Hello, /sci/, No dark matter guy here again.
Long video in which I argue against a comment defending the current black hole model.
https://www.youtube.com/watch?v=8nwS708KOtk
i like the video
>>8172611
Finally someone standing up against this nuts concept? I'll watch your videos later
>>8172611
Good OP!
Sick and tired of people taking a mathematical equation as proof that black holes and dark matter exist. All fucking nonsense.
>>8172611
>4 unique IP's in this thread.
Color me surprised, OP. Did you ask three of your friends to post these replies, then?
Nice vid OP! I gave a like! I did a for fun video a while ago on superluminal travel myself!
https://www.youtube.com/watch?v=zCKgcUnF6VQ
really makes me think
Its too...supportive... to be real responses.
>>8172611
https://www.youtube.com/watch?v=vU-mKsQLWXQ
https://www.youtube.com/watch?v=DJMf9a8OSbs
https://www.youtube.com/watch?v=dVfnd5r8bM0
https://www.youtube.com/watch?v=GA-cUVotYps
>>8173984
I'm not saying that black holes don't exist. I'm saying that crossing the event horizon is unreasonable because the method used to do it applies a speed of light in the field that does not belong there. Watch the video. All gets explained.
>>8172611
The Schwarzschild metric is a weak-field approximation. The singularity that you're so upset about is a coordinate singularity that can be removed by choosing Eddington-Finkelstein coordinates.
>changing the coordinate system doesn't make sense to me
Yeah, no shit.
>samefag-tier responses
>10 replies 11 posters
This thread is sketchy
>>8176006
What you're actually saying there is that you need to change the speed of light in the field. The light cone edges you are applying by doing that come from light speed in flat spacetime. Those edges have nothing to do with the coordinates to which you are applying them. It's not merely a coordinate transformation it's applying a new constant, a different speed of light to the field.
Science is some scary shit
Don't go back in time and reverse the universe
If you do that is a dick move and you have to accommodate the past let's make a rule
>>8176018
>you need to change the speed of light in the field
No, the coordinate speed in E-F coordinates is constant, unlike in the Schwarzschild metric. You should really learn how to use google.
>>8176035
I know that EF speed of light it is constant. The Schwarzschild metric reaches zero at the event horizon. The Schwarzschild is the correct speed of light for the metric because it is the metric. The E-F speed of light does not belong in the field.
>>8176014
wow, one guy posted twice
>>8173984
>Sick and tired of people taking a mathematical equation as proof that black holes and dark matter exist.
this
I can't believe to see such an intelligent post on /sci/ of all boards
>>8172611
NICE JOB OP
I WISH MORE PEOPLE WOULD POST OC
I WOULD TOTALLY SUCK YOUR DICK
>>8176065
No it means nobody posted twice which could mean that OP just brought in a load of people to support his thread by posting once and leaving.
>>8176074
Yeah, because math is sooo faulty and like such a nerd thing to do, senpai
:^)
>>8176080
>I don't understand what math and science are
then why are you on this board you idiot?
>>8176053
What do you mean "does not belong in the field"? The E-F coordinates are adapted to a null geodesic (i.e. photon geodesics), meaning the velocity will always be c.
>>8176114
The field is curved. C decreases until it reaches zero at the event horizon. The E-F corresponds to c in flat space which is, yes, constant. A constant speed of light does not belong in a field where c decreases until it reaches zero.
>>8176118
>C decreases until it reaches zero at the event horizon
Please learn what a null geodesic is and then get back to me.
>>8173990
no, screw this OP.
I only posted >>8172636 because I was hoping some autist/physicist would get triggered.
>>8176083
I thought
>:^)
would make absolutely clear that I'm sarcastic. But one cant expect the depths of autism on this board
>>8176132
Different dude here, sarcasm doesn't carry through text and obnoxious fucks frequently use that face while baiting. Which is still baiting, but people will always fall for it so you shouldn't be surprised.
>>8176136
>so you shouldn't be surprised
thats really a fair point
But I thought shitface smiley and ALL CAPS were the universally accepted signs of "guys, I'm not entirely serious here". You know, not even bait, but more satirical in nature
>>8176158
Sometimes I think it's a new form of meta-bait to respond negatively to something you recognize is sarcasm.
>>8176122
I don't feel any need to repeat myself.
>>8176249
because you would be wrong for the second time
>>8176074
Please fuck off, nobody thinks that. Dark matter was empirically motivated by the observation of galaxy clusters.
>>8176325
The null geodesics to a light line at the event horizon. This makes sense as the event horizon is a light like surface.
E-F Null geodesics to not match the curvature of the field.
>>8176132
>I was just pretending to be retarded
>look how much better than everyone else I am
ok kid
>>8176567
>our observations don't match our models
>could our models be wrong?
>lol no way, reality is wrong, lets invent something invisible and undetectable and pretend that our models are right
yeah good job there
I can't believe there are people so unintelligent they genuinely believe that theoretical physics is science
>we don't have to observe reality and attempt to model it
>we create the reality in our own minds and if the observations do not fit our fantasies then reality has to change
it should become mandatory to teach childen the scientific method in school
>>8177156
Not my fault, that you are new and dont no obvious 4chan conventions. I'm not better than everyone else, I'm just better than you
>>8177178
>could our models be wrong?
The models were wrong. What you ignore is that the predictions were made with gravity and with models of the mass of galaxies and clusters. In the case of dark matter the later was assumed to be wrong. People have tried the opposite. It doesn't have anywhere near the predictive power and still can't explain observations like the bullet cluster. Cold dark matter on the other hand made many predictions like the CMB powerspectrum, the growth rate and the Baryon acoustic oscillation amplitude.
>lol no way, reality is wrong
You reveal your bias. Nothing tells us all the matter in the universe is already known. That's just a baseless assumption.
>theoretical physics
This is observational cosmology. Observational.
>we don't have to observe reality and attempt to model it
That's exactly what dark matter does. You don't observe the mass distribution of a galaxy, you have to model it. With dark matter the model is simply different. Dark matter isn't changing any observations.
I don't know how someone can be so ignorant. You don't understand model selection much less the scientific method.
>>8177410
>dark matter
>observational cosmology
>>8177599
Yes. As I said, it was motivated by observations.
>>8178129
its theoretival physics, mate. you cant even observe dark matter
>>8178187
It's matching models to data, that's observational astronomy.
>>8178254
There is no direct proof, no direct observation, for the existence of "dark matter". The effects we see could be explained by other models or simply by errors in our current models.
This whole thing works but is not elegant at all and we shouldnt assume that there is really something like "dark matter"
>>8178263
>There is no direct proof, no direct observation, for the existence of "dark matter".
Doesn't matter, it's still part of observational astronomy. The Hulse-Taylor binary showed the existence of gravitational waves decades before LIGO.
>The effects we see could be explained by other models or simply by errors in our current models.
That's always true in all of science, it's not a criticism of model.
>This whole thing works but is not elegant at all and we shouldnt assume that there is really something like "dark matter"
Opinion, irreverent. You can only quantify elegance when you multiple models which have the same explanatory power, then you can do model selection. No such alternative model exists. If you really feel you can do much better I suggest you build a better model, people have been trying for decades. Even after a decade of work there is no explanation for the Bullet cluster in modified gravity models.
>>8178263
"Elegance" shouldn't be used as a metric. What fits the observed facts should be used as a metric, what you think about the model is irrelevant.
Look, you can go ahead and make your own models that fit the observations of galaxy clusters, but until then, don't baselessly argue against the best current model.
Dark matter explains what we see, and it does it well. If your only real complaint is "hurr durr we can't observe something that is currently unobservable" than fuck outta here. We used special relativity for almost a century before finally directly observing gravity waves. We used particle physics models before we directly observed the Higgs boson. Saying that theoretical physics is "theoretical and thus worthless" ignores all the progress we have made because we assumed the best mathematical model was correct, and working off that. Direct observation in physics tends to follow theoretical prediction.
So, OP, give me an alternative solution that explains all the phenomena better than the solution that thousands of better-qualified and better funded scientists than you have worked on, or else your whole argument is a gigantic appeal to incredulity.
>>8178271
>>8178277
By elegance, I meant that this is just an ad-hoc explanation. Just a device to make our models correct again. These models should set out how the universe works and explain reality wether to just be forcefully consistent.
Just because the math works now with the concept of it in mind, doesnt mean that there really is dark matter out there.
You shouldt wave away the notion of hard scientific evidence, just because something is convenient and we already have "figured it out". Thats not how we do it.
Not OP here, btw
>>8178332
OP here. Completely agree.
>>8178332
>Just a device to make our models correct again.
You're missing the point. The inclusion of dark matter was a new model, the old model was wrong. you seem to ignore the fact that mass distributions of galaxies were models, they were built on assumptions, there was no reason to believe they were correct over gravity.
>These models should set out how the universe works and explain reality wether to just be forcefully consistent.
And how does one deduce how the universe really works? I don't think you understand science.
>doesnt mean that there really is dark matter out there.
The quark model doesn't mean that quarks are physical. All of astronomy (and particle physics) is based on models, the most powerful models are the ones that become the standard models. It doesn't mean they're physical, but we have no way of knowing what is truly physical.
Dark matter was an empirical model but it has made many confirmed predictions.
>>8178332
Do you have hard scientific evidence, or are you just shitposting? As the other guy and I have said, we're not dismissing any evidence, because no superior model has been given. Dark matter is the best model to fit our observations. You're right, it's entirely possible that dark matter doesn't exist, but you don't have a better solution, so stop complaining.
>>8178332
>By elegance, I meant that this is just an ad-hoc explanation. Just a device to make our models correct again.
I never understood this retarded argument. What exactly do you want? An incorrect model that ignores empirical findings? Is that better than dark matter? Until you provide a model that explains everything better than the current one, your argument is completely impotent and nonsensical.
>>8178359
It seems like you are missing my point.
>The quark model doesn't mean that quarks are physical
But you know we have things like the LHC and particle detectors, right? There is a different between an ad-hoc model and something we have cleat evidence for through experiments.
>Dark matter was an empirical model but it has made many confirmed predictions.
I never denied that it can make predictions. That doesnt really mean anything. I saw flat earth "theories" that could predict the movement of the moon.
>>8178360
>we're not dismissing any evidence,
thats not really what I'm saying. There just is no evidence for dark matter.
>You're right, it's entirely possible that dark matter doesn't exist
exactly. But some people like to pretend that its existence is certain and that we have figured it all out yet and I dont think that this is a productive attitude.
>but you don't have a better solution, so stop complaining
fair enough
But sometimes it is not wrong to admit "Well we just dont really know yet. But we can use this very helpful crutch here, lets see, maybe we are on to something"
>>8178378
>An incorrect model that ignores empirical findings?
No I dont want that. I never said that. Stop strawmanning.
>>8178388
Then why are you complaining that the model was corrected to explain empirical findings? I can't strawman an argument that doesn't exist. Why don't you explain exactly what you want to replace the current model with, and why.
>>8178384
>But you know we have things like the LHC and particle detectors, right? There is a different between an ad-hoc model and something we have cleat evidence for through experiments.
Clear evidence of a quark? LOL no. We have many experiments that confirm the predictions made from the model that requires quarks to exist. But we have never seen a quark. It's a good analogy.
>I never denied that it can make predictions. That doesnt really mean anything.
OK, so you don't know anything about science.
>I saw flat earth "theories" that could predict the movement of the moon.
And if the flat earth theories could explain things better and make better predictions than current theory, we would adopt it. But they don't and all suffer from several flaws. So what flaws are caused by dark matter?
>thats not really what I'm saying. There just is no evidence for dark matter.
The evidence is that predictions made by them are the best so far. Just like quarks.
>exactly. But some people like to pretend that its existence is certain and that we have figured it all out yet and I dont think that this is a productive attitude.
WHO? Name one legitimate physicist.
>But sometimes it is not wrong to admit "Well we just dont really know yet. But we can use this very helpful crutch here, lets see, maybe we are on to something"
I don't think any physicist takes dark matter for granted. You are making a huge strawman.
>>8178384
>It seems like you are missing my point.
It seems like you've released you're talking shit. There is no way in science to tell what is occurring in "reality".
>But you know we have things like the LHC and particle detectors, right?
They don't detect individual quarks.
>I never denied that it can make predictions. That doesnt really mean anything.
Predicting the motion of the Moon isn't a prediction, it's a postdiction. Dark matter on the other hand made true predictions before the observations were even possible. Even if you predict the motion of the Moon in the future you're just pining it to an already successful model, there was no such cosmology before CDM. Come back to me when this flat earth model makes a confirmed novel prediction that orbital theory does not.
>>8178402
>I can't strawman an argument that doesn't exist
yes. thats pretty much exactly what you have done. attacking a point I never made.
People can criticise things without having a better alternative. dont be silly
>Clear evidence of a quark? LOL no
You might pick up a textbook on this subject. I dont think there is any real controversy on the existence of what we call quarks
>OK, so you don't know anything about science.
Thats just namecalling. I indeed never claimed, that it cant make predictions, so I dont know whats your point here.
>And if the flat earth theories could explain things better and make better predictions than current theory, we would adopt it.
way to miss the point
>he evidence is that predictions made by them are the best so far.
we agree on the predictions part, but that doesnt make it evidence
> don't think any physicist takes dark matter for granted
so what is it? real or not? Most people itt seem to think dark matter is real without a doubt. I dared to be sceptic and there are 2-3 people jumping at me.
I am not the only one who criticises this theory.
>>8178427
>It seems like you've released you're talking shit.
No, you missed my point and now you are just namecalling. irrelevant point, mate
>They don't detect individual quarks.
strawman
>Predicting the motion of the Moon isn't a prediction
yeah
But anyway, it was an analogy to point out that a model that can predict reality doesnt really have to explain the universe.
Guys, please calm down. All I'm saying is that there is no clear evidence for the existence of dark matter, so we shouldnt take it for granted that it really exist. Thats my only criticism.
>>8178263
Not direct, but supposedly black holes have been observed with elevated radiation caused by dark matter crowding around and annihilating itself.
>>8178423
we have data that points to something that behaves like a quark that we describe in our model
that is how particle physics works, five sigma
>>8178678
>strawman
Not a strawman. You said they have particle detectors. I pointed out those particle detect don't detect individual quarks. The evidence for the quark model is indirect.
>yeah
If you didn't cut my reply in half I responded to this cheap dismissal. You've just ignored both of my points without counterargument.
>to point out that a model that can predict reality doesnt really have to explain the universe.
Nobody is claiming that. In fact I said that much earlier.: >>8178359
>You might pick up a textbook on this subject. I dont think there is any real controversy on the existence of what we call quarks
>Ehh, err, emm. Look it up idiot!
Answer the question. What is this direct evidence for quarks?
>>8178774
No, that was a theoretical paper suggesting in some mass ranges black holes would be the best places to look for annihilation signatures. There are many candidate signatures but none are unambiguous and all of them are treated with extreme skepticism in most of the field.
>>8178817
>Not a strawman
Well to me it seems, you are arguing against a point I never made. I never claimed that there was DIRECT evidence for quarks.
>ou've just ignored both of my points without counterargument
well, sorry. But that was just nitpicking at my analogy. I concede that it was a bad analogy.
But again, the point was that a model that can predict reality doesnt really have to explain the universe. Which you seem to agree with.
>>8176567
That's your personal view. Thing is, hard science can't really admit those observations as evidence. The dark matter hypothesis is still there, it's just extremely weak. Noone is stopping you from looking, just don't expect the mainstream scientific community to use the same standards of proof you do. This is all there is to this debate.
>>8178806
We have data that points to something that behaves like dark matter that we describe in our model.
How do you not get this? What is special about dark matter?
>>8177036
>The null geodesics to a light line at the event horizon.
>E-F Null geodesics to not match the curvature of the field.
Dislike this "make a word salad and pass it off as an argument" meme.
>>8180647
The null geodesics of the E-F correspond to flat spacetime. The spacetime of the Swarzschild is curved by definition. The incompatibility couldn't be more glaring or obvious. But here we are.
>>8178678
>yes. thats pretty much exactly what you have done. attacking a point I never made.
Can you read? I can't strawman an argument that doesn't exist. You claimed that my reply did not attack your argument. What is your argument then?
>You might pick up a textbook on this subject. I dont think there is any real controversy on the existence of what we call quarks
There is no controversy over dark matter, except among laymen who think that every new part of a model is bullshit because they don't understand it.
>Thats just namecalling. I indeed never claimed, that it cant make predictions, so I dont know whats your point here.
How is that namecalling? If you think the ability to make correct predictions is irrelevant, you don't know anything about science.
>way to miss the point
What is the point of comparing dark matter to flat earth then?
>we agree on the predictions part, but that doesnt make it evidence
That is evidence. Apparently when we observe effects that are predicted by quarks, that is clear evidence of quarks. When we observe predictions made by dark matter, that is not evidence, because... dark matter is something you don't like for some reason that you won't elucidate. Again, how can I strawman you when you won't make an argument? All I said was that saying that the model is wrong because it was corrected to account for empirical findings is ass backwards. You have not presented reasoning as to why dark matter is "wrong".
>so what is it? real or not?
Was the Higgs boson real or not when it was part of the standard model but we had not observed it yet? The question is meaningless. Models are approximations of what is real. Science is the attempt to continuously improve the approximation of what is real. Dark matter is simply another step in this. We will use the standard model including dark matter until it needs to be corrected again. Are you just shitposting about dark matter because it makes you feel smarter?
>>8178678
>Most people itt seem to think dark matter is real without a doubt.
WHO? You can't name a single scientist and you can't even show a single person in this thread. Pathetic.
>I dared to be sceptic and there are 2-3 people jumping at me.
Nice persecution complex. You dared to write a barely coherent opinion that you can't even defend and others called you out on it. Are you going to cry?
>I am not the only one who criticises this theory.
There are legitimate criticisms of dark matter based on substantive reasoning. Yours does not even come close. Don't flatter yourself.
Of course we can't directly observe something that reacts arbitrarily weakly with light.
Therefore, we have to rely on indirect observation.
What is your problem with this OP?
>>8180625
>I never claimed that there was DIRECT evidence for quarks.
Earlier you said there was "just is no evidence for dark matter", but there is indirect evidence. So it seems reasonable you don't consider indirect evidence as evidence at all.
I'll ask again, what is this evidence you consider to be so clear?
>the point was that a model that can predict reality doesnt really have to explain the universe
Well then you're debating a strawman. No one in this thread or in science is claiming that.
>>8180631
>That's your personal view.
No, it's a historical fact. Dark matter was coined by Zwicky who was observing motions of galaxies in the Coma cluster.
>hard science can't really admit those observations as evidence.
They can and science does, hence the reason the standard model of cosmology is the standard model. Nobody is claiming these observations uniquely point to dark matter, no experiment in science ever uniquely points to a model. However any observation which favours a new model (no dark matter) over the null (standard M/L ratios) is evidence.
>>8180681
>favours a new model (*dark matter*) over the null (standard M/L ratios) is evidence.
>>8174045
First and last are dank.
Others are closer to garbage than good.
Most of the people who believe in "dark matter" are probably the same people who whould have believed in the "cosmic aether" back in the days.
>>8180931
The aether was introduced from theory, dark matter was observationally motivated.
>>8180953
It was introduced to explain observable electromagnetic phenomena.
>>8180992
Nope, it was introduced as an analogy. Mechanical waves had to propagate though a medium, therefore electromagnetic waves should also propagate though a medium. In fact aether hypothesis had a hard time explaining most electromagnetic phenomena.
>>8181016
>therefore electromagnetic waves should also propagate though a medium
and this assumption was made to explain observable electromagnetic phenomena, Many people believed it and now we know it isnt real.
Dark matter doesnt have an explanation for everything, too.
>>8181016
>Analogy
>Published in peer review
lol. It was thought to be real and that was wrong.
>>8181016
read a book sometime instead of proclaiming history by your gut feels
>>8181030
>and this assumption was made to explain observable electromagnetic phenomena
Right, but that isn't what you were saying. You're trying to say the Aether was introduced on an experimental basis, but it wasn't, it was theoretical.
>>8181034
>It was thought to be real and that was wrong
Correct. It was a theoretical model that couldn't fit data. However dark matter was empirical and can make additional predictions, such as the CMB powerspectrum.
>>8181041
That is literally why it was introduced, physics of the 19th century couldn't explain how light could propagate through a vacuum. Since other waves needed a medium, they postulated that there must also be a medium that pervades all space.
/sci/ really has gone to shit.
>>8181054
>You're trying to say the Aether was introduced on an experimental basis
nope. It doenst even matter anyway. People believed it just because it explained what they saw.
I'm saying people believe in dark matter making the same mistake as people who believed in the aether
/sci/ has indees gone to shit
>>8181054
>That is literally why it was introduced, physics of the 20th century couldn't explain how galaxies behave on a large scale. Since smaller objects were moved by mass, they postulated that there must also be a "dark matter" that pervades all space.
>>8181087
>People believed it just because it explained what they saw.
Until it didn't then they removed it, eventually, it was a big revolution happened early in the 20th century. I doubt you've heard of it, from what I can tell you're quite uneducated. Also it didn't explain what they saw, which is why they abandoned it.
>'m saying people believe in dark matter making the same mistake as people who believed in the aether
Let meme arrow this for you, really get down to your level:
>Observation doesn't match model
>Adapt model to fit observations
>Holy shit, new model is even more powerful than before
Contrast with:
>I can't explain that
>Well let's just suppose that something exists, that makes it explainable
>Model now can't explain observations or conflicting theory
>Create ad hoc additions to model to force it conform to observations
>Model has literally 0 predictive power
Can you really not see how these two things are different? Are you that dense?
>/sci/ has indees gone to shit
It's gone to shit because of people like you. You can't even put forth a substantive argument beyond "science was wrong before". Please if you've got a better model then show how it can predict what anon here pointed out to you >>8177410
>>8181106
See above. All you've got is "science has been wrong before". It's a model that can make predictions, that's why it's still around.
>>8181119
>his bullshit got pointed out and now he starts to throw baseless assumptions and insults around
oh boy.
If you believe hard enough, maybe it becomes real.
>I can't explain that
>Well let's just suppose that something exists, that makes it explainable
thats literally what happened with "dark matter".
Of course you can call it "adapting the model to fit observations", but in the end they literally made up an unobservable matter nobody knows shit about, just so that the model fits the observations.
>>8181143
>No arguments
I'm shocked. When can we have simple problems for Captcha, weed out the brainlets.
>Dark matter has impressive predictive power
>DARC MATER DONT REAL BECUZ MUH FEELS!!1!!!
Brainlets, both irritating and amusing.
>>8181157
>No arguments
Oh the irony. What "FEELS" exactly? You are the one who is upset and throws around insults as if they are arguments.
>>8181119
>All you've got is "science has been wrong before"
NOPE. All you got is "lol, the math works"
That is literally why it was introduced, physics of the 20th century couldn't explain how galaxies behave on a large scale. Since smaller objects were moved by mass, they postulated that there must also be a "dark matter" that pervades all space.
>>8181167
>What "FEELS" exactly?
What else can it be other than you being emotionally invested in proving something wrong? If not why not just layout why you think we should give up on a model with good predictive power.
>ITT: OP doesnt realize science will never directly reflect the underlying universe and doesnt understand the need for intermediary approximations in a scientific model, dozens fall for his memes
Never change, /x/
dark matter faggots getting BTFO in this thread
>>8181143
>I can't explain that
>Well let's just suppose that something exists, that makes it explainable
You ignored the last bit which covers the last 40 years of cosmology.
>We have the hypothesis, now lets test it.
And tested it has been. The CMB powerspectrum, one halo and two halo clustering, the bullet cluster, the amplitude of the BAO peak in the modern universe. These predictions were made before the measurements could be made.
>>8181175
Thanks for the commentary from the mentally disabled.
Take note. Nobody in this thread has made any scientific criticism of dark matter. Nobody has claimed it can't fit galaxy-galaxy lensing from SDSS, nobody has claimed they have a 5 parameter fit for the CMB TT powerspectrum. All the people are arguing about here is the philosophy of science, it has no impact on dark matter as a scientific model.
>not using M.O.N.D.
>>8181262
>Newtonian gravity
>2016
>>8181262
MOND doesn't explain galaxy clusters, galaxy clustering or cosmology. Even Moti Milgrom admits it needs dark matter. It's just not comparable. It's also deeply ugly, it simply fixed their modification to gravity to existing observational results, the model itself can take any form fitting function within given boundary conditions. The fitting functions used have been shown not to work simultaneously in red and blue galaxies ot the milky way and other galaxies.
So how does dark matter explain the surprisingly uniform rotation speed of galaxies? Is is it precisely distributed to archive that effect in every galaxy we observe? How do you know?
Was there ever even a single dark matter particle detected? Does it consist of a variety of different particles? What is it made of? Are there counterparts to those particles (like anti matter) How is it possible to have the properties it needs to have in order for the hypothesis to work? How do you know?
How does dark matter interact with regular matter? Does it interact in the same way with itself? If not, why?
Why is there seemingly no dark matter close to our solar system?
>>8181187
People have indeed pointed out that it cant explain everything, next to other inherent flaws.
It is always easy to dismiss criticism with "lol u retard" and "thats just philosophy because I say so"
>>8181288
>So how does dark matter explain the surprisingly uniform rotation speed of galaxies?
Cold dark matter simulations showed that dark matter collapses to form halos which have a ubiquitous profile termed the NFW profile. This profile flattens rotation curves.
Not every galaxy has an exactly flat rotation curve, some rise further and some fall off.
There are no confirmed detection of dark matter although there are claims of it, these are widely treated with skepticism. It isn't known what type(s) of particle makes up dark matter but there are constraints. Cold dark matter doesn't require a very specific particle, if neutrinos were heavier they would do. Particle physicists belie there are candidates like sterile neutrinos and supersymetric particles but there are theoretical for now. How it interacts depends on the type particle. Observationally there are limits on how much it can interact with itself from colliding galaxy clusters, there is one system which may be evidence of self-interacting dark matter but it's a single system which just happens to have a very good strong lensing configuration. More are needed.
Dark matter in the solar system isn't expected. The mass expected to be enclosed will be on the order of asteroid masses. Dark matter in the neighborhood of the Sun has been widely debated, people have claimed not to see it but there are more analyses now showing it's there. It's a rather difficult measurement to make however, it's easier to study more distant galaxies that way you can study the galaxies further out where the dark matter dominates.
>>8181292
No, people have said "it can't explain everything" and haven't furthered that discussion any more. I've not seen anyone point out any "inherent flaws". There's no actually technical discussion here.
And yes it is philosophy of science. People aren't discussing LCDM, they're debating whether or not the dark matter is the new aether because of how it came about, that is philosophy of science. You can cheaply dismiss this but it is still true.
>>8181315
If you already know examples of things it cant explain, why do you even need examples for "it can't explain everything?
Do you need a list of every little thing it cant explain to believe it?
>I've not seen anyone point out any "inherent flaws"
then read the thread without confirmation bias
>>8180664
Opted for a video response.
https://www.youtube.com/watch?v=E3NJk-4JDrQ
Keep in mind I submit that everything I say about replacing dark matter with my hypothesis can be wrong and I still will maintain that light cones close at event horizons regardless of coordinate transformations and that the idea of a substantive, particle based "Dark Matter" is more conjecture than science.
>>8181376
>If you already know examples of things it cant explain, why do you even need examples for "it can't explain everything?
I didn't ask for a list. I'm pointing out that nobody here has pointed to any substantial criticism of dark matter. If you want to show a model is flawed you can't just say "it doesn't explain some things". No shit, QED doesn't explain the the dynamics of ping-pong but it doesn't make it wrong. Something it doesn't explain isn't necessarily a failure. If you want to convince people that cold dark matter is flawed this is the battleground, not relating it to the aether. If you don't venture into the technical then you aren't doing science.
>then read the thread without confirmation bias
This is your problem. Instead of pointing to a single example you just throw an insult. Dark matter is obviously wrong and anyone who asks you to show why is just a shill.
>>8181405
>particle based "Dark Matter" is more conjecture than science.
>my hypothesis
Please shut up. Your word salad about wormholes is not a testable fucking hypothesis. CDM on the other hand is. It's a model that works and has made numerous successful tests. Have you even shown in GR your assertion could reproduce any of the observations attributed to dark matter? No. You don't do math. What you have produced is not a scientific hypothesis because it is not at the stage it can be tested. You further demonstrate your ignorance by calling dark matter a conjecture despite it's theoretical and observational successes.
>>8181304
Thanks for giving a coherent answer. You seem to know a bit about the topic, so I will nitpick to extend the discussion.
>Cold dark matter simulations
Like computer simulations? Arent they based on the data we already have? I understand how they help to further understanding, but can we really handle this as evidence when it comes to such a "mysterious" matter?
>Not every galaxy has an exactly flat rotation curve, some rise further and some fall off.
Oh sure. I meant "surprisingly uniform" compared to what we would expect with no dark matter in mind.
>There are no confirmed detection...
So is it fair to say, that the "true nature" of dark matter is entirely unknown and pretty much based on educated guesses?
>there are limits on how much it can interact with itself
Exactly. But why? It already seems weird to me that it only interacts through gravity, but then it doesnt interact with itself? Does it have mass? What stops it from forming planet like objects?
>Dark matter in the solar system isn't expected
Well, it was expected around our system at least. I know it doesnt play a big part on a solar system scale.
But I read about observations of our "neighborhood", that mapped close stars and clouds. The mass distribution didnt leave room for dark matter. But maybe I'm a slowpoke here and dont know about more recent studies and as you said, its hard to detect close dark matter anyway.
How much optimism is reasonable when it comes to the "demystification" of dark matter? Will we ever fully understand it or are there problems that go beyond present day technological shortcomings?
>>8181427
If I'm not wrong my hypothesis will emerge from normal calculation once physics fixes the light cone problem, and yes it is a problem. You can't just assign a new flat spacetime speed of light constant for curved spacetime and insist that nothing has changed in the metric.
>>8176567
Why couldn't that be like a Dyson """sphere""" or something.
>>8181436
>are there problems that go beyond present day technological shortcomings?
Why did Newton invent Calculus?
>>8181499
Calculations are half the battle. You need experimental confirmation.
>>8181436
>Like computer simulations? Arent they based on the data we already have?
No, it depends what you base your simulation on. Back in the late 80's when people started doing cosmological simulations we didn't have really data on the CMB for example to use as initial conditions. In the case of cold dark matter simulations it was shown that from simple initial conditions (Gaussian fluctuations from inflation) NFW halos would collapse. These were dark matter only simulations, they didn't incude what we observe as galaxies. It's just initial conditions and gravity. In modern times more complicated simulations which include normal matter are based on more data but NFW profiles don't require data.
>So is it fair to say, that the "true nature" of dark matter is entirely unknown and pretty much based on educated guesses?
There is a long list of things we know it isn't. The constraints are pretty certain, what it really is isn't known. From astronomy it's rather difficult to test different models, that's largely up to the particle physicists.
>Exactly. But why? It already seems weird to me that it only interacts through gravity, but then it doesnt interact with itself? Does it have mass? What stops it from forming planet like objects?
Planets exist because the gravitational force can be balanced by electromagnetic forces. If we believe our particle doesn't interact that way (the common belife), then it can never be a planet, it would just continue to collapse. Planets form because of friction in planetary disks allows for particles to loose energy and move inward, in cases where there is no friction (like non-interactive dark matter) the collapse is very slow on small scales.
cont...
>>8181436
>>8181507
>I know It doesn't play a big part on a solar system scale.
I should be more specific, it's negligible but probably there.
>The mass distribution didnt leave room for dark matter.
Which is why it is controversial somewhat, people have got conflicting results. GAIA will give us the full story in a few years.
>How much optimism is reasonable when it comes to the "demystification" of dark matter?
Cosmologists largely aren't that optimistic about finding out what it is anytime soon. It would be great but particle physics is restricted to parameter spaces. Something could come out of strong lensing but nobody is holding their breath.
Dark energy on the other hand is a better bet. The observations to constrain it are much more straight forward. Dozens of experiments are underway now or in prep (eBOSS, HETDEX, DES, KIDS, DESI, LSST, Euclid, WFIRST, SKA...) to try to figure out if it's a modification to gravity or a property of spacetime.
>>8181468
That's not a hypothesis then, it's huge towering assumption.
And no, we've established you didn't convince anyone of your problem.
>>8181485
In a couple years people will measure the shadow.
In about a decade we will be able to measure general relativistic effects on the stars nearest the black hole to measure it's spin. That will tell us if it is a Kerr black hole which makes a specific prediction.
>>8181527
Towering assumption? Yeah. That tends to be a hypothesis. It's also not really my problem. Light cones in text books being wrong doesn't effect me on a day to day basis, but for the world of physics I submit that they pose a large problem.
>>8181527
So you're saying it could be aliens and we don't know until a decade from now when we have the technology to know for sure.
Do cosmologists take into account the fact that the sun's accelerating towards the singularity at the middle of our milky way?
The only reason I say that it's accelerating toward is because of our sun's orbital velocity shrinking and a juxtapositional analysis pertaining to how a marble will accelerate towards the center of a conical structure dependent of a shrinking orbital velocity.
Orbital velocity = sqrt(GMm/r^2)
With the sun losing trillions of grams per second.
Of course the marble experiment doesn't have a M.
Can anyone link me to gravitational field equations? Ones which elicit how orbits can exist?
>>8181569
>Damage control
Such a knee jerk reaction to anything not explicitly taught in your lectures. I'm not saying I believe in alein structures or that black matters don't exist, but to be so opposed to an idea without any evidence for or against it is kinda childish. I like to think /sci/ is an intelligent board and that kind of thinking only serves to dismantle any possible intelligent discussion. Try to be a little less pessimistic and a little more open minded haha!
>>8181569
>A hypothesis in science is testable, yours is not.
As testable as dark matter and testable in the same way as dark matter is the claim I aim to dispute.
>>8181591
Furthermore, again I submit I could be absolutely wrong about the hypothesis resulting in the dark matter gravity and the application of flat space null geodesics to the curved spherically symmetric Schwarzshchild would still be wrong.
>>8181577
>Damage control
No, that's called honestly. Can I prove it's not aliens? No. Did I claim it definitely wasn't aliens? No. You seem to be arguing with a strawman here.
Is it sensible to assume it's aliens? No. If it's a black hole it explains why we see them at the centers of most galaxies, as they sink to the bottom of the potential though dynamical friction. If it's aliens, we have no idea why they would select the center of our galaxy and the rest of the large galaxies we have surveyed. If it's a black hole it goes further and links our galaxy with active galaxies. If you look at the wider context, yes you can put some alien magic at the center of the milky way but it doesn't explain the wider observations.
>>8181591
>As testable as dark matter
Did your model also predict the CMB powerspecturm? No.
CDM is making quantified predictions and therefore it is testable.
>>8181602
>Did your model also predict the CMB powerspecturm? No
Might not predict but if it is modeled and the result does not match the observation then it's disproved.
Falsifiable.
>>8181602
Whatever dude I'm a marketing major idgaf
>>8173984
Guess what, just because you don't understand gravity, doesn't stop it from existing.
>>8181606
And you assume there is a single way to model this. A suggestion rarely turns into a model, particularly not when it's a vague as your suggestion.
Also not all models are falsifiable, like cosmological scalar fields.
If you build a model, that may be falsifiable but what you have here is not a hypothesis.
>>8181507
>In modern times more complicated simulations which include normal matter are based on more data but NFW profiles don't require data.
sure. I'm still a little bit sceptical when it comes to things we learned through simulations, but they certainly help.
>The constraints are pretty certain, what it really is isn't known.
Roger roger. Thats what I meant with "true nature"
>Planets exist because the gravitational force can be balanced by electromagnetic forces
Oh shit, kind of forgot that. Yeah, that was a stupid question. But how can it only interact gravitational? This is such a head scratcher for me.
> GAIA will give us the full story in a few years.
looking forward to this, too
>but nobody is holding their breath.
Thats the impression that I got, too. Was hoping you had some silver lining I missed.
>HETDEX
>WFIRST, SKA
Never heard of those. Looking into them now. Very interesting, thanks
What a time to be alive
>>8181577
>I know of no construction which could be under 45 AU in radius and yet weight 4 million solar masses. I don't really believe it's possible.
>Damage control
>knee jerk reaction
holy shit dude, he gave you an irrefutable argument as to why it is impossible.
Mcfucking kill yourself
>>8181569
lol moron
>>8180656
>The null geodesics of the E-F correspond to flat spacetime
Fucking what? The E-F coordinates are essentially the Schwarzschild metric with a modified time coordinate. To claim that they represent "flat spacetime" is utterly absurd and shows that you know incredibly little about GR.
>>8182343
The speed of light in the EF is not the same as the Schwarzschild. It corresponds to the speed of light infinitely distant to the metric, flat space.
>>8182482
>The speed of light in the EF is not the same as the Schwarzschild.
Yes, because you are using different coordinates.
>It corresponds to the speed of light infinitely distant to the metric, flat space.
Why is this such a problem for you? Einstein's equations are invariant w.r.t. coordinate transformations, so changing the coordinates doesn't change the physics. What you're essentially saying is "if we change the coordinates and don't correspondingly change our interpretation of the variables, then it looks wrong", which is true but doesn't invalidate EF coordinates in any way.
>>8182514
His argument is essentially that a certain coordinate system and reference frame are privileged. He doesn't know anything about general relativity besides the words he needs to convince himself he's right.
>>8182516
I am not arguing that. I am arguing that all reference frames will see the Speed of light reach zero at the event horizon.
>>8182514
It's a problem because the way the speed of light is reduced in a gravitational field is consistent and, as stated, reaches zero at the event horizon. The 'coordinate transformation' alters the null geodesics of the field, not merely coordinates, the actual speed of light is being altered to that of flat spacetime and being declared a new constant in a metric where it does not belong. This is not just a coordinate transformation it is a null geodesic alteration.
>>8183029
>I am arguing that all reference frames will see the Speed of light reach zero at the event horizon.
Including the frame of an in-falling observer? You know this violates a fundamental principle of relativity, right?
>>8183060
The in-falling observer is still in space governed by the curvature which is observed in the null geodesics and those converge and cut off at the event horizon.
You want to copy and paste geodesics from infinitely far away to apply in the field? I have no idea how one would go about doing so. The geodesics of the field are not arbitrary. They never have been.
>>8173984
All times were math proved something was happening but you couldn't understand it, it was because people were too stupid to understand it, math is always right even if it's hard to interpretate
>>8183698
The in-falling observer is an inertial frame, please stop embarrassing yourself.
>>8184479
It is not an inertial frame relative to the black hole. It's an accelerated frame. It's the metric of the black hole that we are talking about.
I can put a falling observer in a box in orbit or free fall over a black hole and the observer will think 'I am at rest.' But we are not talking about the observer. We are talking about the black hole. As soon as the observer looks out a window at the gravitating object that observer must realize 'I am being accelerated.'
>>8184723
Relative to the black hole the observer is in the state of constant acceleration. Acceleration has an upward limit: The speed of light. The observer cannot cross the event horizon because it is a reference frame equivalent to acceleration beyond the speed of light.
https://www.youtube.com/watch?v=AIUSi_dxM2c
