. Why don’t our models of gravity work? I guess the universe is made up of weird, invisible stuff. Humans don’t like not knowing. So they make wild theories about stuff no one can explain. Someone will come along and figure it out eventually.
- exe34 3y ago
  The whole point of "dark" in the dark matter and energy cases is to indicate "we don't know." It looks like there needs to be something there for everything to make sense, but we can't see it. Let's try to work out what the properties of the stuff is based on what we can measure and see if anything starts to make sense.
- andrewflnr 3y ago
  If you know anything about physics at that level, you would know that cosmologists don't like dark matter either. They'd love an alternative but the evidence keeps beating the candidates to death.
  - Sysreq2 3y ago
    Aristotle believed that all objects desire to be in their natural state. Throw a rock and it aims to return to the earth. Burn some twigs and the fire eventually stops. And the natural state of any object is at rest. Every piece of evidence for hundreds of years proved this point. Every scientist knew it to be true. And yet I ask you today, does an object in motion desire to rest OR does it stay in motion until acted upon by an outside force? It wasn’t until later that people had the tools to say, hey, wait a minute, this isn’t right. There is more here than we understand. Which of these scenarios seems more likely: 85% of the matter and 95% of the universe is made up of stuff that we can’t detect, doesn’t interact with anything and doesn’t follow the rules of everything else OR there is something going on that we don’t yet understand?
dotnet00 3y ago
The deeper you get into scientific communities, the less controversial it is to speculate since the more likely you are to care about knowing enough about the topic before saying anything (or otherwise have a better read on how much you don't know of what you're talking about). The controversy comes up because it has become pop science to discuss alternative proposals to DM/DE without properly conveying why DM/DE are the leading candidates for their associated measurement abnormalities. So you get a lot of people who functionally know nothing about the topic arguing that DM/DE are illogical because according to them scientists are just fudging the data. This is a thing even with the more informed/STEM-minded crowd of HN.
rcxdude 3y ago
The thing is, MOND was for a long time the preferred option, for basically all the same reasons a scientifically-literate layman would prefer it. The only reason DM is generally the more popular option amongst physicists is because it's beaten out the other theories at explaining the data (and it's not like it's universal: as can be seen by this paper there are many credible scientists still exploring and advocating for the idea, even if they are the minority). What I think gets tiring is people looking at it without that much depth (and pop-sci articles are a puddle) and then jumping to the conclusion that the majority of scientists are wrong because obviously MOND-type theories are a more appealing option. They would be, if they worked well enough. DM itself still has problems with some observations. It's not settled, but it's not going to get settled by a bunch of internet comments.

boxed 3y ago

Does it? I think it's more that we collectively try to tamp down on the breathless reporting of revolutions in media when there isn't any. As you say science should be challenged, but popular science reporting doesn't really do that...

proaralyst 3y ago

I tend to understand 'controversial' here as a shorthand for new theories not explaining some observations. There's lots of good evidence for the models that require dark matter and dark energy (which I also understand to be very different), so if you want to propose an alternative model it must do at least as well as those. My second belief is that popular science articles are not good at explaining nuance, and tend to focus on human factors. Both of these are fine for lay audiences but should probably not be used to judge the health of the scientific process itself

candiodari 3y ago
It's just that people just can't deal with existence proofs. In Math people seriously tried for ~180 years to prove that you don't need a single existence proof (which notably means you can't have real numbers, or calculus) For Dark Matter we have existence proofs. It MUST exist, in some form, we just don't know what it is. It will take another century before we're at 180 years ...

3abiton 3y ago

But in real life, there is a spillover of cultural norm into science communities, thus controversies in the sciences are born. In my university there used to be these 2 competing professor (and their respective teams) working on Dark Energy vs Modified Gravity, and their rivalry was very known on the campus. Whenever an external speaker invited by either one, you'd expect a presence from the other with very sharp round of questioning. It made physics fun for us.

chongli 3y ago

That’s because dark matter is frequently referred to as a theory. It’s not. Dark matter is a set of observations which we try to account for in our theories. New theories which account for some observations of dark matter but ignore others are rightfully considered suspect.

willis936 3y ago
This assumes that dark matter exists when there has been no direct evidence of it. The observations demand that the models change to fit the data. Some argue a light touch (dark matter).
- chongli 3y ago
  Entirely on the contrary. Dark matter is the label given to a set of anomalous observations. The entire problem is that we called it “dark matter” when we should have called it “missing mass”, because that’s what it is. There would be no controversy with the latter name.
  - queuebert 3y ago
    Technically, "missing gravity". The mass is inferred, but not absolutely required. (Though it is by far the simplest explanation.)
rcxdude 3y ago
I'm not really sure that's a useful way of putting it. There are a set of observations which don't match expectations, one idea which explains most of them is that there is some matter present that we can't directly observe (and then there's a wide variety of more specific ideas of what the nature of this matter may be, some of which fit observations better than others). That's in contrast to the idea that our theory of gravity may be incorrect, which also explains some of the observations (including ones which dark matter does not), but less of them overall, and there's a wide variety of specific ideas of how we might modify gravity to fit the observations (and generally I think the difficulty is you can come up with modifications that explain one obversation well but it's hard to explain a lot of them at once). DM and MOND are referring to different ideas of matching the anomolous observations, not the observations themselves. And each is really a family of different theories, as opposed to one singular theory each.

ordu 3y ago

When I see people being yelled at for their non-standard theories in internet it mostly boils down to them ignoring (let's call it) the structure of a scientific knowledge, when they just pick from a textbooks statements they like, reject other statements they do not like, and then try to build something on top of a resulting mess. Scientific knowledge has a structure, similar to a structure of a math theory where axioms and definitions are used to prove theorems which in their turn are used to prove even more statements and so on. You can trace a path from any statement to axioms and definitions. But empirical sciences have structure more complex than that of math. They rely on empirical evidence which is limited by abilities of instruments, and they are subject to change when instruments become better. Sometimes they reject some hypotheses not due to contradicting evidence, but because there were several competing hypotheses and one of them had more supporting evidence. If you start asking questions why physics thinks that X is true, and ask a lot of them not accepting any statement without asking such question then you'll get a lot of answers (conditionally on a benevolent physicist willing to answer them all), and you'll get eventually the structure of physics. But then comes some freak and claims he proved Einstein wrong, while it is clear to physicists that he doesn't understand the structure of the theory. To get a simple example I can resort to a calculus and... Imagine a student that when asked to prove that sin(x)/x -> 1 when x->0, "proved" it with a help of L'Hôpital's rule by taking derivatives of nominator and denominator. L'Hôpital's rule doesn't forbid it explicitly, and it may seem to be ok, but the trouble is the derivative of sin is proved with reference to a limit of sin(x)/x when x->0. So it becomes a circular reasoning and if you see how student does it you know that the student doesn't understand a thing about calculus, his attempts to pretend to know calculus are pathetic. Similar mistakes one can make in any discipline, though in them the structure or reasoning behind the theory is more complex, in math you can rely on pure logic, you need no Occam's Razor or something like. In social sciences you need to know all the history of your chosen domain of knowledge, how it evolved and why so. In physics it is simpler but still you need to understand at least some decisions made in the past (or maybe all of them, I'm not a physicist, so I'm just speculating). One can propose any insane theory contradicting to Einstein, Newton or anyone else and not to be yelled at, but you need to state your starting position carefully with regard to a structure of a scientific knowledge. Like if you want to derive statement sin(x)/x->1 when x->0 by resorting to L'Hôpital's rule then you need first to build your own calculus with blackjack and hookers from scratch in a way that make it to be a non-circular reasoning. And probably you will need to explain your motivation why are you doing that, because people will be asking about it a lot.

mr_mitm 3y ago

The controversy is really only present in laymen circles. In scientific circles, DM proponents vastly outnumber MOND proponents. I agree that science is meant to be challenged, but a worthy challenger must produce a better theory. The consensus is that DM fits the available evidence best. The case about dark energy is way less settled and way less clear due to lack of evidence. The standard model (i.e. a cosmological constant) fits best while having the least number of parameters, but I'd say that most cosmologists agree that it is not the final answer. It is expected that another theory with more free parameters will prevail, but current observations are not precise enough to decide which ones can be ruled out.

yieldcrv 3y ago

faithful die with their beliefs, scientists let their beliefs die its a pretty easy rubric to tell what you're currently doing on any topic ask yourself what information would alter your belief, is reproducibility a factor in your belief at all, does your belief conveniently exempt itself from reproducibility in some way, such as a reward for maintaining your belief ... perhaps after you die?

Sysreq2 3y ago

I don’t know anything about physics at that level. Really just the pop science stuff. But I know how people work pretty damn well. I will tell you, right now, with 100% certainty: dark matter is modern witch craft. Bunch of nerds got together and convinced themselves of magical forces that can’t be seen, heard, felt, or touched because their models of the universe don’t work without it. Might be 200 years until we figure it out, but there is an error somewhere and scientists are too proud to admit that they ain’t got a clue. How’d the moon get in the sky? Well I guess someone had to put it up there. How do birds fly? I guess God made them float on account of their lack of sin. Why don’t our models of gravity work? I guess the universe is made up of weird, invisible stuff. Humans don’t like not knowing. So they make wild theories about stuff no one can explain. Someone will come along and figure it out eventually.

exe34 3y ago
The whole point of "dark" in the dark matter and energy cases is to indicate "we don't know." It looks like there needs to be something there for everything to make sense, but we can't see it. Let's try to work out what the properties of the stuff is based on what we can measure and see if anything starts to make sense.
andrewflnr 3y ago
If you know anything about physics at that level, you would know that cosmologists don't like dark matter either. They'd love an alternative but the evidence keeps beating the candidates to death.
- Sysreq2 3y ago
  Aristotle believed that all objects desire to be in their natural state. Throw a rock and it aims to return to the earth. Burn some twigs and the fire eventually stops. And the natural state of any object is at rest. Every piece of evidence for hundreds of years proved this point. Every scientist knew it to be true. And yet I ask you today, does an object in motion desire to rest OR does it stay in motion until acted upon by an outside force? It wasn’t until later that people had the tools to say, hey, wait a minute, this isn’t right. There is more here than we understand. Which of these scenarios seems more likely: 85% of the matter and 95% of the universe is made up of stuff that we can’t detect, doesn’t interact with anything and doesn’t follow the rules of everything else OR there is something going on that we don’t yet understand?

dotnet00 3y ago

The deeper you get into scientific communities, the less controversial it is to speculate since the more likely you are to care about knowing enough about the topic before saying anything (or otherwise have a better read on how much you don't know of what you're talking about). The controversy comes up because it has become pop science to discuss alternative proposals to DM/DE without properly conveying why DM/DE are the leading candidates for their associated measurement abnormalities. So you get a lot of people who functionally know nothing about the topic arguing that DM/DE are illogical because according to them scientists are just fudging the data. This is a thing even with the more informed/STEM-minded crowd of HN.

rcxdude 3y ago

The thing is, MOND was for a long time the preferred option, for basically all the same reasons a scientifically-literate layman would prefer it. The only reason DM is generally the more popular option amongst physicists is because it's beaten out the other theories at explaining the data (and it's not like it's universal: as can be seen by this paper there are many credible scientists still exploring and advocating for the idea, even if they are the minority). What I think gets tiring is people looking at it without that much depth (and pop-sci articles are a puddle) and then jumping to the conclusion that the majority of scientists are wrong because obviously MOND-type theories are a more appealing option. They would be, if they worked well enough. DM itself still has problems with some observations. It's not settled, but it's not going to get settled by a bunch of internet comments.