Questions on the big bang expanding universe.

[Polymath257]

IMO the theory isn´t "very well tested" when it cannot be connected with other needed models.
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if the predictions a theory makes agree with the observations in a large collection of tests, then it *is* well tested. That is true whether or not it can be 'connected' to other tested theories.

Of course, the next step would be to test the overlap between those theories.

 

[ratiocinator]

IMO the theory isn´t "very well tested" when it cannot be connected with other needed models.

I see we can add "very well tested" to the list of things you don't understand.

Are you serious!? "Dark matter" was specifically invented when the celestial laws of orbital motions was directly contradicted by the discovey of the galactic rotation curve. "Dark matter" is NOT an "actual matter" but a pure assumption...

It was originally introduced as a (fairly obvious) possibility to explain the discrepancy but more detailed study has shown that we can discover exactly where it is and build maps. There are galaxies that don't have any dark matter, so a correction the the theory of gravity simply wouldn't explain the observations.

 

[Native]

Wrt religion since it seems to be a pet hatred of yours', you need to know that you would have to spend decades in, say for example, meditative practice to understand what the state of samadhi is in the context of cosmic being. And obviously you would need to believe it was real and attainable to make the sacrifice to devote that amount of time and effort out of your life to realize it. And it is probably true like the boy who keeps falling off his bike, that the aspirant's ego falls into a false belief at some point that they have realized enlightenment when it wasn't. So yes, belief is not understanding, but I dare say every aspirant that ever travels the path will have their falls due to mistaking belief for true understanding

Well said and explained indeed, ben d

 

[Native]

My oh my. . . That is some first class ignorance. You are partially right.

Can you come to agreement with yourself here ?

It is a testable hypothesis that was later confirmed by more evidence.

Obviously you confuse human ad hoc additions to a direct contradicted law as "tested and confirmed evidences".

Unfortunately you do not appear to understand the concept of evidence and like most science deniers refuse to attempt to learn what is and what is not evidence.

Well then: How does your "dark matter evidence" in galaxies influence the different celestial orbital motions in the Solar System?

 

[Native]

Native said: ↑
IMO the theory isn´t "very well tested" when it cannot be connected with other needed models.

I see we can add "very well tested" to the list of things you don't understand.

Who "we"? Are you of a royal family?

You don´t understand if your favorite or chosen cosmological model cannot be fully tested aginst other models, it is NOT an Universal theory at all. As long as this cannot be done, it isn´t much more than a temporary guess work.

 

[ratiocinator]

You don´t understand if your favorite or chosen cosmological model cannot be fully tested aginst other models, it is NOT an Universal theory at all.

Who said it was universal? We don't have a 'theory of everything' yet.

As long as this cannot be done, it isn´t much more than a temporary guess work.

Nonsense - it can be, and has been, extensively tested against observation and experiment. The fact is that we have two very well tested theories (GR and QFT) and they both work incredibly well within their domains of applicability. The reason we are having problems with uniting them is that situations in which their domains overlap are very extreme and beyond our technological ability to directly test.

 

[Native]

There are galaxies that don't have any dark matter, so a correction the the theory of gravity simply wouldn't explain the observations.

Interesting indeed. How is this observation explained? What is the difference between "galaxies which assumingly has "dark matter" and which has not? Which other attempts to corrections were tried?

 

[Native]

Who said it was universal? We don't have a 'theory of everything' yet.

That´s my very point and as long as we haven´t, no models are and can be tested as concrete evidences at all.

 

[Polymath257]

Who said it was universal? We don't have a 'theory of everything' yet.

Nonsense - it can be, and has been, extensively tested against observation and experiment. The fact is that we have two very well tested theories (GR and QFT) and they both work incredibly well within their domains of applicability. The reason we are having problems with uniting them is that situations in which their domains overlap are very extreme and beyond our technological ability to directly test.

I'll go further. Both GR and QFT are very well tested in their domains.

What that means is that any *new* theory will have to *agree with them* in those cases where we have been able to test them. In other words, anything that will replace either GR or QFT will have to agree with the observations already made.

And that means that even if GR and QFT are 'wrong', they are incredibly good approximations.

And, since they have been tested extensively, any new theory will only differ from either of them in incredibly extreme circumstances.

So, for energy scales less than several TeV per particle or in gravitational fields less than what you get around neutron stars or large black holes, any *new* theory will have to agree with either QFT or GR in the predictions it makes, at least to a very high degree of approximation.

This already excludes such fantasies as the Electric Universe, which don't actually make any specific predictions at all, nor give any detailed descriptions of even well-known situations.

If all you have is 'the overall rotation produces the orbits of the planets' without being able to give actual predictions of planetary motions, then you have absolutely nothing.

 

[Polymath257]

Interesting indeed. How is this observation explained? What is the difference between "galaxies which assumingly has "dark matter" and which has not? Which other attempts to corrections were tried?

The observation is explained by there being no accumulation of dark matter in those galaxies. it really is as simple as that.

Generally speaking, the galaxies without dark matter are smaller and more diffuse (which is expected if they don't have dark matter). The fact that such galaxies exist at all shows that a change in the theory of gravity isn't enough to explain away dark matter.

Attempts to change the description of gravity to explain away dark matter are numerous. The most famous on is MOND, but there are relativistic variants (TeVeS) and other possibilities. At this point, nobody has been able to come up with any description that fits the data and does not include at least some dark matter.

 

[Polymath257]

That´s my very point and as long as we haven´t, no models are and can be tested as concrete evidences at all.

Well, this is simply false. Newtonian physics was well tested. Then, some tests came along that it didn't pass. Thereby quantum mechanics and general relativity were developed. These passed the tests that Newtonian physics failed. But we keep testing, always exploring new situations to see if the theories continue to give accurate results.

Models *are* tested. Some pass the tests. Others do not and are either modified or discarded.

The way we build up more comprehensive models is by looking at the smaller models that work and attempting to merge them into a common viewpoint. The testing of the incomplete models and the determination of when they do and do not work is a huge part of this endeavor.

 

[shunyadragon]

Apparently you do not understand that understanding is not the same thing as belief. If a young boy learns to ride a bicycle, he then understands how to ride a bicycle, it's not a matter of belief. Now there may be a case where another boy believes he can ride a bicycle and keeps falling off because he does not understand yet.. Do you see the difference?

This is true for all learning, the artist, the athlete, the scholar, etc... True understanding in whatever area of interest you have is not just understanding, it's also about what you do not understand. Belief can play a role at the beginning of an endeavor as a confidence thing that one will eventually gain mastery, ie. true understanding, but it naturally falls away as true understanding is realized.

Wrt religion since it seems to be a pet hatred of yours', you need to know that you would have to spend decades in, say for example, meditative practice to understand what the state of samadhi is in the context of cosmic being. And obviously you would need to believe it was real and attainable to make the sacrifice to devote that amount of time and effort out of your life to realize it. And it is probably true like the boy who keeps falling off his bike, that the aspirant's ego falls into a false belief at some point that they have realized enlightenment when it wasn't. So yes, belief is not understanding, but I dare say every aspirant that ever travels the path will have their falls due to mistaking belief for true understanding. As the saying goes, many are called but few are chosen.

I can acknowledge this as apart of religious/philosophical understand, but the subject of the thread is science, which you are sidestepping and neglecting consideration in the above. Please address this as per the subject of the thread.

 

[shunyadragon]

Then, what would you call Newton´s initial conclusions of gravity which was his belief and wich later on was refused by Einstein for another belief?

Einstein's science of relativity and Quantum Mechanics does not refuse Newtonian physics, nor is it another belief. Newtonian physics still works very well and applies to the macro world. Einstein's physics began the explanation of the physics of the micro world not explained by Newtonian physics, and both are in harmony explaining the descriptive science of out physical existence.

No it´s not. Cosmological ideas all derives from philosophical belief systems - just as in the case of the Natural Philosopher, Newton - and all observations are connected to the initial and prime belief, whether this is right or wrong.

ALL science, whether Newtonian or contemporary physics and cosmological science is based on direct objective verifiable evidence and Methodological Naturalism and not philosophy.

To a large extend observations and experiments in modern cosmology are nothing more by "confirmations on the initial guessworks", apropos the Feynman opening comment in his video posted above.

No, not guesswork, but repeated consistent and predictable direct observations base don contemporary physics.

 

[shunyadragon]

Well said and explained indeed, ben d

Not explained anything, actually a conflicting incoherent word salad.

 

[Subduction Zone]

Can you come to agreement with yourself here ?

I see that you are still confused.

Obviously you confuse human ad hoc additions to a direct contradicted law as "tested and confirmed evidences".

Like I said, you are ignorant about the subject. You only know one piece of evidence for dark matter.

Well then: How does your "dark matter evidence" in galaxies influence the different celestial orbital motions in the Solar System?

It has almost no effect. It would be immeasurably small. Why would it? Again your question indicates that you do not understand this topic at all.

 

[ValdresRose]

Special relativity is a theory that has been extensively tested and verified.

Thanks. I would like to take some 'time' (no pun intended) to look closer at the theory.

If I may, please, pick you mind on an entirely different subject: If we use an observable galaxy in space as our point of reference and we determine from that point that we are looking down on our own galaxy, which direction is our galaxy turning, clockwise or counterclockwise?

Further, if we are looking down and we observe that the spiral arms appear to be expanding and receding from the center to the right, cw, and to the left the spiral arms appear to be narrowing and contacting into the center, ccw, which way is our galaxy turning?

 

[Subduction Zone]

Thanks. I would like to take some 'time' (no pun intended) to look closer at the theory.

If I may, please, pick you mind on an entirely different subject: If we use an observable galaxy in space as our point of reference and we determine from that point that we are looking down on our own galaxy, which direction is our galaxy turning, clockwise or counterclockwise?

Further, if we are looking down and we observe that the spiral arms appear to be expanding and receding from the center to the right, cw, and to the left the spiral arms appear to be narrowing and contacting into the center, ccw, which way is our galaxy turning?

There is no "up" or "down" in space when looking at galaxies. And depending upon where one is our galaxy would look like it was rotating clockwise or counterclockwise. We could make an arbitrary definition of which way was "up" from our galaxy, but then the direction of rotation would only depend upon our definition.

 

[Polymath257]

Thanks. I would like to take some 'time' (no pun intended) to look closer at the theory.

If I may, please, pick you mind on an entirely different subject: If we use an observable galaxy in space as our point of reference and we determine from that point that we are looking down on our own galaxy, which direction is our galaxy turning, clockwise or counterclockwise?

Further, if we are looking down and we observe that the spiral arms appear to be expanding and receding from the center to the right, cw, and to the left the spiral arms appear to be narrowing and contacting into the center, ccw, which way is our galaxy turning?

Clockwise and counter clockwise are, again, relative notions. There is no well-defined 'upwards' or 'downwards' in space.

So, if you look at our galaxy from one side, it will appear to rotate clockwise. if you look at it from the other side, it will appear to rotate counter clockwise.

That said, most spiral galaxies (ours included) rotate in such a way that the spiral arms trail in the rotation. In a very few, there have been interactions with other galaxies that have disturbed the rotation and the arms precede the rotation.

I don't understand your question in the last paragraph. What do you mean by 'expanding and receding from the center to the right'? That phrase doesn't make sense to me as you have written it. Could you elaborate?

 

[ValdresRose]

That said, most spiral galaxies (ours included) rotate in such a way that the spiral arms trail in the rotation. In a very few, there have been interactions with other galaxies that have disturbed the rotation and the arms precede the rotation.

Thanks. I notice Subduction Zone chimed in here but I don't know how to send this to both of you at the same time. I'm going to use galaxy NGC 6814 as found in Google and APOD (Aug 16, 2020), (Astronomy Picture of the Day). Looking at the upper arm of the galaxy in the photo it appears that the right side of the arm is expanding, and the arm appears to be moving away from the center. Your quote above suggests that the galaxy is turning ccw, please correct me if I'm mistaken. Can we assume that the Super Massive at the center is turning ccw? Can we determine if 'matter' is being cast out from the center, or is the 'matter' being drawn into the center?

I realize the ambiguity of 'up - down', simply take a plate and look down on the flat surface, rotate the plate ccw, raise the plate above our eyes and we're seeing it cw.

 

[alsome]