RE: Do we still need to build models beyond the Standard Model of particle physics ?
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Absent some ongoing event that is creating the time aspect of spacetime, which no observation supports, spacetime is extant as a field, which we observe of it's spatial aspect. Given that space is visibly a field, how could time not be, since spacetime is one thing?
This idea is absent from the list because it has no mathematical formulation. Qualitatively, there are issues with it (we already discussed them) and without any way to make predictions to be compared with data, there is no way to get it considered by physicists. For this, a way to make predictions is unavoidably needed.
We have evidence that mass in the past and future do effect gravity in the past - the same evidence used to claim some other form of matter must exist - of more gravity being effected than matter observed effects in a given instant. The matter observed presently isn't extant presently. It is present at various times in the past, depending on how far away from us it is and how long it took light from there to reach us. It is assumed to only effect gravity in a series of sequential instants, across a spatial field. But spacetime is a field and time is not separate from that field, not only occurring as a sequence of instants that confine the affect of matter in that field to such instants.
Do you mind showing me which evidence we have that future events impact us? I am not aware of any.
Note that there is no direct evidence for dark matter. The only thing we know is that the simplest explanation for many cosmological observations requires it. This is not an evidence, which is actively searched for today.
Moreover, it is not a proof we need dark matter at all costs. Maybe the greatest explanation has not been invented yet. Who knows? In the meantime, this is a model (which is slightly different from a theory) that works well.
[…] Math is very powerful, but it is not the only thing necessary to understand physical reality.
The purpose of physics is to provide a description of any phenomenon from a small number of fundamental principles. There, we rely on what we call a theory. In common parlance the word “theory” describes an attempt to explain events. In scientific language, it is different. A theory is a mathematical structure which precisely explains all known experimental facts in a certain domain.
Therefore, maths are needed for physics. Also, the example of the clock you raised, I don’t see how it does not agree with what I wrote. For each aspect, there are laws allowing to understand it, that we can formulate mathematically.
Let me know move on with the discussion on falsification.
Estimating the movements of the masses involved over time would be necessary to estimate the intensity of the acceleration from masses in former and future positions than observed presently, as well as the impact of the inverse square law on mass earlier or later than the time of observation.
How is this possible? You could this estimation be done? How should I modify the calculations to account for this? Without this, the idea is neither testable nor falsifiable, isn’t it? This is what puzzles me from the beginning.
these are the kinds of calculations that have produced the claim ~85% of the mass effecting gravity is invisible,
I disagree with this. Classical mechanics and observations of visible objects in the universe have shown a disagreement. Adding some invisible mass and redoing the calculations using the same laws allowed to obtain agreement between theory and data.
However, the story does not stop with galaxy rotation curves. There are many cosmological observations for which predictions can be made and that feature agreement with data once the same dark matter is accounted for. For that reason, I insisted several time on the fact that the standard model of cosmology will only be replaced by something that does as good related to data.
You are quite correct to state that physics is utterly dependent on math. While I cannot understand the math, it is clear from having a look at gauge fields, charge carriers, and Lagrangians, that we'd have no standard model without math. The language of math is vital to the purpose of physics, and I am not a physicist because I am incompetent to communicate in that primary language of physics, at least.
Einstein's explanation for why the speed of light is the absolute limit points out that the faster an object is moving across space, the slower it is moving across time, until at lightspeed time is frozen. His famous equation, E=MC^2, relates space and time such that they are inextricable. How seconds to meters is accounted I remain blithely unaware, but this is not my original concept, rather that of Einstein. I only point out that when gravity affects a region of this continuum, it is reaching across both aspects of it, and not space alone.
However, observations reveal that the universe is expanding, and the farther away something is, the faster it is moving away. The general consensus regarding this phenomenon is that spacetime is erupting into being between gravitationally bound systems. I am unaware of any source of this creation of spacetime, of any cost of it, or of any disturbance it's birth may cause. There's no explanation for it at all, but it fits the observation that the universe is expanding in the way it is.
https://www.cs.mcgill.ca/~rwest/wikispeedia/wpcd/wp/c/Cosmic_inflation.htm
How there can be a spacetime continuum that is complete, yet erupts from the vacuum in bits and pieces, I can neither explain. It seems that observation trumps speculation and things are what they are whether we can derive the reason they are that way or not.
The visible mass observed is calculated to be insufficient to account for observed motion of galactic arms, or the collision of the Bullet Cluster, and these are amongst the observations that are the basis for theories proposing dark matter.
Such observations depend on estimations of how matter is distributed across time and space. That estimation clearly is undertaken and considered rigorous enough to have mathematical validity, or such claims would not bother physicists much, as you state.
Such estimation is not solely potential to theories proposing novel forms of matter, and should be no different undertaken to consider mass affecting spacetime from other moments. Both are theories involving dark, or invisible, matter, although one involves novel form(s) of matter and the other normal matter effecting gravity across time. It seems the estimations have been done and dark matter theories just plug in enough mass where and when it needs to be to satisfy those estimations, as you state.
Just stating that ordinary matter satisfies those estimations isn't any different, except in that it doesn't require adding to the bestiary of particles in the standard model, and treats spacetime as Einstein showed it to be, a unitary field, a continuum.
While the effect of gravity across time seems a novel concept, it is the only way gravity occurs. There is no universal instant of time across the spacetime continuum, but an objects time and movement through it is relative to it's movement through space. All gravity has to be effected across time, because time for every massive object is unique to it's inertial frame, and there is no universal instant of shared time. All time is relative. The inverse square law is sufficient to cover all gravity, since all gravity is effected across time.
We are matter. We cannot peer into the future because light cannot reveal it to us. Gravity is not matter, not a force, and is not constrained by time like we are. Physicists can show the gravity caused by unseen mass, but cannot see mass causing the gravity across the spacetime continuum.
I have attempted to discuss spacetime as a field. How can a thing that is a field, that we observe to be a field in which mass exists, be somehow not a field? Space is not something that exists. Space cannot be mathematically treated without time and reflect physical reality, as Einstein pointed out.
Both dimensions of distance and delay, of space and time, are part of the spacetime continuum. Gravity warps spacetime spatiotemporally, not spatially and temporally. How can it reach across the spatial aspect but not the temporal? It makes no sense that gravity is considered to be not reaching across time to affect spacetime. How can time be excluded from spacetime for that purpose?
If the aspects of spacetime are labeled, S=space, T=time, and G=gravity, the calculation can be represented such that (matter in STG affects ST = G) = (matter in (STG)). While math can be used to state (matter in STG affects (S)(T) = G), this is not what happens in the actual universe, because S and T are not different things that are added together, but features of one thing. STG is unitary. It isn't separate parts that can be added together, despite math having rules that allows separate parts to be added together, because math is a language that can be used on things that are separate parts that can be added together, like apples. STG isn't separate apples. It is one apple.
Just following grammatical rules does not create true statements. Just like I can say in English following grammatical rules 'Valued-customer is a horrible person.' and that statement is grammatically correct but completely false, just so the mathematical statement (matter affects (S)(T) = G) is just as false. S and T aren't different things that can be added together, just like valued-customer and horrible person aren't things that can be added together in this way to make a true statement. This is an example of how we can lie in any language, including math.
Just like people, spacetime is not the sum of it's parts. If you break valued-customer into constituent parts you would not be able to spot little bits of horribleness, because I only am valued-customer as a whole. Gravity is an aspect of spacetime and not of it's parts, which do not exist separately but only emerges as a whole. Regardless of whether some novel form of matter does or does not exist, matter affects spacetime it exists in, and since time is relative to a massive object's inertial frame, and there is no universal instant during which gravity is effected, it can only reach across time and space together.
Note that this may be my last answer for the next 3-4 weeks as I will soon take some long offline time. I will come back to you at my return or during the break if I have enough strength to connect.
I don’t understand what you mean by “creation of spacetime”. The universe is in a state of accelerated expansion (a fact). What are the cosmic ingredients behind this? Well we don’t know and this is an open question.
What do you mean by “complete”? I don’t understand this word in this context. If you discuss the ingredients I mentioned above, then well, we don’t know.
There is no fundamental principle behind the model, but it works. Moreover, the standard model of cosmology is mathematically sound, and you seem to ignore structure formation and the cosmic microwave background that are important indirect support for it. From there, finding the fundamental principles behind all of this consist of open questions. Many work on this.
In other words, the standard model offers us a way to get an idea about the true nature of cosmology and to make predictions in the meantime we have a better framework that does at least as good.
Maybe. Then show me the associated predictions and let's compare them with data. As in the beginning of this thread, I don’t understand how the future could impact the present (even within a curved spacetime).
Again, how could we integrate the future in calculations? Even if time is relative, causality and the arrow of time are important. This applies to the rest of the previous comment: we observe events today, that date from the past (light takes time to travel). I don’t see how to explain present observations with future ones.
I need to see the theoretical formulation to try to understand this. It is clear that gravity and spacetime are related and no one has ever said that we should ignore relativistic effects. This is not the problem. The problem is how something happening in the future could affect us today.
I have realized I can make a prediction based on my idea that ordinary matter is the dark matter causing excess gravity. It is that where ordinary matter is observed to be, dark matter should be, since it is the ordinary matter we observe I propose is the dark matter affecting spacetime across time.
It is my understanding that observation has not shown this to be so. Instead, dark matter appears to be locally flat, and it's effect is negligible and lost in the large gravitational field caused by normal matter hereabouts, while having significant impact from places we do not observe matter to be.
My speculation appears to be falsified.
I hope you have a great vacation, and I am very grateful for the kindness you showed me.
Thanks!
I agree with your conclusion. We know precisely where dark matter should be, and it is not everywhere where we have normal matter. This therefore seems to contradict your predictions.
See you in three weeks! (I will disconnect in 2 days.)