Is Time Just an Idea?

[Sy Borg]

Just as well, being an inveterate thought experimenter, I would have guessed that the central part of the black hole is completely "full" - at 100% possible intensity, with stuff constantly smashing into it at around the speed of light. Thus, any extra mass attracted by the BH would not settle in the centre (I cannot bring myself to say "singularity", which is an unrealistic concept) so any extra mass just increases the BH's radius.

Yes, I can imagine that. It's kind of how you'd imagine things to happen if black holes continued to behave more or less as they were when they were just regular stars, but with a surface escape velocity greater than light speed. I guess we can kind of visualize it, in a hellish sort of way.

But I think the environment inside the event horizon of a black hole predicted by General Relativity is so utterly alien that it's very difficult to imagine experiencing in any direct way (as opposed to "experiencing" it indirectly via the theory). As I understand it, the event horizon (defined in a particular class of black holes by the Schwarzschild radius) is the notional sphere on the surface of which the escape velocity is the speed of light. Presumably that wouldn't generally coincide with the physical surface of the object which became the black hole, if that object has continuned to contract below that surface. But I don't know whether, once that has happened, that underlying object must always contract to a singularity. (I see why you can't bring yourself to say "singularity". It seems, by its nature, to be an abstract, mathematical concept does't it.). I presume it depends what forces are left that are man enough to fight against gravity. In normal stars and planets that would be electrostatic repulsion (i.e. the EM force). But when gravity overcomes that there are more exotic repulsive forces, such as neutron degeneracy pressure (the force which keeps neutron stars "inflated").

Imagining being inside the event horizon, perhaps in orbit around the singularity, or whatever is in there, is extremely weird. As I said, as I understand it, according to the GR model, the curvature of spacetime is such that at any given distance from the centre of the BH, distances further away from that centre are not just further away in space; they're in the past. So all possible futures are closer to the centre. So, presumably, simply by existing you get closer to the centre. If it was somehow possible to be alive in that environment it's impossible to intuitively imagine what it would feel like.

No argument there - if you are in a black hole then all possible futures of your spaghettified stream of atoms will most certainly lie closer to the centre! :)

While we can't say quite what it would be like to be capable of surviving in a black hole, I suspect it would be so overwhelmingly and disorientingly psychedelic that one would wish not to survive. Everything would be distorting wildly as if in a hall of mirrors, except it wouldn't just be visual, but physical.

Then again, we all live our lives at the bottom of a gravity well, with feet usually ageing slower than heads, that is, feet live very, very slightly in the past in relation to the head. Google says that, over the usual lifespan, the difference will be around 90 billionths of a second. That's about as much

Yes, I can't abide singularities. It would make more sense if a BH's centre turned out to be a quark-gluon or Planck point. Still, reality is weird and there's still much to be explained, so I probably should be more broad-minded about it.

[Sy Borg]

Cool simulations BTW. As science probes questions that cannot be accessed physically, simulations will be ever more important.

Thanks. The simulation in that site of two gravitating objects colliding is a sample of a few that I did. I intended that site to contain various things that I regard as being on the border between art, science and software, but I haven't got around to putting much on it. The simulation involved just plotting the paths of a few hundred objects as they are each attracted to each other by Newtonian gravity and then, when they get to within a defined distance of each other, adding a repulsive force to keep them apart. Other people have done some more realistic 3D ones, with much larger numbers of particles. But the number of calculations involved means that these kinds of things take a long time to render on a desktop computer. I think the one on the site took a couple of hours.

There's a colliding galaxy simulation that gets trotted out regularly in any documentary about galaxies.

Really, just about any aspect of science/nature is art - as with paintings, all that's needed is to be at the optimal distance.

A bit off topic but whattheheck. TGIF.

[NickGaspar]

Some factoids:

1. The arrow of time is not absolute. Gravity impacts on its rate of passing and, at quantum scales, time can be reversed.

2. Time only passes subjectively if we are conscious; unconsciousness is subjective timelessness.

3. We don't know what goes on in the centre of black holes. Theoretically, you would see the entire universe's history immediately come and go in a flash (which begs the question about before and after the flash, of it before or after is possible).

4. It's said that the arrow of time stems from entropy (which is argued), which in turn stems from dark energy (also argued).

Hopefully someone else will know what to do with them because I don't Time remains as mysterious to me as ever.

Gravity impacts processes...not time. Time is just a concept we use to quantify temporal properties of evolving processes.
Time doesn't passes.....the processes of things (we as a biological process, a day on earth) have a standard pace independent of the observer.

-"4. It's said that the arrow of time stems from entropy (which is argued), which in turn stems from dark energy (also argued). ''
-The "arrow of time" is just a symbol that shows to the direction all processes unfold...entropy is just an observer relative term we use to describe the inevitable stage of a process to reach equilibrium.

[Sy Borg]

Some factoids:

1. The arrow of time is not absolute. Gravity impacts on its rate of passing and, at quantum scales, time can be reversed.

2. Time only passes subjectively if we are conscious; unconsciousness is subjective timelessness.

3. We don't know what goes on in the centre of black holes. Theoretically, you would see the entire universe's history immediately come and go in a flash (which begs the question about before and after the flash, of it before or after is possible).

4. It's said that the arrow of time stems from entropy (which is argued), which in turn stems from dark energy (also argued).

Hopefully someone else will know what to do with them because I don't :) Time remains as mysterious to me as ever.

Gravity impacts processes...not time. Time is just a concept we use to quantify temporal properties of evolving processes.
Time doesn't passes.....the processes of things (we as a biological process, a day on earth) have a standard pace independent of the observer.

-"4. It's said that the arrow of time stems from entropy (which is argued), which in turn stems from dark energy (also argued). ''
-The "arrow of time" is just a symbol that shows to the direction all processes unfold...entropy is just an observer relative term we use to describe the inevitable stage of a process to reach equilibrium.

Fair enough response. Your thoughts on the relationship between gravity and time?

[NickGaspar]

Some factoids:

1. The arrow of time is not absolute. Gravity impacts on its rate of passing and, at quantum scales, time can be reversed.

2. Time only passes subjectively if we are conscious; unconsciousness is subjective timelessness.

3. We don't know what goes on in the centre of black holes. Theoretically, you would see the entire universe's history immediately come and go in a flash (which begs the question about before and after the flash, of it before or after is possible).

4. It's said that the arrow of time stems from entropy (which is argued), which in turn stems from dark energy (also argued).

Hopefully someone else will know what to do with them because I don't Time remains as mysterious to me as ever.

Gravity impacts processes...not time. Time is just a concept we use to quantify temporal properties of evolving processes.
Time doesn't passes.....the processes of things (we as a biological process, a day on earth) have a standard pace independent of the observer.

-"4. It's said that the arrow of time stems from entropy (which is argued), which in turn stems from dark energy (also argued). ''
-The "arrow of time" is just a symbol that shows to the direction all processes unfold...entropy is just an observer relative term we use to describe the inevitable stage of a process to reach equilibrium.

Fair enough response. Your thoughts on the relationship between gravity and time?

The relationship between gravity and time is more of an observer dependent narrative. We observe that Gravity affects the "pace/duration" of physical/material processes. Those two temporal qualities are constant on earth, but when we observe them away from the surface of the earth, they change. We are able to observe that through "Time". "Time" is the concept and scale we use to quantify those processes.
i.e.A human biology has specific rhythms on earth. By studying Astronauts we observe that their biological rhythms are slower when in space.
So Time as a scale or a concept doesn't really change, but it help us detect changes caused by gravity on the pace of natural processes.

[Sy Borg]

Some factoids:

1. The arrow of time is not absolute. Gravity impacts on its rate of passing and, at quantum scales, time can be reversed.

2. Time only passes subjectively if we are conscious; unconsciousness is subjective timelessness.

3. We don't know what goes on in the centre of black holes. Theoretically, you would see the entire universe's history immediately come and go in a flash (which begs the question about before and after the flash, of it before or after is possible).

4. It's said that the arrow of time stems from entropy (which is argued), which in turn stems from dark energy (also argued).

Hopefully someone else will know what to do with them because I don't :) Time remains as mysterious to me as ever.

Gravity impacts processes...not time. Time is just a concept we use to quantify temporal properties of evolving processes.
Time doesn't passes.....the processes of things (we as a biological process, a day on earth) have a standard pace independent of the observer.

-"4. It's said that the arrow of time stems from entropy (which is argued), which in turn stems from dark energy (also argued). ''
-The "arrow of time" is just a symbol that shows to the direction all processes unfold...entropy is just an observer relative term we use to describe the inevitable stage of a process to reach equilibrium.

Fair enough response. Your thoughts on the relationship between gravity and time?

The relationship between gravity and time is more of an observer dependent narrative. We observe that Gravity affects the "pace/duration" of physical/material processes. Those two temporal qualities are constant on earth, but when we observe them away from the surface of the earth, they change. We are able to observe that through "Time". "Time" is the concept and scale we use to quantify those processes.
i.e.A human biology has specific rhythms on earth. By studying Astronauts we observe that their biological rhythms are slower when in space.
So Time as a scale or a concept doesn't really change, but it help us detect changes caused by gravity on the pace of natural processes.

Thanks, that makes sense.

Time to us humans in a practical sense is based on rhythm, the Earth's and Moon's respective orbits and the Earth's rotation. I thus always thought it was illogical for scientists to claim time didn't exist before the big bang. I would think, rather, that time simply could not be measured. Things still would have happened back then, presumably the winking in and out of existence of virtual particles, just nothing that could be timed.

I suppose the claim that time didn't exist back then can be seen as an admission that time is only a construct.

[NickGaspar]

Gravity impacts processes...not time. Time is just a concept we use to quantify temporal properties of evolving processes.
Time doesn't passes.....the processes of things (we as a biological process, a day on earth) have a standard pace independent of the observer.

-"4. It's said that the arrow of time stems from entropy (which is argued), which in turn stems from dark energy (also argued). ''
-The "arrow of time" is just a symbol that shows to the direction all processes unfold...entropy is just an observer relative term we use to describe the inevitable stage of a process to reach equilibrium.

Fair enough response. Your thoughts on the relationship between gravity and time?

The relationship between gravity and time is more of an observer dependent narrative. We observe that Gravity affects the "pace/duration" of physical/material processes. Those two temporal qualities are constant on earth, but when we observe them away from the surface of the earth, they change. We are able to observe that through "Time". "Time" is the concept and scale we use to quantify those processes.
i.e.A human biology has specific rhythms on earth. By studying Astronauts we observe that their biological rhythms are slower when in space.
So Time as a scale or a concept doesn't really change, but it help us detect changes caused by gravity on the pace of natural processes.

Thanks, that makes sense.

Time to us humans in a practical sense is based on rhythm, the Earth's and Moon's respective orbits and the Earth's rotation. I thus always thought it was illogical for scientists to claim time didn't exist before the big bang. I would think, rather, that time simply could not be measured. Things still would have happened back then, presumably the winking in and out of existence of virtual particles, just nothing that could be timed.

I suppose the claim that time didn't exist back then can be seen as an admission that time is only a construct.

Well scientists use these terms pretty differently from their colloquial usages. Since all processes in the universe are contingent to the temporal qualities of the main process we call universe, I can see what they are attempting to explain and I can see how wrong it can sound for our "ears"!
Its a fact that we can not talk about anything before or after our Universe so any assumption beyond that point would be irrational.

The relative new concept of Cosmos try to "correct" this limited view, by allowing other processes outside and preceding our Universe to "exist".(like virtual particles, extra dimension, multiverse etc)
After all big bang cosmology says NOTHING about what existed before the BB or what caused this cataclysmic event .... it has zero conflicts with any of those ideas.
But I think we are in agreement.
Time is a concept based on a real phenomenon. Processes do not happen all at once and in a steady rhythm(to use your term) and we can use a scale to quantify, compare and find discrepancies between processes under different conditions(i.e. affected by gravity etc).
The rhythm of expansion of this Universe provides us info for the age of this process and its "birth" the "oldest" thing that we can observe and quatify.
Time might be more than a construct, but it is observer dependent.
Defining time based on the actual phenomenon that forced us to come up with this concept in the first place is the best way to understand why time shouldn't be limited by the temporal properties of our Universe.
We have indications(not even good evidence though) to believe that cosmic events/processes thus "time" didn't start and won't end with the process of our Universe.

[SteveKlinko]

I think you alluded to this already, but this is my thinking on Time: There is no actual Time Phenomenon that exists apart from the relationships between Physical Objects and Processes. Without Physical Objects and Processes there is no Phenomenon of Time. If we can say there was nothing (no Physical Things) before the Big Bang then we can say that there was no Phenomenon of Time before the Big Bang. There was no Infinite past and not even a 1 year, or 1 day, or 1 second before the Big Bang. Before the Big Bang there was no Matter, Energy, or Space, and therefore no Time. This is because Time is merely the relationship between and within Matter, Energy, and Space.

[Belindi]

Nick Gaspar wrote:

Time is a concept based on a real phenomenon.

phenomenon
/fəˈnɒmɪnən/
Learn to pronounce
noun
1.
a fact or situation that is observed to exist or happen, especially one whose cause or explanation is in question.
"glaciers are interesting natural phenomena"
Similar:
occurrence
event
happening
fact
situation
circumstance
experience
case
incident
episode
sight
appearance
thing
2.
a remarkable person or thing.
"the band was a pop phenomenon just for their sales figures alone"

It's obviously definition number 1. that this is about.

No phenomenon is real in the sense that it's independent of being experienced. Some would claim phenonema are real whether or not they are experienced. The question is not physical but metaphysical. As metaphysical, the question will not be amenable to empirical investigations but will be embedded in some large theory of existence.

Time might be more than a construct, but it is observer dependent.

(NG)

If so then time is dual aspect and may be understood both ways depending on the Dasein, or depending on a consensus so a conversation can take place.

[NickGaspar]

Nick Gaspar wrote:

Time is a concept based on a real phenomenon.

phenomenon
/fəˈnɒmɪnən/
Learn to pronounce
noun
1.
a fact or situation that is observed to exist or happen, especially one whose cause or explanation is in question.
"glaciers are interesting natural phenomena"
Similar:
occurrence
event
happening
fact
situation
circumstance
experience
case
incident
episode
sight
appearance
thing
2.
a remarkable person or thing.
"the band was a pop phenomenon just for their sales figures alone"

It's obviously definition number 1. that this is about.

No phenomenon is real in the sense that it's independent of being experienced. Some would claim phenonema are real whether or not they are experienced. The question is not physical but metaphysical. As metaphysical, the question will not be amenable to empirical investigations but will be embedded in some large theory of existence.

Time might be more than a construct, but it is observer dependent.

(NG)

If so then time is dual aspect and may be understood both ways depending on the Dasein, or depending on a consensus so a conversation can take place.

-"No phenomenon is real in the sense that it's independent of being experienced."
-Pls read again the first definition. (a fact or situation that is observed to exist or happen...) A fact are objective and independent of an observer. An observer only experiences and identifies a fact as specific phenomenon.

-" Some would claim phenonema are real whether or not they are experienced. "
-Only those who understand Forensic Reasoning.

-" The question is not physical but metaphysical. "
-Those are not mutually exclusive terms. A metaphysical question can either address a physical or a non physical subject. The problem rises when a question addresses the supernatural.

-"As metaphysical, the question will not be amenable to empirical investigations but will be embedded in some large theory of existence."
-I think you use a definition of metaphysical that isn't used in Philosophy. Metaphysical in philosophy doesn't mean "non physical". It means beyond our current knowledge.
So if a metaphysical question is not amenable to empirical investigation, then the problem lies in our question.

-"If so then time is dual aspect and may be understood both ways depending on the Dasein, or depending on a consensus so a conversation can take place."
-Time is a simple concept based on an observable fact of "Processes not happening all at once and in different rhythms". The process has properties (duration, pace etc) that we can quantify by a simple scale (time). There is nothing supernatural or dualistic or magical in the concept of time.
When I say its more than a concept I point out the facts that render the concept useful and meaningful for its quantification.

[Belindi]

Nick Gaspar wrote:

Time is a concept based on a real phenomenon.

phenomenon
/fəˈnɒmɪnən/
Learn to pronounce
noun
1.
a fact or situation that is observed to exist or happen, especially one whose cause or explanation is in question.
"glaciers are interesting natural phenomena"
Similar:
occurrence
event
happening
fact
situation
circumstance
experience
case
incident
episode
sight
appearance
thing
2.
a remarkable person or thing.
"the band was a pop phenomenon just for their sales figures alone"

It's obviously definition number 1. that this is about.

No phenomenon is real in the sense that it's independent of being experienced. Some would claim phenonema are real whether or not they are experienced. The question is not physical but metaphysical. As metaphysical, the question will not be amenable to empirical investigations but will be embedded in some large theory of existence.

Time might be more than a construct, but it is observer dependent.

(NG)

If so then time is dual aspect and may be understood both ways depending on the Dasein, or depending on a consensus so a conversation can take place.

-"No phenomenon is real in the sense that it's independent of being experienced."
-Pls read again the first definition. (a fact or situation that is observed to exist or happen...) A fact are objective and independent of an observer. An observer only experiences and identifies a fact as specific phenomenon.

-" Some would claim phenonema are real whether or not they are experienced. "
-Only those who understand Forensic Reasoning.

-" The question is not physical but metaphysical. "
-Those are not mutually exclusive terms. A metaphysical question can either address a physical or a non physical subject. The problem rises when a question addresses the supernatural.

-"As metaphysical, the question will not be amenable to empirical investigations but will be embedded in some large theory of existence."
-I think you use a definition of metaphysical that isn't used in Philosophy. Metaphysical in philosophy doesn't mean "non physical". It means beyond our current knowledge.
So if a metaphysical question is not amenable to empirical investigation, then the problem lies in our question.

-"If so then time is dual aspect and may be understood both ways depending on the Dasein, or depending on a consensus so a conversation can take place."
-Time is a simple concept based on an observable fact of "Processes not happening all at once and in different rhythms". The process has properties (duration, pace etc) that we can quantify by a simple scale (time). There is nothing supernatural or dualistic or magical in the concept of time.
When I say its more than a concept I point out the facts that render the concept useful and meaningful for its quantification.

Observation doesn't imply observer. Observations attributed to Nick Gaspar or to Belinda do not imply Nick Gaspar or Belinda exist other than as collections of observations.

[NickGaspar]

Nick Gaspar wrote:

Time is a concept based on a real phenomenon.

phenomenon
/fəˈnɒmɪnən/
Learn to pronounce
noun
1.
a fact or situation that is observed to exist or happen, especially one whose cause or explanation is in question.
"glaciers are interesting natural phenomena"
Similar:
occurrence
event
happening
fact
situation
circumstance
experience
case
incident
episode
sight
appearance
thing
2.
a remarkable person or thing.
"the band was a pop phenomenon just for their sales figures alone"

It's obviously definition number 1. that this is about.

No phenomenon is real in the sense that it's independent of being experienced. Some would claim phenonema are real whether or not they are experienced. The question is not physical but metaphysical. As metaphysical, the question will not be amenable to empirical investigations but will be embedded in some large theory of existence.

Time might be more than a construct, but it is observer dependent.

(NG)

If so then time is dual aspect and may be understood both ways depending on the Dasein, or depending on a consensus so a conversation can take place.

-"No phenomenon is real in the sense that it's independent of being experienced."
-Pls read again the first definition. (a fact or situation that is observed to exist or happen...) A fact are objective and independent of an observer. An observer only experiences and identifies a fact as specific phenomenon.

-" Some would claim phenonema are real whether or not they are experienced. "
-Only those who understand Forensic Reasoning.

-" The question is not physical but metaphysical. "
-Those are not mutually exclusive terms. A metaphysical question can either address a physical or a non physical subject. The problem rises when a question addresses the supernatural.

-"As metaphysical, the question will not be amenable to empirical investigations but will be embedded in some large theory of existence."
-I think you use a definition of metaphysical that isn't used in Philosophy. Metaphysical in philosophy doesn't mean "non physical". It means beyond our current knowledge.
So if a metaphysical question is not amenable to empirical investigation, then the problem lies in our question.

-"If so then time is dual aspect and may be understood both ways depending on the Dasein, or depending on a consensus so a conversation can take place."
-Time is a simple concept based on an observable fact of "Processes not happening all at once and in different rhythms". The process has properties (duration, pace etc) that we can quantify by a simple scale (time). There is nothing supernatural or dualistic or magical in the concept of time.
When I say its more than a concept I point out the facts that render the concept useful and meaningful for its quantification.

Observation doesn't imply observer. Observations attributed to Nick Gaspar or to Belinda do not imply Nick Gaspar or Belinda exist other than as collections of observations.

Oh! So we are already in the woo territory where definitions and facts do not play a role in how we confirm or verify claims. How convenient!
Existence is necessary for observations to be made. Both the observer and what it observes need to exist.
If you want to play tennis without the net then you are not in the correct forum. They are theological and new age forums that you can talk about your non existence while eating a sandwich...in order to provide fuel to your metabolism...for no reason at all (according to you).
I am sure if you identify the thief taking your car, you won't repeat the same ideas in the court of law....

[Sy Borg]

Fair enough response. Your thoughts on the relationship between gravity and time?

The relationship between gravity and time is more of an observer dependent narrative. We observe that Gravity affects the "pace/duration" of physical/material processes. Those two temporal qualities are constant on earth, but when we observe them away from the surface of the earth, they change. We are able to observe that through "Time". "Time" is the concept and scale we use to quantify those processes.
i.e.A human biology has specific rhythms on earth. By studying Astronauts we observe that their biological rhythms are slower when in space.
So Time as a scale or a concept doesn't really change, but it help us detect changes caused by gravity on the pace of natural processes.

Thanks, that makes sense.

Time to us humans in a practical sense is based on rhythm, the Earth's and Moon's respective orbits and the Earth's rotation. I thus always thought it was illogical for scientists to claim time didn't exist before the big bang. I would think, rather, that time simply could not be measured. Things still would have happened back then, presumably the winking in and out of existence of virtual particles, just nothing that could be timed.

I suppose the claim that time didn't exist back then can be seen as an admission that time is only a construct.

Well scientists use these terms pretty differently from their colloquial usages. Since all processes in the universe are contingent to the temporal qualities of the main process we call universe, I can see what they are attempting to explain and I can see how wrong it can sound for our "ears"!
Its a fact that we can not talk about anything before or after our Universe so any assumption beyond that point would be irrational.

The relative new concept of Cosmos try to "correct" this limited view, by allowing other processes outside and preceding our Universe to "exist".(like virtual particles, extra dimension, multiverse etc)
After all big bang cosmology says NOTHING about what existed before the BB or what caused this cataclysmic event .... it has zero conflicts with any of those ideas.
But I think we are in agreement.
Time is a concept based on a real phenomenon. Processes do not happen all at once and in a steady rhythm(to use your term) and we can use a scale to quantify, compare and find discrepancies between processes under different conditions(i.e. affected by gravity etc).
The rhythm of expansion of this Universe provides us info for the age of this process and its "birth" the "oldest" thing that we can observe and quantify.
Time might be more than a construct, but it is observer dependent.
Defining time based on the actual phenomenon that forced us to come up with this concept in the first place is the best way to understand why time shouldn't be limited by the temporal properties of our Universe.
We have indications(not even good evidence though) to believe that cosmic events/processes thus "time" didn't start and won't end with the process of our Universe.

Yes, it seems we agree on this. I see nothing to add or "correct" in the above. My gut feeling is that there are some "unknown unknowns" regarding time because scientific orthodoxy on the subject seems so logical and reasonable, but is rather unsatisfying.

[NickGaspar]

The relationship between gravity and time is more of an observer dependent narrative. We observe that Gravity affects the "pace/duration" of physical/material processes. Those two temporal qualities are constant on earth, but when we observe them away from the surface of the earth, they change. We are able to observe that through "Time". "Time" is the concept and scale we use to quantify those processes.
i.e.A human biology has specific rhythms on earth. By studying Astronauts we observe that their biological rhythms are slower when in space.
So Time as a scale or a concept doesn't really change, but it help us detect changes caused by gravity on the pace of natural processes.

Thanks, that makes sense.

Time to us humans in a practical sense is based on rhythm, the Earth's and Moon's respective orbits and the Earth's rotation. I thus always thought it was illogical for scientists to claim time didn't exist before the big bang. I would think, rather, that time simply could not be measured. Things still would have happened back then, presumably the winking in and out of existence of virtual particles, just nothing that could be timed.

I suppose the claim that time didn't exist back then can be seen as an admission that time is only a construct.

Well scientists use these terms pretty differently from their colloquial usages. Since all processes in the universe are contingent to the temporal qualities of the main process we call universe, I can see what they are attempting to explain and I can see how wrong it can sound for our "ears"!
Its a fact that we can not talk about anything before or after our Universe so any assumption beyond that point would be irrational.

The relative new concept of Cosmos try to "correct" this limited view, by allowing other processes outside and preceding our Universe to "exist".(like virtual particles, extra dimension, multiverse etc)
After all big bang cosmology says NOTHING about what existed before the BB or what caused this cataclysmic event .... it has zero conflicts with any of those ideas.
But I think we are in agreement.
Time is a concept based on a real phenomenon. Processes do not happen all at once and in a steady rhythm(to use your term) and we can use a scale to quantify, compare and find discrepancies between processes under different conditions(i.e. affected by gravity etc).
The rhythm of expansion of this Universe provides us info for the age of this process and its "birth" the "oldest" thing that we can observe and quantify.
Time might be more than a construct, but it is observer dependent.
Defining time based on the actual phenomenon that forced us to come up with this concept in the first place is the best way to understand why time shouldn't be limited by the temporal properties of our Universe.
We have indications(not even good evidence though) to believe that cosmic events/processes thus "time" didn't start and won't end with the process of our Universe.

Yes, it seems we agree on this. I see nothing to add or "correct" in the above. My gut feeling is that there are some "unknown unknowns" regarding time because scientific orthodoxy on the subject seems so logical and reasonable, but is rather unsatisfying.

Rumsfeld's unknownism haha. Sure I can see that.
There are also unknown knows, things we already know but we either straight up don't realize it or we question them so much on whether they are our final answers that makes us believe that there are uknown unknowns.
This is the whole issue in Proof, verification and falsification methods of evaluation. We can never be sure if we the answer we have is the final one so we can only attempt to falsify it.

[Sy Borg]

Thanks, that makes sense.

Time to us humans in a practical sense is based on rhythm, the Earth's and Moon's respective orbits and the Earth's rotation. I thus always thought it was illogical for scientists to claim time didn't exist before the big bang. I would think, rather, that time simply could not be measured. Things still would have happened back then, presumably the winking in and out of existence of virtual particles, just nothing that could be timed.

I suppose the claim that time didn't exist back then can be seen as an admission that time is only a construct.

Well scientists use these terms pretty differently from their colloquial usages. Since all processes in the universe are contingent to the temporal qualities of the main process we call universe, I can see what they are attempting to explain and I can see how wrong it can sound for our "ears"!
Its a fact that we can not talk about anything before or after our Universe so any assumption beyond that point would be irrational.

The relative new concept of Cosmos try to "correct" this limited view, by allowing other processes outside and preceding our Universe to "exist".(like virtual particles, extra dimension, multiverse etc)
After all big bang cosmology says NOTHING about what existed before the BB or what caused this cataclysmic event .... it has zero conflicts with any of those ideas.
But I think we are in agreement.
Time is a concept based on a real phenomenon. Processes do not happen all at once and in a steady rhythm(to use your term) and we can use a scale to quantify, compare and find discrepancies between processes under different conditions(i.e. affected by gravity etc).
The rhythm of expansion of this Universe provides us info for the age of this process and its "birth" the "oldest" thing that we can observe and quantify.
Time might be more than a construct, but it is observer dependent.
Defining time based on the actual phenomenon that forced us to come up with this concept in the first place is the best way to understand why time shouldn't be limited by the temporal properties of our Universe.
We have indications(not even good evidence though) to believe that cosmic events/processes thus "time" didn't start and won't end with the process of our Universe.

Yes, it seems we agree on this. I see nothing to add or "correct" in the above. My gut feeling is that there are some "unknown unknowns" regarding time because scientific orthodoxy on the subject seems so logical and reasonable, but is rather unsatisfying.

Rumsfeld's unknownism haha. Sure I can see that.
There are also unknown knows, things we already know but we either straight up don't realize it or we question them so much on whether they are our final answers that makes us believe that there are unknown unknowns.
This is the whole issue in Proof, verification and falsification methods of evaluation. We can never be sure if we the answer we have is the final one so we can only attempt to falsify it.

We might agree to disagree there. Given that, in historical terms, science has barely emerged from its infancy, I think it likely that there are significant unknowns regarding time that our brains may not even be equipped to comprehend.