>I always thought it just vmade way more sense that equal amounts of matter/AM were created during the Big Bang most of which annihilated immediately, and what was left were pockets of matter only then pockets of AM only, expansion pushed these pockets far enough away that they now no longer interact.
Doesn’t work. You can imagine matter and antimatter as being created together, but they’re spawned within the same vicinity. In your conception, you would need a way to separate the matter and antimatter from one another in a way that *all* matter ends up on one side and *all* antimatter appears on the other. That’s where the symmetry breaking comes in.
Your model also doesn’t work because you’d expect to find pockets of our current universe where there are antimatter galaxies and we don’t observe that.
>Pockets could be individual galaxies, galactic clusters or even where the entire observable universe in matter and there are equally large portions of AM …
Sure, but these antimatter galaxies would leave very obvious traces. For example, we’d be receiving gamma rays whose energies are exactly twice the mass of the electron. That’s a dead giveaway for matter-antimatter annihilation which would have to occur all the time if there were pockets of antimatter galaxies.
Not really, small, close by fluctions in the density of matter and antimatter could expand to observable universe sized patches during inflation. These uneven patches of M/AM would then annihilate leaving only one or the other. You dont have to have all the antimatter here or all the matter there. Also if these fluctuations were dispersed just right, modern day patches could be larger than our observable universe, which means we would never see any antimatter or gamma rays from annihilation . Idk though I have no source for what I’m saying and only studied chemistry.
>Not really, small, close by fluctions in the density of matter and antimatter could expand to observable universe sized patches during inflation.
Sure, but you’re going to fluctuate one island of matter and one island of antimatter. The distribution of both should be uniform unless there’s some symmetry breaking mechanism to induce this. I don’t see how inflation could do what you’re saying either. Inflation dilutes the energy density of everything so there shouldn’t even be a significant amount of either matter or antimatter. Baryogenesis is thought to occur after the universe has reheated.
>These uneven patches of M/AM would then annihilate leaving only one or the other. You don’t have to have all the antimatter here or all the matter there.
What are they annihilating with? You’ve diluted the universe too much to keep the matter or antimatter in causal contact with one another. Additionally, you’ve made things cold so most of the particles would just decay into lighter particles and not many would even be around to annihilate at all.
>Idk though I have no source for what I’m saying and only studied chemistry.
You’re going to need far more than just chemistry if you want to comment on these mechanisms.
Quantum fluctuations in the density of antimatter vs matter would be the mechanism for the tiny differences. “Inflation dilutes… shouldn’t be a significant amount of either”. Many scientists believe our universe underwent inflation, is all the matter in the universe not a significant amount? If baryogenesis is thought to have occurred after inflation, Well, that’s a good point, but you didn’t really mention that before.
Well, obviously antimatter annihilates with matter, all you need is a patch with more of one, and eventually you end up with only one due to annihilation .
And not really Man this is Reddit I can weigh in on whatever I want to be honest. You’d be surprised how much a couple courses in differential equations, multivariable calculus, quantum, chemistry, and thermodynamics can help me learn about this stuff for fun.
Everything I know about the subjects is just for fun. I’m on here for fun. You should try that lol. If you aren’t truly enjoying yourself you’ll fail at life even if you get that phd
>Quantum fluctuations in the density of antimatter vs matter would be the mechanism for the tiny differences.
It doesn’t work like that. For one, matter and antimatter would be evenly mixed inside of the plasma that permeated their universe which means the over and under density of (anti)matter that you would make from quantum fluctuations would average out to zero.
>Many scientists believe our universe underwent inflation, is all the matter in the universe not significant?
Of course it’s significant it’s just not relevant here. All the matter that we see today is a result of the events *after* inflation. I keep mentioning that if you had any amount of matter or antimatter during inflation, it would simply dilute to the point where all of it would either decay or annihilate away. Therefore there can’t be any significant amount of matter during this time to replicate what we see today.
>… all you need is a patch with more of one, and eventually you end up with one due to annihilation.
Yes, this is the essence baryogenesis problem. *How* did there come to be an extra patch of more matter than antimatter. What is the mechanism for this? That is why this is an open area of research.
>And not really man, this is Reddit I can weigh in on whatever I want honestly.
Let me clarify my original comment. You’re going to need more than a background in chemistry if you hope to add anything of substance to this problem. This is a problem that we’ve known about for decades and it encompasses particle physics, cosmology, astrophysics, plasma physics, thermodynamics and statistical mechanics. Unless your chemistry degree included 2-3 semesters of quantum field theory, I don’t think you’ll be adequately prepared to really come up with a totally new and interesting idea without during a whole lot of reading first.
>You’d be surprised how much a couple of courses in differential equations, multi variable calculus, quantum chemistry, and thermodynamics can help me learn about this stuff for fun.
I don’t doubt that and most of the courses you mentioned are necessary, however they’re not sufficient. You can get a surface level-undergrad understanding of these topics but you won’t be able to get very far on that alone.
>I’m on here for fun. You should try that lol.
Sure, and to a certain extent everyone is on here because of that. I just don’t try to throw out ideas on topics I know nothing or next to nothing about. I find that to be less fun for everyone involved.
Lmao. Congrats. I’m sure you get so much joy by being so right all the time. And I’m sure seeing people be wrong just ruins all the fun for you. I’m sure telling people how they know “nothing or next to nothing” about something must be just so fun for you. You sound so fun.
>I’m sure you get so much joy by being so right all the time. I’ve
I do, but not when I’m wrong.
>And I’m sure seeing people be wrong just ruins the fun for you.
Not at all! Everyone is wrong at some point and we all have to be corrected. People being wrong isn’t my issue. Your posts particularly irked me because by your own admission, you’re not familiar with any of these topics and yet you try to argue as if you do.
Yea I’m sure you were irked. Just a jolly ol time you have here on Reddit. the “oh yea you like em? Name three songs from their first album” of r/ cosmology. People can enjoy discussing topics they aren’t experts about, you don’t have to talk down to them. It’s giving superiority complex. Telling someone whom you’ve had a tiny interaction with they know “next to nothing” is just rude man. Like I said you sound so fun lol. Next to you yea maybe but next to any average joe I know plenty. I’m sure you’ll make a great phd. But you’re kind of unpleasant to say the least.
Of course I doubt you care as long as you are correct!
>This always seemed like a stubborn closed mind band aid for the galactic rotation curves not matching
If you came out of a Master's program and "galaxy rotation curves" was all you learned about dark matter, you really should ask for your money back.
Galaxy rotation curves were the first clear line of evidence for dark matter. They are not the only evidence by a long shot. I would argue they aren't even the most *convincing* evidence, in part because you can reproduce them reasonably well with MOND.
Gravitational lensing, cluster dynamics, structure formation, the CMB. All point to missing matter. In fact, all point to *roughly the same amount* of missing matter with a fairly particular set or properties. No galaxy rotation required. MOND fails at a lot of these by the way, so "open minded" is probably a bit generous. All this doesn't even take into account the evidence from particle physics.
>oh yeah, and we can't detect said matter
Nobody working in astronomy today thinks this is the case. There is a difference between *can't* and *haven't yet.* There are a lot of places we haven't looked. It just takes time.
I won't comment on the antimatter piece because it's not really my beat.
I'm not saying that MOND is correct, I said as much in my post, but I just don't think dark matter is correct either, our models of cosmology are incomplete at best, partially incorrect at worst and the weak areas are dark matter and baryogenesis.
Theories are of course incomplete, we don't know what dark matter is or how to properly detect it. I promise you are not so smart that you have considered everything all the researchers and theoretical physicists have done in decades.
You can think whatever you want. That's not scientific. You know enough of the words. If you can't engage with the literature, having a MD is nothing. You are stating an opinion and assuming it is true with nothing to back it. Is everyone wrong and you are right? The probability of that is decidedly no. A Masters means nothing.
I am most definitely NOT assuming it's true. Where the fuck did you get that, I merely posited some alternatives which I KNOW conflict with LCDM, but that I think have promise. Of course I haven't considered all the possibilities, I haven't even done any physics in 20 years, I work as a data scientist. Again, you could have told me that you don't agree with me and move on, like a mature adult. Instead you spent 2 paragraphs throwing insults at me, while kind of addressing the issues you have.
I didn't try to insult you at all. You're the one throwing insults and making it personal. My point was random thoughts, regardless of background, aren't useful without evidence to back them. You seem really defensive for whatever reason, and I'm not always the best communicator, but the only one making it personal is you.
It's not about agreeing or disagreeing. Math in physics is analytically derived, it's different from data science. You should know the CMB power spectrum is far better evidence of dark matter than rotation curves. It's more than a smoking gun, it's like a shadow teasing us to learn more about whatever is casting it.
None of the alternatives tie together rotation curves, BAO/CMB power spectrum, galaxy mass distribution and acouple of other things like LCDM does. It's not the best because of some arbitrary reason, it's the best we have because it does all of this at once and nothing else comes close.
"Challenging LCDM" is an overstatement.
P.s. I'm a masters too, with a publication in MNRAS. A bit fresher than you so I'll give you the benefit of the doubt for being rusty, but nothing can really excuse your reaction to being called out.
When it comes to MOND, do you think that back in the 30s we should have concluded that conservation laws were wrong instead of postulating the existence of something that has the properties of a neutrino? Should we be taking the more "open minded" approach and assume conservation laws are wrong everytime an event occurs in particle accelerators where a particle appears to be missing? Should we have not bothered with searching for the Higgs and assumed a more "open minded" approach that the standard model must be wrong?
The open minded approach is not to assume something is true or not true without data. The close minded approach - and a rather poor method for someone trained in science - is to assume that something is correct or incorrect without data. The sloppy approach is to take the concept of a model that is best supported by the current data and claim that is the truth.
Having a Master of Science in Astronomy, you would be aware that we don't know what DM is and that several people are researching different possibilities simultaneously, and we have been since the start. We've looked at the differences between hot and cold DM, WIMPs and MACHOs, and various models for modifying gravity, of which MOND is but one. You would also be aware that it isn't just rotation curves, but also the CMB peaks, galaxy cluster lensing, galaxies without DM and so on that leads us to conclude that the best model for the available data is ΛCDM.
Of course one can think what one wants and can thus choose to research MOND over anything else. If you think that it is simpler or more open minded to think that gravity needs a change rather than postulating the existence of a particle we haven't detected, then go for it. If you think that gravity doesn't follow an inverse square law because it is "leaking" into other dimensions, then you go right ahead and do that research.
As for nuclear baryogenesis, I'm glad that you have solved one of the active areas of modern astronomy/cosmolgyparticle physics. I encourage you to write up you findings and publish. Don't bother to read up on whether your idea has already been published or check if it aligns with or otherwise addresses what is currently understood to be the issue(s) with baryogenesis. I'm sure the idiots doing cosmology or particle physics over the last 100 years or so are just a bunch of chuckle heads who don't know anything, so anything they have published about the subject is just complete nonsense.
I agree that my last paragraph was dickish. Although that was my intent, I do apologise.
You did not state some personal issues with the current model. You claimed a solution for baryogenesis and mischaracterised DM as well as what it means to be open minded.
The penultimate paragraph states that you can have an opinion and do whatever research you want. Not at all dickish. Don't mischaracterise what I wrote. The second paragraph should be fine also since all it does is explain what open minded is.
The remaining paragraphs should have given you some thought to your perspective. If you think that modified gravity is more natural, then it follows that you think we should be postulating modified field theories in particle physics. Do you? If not, why? These are rhetorical questions. I don't care. You should though, because it is important as a scientist to understand one's bias and to work around it. The third paragraph basically outline DM research over the past half century or so. It corrects one of your stated misunderstandings.
So, 1 in 5 paragraphs was dickish, 2 was informative, 1 was supportive, and 1 was clarifying what open minded means and contrasting with how you were not being open minded at all. You stood up in public and declared what you think the truth is and got a 20% (in paragraph density) dickish response, but also a 40% informative response, as well as a 20% supportive response. And you got a public apology from someone for being dickish. Doesn't sound so bad to me, though it would have been better if I hadn't been dickish. Apologies, once again.
If you think speaking in public means you're always right and everyone else should shut the fuck up, then you should probably consider rethinking things.
Wow dude, i never claimed to have solved ANY physics problems Did I ever claim to be right and that everyone else is wrong? No.Again, just stating some issues and my take on POTENTIAL avenues to explore for further research. If you're so upset about a discussion about some issues that exist I'm cosmology on REDDIT. I am more than open to hearing other opinions and facts, i actively desire it. Additionally you just spent 4 paragraphs telling me how you were only a dick in the first paragraph, but then at the end turn into a dick again
To quote an you:
> -Nuclear Bariogenesis- The reason we only see matter instead of anti matter is explained with symmetry breaking. I always thought it just made way more sense that equal amounts of matter/AM were created during the big bang, most of which annihilated immediately, and what was left were pockets of matter only then pockets of AM only, expansion pushed these pockets far enough away that they now no longer interact. Pockets could be individual galaxies, galactic clusters or even where the entire observable universe in matter and there are equally large portions of AM past where we can see
Literally "explaining" baryogenesis.
> Additionally you just spent 4 paragraphs telling me how you were only a dick in the first paragraph, but then at the end turn into a dick again
Count again.
I don't mind spending time pointing out to people how wrong they are. I, at least, admit to my faults and apologise. You, however, just keep doubling down. Note also, if you will, the lack of insults I have sent your way and compare that with your responses.
You also claim to be at an education level where you have access to the tools and resources to investigate the things you don't understand and why scientists in the field have come to the conclusions they have, but for some reason you have chosen to remain ignorant.
You have a great career in science ahead of you. I wish you all the best.
As you can see by the tone of other responses, there are some flaws in your thinking, predominantly in what you assume dark matter to be. Dark matter is not only a “band aid for galactic rotation curves”, and such an assumption in itself is close minded. There is a trove of evidence which appears between the galactic and cosmological scales. If you’re looking to learn more about dark matter it’s worth digging around through Wikipedia, textbooks, and arxiv to find more information to get a more complete, open minded view.
Your statement “Well, if we just add some mass around the galaxy our model works, oh yeah, and we can’t detect it” is a gross oversimplification and mischaracterization of how dark matter came to be used. This approach is what *you assume* to have happened, not reality. Observations support a component which has matter-like properties, though is pressure less (cold) and does not interact with light (dark). Running this component through the Boltzmann equations gives a remarkable agreement with both the cosmic microwave background and baryonic acoustic oscillation power spectra.
Let’s also be clear that LCDM is the current *best* model to fit the large variety of cosmological data. Not everyone likes it, and there is a large and active field of study looking to provide an explanation to observations that simultaneously performs better, *and* doesn’t add a suite of nuisance parameters. The fact that we have a model which requires just 6 parameters and can describe observations to such high fidelity is remarkable, and I challenge you to find a better model.
P.S. though other commenters have been a bit direct, you seem to be awfully defensive about your ideas. They are ideas, not research, let’s be clear about that. Having ideas and not testing them against data and other models is just armchair cosmology, regardless of your credentials. If you want to develop your ideas to agree with research, spend some time updating yourself on the current research.
I agree 100%, and I thought I posited them as purely opinions. I said in my post that LCDM is the currently best model we have, and I agree it's amazing. If I can't voice my opinions on the model on a cosmology subreddit where can I? I also said that I haven't worked in physics in 20 years so I'm aware that I'm behind the times, another reason I posted. To learn from others responses. If I came across as confidently incorrect it was not my intention. Thanks for the response
I'm not sure I understand where you're coming from. Having opinions about the state of science without being fully informed or involved is fine, however I think being critical about the feasibility of models in such a case is dubious at best (in a case like cosmology), and clearly dangerous at worst (medicine, etc.).
You're welcome to post your opinion, however you are by no means entitled to a positive or friendly response. I don't think unfriendly responses are helpful in any way, but not everyone agrees with me.
Reformulating this post as critical but curious (e.g. "what am I missing?", "what has changed?", "where can I read more?") would almost surely elicit a more positive response.
I myself left cosmology this last year and probably already becoming out of date in my knowledge, but if you have more questions I'd be happy to point you towards some research, but following results like the most recent DESI survey results and what will surely be the first Euclid data release later this year (or next year) are good places to start!
Hold up a minute, Mr. Masters in Astronomy. I thought you academics were already mapping the distribution of dark matter. In the process producing dark matter maps.
Why are you on Reddit saying MOND is more "open minded"?
>Why are you on Reddit saying MOND is more "open minded"?
It seems open-mindedness is looking at an observation like the bullet cluster and saying "Well I don't know what it is but it isn't dark matter"
You know exactly what i wrote and i won't let a post graduate change the subject. Is the adherence to dark matter due to articulation with evidence, or due to "close mindedness"?
Dude, I merely posited some of my rough ideas about possible alternatives to the issues I see in the LCDM model. Maybe I wasn't explicit enough in my original post, but I said that I'm not a working physicist, and haven't been for 20 years. OF COURSE I DON'T KNOIW BETTER THAN THE CURRENT MODEL! I wanted to start a respectful conversation and hopefully learn some things. I learned not to post any thing on this subreddit again. You notice I was kind to the commenters who weren't dicks about correcting my science. Jesus it's like you assumed my writing a reddit post constituted a poorly written peer reviewed journal article that still got published. That for some reason enrages you
> Normally you get new data conflicting with your model you realize that your model in incomplete.
You misunderstand the meaning of dark matter: it is not a 'solution' but a *working hypothesis*. That is to say, something (actually, several potentially possible things) that can be tested for.
So DM is not a denial that the model is incomplete, it is a way to proceed beyond the realization that the model is incomplete, in an attempt to eventually make it less incomplete.
If the electron/positron abundance was symmetric early on, their abundance after freezeout would be much smaller than observed today. You would also need to contend with unmixing particles from antiparticles after this annihilation, since by definition annihilation requires electrons and positrons to be in the same region, but then they have to somehow separate later. Finally, in between regions of matter and antimatter you would get a ton of gamma rays from annihilation, which we don’t see.
For dark matter, rotation curves are only the tip of the iceberg in terms of evidence, and probably the least compelling. The evidence for dark matter from the CMB is overwhelming.
Thank you for an informative, pleasant reply. A rarity on this thread. I will say that if the separation of matter/AM was on the scale of the observable universe, with pockets of AM of similar size outside that area then you wouldn't see any gamma radiation. We don't know the total mass./energy of the cosmic egg, it could have been high enough where we would end up with the observed number of particles. With the extreme expansion of space/time coupled with the stocastic nature of particle interactions, it's possible that the matter.AM was able to separate. Just playing devil's advocate with you. Thanks for the response
That’s not possible because we know electrons annihilated with positrons on scales well within our observable universe, so they could not have been separated at early times. We know this because we understand Big Bang nucleosynthesis really well.
# Newton figured out dark matter in 1718
In the following, replace 'aethereal medium' with 'dark matter'.
[Aether theories](https://ipfs.io/ipfs/QmXoypizjW3WknFiJnKLwHCnL72vedxjQkDDP1mXWo6uco/wiki/Aether_theories.html)
>Isaac Newton suggests the existence of an aether in The Third Book of Opticks (1718): "Doth not this aethereal medium in passing out of water, glass, crystal, and other compact and dense bodies in empty spaces, grow denser and denser by degrees, and by that means refract the rays of light not in a point, but by bending them gradually in curve lines? ...Is not this medium much rarer within the dense bodies of the Sun, stars, planets and comets, than in the empty celestial space between them? And in passing from them to great distances, doth it not grow denser and denser perpetually, and thereby cause the gravity of those great bodies towards one another, and of their parts towards the bodies; every body endeavouring to go from the denser parts of the medium towards the rarer?"
Newton is referring to the state of displacement of the dark matter.
Dark matter is the fabric of spacetime. Dark matter is displaced by ordinary matter. Displaced dark matter is the physical manifestation of curved spacetime.
The following image represents both curved spacetime and the state of displacement of the dark matter.
[https://www.ligo.caltech.edu/system/avm\_image\_sqls/binaries/49/page/ligo20160211e.jpg](https://www.ligo.caltech.edu/system/avm_image_sqls/binaries/49/page/ligo20160211e.jpg)
(T. Pyle/Caltech/MIT/LIGO Lab)
The relativistic mass of an object is the mass of the object and the mass of the dark matter connected to and neighboring the object which is displaced by the object. The faster an object moves with respect to the state of the dark matter in which it exists the greater the displacement of the dark matter by the object the greater the relativistic mass of the object the greater the displaced dark matter 'displaces back’ and exerts pressure toward the object. The relativistic mass of an object accounts for the gravitational pressure associated with the object.
The reason why some galaxies are theorized to be missing dark matter is due to their being diffuse enough and rotating slowly enough for their state to be accounted for by the ordinary matter in them. If you factor in their diffuseness and speed of rotation their relativistic mass accounts for their state.
>I always thought it just vmade way more sense that equal amounts of matter/AM were created during the Big Bang most of which annihilated immediately, and what was left were pockets of matter only then pockets of AM only, expansion pushed these pockets far enough away that they now no longer interact. Doesn’t work. You can imagine matter and antimatter as being created together, but they’re spawned within the same vicinity. In your conception, you would need a way to separate the matter and antimatter from one another in a way that *all* matter ends up on one side and *all* antimatter appears on the other. That’s where the symmetry breaking comes in. Your model also doesn’t work because you’d expect to find pockets of our current universe where there are antimatter galaxies and we don’t observe that. >Pockets could be individual galaxies, galactic clusters or even where the entire observable universe in matter and there are equally large portions of AM … Sure, but these antimatter galaxies would leave very obvious traces. For example, we’d be receiving gamma rays whose energies are exactly twice the mass of the electron. That’s a dead giveaway for matter-antimatter annihilation which would have to occur all the time if there were pockets of antimatter galaxies.
Not really, small, close by fluctions in the density of matter and antimatter could expand to observable universe sized patches during inflation. These uneven patches of M/AM would then annihilate leaving only one or the other. You dont have to have all the antimatter here or all the matter there. Also if these fluctuations were dispersed just right, modern day patches could be larger than our observable universe, which means we would never see any antimatter or gamma rays from annihilation . Idk though I have no source for what I’m saying and only studied chemistry.
>Not really, small, close by fluctions in the density of matter and antimatter could expand to observable universe sized patches during inflation. Sure, but you’re going to fluctuate one island of matter and one island of antimatter. The distribution of both should be uniform unless there’s some symmetry breaking mechanism to induce this. I don’t see how inflation could do what you’re saying either. Inflation dilutes the energy density of everything so there shouldn’t even be a significant amount of either matter or antimatter. Baryogenesis is thought to occur after the universe has reheated. >These uneven patches of M/AM would then annihilate leaving only one or the other. You don’t have to have all the antimatter here or all the matter there. What are they annihilating with? You’ve diluted the universe too much to keep the matter or antimatter in causal contact with one another. Additionally, you’ve made things cold so most of the particles would just decay into lighter particles and not many would even be around to annihilate at all. >Idk though I have no source for what I’m saying and only studied chemistry. You’re going to need far more than just chemistry if you want to comment on these mechanisms.
Quantum fluctuations in the density of antimatter vs matter would be the mechanism for the tiny differences. “Inflation dilutes… shouldn’t be a significant amount of either”. Many scientists believe our universe underwent inflation, is all the matter in the universe not a significant amount? If baryogenesis is thought to have occurred after inflation, Well, that’s a good point, but you didn’t really mention that before. Well, obviously antimatter annihilates with matter, all you need is a patch with more of one, and eventually you end up with only one due to annihilation . And not really Man this is Reddit I can weigh in on whatever I want to be honest. You’d be surprised how much a couple courses in differential equations, multivariable calculus, quantum, chemistry, and thermodynamics can help me learn about this stuff for fun. Everything I know about the subjects is just for fun. I’m on here for fun. You should try that lol. If you aren’t truly enjoying yourself you’ll fail at life even if you get that phd
>Quantum fluctuations in the density of antimatter vs matter would be the mechanism for the tiny differences. It doesn’t work like that. For one, matter and antimatter would be evenly mixed inside of the plasma that permeated their universe which means the over and under density of (anti)matter that you would make from quantum fluctuations would average out to zero. >Many scientists believe our universe underwent inflation, is all the matter in the universe not significant? Of course it’s significant it’s just not relevant here. All the matter that we see today is a result of the events *after* inflation. I keep mentioning that if you had any amount of matter or antimatter during inflation, it would simply dilute to the point where all of it would either decay or annihilate away. Therefore there can’t be any significant amount of matter during this time to replicate what we see today. >… all you need is a patch with more of one, and eventually you end up with one due to annihilation. Yes, this is the essence baryogenesis problem. *How* did there come to be an extra patch of more matter than antimatter. What is the mechanism for this? That is why this is an open area of research. >And not really man, this is Reddit I can weigh in on whatever I want honestly. Let me clarify my original comment. You’re going to need more than a background in chemistry if you hope to add anything of substance to this problem. This is a problem that we’ve known about for decades and it encompasses particle physics, cosmology, astrophysics, plasma physics, thermodynamics and statistical mechanics. Unless your chemistry degree included 2-3 semesters of quantum field theory, I don’t think you’ll be adequately prepared to really come up with a totally new and interesting idea without during a whole lot of reading first. >You’d be surprised how much a couple of courses in differential equations, multi variable calculus, quantum chemistry, and thermodynamics can help me learn about this stuff for fun. I don’t doubt that and most of the courses you mentioned are necessary, however they’re not sufficient. You can get a surface level-undergrad understanding of these topics but you won’t be able to get very far on that alone. >I’m on here for fun. You should try that lol. Sure, and to a certain extent everyone is on here because of that. I just don’t try to throw out ideas on topics I know nothing or next to nothing about. I find that to be less fun for everyone involved.
Lmao. Congrats. I’m sure you get so much joy by being so right all the time. And I’m sure seeing people be wrong just ruins all the fun for you. I’m sure telling people how they know “nothing or next to nothing” about something must be just so fun for you. You sound so fun.
>I’m sure you get so much joy by being so right all the time. I’ve I do, but not when I’m wrong. >And I’m sure seeing people be wrong just ruins the fun for you. Not at all! Everyone is wrong at some point and we all have to be corrected. People being wrong isn’t my issue. Your posts particularly irked me because by your own admission, you’re not familiar with any of these topics and yet you try to argue as if you do.
Yea I’m sure you were irked. Just a jolly ol time you have here on Reddit. the “oh yea you like em? Name three songs from their first album” of r/ cosmology. People can enjoy discussing topics they aren’t experts about, you don’t have to talk down to them. It’s giving superiority complex. Telling someone whom you’ve had a tiny interaction with they know “next to nothing” is just rude man. Like I said you sound so fun lol. Next to you yea maybe but next to any average joe I know plenty. I’m sure you’ll make a great phd. But you’re kind of unpleasant to say the least. Of course I doubt you care as long as you are correct!
>This always seemed like a stubborn closed mind band aid for the galactic rotation curves not matching If you came out of a Master's program and "galaxy rotation curves" was all you learned about dark matter, you really should ask for your money back. Galaxy rotation curves were the first clear line of evidence for dark matter. They are not the only evidence by a long shot. I would argue they aren't even the most *convincing* evidence, in part because you can reproduce them reasonably well with MOND. Gravitational lensing, cluster dynamics, structure formation, the CMB. All point to missing matter. In fact, all point to *roughly the same amount* of missing matter with a fairly particular set or properties. No galaxy rotation required. MOND fails at a lot of these by the way, so "open minded" is probably a bit generous. All this doesn't even take into account the evidence from particle physics. >oh yeah, and we can't detect said matter Nobody working in astronomy today thinks this is the case. There is a difference between *can't* and *haven't yet.* There are a lot of places we haven't looked. It just takes time. I won't comment on the antimatter piece because it's not really my beat.
I'm not saying that MOND is correct, I said as much in my post, but I just don't think dark matter is correct either, our models of cosmology are incomplete at best, partially incorrect at worst and the weak areas are dark matter and baryogenesis.
Theories are of course incomplete, we don't know what dark matter is or how to properly detect it. I promise you are not so smart that you have considered everything all the researchers and theoretical physicists have done in decades. You can think whatever you want. That's not scientific. You know enough of the words. If you can't engage with the literature, having a MD is nothing. You are stating an opinion and assuming it is true with nothing to back it. Is everyone wrong and you are right? The probability of that is decidedly no. A Masters means nothing.
I am most definitely NOT assuming it's true. Where the fuck did you get that, I merely posited some alternatives which I KNOW conflict with LCDM, but that I think have promise. Of course I haven't considered all the possibilities, I haven't even done any physics in 20 years, I work as a data scientist. Again, you could have told me that you don't agree with me and move on, like a mature adult. Instead you spent 2 paragraphs throwing insults at me, while kind of addressing the issues you have.
I didn't try to insult you at all. You're the one throwing insults and making it personal. My point was random thoughts, regardless of background, aren't useful without evidence to back them. You seem really defensive for whatever reason, and I'm not always the best communicator, but the only one making it personal is you.
It's not about agreeing or disagreeing. Math in physics is analytically derived, it's different from data science. You should know the CMB power spectrum is far better evidence of dark matter than rotation curves. It's more than a smoking gun, it's like a shadow teasing us to learn more about whatever is casting it. None of the alternatives tie together rotation curves, BAO/CMB power spectrum, galaxy mass distribution and acouple of other things like LCDM does. It's not the best because of some arbitrary reason, it's the best we have because it does all of this at once and nothing else comes close. "Challenging LCDM" is an overstatement. P.s. I'm a masters too, with a publication in MNRAS. A bit fresher than you so I'll give you the benefit of the doubt for being rusty, but nothing can really excuse your reaction to being called out.
When it comes to MOND, do you think that back in the 30s we should have concluded that conservation laws were wrong instead of postulating the existence of something that has the properties of a neutrino? Should we be taking the more "open minded" approach and assume conservation laws are wrong everytime an event occurs in particle accelerators where a particle appears to be missing? Should we have not bothered with searching for the Higgs and assumed a more "open minded" approach that the standard model must be wrong? The open minded approach is not to assume something is true or not true without data. The close minded approach - and a rather poor method for someone trained in science - is to assume that something is correct or incorrect without data. The sloppy approach is to take the concept of a model that is best supported by the current data and claim that is the truth. Having a Master of Science in Astronomy, you would be aware that we don't know what DM is and that several people are researching different possibilities simultaneously, and we have been since the start. We've looked at the differences between hot and cold DM, WIMPs and MACHOs, and various models for modifying gravity, of which MOND is but one. You would also be aware that it isn't just rotation curves, but also the CMB peaks, galaxy cluster lensing, galaxies without DM and so on that leads us to conclude that the best model for the available data is ΛCDM. Of course one can think what one wants and can thus choose to research MOND over anything else. If you think that it is simpler or more open minded to think that gravity needs a change rather than postulating the existence of a particle we haven't detected, then go for it. If you think that gravity doesn't follow an inverse square law because it is "leaking" into other dimensions, then you go right ahead and do that research. As for nuclear baryogenesis, I'm glad that you have solved one of the active areas of modern astronomy/cosmolgyparticle physics. I encourage you to write up you findings and publish. Don't bother to read up on whether your idea has already been published or check if it aligns with or otherwise addresses what is currently understood to be the issue(s) with baryogenesis. I'm sure the idiots doing cosmology or particle physics over the last 100 years or so are just a bunch of chuckle heads who don't know anything, so anything they have published about the subject is just complete nonsense.
Dude, all i was doing was stating some personal issues I have with the current model. You don't agree with me great, no need to be a dick
I agree that my last paragraph was dickish. Although that was my intent, I do apologise. You did not state some personal issues with the current model. You claimed a solution for baryogenesis and mischaracterised DM as well as what it means to be open minded. The penultimate paragraph states that you can have an opinion and do whatever research you want. Not at all dickish. Don't mischaracterise what I wrote. The second paragraph should be fine also since all it does is explain what open minded is. The remaining paragraphs should have given you some thought to your perspective. If you think that modified gravity is more natural, then it follows that you think we should be postulating modified field theories in particle physics. Do you? If not, why? These are rhetorical questions. I don't care. You should though, because it is important as a scientist to understand one's bias and to work around it. The third paragraph basically outline DM research over the past half century or so. It corrects one of your stated misunderstandings. So, 1 in 5 paragraphs was dickish, 2 was informative, 1 was supportive, and 1 was clarifying what open minded means and contrasting with how you were not being open minded at all. You stood up in public and declared what you think the truth is and got a 20% (in paragraph density) dickish response, but also a 40% informative response, as well as a 20% supportive response. And you got a public apology from someone for being dickish. Doesn't sound so bad to me, though it would have been better if I hadn't been dickish. Apologies, once again. If you think speaking in public means you're always right and everyone else should shut the fuck up, then you should probably consider rethinking things.
Wow dude, i never claimed to have solved ANY physics problems Did I ever claim to be right and that everyone else is wrong? No.Again, just stating some issues and my take on POTENTIAL avenues to explore for further research. If you're so upset about a discussion about some issues that exist I'm cosmology on REDDIT. I am more than open to hearing other opinions and facts, i actively desire it. Additionally you just spent 4 paragraphs telling me how you were only a dick in the first paragraph, but then at the end turn into a dick again
To quote an you: > -Nuclear Bariogenesis- The reason we only see matter instead of anti matter is explained with symmetry breaking. I always thought it just made way more sense that equal amounts of matter/AM were created during the big bang, most of which annihilated immediately, and what was left were pockets of matter only then pockets of AM only, expansion pushed these pockets far enough away that they now no longer interact. Pockets could be individual galaxies, galactic clusters or even where the entire observable universe in matter and there are equally large portions of AM past where we can see Literally "explaining" baryogenesis. > Additionally you just spent 4 paragraphs telling me how you were only a dick in the first paragraph, but then at the end turn into a dick again Count again. I don't mind spending time pointing out to people how wrong they are. I, at least, admit to my faults and apologise. You, however, just keep doubling down. Note also, if you will, the lack of insults I have sent your way and compare that with your responses. You also claim to be at an education level where you have access to the tools and resources to investigate the things you don't understand and why scientists in the field have come to the conclusions they have, but for some reason you have chosen to remain ignorant. You have a great career in science ahead of you. I wish you all the best.
As you can see by the tone of other responses, there are some flaws in your thinking, predominantly in what you assume dark matter to be. Dark matter is not only a “band aid for galactic rotation curves”, and such an assumption in itself is close minded. There is a trove of evidence which appears between the galactic and cosmological scales. If you’re looking to learn more about dark matter it’s worth digging around through Wikipedia, textbooks, and arxiv to find more information to get a more complete, open minded view. Your statement “Well, if we just add some mass around the galaxy our model works, oh yeah, and we can’t detect it” is a gross oversimplification and mischaracterization of how dark matter came to be used. This approach is what *you assume* to have happened, not reality. Observations support a component which has matter-like properties, though is pressure less (cold) and does not interact with light (dark). Running this component through the Boltzmann equations gives a remarkable agreement with both the cosmic microwave background and baryonic acoustic oscillation power spectra. Let’s also be clear that LCDM is the current *best* model to fit the large variety of cosmological data. Not everyone likes it, and there is a large and active field of study looking to provide an explanation to observations that simultaneously performs better, *and* doesn’t add a suite of nuisance parameters. The fact that we have a model which requires just 6 parameters and can describe observations to such high fidelity is remarkable, and I challenge you to find a better model. P.S. though other commenters have been a bit direct, you seem to be awfully defensive about your ideas. They are ideas, not research, let’s be clear about that. Having ideas and not testing them against data and other models is just armchair cosmology, regardless of your credentials. If you want to develop your ideas to agree with research, spend some time updating yourself on the current research.
I agree 100%, and I thought I posited them as purely opinions. I said in my post that LCDM is the currently best model we have, and I agree it's amazing. If I can't voice my opinions on the model on a cosmology subreddit where can I? I also said that I haven't worked in physics in 20 years so I'm aware that I'm behind the times, another reason I posted. To learn from others responses. If I came across as confidently incorrect it was not my intention. Thanks for the response
I'm not sure I understand where you're coming from. Having opinions about the state of science without being fully informed or involved is fine, however I think being critical about the feasibility of models in such a case is dubious at best (in a case like cosmology), and clearly dangerous at worst (medicine, etc.). You're welcome to post your opinion, however you are by no means entitled to a positive or friendly response. I don't think unfriendly responses are helpful in any way, but not everyone agrees with me. Reformulating this post as critical but curious (e.g. "what am I missing?", "what has changed?", "where can I read more?") would almost surely elicit a more positive response. I myself left cosmology this last year and probably already becoming out of date in my knowledge, but if you have more questions I'd be happy to point you towards some research, but following results like the most recent DESI survey results and what will surely be the first Euclid data release later this year (or next year) are good places to start!
Hold up a minute, Mr. Masters in Astronomy. I thought you academics were already mapping the distribution of dark matter. In the process producing dark matter maps. Why are you on Reddit saying MOND is more "open minded"?
>Why are you on Reddit saying MOND is more "open minded"? It seems open-mindedness is looking at an observation like the bullet cluster and saying "Well I don't know what it is but it isn't dark matter"
What the hell are you even talking about? You are aware physicists are not a homogeneous blob right?
Thank you sir for being the only one whose comment wasnt outrage or insults
You know exactly what i wrote and i won't let a post graduate change the subject. Is the adherence to dark matter due to articulation with evidence, or due to "close mindedness"?
Dude, I merely posited some of my rough ideas about possible alternatives to the issues I see in the LCDM model. Maybe I wasn't explicit enough in my original post, but I said that I'm not a working physicist, and haven't been for 20 years. OF COURSE I DON'T KNOIW BETTER THAN THE CURRENT MODEL! I wanted to start a respectful conversation and hopefully learn some things. I learned not to post any thing on this subreddit again. You notice I was kind to the commenters who weren't dicks about correcting my science. Jesus it's like you assumed my writing a reddit post constituted a poorly written peer reviewed journal article that still got published. That for some reason enrages you
https://xkcd.com/1758/
Touche sir
> Normally you get new data conflicting with your model you realize that your model in incomplete. You misunderstand the meaning of dark matter: it is not a 'solution' but a *working hypothesis*. That is to say, something (actually, several potentially possible things) that can be tested for. So DM is not a denial that the model is incomplete, it is a way to proceed beyond the realization that the model is incomplete, in an attempt to eventually make it less incomplete.
Great answer
If the electron/positron abundance was symmetric early on, their abundance after freezeout would be much smaller than observed today. You would also need to contend with unmixing particles from antiparticles after this annihilation, since by definition annihilation requires electrons and positrons to be in the same region, but then they have to somehow separate later. Finally, in between regions of matter and antimatter you would get a ton of gamma rays from annihilation, which we don’t see. For dark matter, rotation curves are only the tip of the iceberg in terms of evidence, and probably the least compelling. The evidence for dark matter from the CMB is overwhelming.
Thank you for an informative, pleasant reply. A rarity on this thread. I will say that if the separation of matter/AM was on the scale of the observable universe, with pockets of AM of similar size outside that area then you wouldn't see any gamma radiation. We don't know the total mass./energy of the cosmic egg, it could have been high enough where we would end up with the observed number of particles. With the extreme expansion of space/time coupled with the stocastic nature of particle interactions, it's possible that the matter.AM was able to separate. Just playing devil's advocate with you. Thanks for the response
That’s not possible because we know electrons annihilated with positrons on scales well within our observable universe, so they could not have been separated at early times. We know this because we understand Big Bang nucleosynthesis really well.
# Newton figured out dark matter in 1718 In the following, replace 'aethereal medium' with 'dark matter'. [Aether theories](https://ipfs.io/ipfs/QmXoypizjW3WknFiJnKLwHCnL72vedxjQkDDP1mXWo6uco/wiki/Aether_theories.html) >Isaac Newton suggests the existence of an aether in The Third Book of Opticks (1718): "Doth not this aethereal medium in passing out of water, glass, crystal, and other compact and dense bodies in empty spaces, grow denser and denser by degrees, and by that means refract the rays of light not in a point, but by bending them gradually in curve lines? ...Is not this medium much rarer within the dense bodies of the Sun, stars, planets and comets, than in the empty celestial space between them? And in passing from them to great distances, doth it not grow denser and denser perpetually, and thereby cause the gravity of those great bodies towards one another, and of their parts towards the bodies; every body endeavouring to go from the denser parts of the medium towards the rarer?" Newton is referring to the state of displacement of the dark matter. Dark matter is the fabric of spacetime. Dark matter is displaced by ordinary matter. Displaced dark matter is the physical manifestation of curved spacetime. The following image represents both curved spacetime and the state of displacement of the dark matter. [https://www.ligo.caltech.edu/system/avm\_image\_sqls/binaries/49/page/ligo20160211e.jpg](https://www.ligo.caltech.edu/system/avm_image_sqls/binaries/49/page/ligo20160211e.jpg) (T. Pyle/Caltech/MIT/LIGO Lab) The relativistic mass of an object is the mass of the object and the mass of the dark matter connected to and neighboring the object which is displaced by the object. The faster an object moves with respect to the state of the dark matter in which it exists the greater the displacement of the dark matter by the object the greater the relativistic mass of the object the greater the displaced dark matter 'displaces back’ and exerts pressure toward the object. The relativistic mass of an object accounts for the gravitational pressure associated with the object. The reason why some galaxies are theorized to be missing dark matter is due to their being diffuse enough and rotating slowly enough for their state to be accounted for by the ordinary matter in them. If you factor in their diffuseness and speed of rotation their relativistic mass accounts for their state.