Scientific results here and now apply to there and then

[Job 33:6]

This is what I meant by the original claim being, at best, an unproven assertion. You can assert that there might be some sort of phenomenon that messes everything up. But there is no evidence for such a thing. In fact, the evidence is entirely consistent with physics being the same long ago and far away as it is here and now.

This all a Creationists can really do. If it looks like a duck, walks like a duck and quacks like a duck, the logical conclusion is that it is a duck. Creationists simply cannot accept physical reality as it is, and thus are left with very abstract and unclear thoughts, confused with last thursdayism, and bent on the need for a time machine to understand what happened in the past.

 

[pitabread]

Creationists simply cannot accept physical reality as it is, and thus are left with very abstract and unclear thoughts, confused with last thursdayism, and bent on the need for a time machine to understand what happened in the past.

In my experience a lot of creationists, whether they realize it or not, reject the idea of an objective universe. Hence why there are so many contradictory versions of creationism out there, because they have no way to objectively test and validate their ideas.

I also think that a lot of creationists that hold this view have not thought through the logical consequences thereof.

 

[Tinker Grey]

In my experience a lot of creationists, whether they realize it or not, reject the idea of an objective universe. Hence why there are so many contradictory versions of creationism out there, because they have no way to objectively test and validate their ideas.

I also think that a lot of creationists that hold this view have not thought through the logical consequences thereof.

Like somehow believing in objective morality while denying the objectiveness of reality itself.

 

[Sam91]

Warp speed: How the outer edges of the universe travel faster than the speed of light

@sjastro
An astrophysicist refers to what he calls local physics. What does he mean? Could it back up some of my views? Thanks

 

[Bungle_Bear]

This all a Creationists can really do. If it looks like a duck, walks like a duck and quacks like a duck, the logical conclusion is that it is a duck.

But you can't prove it's a duck, can you? My book says it's actually a guinea pig, and my book also is says it is right. Checkmate, Evolutionist.

 

[sjastro]

Warp speed: How the outer edges of the universe travel faster than the speed of light

@sjastro
An astrophysicist refers to what he calls local physics. What does he mean? Could it back up some of my views? Thanks

First of all there is a glaring typo in the article 1 parsec = 3.26 light years not 3.26 million light years.

In metric expansion where everything is moving away from everything else the recession velocity of a distant galaxy increases as the distance from the observer increases.
The recession velocity Vrec can exceed the speed of light.
For small redshift z (=smaller distances) the relationship is linear as governed by Hubble’s law.

In the graph are three models for describing the relationship between redshift z and recession velocity Vrec.
(1) The linear relationship based on the equation Vrec(z)=cz.
(2) Special relativity using the equation V(z)rec=V(z)pec = c[((1+z)²-1)/((1+z)²+1)];
V(z)pec is the "peculiar" velocity in spacetime.
(3) General relativity.

The term “local physics” applies to distances where the recession velocities of objects with mass have recession velocities less than the speed of light c.
In the graph this occurs at z<1.46 or where the distances between observer and galaxy are less than 4200 megaparsecs.

The term “local physics” needs to be qualified however.
Objects with mass whether they be atoms or galaxies cannot reach or exceed the speed of light when moving in spacetime.
In metric expansion however distant galaxies not in gravitationally bound systems are being carried along by expanding spacetime known as the Hubble flow.
For z<1.46 the recession velocities resembles conditions where special relativity applies for objects travelling in spacetime (Vrec = Vpec) hence the term “local physics”.

Unfortunately it doesn’t justify your views.

 

[Sam91]

First of all there is a glaring typo in the article 1 parsec = 3.26 light years not 3.26 million light years.

In metric expansion where everything is moving away from everything else the recession velocity of a distant galaxy increases as the distance from the observer increases.
The recession velocity Vrec can exceed the speed of light.
For small redshift z (=smaller distances) the relationship is linear as governed by Hubble’s law.

In the graph are three models for describing the relationship between redshift z and recession velocity Vrec.
(1) The linear relationship based on the equation Vrec(z)=cz.
(2) Special relativity using the equation V(z)rec=V(z)pec = c[((1+z)²-1)/((1+z)²+1)];
V(z)pec is the "peculiar" velocity in spacetime.
(3) General relativity.

The term “local physics” applies to distances where the recession velocities of objects with mass have recession velocities less than the speed of light c.
In the graph this occurs at z<1.46 or where the distances between observer and galaxy are less than 4200 megaparsecs.

The term “local physics” needs to be qualified however.
Objects with mass whether they be atoms or galaxies cannot reach or exceed the speed of light when moving in spacetime.
In metric expansion however distant galaxies not in gravitationally bound systems are being carried along by expanding spacetime known as the Hubble flow.
For z<1.46 the recession velocities resembles conditions where special relativity applies for objects travelling in spacetime (Vrec = Vpec) hence the term “local physics”.

Unfortunately it doesn’t justify your views.

Thanks very much for the explanation. Yeah, I missed that typo about light years to parsecs.

I'm not so sure that it doesn't justify the view that we can't expect the laws of physics to work the whole universe as we know it. I think this is a phenomena that stands out.

 

[FrumiousBandersnatch]

I'm not so sure that it doesn't justify the view that we can't expect the laws of physics to work the whole universe as we know it. I think this is a phenomena that stands out.

All the evidence we have suggests that the laws of physics are the same for the observable universe and a large extent beyond it.

If the whole universe is spatially infinite (or very very many orders of magnitude larger than we can infer), it may be possible that what we consider to be our local constants can vary. It may also be possible that there are expanding 'bubbles' of very different spacetime that might appear when, for example, the Higgs field spontaneously drops to its base energy level. None of this would ever make any difference to us as those volumes are receding from us faster than light, effectively making them causally isolated 'universes' in their own right.

Those possibilities are so speculative that they can't reasonably be used to justify your ideas.

 

[SelfSim]

... Those possibilities are so speculative that they can't reasonably be used to justify your ideas.

But that's exactly what speculations are ... ie: ideas.
How can you rule as invalid the very basis underpinning speculation?
That makes zero logical sense ..

 

[FrumiousBandersnatch]

But that's exactly what speculations are ... ie: ideas.
How can you rule as invalid the very basis underpinning speculation?
That makes zero logical sense ..

I don't see how speculations can justify anything besides further investigation. You can't show how something is correct with speculation.

 

[sjastro]

Thanks very much for the explanation. Yeah, I missed that typo about light years to parsecs.

I'm not so sure that it doesn't justify the view that we can't expect the laws of physics to work the whole universe as we know it. I think this is a phenomena that stands out.

In the linear, special relativity and general relativity models the speed of light c is constant.
If c is a function of time the curves would be different.
Due to selection effects the vast percentage of data is found in the low z range.
This is due to high z galaxies being rarer; not only due to being fainter and harder to detect but also being older and existing in a younger universe where there were fewer galaxies.
In the low z range where recession velocities are well below the speed of light the three models make similar predictions.
Since the data is linear in this range it is customary to convert z into distance r using the formula r = cz/H₀ where H₀ is the value of the Hubble constant.

Here is the data complete with error bars showing a straight line relationship which is only possible if the speed of light is constant.

At higher z values where the general relativity model triumphs the non linearity is not due to the speed of light changing but depends on the density parameters for matter Ω(M) = 0.3 and dark energy Ω(Ʌ) = 0.7.

 

[Sam91]

In the linear, special relativity and general relativity models the speed of light c is constant.
If c is a function of time the curves would be different.
Due to selection effects the vast percentage of data is found in the low z range.
This is due to high z galaxies being rarer; not only due to being fainter and harder to detect but also being older and existing in a younger universe where there were fewer galaxies.
In the low z range where recession velocities are well below the speed of light the three models make similar predictions.
Since the data is linear in this range it is customary to convert z into distance r using the formula r = cz/H₀ where H₀ is the value of the Hubble constant.

Here is the data complete with error bars showing a straight line relationship which is only possible if the speed of light is constant.

At higher z values where the general relativity model triumphs the non linearity is not due to the speed of light changing but depends on the density parameters for matter Ω(M) = 0.3 and dark energy Ω(Ʌ) = 0.7.

Thanks, I'll read this post tomorrow. I'm doing an assessment tomorrow in class and I should be asleep.

I wanted to post this link as it is articles like these which that me very cautious about what astrophysicists say.

There’s Growing Evidence That the Universe Is Connected by Giant Structures

I have also read a lot of the BBC's science articles. Those are dubious sometimes. In fact, I slate those for being farcical... because what some of those say don't even make logical sense. Sometimes I've doubted the author even knows what they are writing about. Maybe he got a different position because there was a run of articles about 18 months ago that were awful. The story didn't match the headlines, one was about what would happen if a person went into a black hole.

As far as the science goes though. An analogy might help. I do feel that when scientists investigate the universe, it is like a Roman trying to understand a working computer. If he presses some keys he can be sure of some results, yet he can not explain the fundamental basis of how it works.. maybe I'm being unkind. Maybe I could choose Galileo. However, I was kind to not choose a caveman. Yeah, you can be Galileo, I'll be the Roman.

Edit: This wasn't the article. I lived in this house when I read it. The article to which I referred is very similar to this, but bite-sized.

The strange fate of a person falling into a black hole

 

[Sam91]

All the evidence we have suggests that the laws of physics are the same for the observable universe and a large extent beyond it.

If the whole universe is spatially infinite (or very very many orders of magnitude larger than we can infer), it may be possible that what we consider to be our local constants can vary. It may also be possible that there are expanding 'bubbles' of very different spacetime that might appear when, for example, the Higgs field spontaneously drops to its base energy level. None of this would ever make any difference to us as those volumes are receding from us faster than light, effectively making them causally isolated 'universes' in their own right.

Those possibilities are so speculative that they can't reasonably be used to justify your ideas.

It seems that not everyone agrees with you. She is a scientist who I would be more likely to trust. She may have a cautious approach to her work and an open mind concerning the validity of her findings. I like her objectivity an the open mind will cause her to examine things from other angles to see what others may miss. It's all relative.

 

[FrumiousBandersnatch]

It seems that not everyone agrees with you. She is a scientist who I would be more likely to trust. She may have a cautious approach to her work and an open mind concerning the validity of her findings. I like her objectivity an the open mind will cause her to examine things from other angles to see what others may miss. It's all relative.

If you're referring to Françoise Delplancke, I agree with her, it is important to check the laws are valid under extreme gravitational conditions. That doesn't conflict with my point that the evidence we currently have suggests that they are valid, in general, as far as we can observe.

There are specific regions, such as black holes, where we know our current models are incomplete because we don't yet have a theory of quantum gravity that covers exotic regimes.

 

[essentialsaltes]

It seems that not everyone agrees with you. She is a scientist who I would be more likely to trust.

"So it's very important in astronomy to also check that those laws are still valid where the gravitational fields are very much stronger," she explained.

This is not in conflict with anything FrumiousBandersnatch or I have been saying. Indeed, she is reiterating the important point from my OP.

Without space and time translation symmetry, experiments carried out in different places and at different times would not be reproducible. In their everyday work, scientists take those symmetries for granted. Indeed, science as we know it would be impossible without them. But it is important to emphasize that we can test space and time translation symmetry empirically. Specifically, we can observe behavior in distant astronomical objects. Such objects are situated, obviously, in different places, and thanks to the finite speed of light we can observe in the present how they behaved in the past. Astronomers have determined, in great detail and with high accuracy, that the same laws do in fact apply.

Her checking is exactly what is meant by testing whether the same laws apply.

 

[Sam91]

"So it's very important in astronomy to also check that those laws are still valid where the gravitational fields are very much stronger," she explained.

This is not in conflict with anything FrumiousBandersnatch or I have been saying. Indeed, she is reiterating the important point from my OP.

Without space and time translation symmetry, experiments carried out in different places and at different times would not be reproducible. In their everyday work, scientists take those symmetries for granted. Indeed, science as we know it would be impossible without them. But it is important to emphasize that we can test space and time translation symmetry empirically. Specifically, we can observe behavior in distant astronomical objects. Such objects are situated, obviously, in different places, and thanks to the finite speed of light we can observe in the present how they behaved in the past. Astronomers have determined, in great detail and with high accuracy, that the same laws do in fact apply.

Her checking is exactly what is meant by testing whether the same laws apply.

It is your OP that I disagree with. I don't think that you can say that with certainty. If you had left room for the possibility of error I would not have even commented on your thread. Admittedly, the word 'suggests' was used once but many more words which shew confidence were also used.
I am also not sure that you can call the measurements and calculations empirical evidence. These formulae are derived from theory, which can be tested locally.

I do not think that there is enough knowledge to determine that what is measured from more distant regions is not affected by phenomena that there is not enough information about.
I don't see how one can be 100% sure about the distance light has travelled. We know just from things on Earth that looking straight on can make things look different if we do not have anything else in between and we are unsure of size. Granted that there is a lot you can tell but these are astronomically vast distances there is a possibility of error and your OP does not reflect that. A very small, negligible error when multiplied so far can lead to a massive difference in distance or time.

I've said this multiple times. I won't agree with the OP until it reflects the possibility of error.

Did you change it by the way? I reread it yesterday and was surprised to find it didn't say what I thought it did. It doesn't say that you did but I thought you had written something that meant that the constants that work locally will work for very distant places and for all time.

(I don't know much about it but how do they know that there isn't something weird going on with things on the subatomic level in a region of space between these measurements.

I guess growing up avidly watching Star Trek TGN, DS9 and Voyager has opened up more than my social imagination and given me an imagination in general lol.)

 

[essentialsaltes]

Did you change it by the way? I reread it yesterday and was surprised to find it didn't say what I thought it did. It doesn't say that you did but I thought you had written something that meant that the constants that work locally will work for very distant places and for all time.

I don't recall editing it, and the post does not have a "Last edited: 7 minutes ago" note at the bottom (as your post above does).

 

[Sam91]

I don't recall editing it, and the post does not have a "Last edited: 7 minutes ago" note at the bottom (as your post above does).

Yh it's 1.29am and I type on a phone. It means that there are plenty of typos, additions and rephrasing going on after I post. It was still being edited when you posted.

Guess I just translated the OP and made it that little bit strongly worded in my mind. I also didn't read your first sentence

 

[sjastro]

Thanks, I'll read this post tomorrow. I'm doing an assessment tomorrow in class and I should be asleep.

I wanted to post this link as it is articles like these which that me very cautious about what astrophysicists say.

There’s Growing Evidence That the Universe Is Connected by Giant Structures

I have also read a lot of the BBC's science articles. Those are dubious sometimes. In fact, I slate those for being farcical... because what some of those say don't even make logical sense. Sometimes I've doubted the author even knows what they are writing about. Maybe he got a different position because there was a run of articles about 18 months ago that were awful. The story didn't match the headlines, one was about what would happen if a person went into a black hole.

Edit: This wasn't the article. I lived in this house when I read it. The article to which I referred is very similar to this, but bite-sized.

The strange fate of a person falling into a black hole

Let me make a general comment about these articles you refer to.
They are examples of popsci articles written for the general public.
Popsci articles can vary from faithfully reproducing the science to exaggeration and sensationalism.
Your links sit somewhere between the extremes.

The first one is fairly restrained although the title “There’s Growing Evidence That the Universe Is Connected by Giant Structures” is somewhat premature as the article goes onto to state this needs to be independently confirmed and more data is required.

The second link is less credible as it portrays speculation as fact.
Anne seeing you stuck at the event horizon is a prediction of the Schwarzschild metric which describes the distortion of spacetime time around massive bodies such as planets, stars and non rotating black holes and is an extreme example of gravitational time dilation, the lesser effects of which have been observed on Earth from the Rebka-Pound experiment to GPS satellite time corrections.
While this part of the article is “reasonably accurate” the rest is not.
Burning up on the event horizon due to Hawking radiation sounds convincing but has never been observed yet the article presents it as a fact.
The rest of the article dealing with the information and firewall paradoxes and entanglement is also based on the assumption that Hawking radiation exists.
In fact there are papers that question whether Hawking radiation exists in the first place.

As far as the science goes though. An analogy might help. I do feel that when scientists investigate the universe, it is like a Roman trying to understand a working computer. If he presses some keys he can be sure of some results, yet he can not explain the fundamental basis of how it works.. maybe I'm being unkind. Maybe I could choose Galileo. However, I was kind to not choose a caveman. Yeah, you can be Galileo, I'll be the Roman.

This is what science is all about.
A cynical definition of a current scientific theory is that it is less wrong than the theory that preceded it.
There are four separate theories for gravity, the strong nuclear force, weak force and electromagnetism.
The problem here is to explain the formation and abundance of elements in the Universe at least three of the forces (strong, weak and electromagnetism) need to be unified in the early universe as explained by a GUT (Grand Unified Theory).

The scientists are getting there; the weak and electromagnetic forces have been unified to form an electroweak force in particle accelerators by the detection of W and Z bosons as predicted by theory.
The problem with testing a GUT is that the energy levels are way beyond what is possible with current particle accelerators.
Unifying gravity is a far greater problem; not only because it requires far larger energy levels than for a GUT but forming the theory itself is problematical using quantum field theory.

 

[Sam91]

Let me make a general comment about these articles you refer to.
They are examples of popsci articles written for the general public.
Popsci articles can vary from faithfully reproducing the science to exaggeration and sensationalism.
Your links sit somewhere between the extremes.

The first one is fairly restrained although the title “There’s Growing Evidence That the Universe Is Connected by Giant Structures” is somewhat premature as the article goes onto to state this needs to be independently confirmed and more data is required.

The second link is less credible as it portrays speculation as fact.
Anne seeing you stuck at the event horizon is a prediction of the Schwarzschild metric which describes the distortion of spacetime time around massive bodies such as planets, stars and non rotating black holes and is an extreme example of gravitational time dilation, the lesser effects of which have been observed on Earth from the Rebka-Pound experiment to GPS satellite time corrections.
While this part of the article is “reasonably accurate” the rest is not.
Burning up on the event horizon due to Hawking radiation sounds convincing but has never been observed yet the article presents it as a fact.
The rest of the article dealing with the information and firewall paradoxes and entanglement is also based on the assumption that Hawking radiation exists.
In fact there are papers that question whether Hawking radiation exists in the first place.



This is what science is all about.
A cynical definition of a current scientific theory is that it is less wrong than the theory that preceded it.
There are four separate theories for gravity, the strong nuclear force, weak force and electromagnetism.
The problem here is to explain the formation and abundance of elements in the Universe at least three of the forces (strong, weak and electromagnetism) need to be unified in the early universe as explained by a GUT (Grand Unified Theory).

The scientists are getting there; the weak and electromagnetic forces have been unified to form an electroweak force in particle accelerators by the detection of W and Z bosons as predicted by theory.
The problem with testing a GUT is that the energy levels are way beyond what is possible with current particle accelerators.
Unifying gravity is a far greater problem; not only because it requires far larger energy levels than for a GUT but forming the theory itself is problematical using quantum field theory.

The credibility issue is why I asked you for different sources the other day. You'd have a better idea at what sites are decent with regards to reliable reporting without being cumbersome to read. Those are what pop up in my google feed.

I agree with you in regards to the BBC article. It was a few articles like this in quick succession that made me stop the periodic perusal of the site's science section. I would love to know more about gravity. I aspired to be a physicist or a medical laboratory scientist as a child. I was particularly interested in chemistry and quantum mechanics, and blackholes.

I'm 20 years out of date with theories. I stopped buying New Scientist and Focus when I had to leave school (homelife). Reading about science kept the disappointment going. I'd spent ten years telling my little brother I was going to invent a force field lol (from the age of 5 or 6).

Still need to read your post properly from yesterday. I haven't forgotten. My brain is too busy and strained from a hectic day with lots of activity, research and essay writing. I'll get to it tomorrow. Right now, I'm trying to slow it down in order to sleep. Unfortunately, its wired and 'buzzing' and although the house is quiet it's like I have air conditioning in my head.. a strange audible yet inaudible noise. An oxymoron but the only way I can describe it. There's a tinnitus sensation but not actually in my ear too.. maybe it's in the eustachian tubes... is that even possible?? It's busy and energetic but with an ordinary amount of conscious thoughts. Think it is trying to process and store information.