If you are trained in seeing everything in a static frame you can come up with all kinds of stuff to explain inconsistencies. Fact is it's all about motion, acceleration and decceleration. If you can show me why dark matter should exist or provide to me how dark matter explains our observations in a more concrete manner, I'll gladly concede my point. Nobody ever explains dark matter. The only argument I hear is well it seems the universe is expanding really fast ?? >> dark matter = antigravity. It's bullocks. Gravity is caused by relative momentum and ripples in spacetime, and we're all just speeding behind another speedy object. Dark matter is matter flowing backwards in time, if you really want to ascribe meaning to the term dark matter. From that point of view you COULD say black holes are dark matter, but truthfully we can't state any of the sorts. We don't know what happens at a black hole.
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That sounds really wrong to me. Dark matter has nothing to do with the acceleration of the universe (this is dark energy). Moreover, the flow of time is related to the notion of particles/antiparticles. Once again, this has nothing to do with dark matter.
Although, we have dark matter particles and antiparticles but this concept is not only related to dark matter. This also exists for standard and observed particles.
Now, dark matter can explain galaxy rotation curves, can give an explanation of the observation from the cosmic wave background, can provide an explanation for excesses in gamma ray and cosmic ray data, etc... You can check all of this in the corresponding scientific publications. Both experimental ones for the results (that are results from some observations) and more phenomenological ones (or theoretical ones) for getting a dark matter interpretation.
In particle physics, dark matter is usually introduced as a particle that we have not observed with properties similar to those of the known particles. There are slight differences, but the theoretical concepts are the same: quantum field theory, gauge symmetries, special relativity, etc. I can cite many other big words but the entire point is that there is nothing really fancy here: only known theoretical concepts.
After this being said, calculations can be made and we can confront predictions to observations. And the point is that it works. Okay this is maybe not concrete enough with respect to what you ask, so let me be a little be more specific by taking one example. Let us assume you want me to calculate the relic density of dark matter for a given dark matter model (designed in a standard way) and compare my prediction to data of the Planck experiment. I could do it with either a blackboard or a dedicated computer code. I am not sure I could do it on steemit [just because it is not convenient to type equations, nothing more]. But the point is: I can do it. A master student can do it. The techniques are well known and there is no magics here.
This being said, you may want to try other theories, without dark matter, to explain the above observations. And guess what? It works too. You can modify gravity, which allows us to get rid of any dark matter particle at all.
So far, having dark matter in the universe is as likely as not having dark matter in the universe. This is often forgotten, but must be kept in mind. We need more data to decide which concept will (or won't) survive in the future.
I hope I have helped a little bit. Don't hesitate to come back to me for further clarifications.
Why or how does dark matter explain any of those things? What is dark matter?
It's made up, sure, as everything else. How is it different from standard matter? Why is it called dark matter? Because we've theorized particles we haven't observed? I feel it's all made up to explain measurements or perhaps even observations that are just interpreted in a wrong manner. It works gravitationally but not electromagnetically? Maybe you're missing something in your calculations. Look, I don't mind fiddling with calculations and trying to define meaning to unexplained variables. Intimidating people from the truth, however, is another matter entirely.
We have data and we have the standard model predictions. We observe a difference a we try to explain it. Dark matter is introduced with properties such that it fills the gap. The nice feature is that one single stuff can fill may many gaps at the same time (all the observations I mentioned, plus others). Those are the attractive features of dark matter.
It is not that different from the standard matter. It is called 'dark' matter because it does not interact electromagnetically. But this is not really special. Neutrinos exist and neutrinos do not interact electromagnetically. Why is a proton called a proton? Why is a quark called a quark? Someone introduced the name at some point and it stayed. That's it.
To repeat: theoretical physicists are trying to explain measurements. That is what theoretical physics is about: explaining the observations and making predictions that can be tested in future experiments (a theory must be falsifiable). This is the scientific method after all. Nothing less, nothing more.
There are different ways to do build theories explaining data, and dark matter is one of them. There are others. As I said it already (but I would like to insist on this point). The dark matter hypothesis is one among many. Whether you like it or not is a matter of taste. The point is that all theoretical options must be considered if we want to understand things better one day. As long as a theory has not been ruled out by data, it is alive. Period. Dark matter is alive. Modified gravity is alive. etc.
Concerning the Standard calculations. These are well known. The risk we are missing something is small, although non zero (zero risk does not exist). There are hypotheses behind each calculation, and these hypotheses sound reasonable. Now, the important point is that we have many observation that cannot be explained with standard calculations. Really many. Missing something in each of them (in the context of standard stuff) is unlikely. Possible but unlikely. If you have an idea on what could be missing, please speak up and show how it works. I have no idea.
Are you suggesting I am trying to intimidate you? That is a little bit insulting. I am trying to detail what are the issues, how dark matter helps, etc... And I have never (but never! please read again) said dark matter was the 'truth'. I have no idea what is the truth. We don't know and this is why people like me have a job. We try to understand how the universe works.
Maybe you have the 'truth' but that is another story... You may like better an alternative option to dark matter. Fair enough. But we are not talking about truth here...
I can hardly believe you're keeping this up. Pretending you're all this and all that but it's too hard to come up with one concrete reason why dark matter is theorized at all? One observation or measurement and an explanation for why it makes a case for dark matter? Anyway fine, take this one. I just think it's weird that for a decade (or longer?) now people have been coming up with this dark matter in populist media and other propaganda channels, clearly separating people from thinking for themselves because this is intimidating matter. Now you're here shilling it up.
That is slightly crazy... I already gave many reasons. Some are all listed in our discussion. Just to repeat: galaxy rotation curves, CMB, cosmic rays, gamma rays, formation of the structures in our universe, etc... This is why I think the dark matter paradigm is a good idea. It works damned well in explaining all these observations.
Scientists are well aware that dark matter is not the only option. And people are thinking hard about both non standard and novel dark matter ideas, and non standard and novel ideas without dark matter too. What you state about intimidation, close-mindedness and so on is just meaningless.
Remember that not everything scientists work on ends up in the media. Medias are selecting what they want to talk about. Dark matter is popular in media, that is true. Other options (that you seem to prefer) are less popular, that is true too. I am not the one choosing what the media like to talk about...
And not everything popular is good science and not all good science is popular. I believe dark matter theories are excellent theories. Who can say whether a theory is good or bad? Certainly neither you nor me, but only data. That is the scientific method...
On the other hand, I decided to work on dark matter and I deicided to talk about what I work on. That is my choice. If I would decide one day to work on modified gravity theories, I will write on this...
You're just copying whatever's mainstream? Sure you're not getting payed?
Oh well now you've explained the paradigm I suppose, good job man you've really enlightened the people.
Okay maybe should we stop this conversation? This leads to nowhere.
I was trying to give you (and just you by the way since you asked the question) keywords explaining why dark matter is not a crazy idea, and you seem to be unhappy regardless what I say. What can I do? I don't know what you want. A full course on dark matter? Good. There are plenty available for free on the web (I am sure you can find them as well as I could. So help yourself) with all detailed calculations that you may want to see and that I don't want to type here for various reasons.
What are you talking about? I discussed, in this post, three scientific papers I have recently read and that I have found interesting. Scientific journals are not usual media to what I know... And I didn't copy anything. IF you accuse my of plagiarism, just proof it.