Wouldn't this cause gravitational force to fall off with distance using something other than an inverse-square law? I think this explanation would be a better fit for the weak force than gravity for this reason. Thoughts?
More broadly: inverse-square behavior (Gravity, EM etc) strikes me as an intrinsic property of 3D geometry; more so of a tell of dimensionality than the magnitude of the force. (I believe the article is inferring higher dimensionality from relative magnitude, vice distance falloff)
Another possibility is if our brane has a lot of folds coming close/touching - that would make gravity there stronger like say that dark matter idea inducing rotation speed curve of the disk stars.
I think you're mixing up two different cases here: 1) Our established 3 dimensions are actually compact, i.e. loop around or hit a boundary somewhere. No multiverse here. 2) There are extra dimensions, meaning that for every point in that extra dimension there's another 3-dimensional universe as we know it.
Do they not loop? What other option is there? I assume you can't sail off the edge of the disk, so to speak.
Option 2: They go on forever without looping.
Option 3: They end - there is some kind of boundary to spacetime.
IIRC experimental gravity data rules out any compactified dimension bigger than 50μm, but a question I keep coming back to is "surely the pictures of atomic bonds taken by electron microscopes rules compactified dimensions larger than 1Å?"
Sometimes compactified dimensions are analogised to a straw: seen from a distance it seems one dimensional, up close (an ant's perspective) it's got one long dimension and one short dimension.
I don't know how far to take the analogy. It sounds like surely photons with wavelengths smaller than the compactified dimension would be likely to take a spiral path, looping around compact dimension n times for every m units of 3-space travelled, which would seem like they were mysteriously slow if you weren't expecting the compact dimension to exist.
I vaguely remember the idea of wavelength-dependent speed of light is a thing that's been ruled out by tests with supernova data, but not to what wavelength or sigma.
Because they can’t see above or below to the rest of the tube. They can only see a single infinitely thin slice of the tube.
An ℝ²-brane such as flatland existing in a ℝ³ bulk is different to an ℝ²⨯S¹.
If the S¹ part* is present in our universe to the degree that it can explain anything about gravity, it should also have an impact on everything else in the universe larger than the radius of the S¹ dimension's circumference.
* well, S^n ⨯ T^m, the version of string theory I hear most about has n+m = 6, but there are others, and this thread is a toy model where n=1, m=0
Edit: Apparently the U+1D54A character is stripped, so put a plain ASCII "S" back in.
Like literally in the middle of your sitting room. Isn’t it a known meme horror thing - monster slices from another dimension splicing across into ours as they move through their planes .
Basically it doesn’t happen but the dimensions do exist so they must be small.
Hence why we don’t bump into them.
In fact, they'd have to be so spread out that rotation curves remain flat past a million light years [1]. There seems to be no plausible particle dark matter distribution that can satisfy all of the necessary constraints at this point.
[1] https://tritonstation.com/2024/06/18/rotation-curves-still-f...
I'm not familiar with the topic. Did you have any particularly suspect assumptions in mind?
Perhaps there is a negative gravity outside of galaxies where space seems to bubble out of nowhere anyway and the universe is expanding.
This seems as an attempt to combine gravity with the standard model again, which in my very amateurish understanding comes with multiple extra dimensions anyway. Isn't the higgs field basically a recently discovered additional dimension already? Among the other forms of particles that can be seen as an excitation of fields that compose these dimensions.
But for extreme cases like neutron stars or black holes, we probably do need to combine these theories since gravity is a main reason these objects exist in the first place. And also isn't a curvature of space not already be an additional dimension as well? It would be mathematically as I understand it.
Nothing in nature prevents gravity from just being super weak. Some forces could just be super weak.
The unspoken premise of gravity being weaker than other forces is that all forces were unified at some point. So iff you assume all forces in nature were once one force, then gravity being weak is an anomaly.
Just adding more parameters to your theory will allow you to overfit the data better, but that does not mean you understand more about nature.
Think that you live on a line, and you see projections of a 2d object doing circles on top of you. You would see the shade moving and changing sizes in a non-explainable manner to you.
More anomalies: simply being near a large gravitational field alters the flow of time. Frame dragging around black holes (spacetime itself twists into a rotating spiral). The final parsec problem (co-orbiting black holes bleeding energy as gravitational waves). And don't forget the gravitational singularity of a black hole.
But perhaps the most important thing to know is that we've only just gained the ability to examine gravitational waves. Once we build more detectors (especially LISA), we'll probably discover a lot more is wrong with our understanding of gravity.
These are not really anomalies per se - they are predicted by the relatively well tested theory of GR and (except for the singularity part) also experimentally observable. They are weird from our point of view, but not weird to contemporary physics.
https://www.theguardian.com/science/2024/mar/09/controversia...
Explain for a layman? I don't know what it means for movement to not make sense.
In one sense this is a vindication of our application of the scientific method and the way we make theories: a bad theory wouldn't be able to be checked, whereas a good theory can make precise enough claims that when a limitation is found (such as when our predictions about reality do not match our observations) that the results of the check are clear.
We get a ball made up of something, and for some reason only it accelerates at 10m/s for no discernible reason.
They greatly simplify models, otherwise they’re too complicated to calculate.
So they simplify the data points, assume point particles, assume no interactions due to electromagnetism, no tidal locks, and Newtonian gravity instead of relativity.
And then it turns out galaxies sometimes rotate too quickly.
Yeah, no shit. If your data is known to be wrong and your model uses the wrong theory of gravity and makes known false simplifications it would be quite strange if it somehow did predict without some discrepancies
What's a good way for a layperson to tell if this is a new scientific consensus arrived at after hundreds of researchers come to the same conclusion or a breakthrough result that has shocked the entire research community?
A promising new theory should fit known observations, explain previously unexplained phenomenon, and predict something testable. That will be difficult to judge as a layperson.
> “The brane-bulk model is a speculative idea for sure, but a fun one.”
I feel like it’s communicated pretty clearly that it isn’t some breakthrough finding that everybody agrees on. You could google the mentioned researchers/theories and find out more information if you still weren’t sure.
The world we live in is crazy. To know such a thing so easily at an earlier time, would be unfathomable :)
This article brings up neutron stars being slightly larger than expected, but the reality is there's no real expected maximum mass for a neutron star - because the equation of state and physics for neutron star interiors is unknown. The spin, and magnetic field of a neutron star can also serve to increase the maximum mass of a neutron star, which are very hard to model as there are no analytic solutions to a spinning body (nor an oblate body)
There are too many approximations in the paper to even come close to saying that the brane model explains this better than standard physics, and there's no reason to think that this event isn't explainable by standard physics
Neutron Stars? Other Dimensions? This has GOT to be woke, right?
The level of flagging on HN lately is totally out of control.
And they complained that the woke were cancelling people...
Paul Dirac predicted antiparticles purely by mathematical intuition. It wasn't until later that the theory proved true, and he was recognized to be the genius that he was.
First comes the theory, then experiments are devised. Then physics gets updated.
I merely suggest these things, not because I have the math to understand how it would affect GR or QED, or even what experiments would be needed to verify them, but merely to plant the seeds of how things work to stimulate those who can do those things to think about what their ramifications might be.
That no one understands how these things can even be known, much less that they are true, is already known by me, but the truth is never beholden to the naysayers. I'm not a Boltzmann who was (sadly) bullied into suicide by the fools of his era. I don't really care if anyone believes what I say. I say these things because I love you all and maybe a few people will be stimulated to contemplate other avenues that may explain the as yet inexplicable.
And, really, y'all are out of ideas as to what or where dark matter or energy are anyway, so there is nothing for anyone to lose.
Put another way, Einstein knew what would happen to light that passed close to the sun (even though his calculations were off), but the naysayers were irrelevant, right? They, too, thought they already knew it all.
That's fair, but I didn't say that I could offer any of that. All I offered was an explanation of the situation, specifically with respect to why only 1/6th of the mass of the universe can be accounted for, yet has been calculated rather accurately by measuring the inertial forces of distant galaxies.
> They may be interesting to some people, but if you want to think about them as physics, you need to provide a prediction.
I'm sorry, but I don't need to do anything, and I couldn't even if I wanted to as it's way out of my area of expertise. I'm merely explaining the situation. It's up to actual physicists to figure out how this situation can be testable, if indeed it can be.
I'm also not putting any responsibility on anyone else. I shared these ideas with people who have no clue whatsoever where all this dark matter is. The universe itself provided this clue to y'all. I don't care if anyone believes it or tries to utilize it at all.
The reality is that with all major advancements in science, someone comes up with a "crazy" idea -- Boltzmann, Gaileo, Copernicus, Einstein, Newton -- and then theories are constructed around it, experiments are devised, and then the theories and experiments are iterated until the details are hammered out.
If I was a physicist, I would know that no one on Earth has a single clue where all this dark matter is, so maybe I would take a random "crazy" idea and stir it around in my head and see if it could be helpful, see if it could be used to tweak an equation or dynamical system description or something.
That's the extent of my thinking about this, and is the fullness of my purpose in my sharing this with y'all. That no one (or very, very few people) in science understands that this informatic universe can be queried directly means that I had no hopes of anything coming of this. I offered a gift and if no one is interested, I really don't care; I made a good intention, and tried to explain the situation as best I could. That is all I am capable of doing in this realm, so I'm at peace with the entire situation. No one here could possibly disappoint me because I expected nothing.
Peace be with you. I wish you the best of luck, success and happiness in your endeavors. I didn't mean to cause anyone here any consternation, but presenting ideas -- if one is honest about reality -- cannot possibly cause anything like that, any more than Boltzmann caused Lord Kelvin and his cohort to be a bunch of brutal bullies. The truth is the truth, and that is all that really matters, and we are all each free to go our own way, and treat others however we see fit. I hope I have treated you well; please forgive me if I have spoken harshly here, I didn't mean to.
My always welcoming new ideas means that I tend to share what I have learned without hesitation. Most people are too provincial to be open-minded enough to listen to foreign ideas with grace and either politely ignore them, or, better yet, see if they can be used to expand their worldview, in whatever dimension, pun appreciated.
I didn't realize you were are the authority.
Or is it that you don't realize that you're not the authority?
I know the answer to these questions, and why your ego is telling you what you are relaying to me.
You have nothing but weak ad hominems.
> You can’t post stuff on the internet comparing yourself and your ideas to great minds and then expect people to politely ignore them or see if they can be used to expand their world view.
I'm not comparing myself to great minds, I'm comparing our situations with respect to our respective status quos.
If someone were to present such ideas to me, I have no ego that would call them names and disregard their ideas out of hand. No, I would listen carefully and then decide whether their ideas were something that I should incorporate into my worldview. And I would damn sure make sure that I wasn't an asshole to them.
I don't expect anything, and I'm not going to re-read all I've written here, but I'm pretty sure I have explicitly laid that out.
> I pity you because you cannot see beyond this and will likely continue to reply anyone and everyone in the same way as long as they keep replying you.
I stopped pitying others once I stopped pitying myself 30 years ago; over time I replaced it with empathy and compassion and humble seeking. You literally have no idea the advantage that gives me over you. It is why I do not condescend to anyone. It is because I know that I am just a human being like everyone else, with my own foibles and failings, and, even if I'm better at some things than they are, I'm sure that they have things to teach me from their superior areas of expertise.
I reply to others in a uniform way because my worldview is the work of decades of work, my friend. That I love you more than you love me is why I am having this conversation with you.
> since you claim they suffer in ignorance that only you can provide.
Please don't put words in my mouth. I never said any such thing. What I provide is rare, especially here on HN, but you can find it elsewhere, you can even beg our Creator to give you the information directly as that is our highest human potential. The problem is that few people seek this kind of knowledge, and one cannot learn what one does not seek to learn.
> Compassion would dictate that you would strive for others to understand
You do not act like a person who has worked for decades to understand compassion.
You do not understand the universe, my friend. That's not condescending; that's just the plain fact of the matter.
My speaking of compassion makes many people angry. You should be asking me why that is the case, instead of telling me how much you know about something you are clearly not manifesting.
The truth is undefeatable, and my commitment to it is why I love you. And your refusal to admit that your lack of understanding is precisely why you are so angry with me explaining the truth of the matter to you.
If you are so superior in all these realms of knowledge, then why don't you just ignore me then? I know why you don't, my friend. The ego is a terrible thing and is ravaging the world in its idiotic self-righteous defense of itself. That's not me, brother. You see what you want to see when you could instead be seeing the truth. That attitude is epidemic on this Earth is is causing vast destruction and misery for many, many human beings.
It would be a lie to say that I don't know the truth of these matters, and I despise lying, so I won't. How you deal with the truth is yours alone to deal with. Maybe someday you will reach the level where you know that you know the truth instead of just thinking you do out of your self-defensive ego.
Special Relativity was accepted almost immediately (within 10 years) by the scientific community since it was so powerful and useful and correct when the community tested it.
General relativity took a longer time to be generally accepted since the sensitivity of the tests were mediocre for the time, but strong evidence of its correctness was already coming about within 25 years. The problem being it was hard to figure out which model was correct due to lack of accurate tests
Saying that the community rejected these theories is just ignorance.
> within 25 years
That is "many years" in my view.
> so untrue
So you're saying his ideas were immediately accepted?
I guess that's why he was still working at the patent office for fourish years after his Miracle Year?
And I guess this is like all the other cases where new scientific theories were immediately accepted, of which you can name precisely zero, I imagine?
You think physicists don't smoke weed and dream up random ideas? Or formally study eastern religions?
The fact that they are trained physicist is why they don't conceive of the universe (and dark energy specifically) the way you do, and probably never will.
>And, really, y'all are out of ideas as to what or where dark matter or energy are anyway, so there is nothing for anyone to lose.
This is an example of your condescension. There are so many assumptions implicit in your statements that it's offensive to the audience. Its like the difference between a person raving in the street that everyone is free to ignore. Versus that same person deliberately entering a physics conference shouting the same things, then claiming they're only there to help.
Check out this book: Combating Cult Mind Control by Steven Hassan.
Keep an open mind. I enjoyed reading your ideas of the universe but without evidence it’s just a fun idea. Science, empirical evidence, is what turns ideas into understanding.
I completely agree, but the truth is that I am not a charlatan, nor am I a liar. A charlatan does his dirty deeds in hopes of some wrongful gain at the expense of others. My efforts here benefit me without negative effect for anyone else. That is a key indicator of a person acting solely on behalf of Love.
You are free to believe that that which you already believe is the truth, or you can learn some new truths that expand your consciousness. I am just here to plant seeds, and it makes me happy and at peace to do so.
I really don't care what you do, for only you are responsible for your choices, not me. I love you anyway, and, while I have recommendations for you that would improve your life's happiness and that of those around you, I have no ill feelings toward anyone here about how they treat me. I, unlike Boltzmann, am only responsible to the truth of love and the love of truth, not to naysayers who have yet to accept greater truths than they currently comprehend. I was once in the same situation, if not more ignorant.
As with all things human, the choice is ours, each of us, utterly freely, but within a sublime system of cause and effect that is relentlessly impersonal.
Peace be with you.