The Trouble with Hubble Constant

[Serendipity]

This is a good summary of the problems scientists are experiencing with measuring the Hubble Constant and what the consequences are... The Hubble constant: a mystery that keeps getting bigger

 

[tegeus-Cromis]

I don't understand why the possibility that the Hubble "constant" is itself increasing over time isn't one of the options they're considering. That would go a long way toward reconciling the figure resulting from observations of the microwave background radiation (which applies to an early state of the universe) and that from local measurements (which applies to the current state).

And adding "dark radiation" is just piling hypothetical notions on top of other hypothetical notions. This just goes to further confirm something I've thought before: no matter how many scientific advances we have made, we are perhaps no more than one millionth of one percent closer to understanding the nature of the universe than was Anaximander 2600 years ago.

 

[tinkerdan]

The more we know--the more we know there is more that we need to know.
I think that sums up where we are today.
We are learning more and we have a lot more to learn before we even have a glimmer of a notion of what the real questions are to ask before we can understand what it is that we need to know. At the moment we can only guess.

It is almost mind-boggling.

If we were to look at the big bang from outside(yes we've been told that that isn't possible); however if we could we would see a mass--what was that mass encased in. One guess is that it was inside nothing and that the bang itself created the universe and space time that seems to us to be expanding at some possibly constant speed. However if it is expanding and there was nothing to expand into then what is it expanding into now? Did it create an infinite something that is what now the universe is expanding into? But then I recall a discussion about the rim of the galaxy and being scoffed at because there is no rim--The answer being that the universe is infinite and is expanding into itself. So maybe for our limited understanding we should say that the first thing that was created at big bang was the universe and it was a void and then there was the mass that exploded outward to expand and fill that void. We really don't know. Maybe there were several bangs and each created its own space time wave that pushed behind the previous space time wave. This is just one of possibly and infinite possible notions we could have and we won't know which ones to toss out until we know the right questions to ask.

Maybe everything was a big infinite marshmallow not dense at all.
The the inside foamy like area compressed into an infinitely small piece within an infinitly large vacuum. The big crunch--just before the big bang. Then refer to above after the infinite space was created.

 

[CupofJoe]

Or... And I'm just putting this out there...
The Programmers of this Reality, weren't as good as they thought...

 

[Ursa major]

first thing that was created at big bang was the universe and it was a void and then there was the mass that exploded outward to expand and fill that void

How does time work if there's nothing but a void.

And how, without time, can there then be anything....

 

[tinkerdan]

Are we still searching for the right questions?

How does time work if there's nothing but a void.

And how, without time, can there then be anything....

The mass from which the big bang came forth exists in whatever form: The first act of the big bang is the infinite void into which everything can then expand. The void may or may not have time as a component; if anything it seems like it may be mostly empty time and as expansion proceeds it is space time.

Maybe the question is what is space-time without the universe.
Or what is the universe without space-time.

Similar to the old which came first....

Anyway is the second question asking if there was anything before the big bang or intimating that there had to be time if there were some mass that experienced the big bang.

 

[Venusian Broon]

How does time work if there's nothing but a void.

And how, without time, can there then be anything....

We are but mortals chained to a dark wall frantically trying to make sense of the shadows dancing about the wall opposite us.

Perhaps some of us have figured out there must be a fire or some other light source and a procession of objects causing these shadows (although some of us believe these shadows to be real)...and some may even hypothesis that this is in fact a cave and therefore there must be an entrance out to an unbelievable real world....but how will we ever know?

Mind you it's fun speculating on the shadows, so let's do that.

I think time and mass are interlinked. (In a nod to Penrose) You have to have something that can change for time to have meaning at all. A proper void doesn't 'need' time in the same way our universe seems to require it.

But then to ponder your second point. Perhaps we don't need time as we think of it right now. Time could be entirely illusionary. I have a nice book on this that I should read soon. However, I am wanting to use it for a novel, so I'm going to remain somewhat tight-lipped about it at the mo'

 

[Ursa major]

I think time and mass are interlinked.

That was the basis on which I commented.

Time could be entirely illusionary. I have a nice book on this that I should read soon.

I've read a book like that. It seemed literally endless (i.e. the explanation for how it worked as we observe it to work, seemed to be missing).

 

[tinkerdan]

So the question seems to be--did time precede the existence of the universe.
Though there still might a question of whether the mass existed.
Maybe both time and mass came into existence at once--though that sounds like magic.

I also believe that what the universe banged out of was at complete rest and that as such it wasn't interlocked with time. It only aquired time when everything was set into motion. [It's possible the big bang was the birth of physics as we know it.]

 

[Ursa major]

It only aquired time when

I think we need to be more careful with the words we use...

...because "when" already (more than) implies the existence of time... as does any change, particularly, one might have thought, a state change as important as that between a universe at complete rest and one where "everything was set in motion".

 

[Venusian Broon]

That was the basis on which I commented.

Apologies, I was just thinking aloud and expanding on your comment.

I've read a book like that. It seemed literally endless (i.e. the explanation for how it worked as we observe it to work, seemed to be missing).

I fear this book could be flawed like this. At best I'm hoping it will lay out a very nice hypothetical argument for it's central ideas, but it will probably have sod all evidence that such a scheme really exists. Like a lot of high end cosmlogical 'answers'.

So the question seems to be--did time precede the existence of the universe.
Though there still might a question of whether the mass existed.

Well, I suppose it depends on what sort of model of the universe/multiverse you are looking at. And whether such models have something in existence before the start of this universe.

Look at the multiverse of eternal inflation - think of the multiverse as a forever expanding inflationary field that at random pops out universes, like they are currants in a bun. An infinite and timeless bun that just grows bigger and bigger, forever. Hopefully you get the analogy.

So perhaps in this case one could view time as a fundamental property of this inflationary field, i.e. the fact that it always expands at a certain rate. And that our universe, embedded as it is has it own 'local' time property derived of the interaction between the universe's expansion and the multiverses expansion.

I also believe that what the universe banged out of was at complete rest and that as such it wasn't interlocked with time. It only aquired time when everything was set into motion.

Interesting. Why? What was the process that 'set everything into motion.'? Could it be withdrawn?

 

[tinkerdan]

This all gets back to the fact that we are dealing with something that is difficult to comprehend because we are limited by what we know of how physics appears to work to us. The beginning of the universe doesn't have to adhere to our understanding.

We model the best we can within our understanding and we usually reach a point where we're unable to ask the right question, so instead we reason in circles and delve into cynical semantic arguments.

Sorry about that aquire thing.

I'm not certain of the argument presented; other than if you are not convinced there wasn't time by virtue of the semantics then there must have been some time before the big bang, I suppose and I'm not sure what difference it makes. Can you prove that there was no time before then? And just when did time begin?

I'm only explaining things within current understanding and my language has difficulty dealing with no-time or nul-time or absence of time so yeah you can punch time into my words any way you want--the question is where is your explanation of the no-time that you so want to see there. I haven't seen that.
I'm not trying to force feed you with my nonsense, you don't need to eat it, however it would be nice to know...
What proof is there of when time began if it has a beginning?

By your reasoning you can't even say there was a big bang because that requires time.
You can't have a beginning because it requires time.
Time requires time for time to have a beginning.

So the universe always was and always will be.
Forever time.

I'm sure you have a smarter explanation and that's all I'm expecting.

 

[Ursa major]

It's a matter of logic: if there is no time, there cannot be events happening in a time-ordered way. Thus without time, there can be no "before" or "when" or "after".

The only issue is whether or not time has always existed (or, at least, existed before our universe came into existence), or came into existence in parallel with our universe (which may have been at the Big Bang or at the creation of the pre-Big bang void you postulated).

 

[tinkerdan]

Not sure why you are so obsessed with time this way.
Time before the universe doesn't have to look like our time--doesn't have to be called time.

We call it time because that's how we've perceived it for so long. Space time is a slight difference but is still based on our perception.
We were not there to perceive it to experience it and to name it, however now that we are here and do perceive it when we talk that is how we speak of things and even if there wasn't a universe at some un-time the universe in our minds eye had to have a beginning and it doesn't matter what type of semantics you toss at it calling it logic.

Without time logically the universe couldn't just appear and logically there couldn't be anything to start with and logically there couldn't be anything to bang big or small, so time always existed in some way shape or form. But you don't know that because logically you weren't there. And we don't exist and are not having this conversation.

Logically nothing can come into existence from nothing to parallel anything not just because there wouldn't be any time for it but it defies physics.

The question is: does any of our understanding have any influence on what happened back then and is it even relevant to what happened--predating our time our universe our thinking. Which gets us back to how this is all nonsense anyway. So whether it makes logical sense to you or not I prefer to fall back on the when, the before, the after and all those artifacts of time because once again until it is proven that the universe always existed and its much older than we think, then in my infinitesimally small mind I can only see that it had a beginning.

However I'm not the one saying that there was no time back before there was space-time and as long as something existed to begin the universe it must have had some form of time even if in its compacted state it was quite different than what we've now defined.

 

[Ursa major]

If something happens before, or after, something else, how is time not involved? What do "before" and "after" mean without the exsitence of time? (And that's without worrying about things that don't happen literally instantaneously.)

Logically nothing can come into existence from nothing to parallel

This is physics' "it's turtles all the way down" problem... a problem that physics is not going to solve.

 

[tinkerdan]

Once again-I never said time wasn't involved--I think the worst I said was that things were not interlocked with time(meaning time as we know it as in space-time) which is because space-time wouldn't exist if what is expanding is the space-time(at least not as we know it) I never took time out of the equation because we simply don't know what things were like back then and we may never know. So I still don't understand....

 

[Ursa major]

I don't know how many ways I can type this, but: anything that allows non-simultaneous events to occur is some sort of time. (Indeed, the very concept of an event** requires time.)

Whether it's like the time in spacetime is neither here nor there (pun not intended).


** - I suppose we might have to consider that, while we see (from within our universe) the creation of our universe as an event, it may not be an event outside our universe.

 

[tinkerdan]

okay so we agree.

 

[CTRandall]

Time is a function of consciousness.

 

[RJM Corbet]

Time and space are the impenetrable walls of the room of nature to which we are confined. But nature is just one of many, perhaps infinite other dimensions within a greater house of Spirit that contains and surrounds and permeates the dimension of Nature. Perhaps?

Dimensions interweave and coexist like threads in a tapestry. My Father's house has many mansions? Sometimes we glimpse but cannot make sense of strange vibrations coming from beyond our own dimension.

The greater wheel of Spirit turns the lesser wheel of nature, but is not turned by it.

Time and space are the walls of our dimension. A bit like noisy children in a nursery our natural senses are not equipped to deal with anything beyond? And our telescopes and microscopes and other truly wonderful and ingenious scientific instruments -- are really just extensions of our own natural senses.

We are not equipped by natural logic to understand beyond nature.

Perhaps?