Energy Vs Dark Energy

[A-wal]

Edit: Something related...sorta.

Nice video. Look at all those views. He obviously struck a scientific nerve.

 

You're catching a bit. The point was Ball (A) hits BEFORE ball (B ) because the forces affecting it have been affecting it for longer. A already has 9.8m/s of speed, because of that 1 second lead time, while (B ) is starting from rest. This is the inverse application of how HC is shown to be Growing rather than shrinking. Kinda. Close enough.

Oh okay. So your point was that distant galaxies have had longer to accelerate away from us? But we're seeing them (and their supposed recessional velocity) as they were in the past. The further away the galaxy, the LESS time it's been moving away from us.

 

If your point is that the light itself has been traveling for longer through expanding space and this has stretched its wavelength and so isn't a true indication that the more distant galaxies are receding faster than the nearby ones then this is a deviation from the accepted model in which the more distant a galaxy, the faster it moves away from us because of a greater amount of expanding space between us and them.

 

There is "more space" between the farther galaxies and us. Since space itself seems to be expanding uniformly, more of it means it expands faster. Maybe the Single bacteria petri dish versin of that same additive equation (total at future time)= (current amount)(1+rate)^time (same equation as the mutual fund one)

 

What that works out to is that if you have 20ly between us and 1 star, that number will expand by the same fixed ratio as the one 10ly away.

Yes I know but even using that expansion model, if galaxies recede faster over a greater distance in space then they're receding faster the further we look back in time and that's a slowing expansion rate. You can't have a universe where galaxies that are more distant in space (further back in time) are moving away from us faster and nearby (less far back in time) galaxies are moving away from us slower AND have an expansion rate that increases over time because it's a contradiction.

 

An expansion rate that increases over time would mean that the further back in time (the greater their distance from us in space) we look, the slower we see them moving away from us.

 

Edit: and if you want to REALLY terrify yourself. Use some grade 10 algebra manipulation on that equation and find out at what future time(or total distance) the added extra amount of space become larger than the max speed of light.

Yea I know. That's another issue I have with the model.

As for other explanations... there's quite a few possible ones that arn't quite so "crazy" as they seem on first look.

Do any of them give any reason to think that redshift being caused by distance traveled isn't a much simpler explanation for redshift being proportional to distance?

 

Or explain how an expansion of the space between two objects is somehow distinct from the objects moving away from each other, faster than the speed of light in this case?

 

Or explain how the expansion could possibly be speeding up despite the fact that the further back in time we look, the faster the supposed expansion?

If two objects are moving away from each other then the space between them is expanding, if two objects are moving towards each other then the space between them is contracting. There's no distinction between objects moving relative to each other and the space between those objects expanding/contracting. If you were to go through the SR thought experiments with expanding contracting space between the objects then nothing changes. You'd still get exactly the same paradoxes and mass increases if objects were able to reach the speed of light relative to other objects.

[GAHD]

If two objects are moving away from each other then the space between them is expanding, if two objects are moving towards each other then the space between them is contracting. There's no distinction between objects moving relative to each other and the space between those objects expanding/contracting. If you were to go through the SR thought experiments with expanding contracting space between the objects then nothing changes. You'd still get exactly the same paradoxes and mass increases if objects were able to reach the speed of light relative to other objects.

Change the word "space" here to "distance"

 

"space" as I am using it here refers to, litteraly, "Space-time" itself. That "material" which stops matter from all being in the same location at one time, which is itself altered by gravity. 

The whole concept isn't that "things are moving" it that space, itself, the material, is propagating like bacteria in a petri dish. That is why you can "spin it on it's head, and look at it like everything is shrinking." You grok the difference? When the fabric of reality itself seems to be just constantly "Popping into existance" everywhere all at once, that is VERY different than things spontaneously gaining momentum via some repulsive force between them.

 

AFAICT the prevailing thoughts on it revolve around the "virtual particles" sometimes ending up in an arrangement that "stays" because it's now the same configuration as the "stuff" around it that makes up the substrate of reality itself. That's (as I understand it) what Wilczek is prattling on about with the idea that "space" seems to be a" quark-antiquark crystaline superconductive structure"...and it's self-propagating like an ice crystal in super-cooled water.

[A-wal]

Change the word "space" here to "distance"

Why? It is true to say that the distance between two objects moving away from each other is expanding but it's also true to say that the space between them is expanding, there's no distinction in this case. The distance in space is expanding between two objects that are moving away from each other.

 

"space" as I am using it here refers to, litteraly, "Space-time" itself. That "material" which stops matter from all being in the same location at one time, which is itself altered by gravity.

Spacetime can't expand, or contract or change in any other way over time because time is already included as part of it.

 

The whole concept isn't that "things are moving" it that space, itself, the material, is propagating like bacteria in a petri dish. That is why you can "spin it on it's head, and look at it like everything is shrinking." You grok the difference? When the fabric of reality itself seems to be just constantly "Popping into existance" everywhere all at once, that is VERY different than things spontaneously gaining momentum via some repulsive force between them.

I know that's the concept but either way, it's an increase in the amount of spacial distance between the two objects. The 'difference' is only in your choice of words to describe recessional motion. It's a way for scientists to handwave out of the fact that it violates SR, but it doesn't work because that increase of the distance in space between objects couldn't possibly accelerate them to a relative velocity of the speed of light however you choose to look at it, for the reasons described in SR that apply to motion itself, regardless of the method of acceleration even if there were some difference, which there isn't.

 

But putting that aside for the moment, it doesn't alter the fact that if the end result is galaxies moving away from us faster the further we look back in time then the rate of the supposed expansion is slowing down, not speeding up.

 

AFAICT the prevailing thoughts on it revolve around the "virtual particles" sometimes ending up in an arrangement that "stays" because it's now the same configuration as the "stuff" around it that makes up the substrate of reality itself. That's (as I understand it) what Wilczek is prattling on about with the idea that "space" seems to be a" quark-antiquark crystaline superconductive structure"...and it's self-propagating like an ice crystal in super-cooled water.

And that fubar is for some inexplicable reason preferred to the interpretation that the reason redshift is proportional to distance is because the light is being redshifted as it's travels through space, not because the object emitting the light is moving away from us.

[GAHD]

" because the light is being redshifted as it's travels through space" is directly related to "that FUBAR"...and once again I'm left with "jargon" as language barrier, as you don't actually seem to grok the jargon used well enough to follow what's being said, or to articulate your point against it in a way that isn't limited by same.

Red-shift-by-distance-traveled is used to determine how much distance was traveled, and how much space has "expanded" over that distance. That's the whole, "standard candle" bit. It's also why I pointed you to a certain exponential equation, and as you showed that you can't actually solve that equation it shows that you don't understand the math used to come to the conclusions to begin with...Seriously, hit Winkey+r, type "calc" then hit enter. Play with that equation and look up how to manipulate it and it's variances so you CAN solve for how many seconds after release each ball will impact the floor and which mutual fund will have which value. Until you can do that much...It's just going to end up with more jargon problems.

That's about as far as all of this relates to the OP though; "dark energy" ->Energy of space itself.

Reminds me of the old joke: One fish asks another "How's the water today?" and the other fish replies" What's 'water'?"

[A-wal]

" because the light is being redshifted as it's travels through space" is directly related to "that FUBAR"...and once again I'm left with "jargon" as language barrier, as you don't actually seem to grok the jargon used well enough to follow what's being said, or to articulate your point against it in a way that isn't limited by same.

Red-shift-by-distance-traveled is used to determine how much distance was traveled, and how much space has "expanded" over that distance.

But the point is that after all the calculations have been made, you're left galaxies that are receding faster the further back in time we look. That's not an increasing rate of expansion, that's a slowing down of the expansion over time.

 

That's the whole, "standard candle" bit. It's also why I pointed you to a certain exponential equation, and as you showed that you can't actually solve that equation it shows that you don't understand the math used to come to the conclusions to begin with...Seriously, hit Winkey+r, type "calc" then hit enter. Play with that equation and look up how to manipulate it and it's variances so you CAN solve for how many seconds after release each ball will impact the floor and which mutual fund will have which value. Until you can do that much...It's just going to end up with more jargon problems.

 

That's about as far as all of this relates to the OP though; "dark energy" ->Energy of space itself.

 

Reminds me of the old joke: One fish asks another "How's the water today?" and the other fish replies" What's 'water'?"

Now you're just sidestepping the issues entirely.

 

1. If we assume no recessional velocity (on average) and attribute redshift entirely to the motion of the light through space then we end up with a very neat direct correlation between redshift and distance that both matches observations and does away with the need for dark energy by providing a vastly simply interpretation.

 

2. No amount of rewording the cause of the relative motions of objects can alter the fact that objects moving at the speed of light and above would cause inescapable and inexplicable paradoxes for the reason described in SR because that model describes the relative motions of objects and has absolutely nothing at all to do with the cause of the increase or decrease of relative velocity of those motions, it makes shitall difference.

 

3. An expansion rate that's faster in the past (which is the conclusion of the model after the calculations have been made) is one that's decreasing over time. It makes no sense at all to claim galaxies move away from us faster the further back in time we look and the rate of expansion is increasing over time. That's not just wrong, it's insane.

Edited December 31, 2018 by A-wal

[GAHD]

Now you're just sidestepping the issues entirely.... An expansion rate that's faster in the past (which is the conclusion of the model after the calculations have been made) is one that's decreasing over time. It makes no sense at all to claim galaxies move away from us faster the further back in time we look and the rate of expansion is increasing over time. That's not just wrong, it's insane.

Learn 2 math. That's it. It's all I can say. You obviously are talking from half-understandings without the underlying fundamental grasp of the mathematical language used. That's fine(not really) but it's the only reason I can identify as to why you don't grasp what's actually being said vs what you seem to be hearing. :) 

 

That's about all the effort I'm willing to put into educating/debating you on it. There is water, drink or do not. I don't need this particular horse for my journey.

 

Cheers. :)

[A-wal]

That's another complete sidestep, the usual goto one always used as a last resort when there's no way out of the corner.

 

I'm not questioning the maths! I'm questioning the conclusion drawn from the maths! Telling me that understanding the maths better will somehow result in the conclusions of the model changing is beyond ridiculous.

 

The model describes galaxies moving away from us at a faster rate the further back in time we look, that's the conclusion drawn from the maths. That's a decreasing rate of expansion over time.

Edited December 31, 2018 by A-wal

[OceanBreeze]

It may be helpful to remember that acceleration is change in velocity with respect to time,

that is a = dv/dt

 

if you plot velocity with respect to time and get a straight line there is no acceleration

 

when dv/dt is plotted for certain “standard candles” at ever increasing distances, it has been found

that the plot is not a straight line, indicating there is acceleration present in the expansion of the universe.

 

And, from the slope of the line, the acceleration is positive, meaning the expansion is speeding up.

 

It also may be helpful to realize that the velocity is a co-moving velocity; it is not due to the farthest objects speeding away from us, any more than it is due to us speeding away from the farthest objects.

 

So, it really makes no sense to say the farthest objects were moving faster in the past than the closest objects are moving away today.

 

Use the farthest object as a frame of reference, and it is we and the closest objects that are moving away the fastest today and the farthest object is at rest!  But, that also makes no sense.

 

The only thing that makes sense is that the co-moving velocity is increasing with respect to time, and that is an accelerated expansion.

 

 

 

[A-wal]

It may be helpful to remember that acceleration is change in velocity with respect to time,

that is a = dv/dt

 

if you plot velocity with respect to time and get a straight line there is no acceleration

You don't say.

 

It also may be helpful to realize that the velocity is a co-moving velocity; it is not due to the farthest objects speeding away from us, any more than it is due to us speeding away from the farthest objects.

Use the farthest object as a frame of reference, and it is we and the closest objects that are moving away the fastest today and the farthest object is at rest!

Well duh!

 

So, it really makes no sense to say the farthest objects were moving faster in the past than the closest objects are moving away today.

Of course it does. 'Moving away from us' is not a frame dependent statement. If the distance between us and another galaxy is increasing then the other galaxy is obviously moving away from us, it in no way implies that we're not moving away from the other galaxy because it's the same thing.

 

The point is that if the rate at which the distance is supposedly increasing between ourselves and other galaxies is greater the further we look back in time then that's a decreasing rate of supposed expansion over time, as in slower as we get closer to the present moment, obviously.

 

And, from the slope of the line, the acceleration is positive, meaning the expansion is speeding up.

The only thing that makes sense is that the co-moving velocity is increasing with respect to time, and that is an accelerated expansion.

If that were true then the further away (further back in time) the galaxy that we looked at, the slower it would be moving away from us and therefore the supposed expansion would be speeding up because galaxies would be moving away faster the closer we see them to our present moment in time. This is not what the model says, it says that the further away (further back in time) we look, the faster the galaxy moves away from us. That's NOT an acceleration of the expansion over time! Obviously.

 

Possibly irrelevant tiny point, but not all galaxies are moving away from us. Andromeda is coming this way ! along with a handful of other blue shifted galaxies

Yes there's actual movement that has nothing to do with the supposed expansion. The expansion model is based on average redshift, that only really becomes noticeable when we look at galaxies far away from us.

 

Oh sorry OceanBreeze, that's wrong according to your logic because we're far away from them as well. I should have said when there's enough space between us and them.

Edited January 3, 2019 by A-wal

[OceanBreeze]

I'm glad I could be of some help!

[A-wal]

Help? :)

Claiming it's invalid to say that an object is moving away from us (which would apply to all relative motion - galaxies, cars, people, etc) because we're also moving away from them?

Of course (according to the expansion model) distant galaxies are moving away from us.

If they're moving away from us faster the further we look back in time and slower the less far back we look in time then that's a slowing rate of expansion over time.

Obviously.

[Dubbelosix]

''If that were true then the further away (further back in time) the galaxy that we looked at, the slower it would be moving away from us and therefore the supposed expansion would be speeding up because galaxies would be moving away faster the closer we see them to our present moment in time. This is not what the model says, it says that the further away (further back in time) we look, the faster the galaxy moves away from us. That's NOT an acceleration of the expansion over time! Obviously.''

 

 

Certainly, I made the same remark in my essay. The fact is, that light from distant sources tend to tell us something about the past, at the very best, we can only say that the past history of the universe is accelerating, this is probably not true today.

[tetrahedron]

One thing that bothers me about Dark Energy and the Big Rip. Eventually every single fundamental particle will be isolated by its own light cone from every other- each then constituting its own nano-universe, if you will. But we know that virtual particle creation in 'empty' space is scale dependent, and the smaller the scale, the larger energies will become, due to uncertainty and conjugate variable mechanics. Wouldn't every single nano-universe then eventually be capable of creating huge energies just because of the shrinking light cone? In this hypothesis, every point in spacetime becomes its own new energized universe in it own Big Bang, 

 

Jess Tauber.

Edited January 3, 2019 by pascal

[A-wal]

''If that were true then the further away (further back in time) the galaxy that we looked at, the slower it would be moving away from us and therefore the supposed expansion would be speeding up because galaxies would be moving away faster the closer we see them to our present moment in time. This is not what the model says, it says that the further away (further back in time) we look, the faster the galaxy moves away from us. That's NOT an acceleration of the expansion over time! Obviously.''

Certainly, I made the same remark in my essay. The fact is, that light from distant sources tend to tell us something about the past, at the very best, we can only say that the past history of the universe is accelerating, this is probably not true today.

Before or after you saw it pointed out here? :)

 

Someone is confused or confusing me and maybe others. :)

What are you confused about? It's actually very simple.

 

If galaxies are moving away from us faster the further away we look then galaxies are moving away from us faster the further we look back in time and so moving away from us at a progressively slower rate the closer we look to the present, so the supposed expansion would be slowing down over time.

 

The distance between us and most of galaxies in the universe is increasing due to dark energy, it is not reducing, ...

No one said the distance was reducing, just that the rate at which they're supposedly moving away from would be reducing over time.

 

... the distance to those galaxies at the outer edges of the visible universe and beyond is increasing at approaching light speed, and beyond the edge of the visible universe they may well be moving away from us at greater than light speed. This is not a violation in c, what it means is that the space between us and them is expanding.

No, definitely not! There is no distinction whatsoever between two objects moving away from each other and the space between them expanding, it's different words describing the exact same thing.

 

But if we put that aside for the moment and assume there is somehow a difference it is still very much a violation of SR because SR deals with relative velocities, the method used to attain those relative velocities has nothing at all to do with validity of the velocity addition formula.

 

If galaxies were able to recede from each other at or over the speed of light then all the paradoxes that arise from that would still apply. Time dilation, length contraction and the mass of the other object would all become infinite at the speed of light because they all measure the same speed of light relative to themselves despite their velocities relative to each other.

 

The galaxies feel no acceleration due to the expansion of space.

That wouldn't make any difference to the applicability of SR to galaxy recession even if it were true.

 

The distance between Galaxies is increasing at a constant rate, ...

According to the model the distance between the galaxies is not increasing at a constant rate, the distance between the galaxies is increasing at an ever increasing rate.

 

... this means on average that galaxies on the edge of the universe will be moving away from us faster than those which are nearer us.

This is not what's observed though. If galaxies were moving away from us faster the greater the distance between us and them then that's just another way of saying that the rate of the supposed expansion is increasing over time but if that were true then we'd have to see galaxies moving away from us slower the further we look back in time.

 

Yes they'd actually be moving away from us faster the further away they are but we're seeing them as they were, not as they are now. The further away in space we look, the further back in time we see.

 

In an expanding universe in which the rate of the expansion is increasing over time we'd be seeing the closer galaxies moving away from us faster than the more distant galaxies because we'd be seeing the closer galaxies at a time closer to the current rate of expansion and further galaxies at a time when the expansion rate was slower.

[Dubbelosix]

Yeah, I was saying the same statement for years even before the essay, but it was before. ;) @awall

[OceanBreeze]

This might help explain where I think you are wrong http://curious.astro.cornell.edu/physics/104-the-universe/cosmology-and-the-big-bang/expansion-of-the-universe/1066-can-two-galaxies-move-away-from-each-other-faster-than-light-intermediate Is there any point in this link you disagree with.

 

The outer edge of the universe is receding away from us at approaching the speed of light. Observed galaxies are eventually red shifted out of view due to the rate of expansion and the fact they are moving away above c. This in no violates SR or GR. The space between us and the outer galaxies is expanding, at approx 70km/s for every parsec away they are. This means the distance from us to galaxies on the outer edge of the visible universe is increasing faster than the distance between us and galaxies that are closer to us. Yes the light arriving from the outer universe left those galaxies a few billion years ago, and light they transmit today will probably never reach this planet, as those galaxies will be receding at above c, and will be red shifted out of existence.

 

I don't think Awal is arguing against the fact that the universe is expanding and galaxies at the edge are moving away faster from our reference point than galaxies closer to us.

 

What he is arguing is that the expansion is accelerating. Sorry for speaking for him, but he is saying the fact that galaxies that are farther away are moving faster and the fact they are further back in time, shows that the expansion is slowing down, not speeding up.

 

I'm not sure how to answer that except this: even though the farther away a galaxy is, the faster it is moving away, it is NOT moving away as fast as predicted by the Hubble constant! That means the galaxies were moving apart slower than they are today, so the expansion is speeding up!

[A-wal]

This might help explain where I think you are wrong http://curious.astro.cornell.edu/physics/104-the-universe/cosmology-and-the-big-bang/expansion-of-the-universe/1066-can-two-galaxies-move-away-from-each-other-faster-than-light-intermediate Is there any point in this link you disagree with.

Cheers, I'll check out the link later.

 

The outer edge of the universe is receding away from us at approaching the speed of light. Observed galaxies are eventually red shifted out of view due to the rate of expansion and the fact they are moving away above c. This in no violates SR or GR.

Still no! The velocity addition formula would still apply, it doesn't go away with increased scale, and the cause of the increase of the relative velocity in no prevents the paradoxes and mass increase that would arise with a relative velocity > c.

 

Try going through the 'expansion of space' method of acceleration on a smaller scale for the examples of SR type thought experiments and then explain how that method of acceleration makes any difference to the SR physics of relative velocity.

 

The space between us and the outer galaxies is expanding, at approx 70km/s for every parsec away they are. This means the distance from us to galaxies on the outer edge of the visible universe is increasing faster than the distance between us and galaxies that are closer to us.

But if that were true then we'd have to see galaxies moving away from slower the further we look back in time and that's not what we see.

 

Yes the light arriving from the outer universe left those galaxies a few billion years ago...

At a time when the the supposed expansion rate was slower, meaning we'd see them moving away slower than closer galaxies.