Is Krauss looking at this right?

[tar]

Spyman,

 

Is the "amount of water" increasing from an outside source? That is, is the water flowing "in" from somewhere?

 

If there is a flow to the universe, what is carried by that flow? Why is it only considered an "outward" flow?

 

Would it not also be an "inward" flow? That is, as much as the universe is flowing away from us, it must be likewise flowing toward us.

 

Whether photons, or matter, or dark energy, or dark matter are carried by, or resist this flow, would make a difference in carrying out the river analogy. If space is the river, we need to define the properties of this river water, and the properties of these boats, in relation to each other, before we can visualize any boundries or impossible achievements.

 

Plus, the big problem for me, with these boundries, is exactly WHEN are you considering the boundry to exist?

 

Now as in what we see. Or now as in what we know must be the case, to see what we see. Light takes time to propagate. Iggy's statement about the scale factor of the universe being different upon emmission and reception of a photon, makes perfect sense, except WHEN was the universe this size, and WHEN was the universe that. There is no godlike perspective that can know both ends, as happening similtaneously, much less, that can then evaluate each end as having occurred at different times. One time, when the universe was simultaneously small, and another time, when the universe was simultaneously larger. I don't believe the universe knows how to do one thing at a time.

 

Regards, Tom Roth

[Spyman]

It is only an analogy and far from perfect, however for describing the effects of accelerated expansion of space to tar I think it is good enough.

 

Photons are not able to reach us when space between them and us is expanding faster than they can propagate, no matter what.

 

There is a very important difference if photons are emitted from objects traveling through space or receding from us due to expansion of space.

When for ever lightyear they travel in our direction there will be two new lightyears between us and them, then they will never reach us. No matter what.

That's what "no matter what" means.

 

And while the concept might seem very peculiar to you, it is still common standard cosmology.

(Bolded mine)

 

But we can observe such objects, don't we?

If "such objects" are objects that where much closer in the remote past when they emitted the light that we can recieve today because our observable sphere have been growing for billions of years and encapsuled those distant photons, such that space BETWEEN them and us did expand slower than light.

 

Then Yes, we can see "such objects" that are receding from us faster than light.

 

But otherwise No, we can NOT recieve photons located beyond where space, BETWEEN us and those photons, is expanding faster than light.

 

 

edit

 

And this sentence of yours:

Photons are not able to reach us when space between them and us is expanding faster than they can propagate, no matter what.

 

placed next to Iggy's

Bob sends a photon off at velocity c. It crosses the universe and Alice receives it measuring its velocity at c. The difference in velocity (there isn't one) has absolutely nothing to do with the scale factor, or how much the scale factor has changed, or how quickly it changed, or any combination of the above.

 

look to contradict each other.

If velocity "has absolutely nothing to do with the scale factor", then it has nothing to do with the scale factor. Point.

Velocity cannot in the same model be influenced by the scale factor in such a way that "Photons are not able to reach us when space between them and us is expanding faster than they can propagate".

No, I am not contradicting Iggy, YOU are the one claiming that velocity is influenced by the scale factor in the model, NOT Iggy and me.

(Velocity has nothing to do with the scale factor, however distances are determined by it.)

Edited October 18, 2012 by Spyman

[zapatos]

Is the "amount of water" increasing from an outside source? That is, is the water flowing "in" from somewhere?

 

If there is a flow to the universe, what is carried by that flow? Why is it only considered an "outward" flow?

 

Would it not also be an "inward" flow? That is, as much as the universe is flowing away from us, it must be likewise flowing toward us.

 

Whether photons, or matter, or dark energy, or dark matter are carried by, or resist this flow, would make a difference in carrying out the river analogy. If space is the river, we need to define the properties of this river water, and the properties of these boats, in relation to each other, before we can visualize any boundries or impossible achievements.

It's just an analogy...

 

Plus, the big problem for me, with these boundries, is exactly WHEN are you considering the boundry to exist?

As Spyman said, at the point in time when "...space, BETWEEN us and those photons, is expanding faster than light."

 

Problem solved.

 

There is no godlike perspective that can know both ends, as happening similtaneously, much less, that can then evaluate each end as having occurred at different times.

Correct. But then so what? No one has to 'evaluate' how something will happen before it can happen. Does a leaf not flutter to the ground because no one has evaluated wind speed, humidity, distance to the ground, aerodynamics of the leaf, etc.?

 

I don't believe the universe knows how to do one thing at a time.

The universe doesn't "know' anything.

[Spyman]

Spyman,

 

Is the "amount of water" increasing from an outside source? That is, is the water flowing "in" from somewhere?

 

If there is a flow to the universe, what is carried by that flow? Why is it only considered an "outward" flow?

 

Would it not also be an "inward" flow? That is, as much as the universe is flowing away from us, it must be likewise flowing toward us.

 

Whether photons, or matter, or dark energy, or dark matter are carried by, or resist this flow, would make a difference in carrying out the river analogy. If space is the river, we need to define the properties of this river water, and the properties of these boats, in relation to each other, before we can visualize any boundries or impossible achievements.

 

Plus, the big problem for me, with these boundries, is exactly WHEN are you considering the boundry to exist?

 

Now as in what we see. Or now as in what we know must be the case, to see what we see. Light takes time to propagate. Iggy's statement about the scale factor of the universe being different upon emmission and reception of a photon, makes perfect sense, except WHEN was the universe this size, and WHEN was the universe that. There is no godlike perspective that can know both ends, as happening similtaneously, much less, that can then evaluate each end as having occurred at different times. One time, when the universe was simultaneously small, and another time, when the universe was simultaneously larger. I don't believe the universe knows how to do one thing at a time.

 

Regards, Tom Roth

My analogy was intended for a discussion of how a varying expansion of space can allow us or prevent us from seeing distant objects receding very fast, as such it doesn't take into consideration any source for the expansion. The water is only a symbol representing space and space is expanding as a scalar, there is no new space flowing into the universe from another outside realm.

 

In the analogy you can view it as the water molecules are multiplying, such that if there are 100 water molecules in a volume and if the growth rate is 10 percent per day then there will be 110 water molecules in that volume the next day, which will force 10 molecules to flow away, on the surface a distance covering 100 molecules will increase to 110 molecules over this day.

 

In this analogy there are only boats and harbours and they all get carried by the flow. It is an outward flow because when the water multiplies everywhere then everything gets pushed apart equally. If space would be contracting then we could discuss models with an inward flow, but as of now observations shows an expanding universe.

 

The only properties needed to understand in the river analogy is that all boats travels with the same speed c relative the surface of the water, that all harbours are stationary with the local water around them and that the speed of the flow increases unlimited with distance from the Earth harbour.

 

The boundary always exists, from the start of the universe to its end, since the expansion has varied it has moved an been at different distances at different times, but it has always been and will always continue to be a certain distance from us depending on the rate of expansion.

 

There is no need for simultaneously communication between different parts of the universe, there is no physical fabric connecting distant objects.

[tar]

Spyman,

 

But hold on a minute.

 

A point in time when...

 

This is a misnomer.

 

We are speaking from a here and now, point of view. We always have, and we always will. It is the only way we think.

We have the ability to remember stuff, and predict stuff, and put ourselves in the shoes of another observer that also has a here and now perspective, at another now, or another here, that we can relate to ours, or map to ours, and we can jump around to various of these positions in space and time, but each time we land, each time we focus on the current landscape it has two important characteristics. We consider it a here and now perspective, and we know where that spot in space and time is, relative to us.

 

"A point in time" means something, only from a here and now perspective.

 

The universe is contructed, or contains very many of these points. There is not a point in time, a human focus, here and now perspective type point in time, that embraces all of the universe at once...except for the view we actually have. Our here and now. Where the whole observable universe exists currently, all at once. The hand reached above your hand, and the distant star, existing similtaneously, right next to each other, in your view.

 

If one is looking at the output of a powerful telescope, mounted on a space station, and sees a distant galaxy...there it is, at this point in time. The point in time when it is moving away from us at superluminal speeds, is on the one hand, already passed. Yet there it sits, within our view. So "at this point in time" when the galaxy is moving away from us, at greater than C due to the expansion of space, we can see it, with our equipment, just fine. We have many "points in time" to come, where we will still be able to see said galaxy. And they all, all these future points in time, will occur "after the point in time when the galaxy's recessional speed exceeded C".

 

So I am not concerned with such a point in time, when said galaxy's photons can no longer reach the Milky Way. I am leary of there being such a point in time.

 

If we can see said galaxy now, then chances are, a galaxy half way between us and it, can see it now as well.

As long as we can see the galaxy, halfway between, and that galaxy can see said galaxy, then we can see said galaxy too.

 

Consider a photon from said Galaxy, passing by the galaxy halfway between, and not being collected by a electron within the halfway galaxy, and headed in our direction. It has an equal chance of reaching us, as any photon emmited by the halfway galaxy, at that point in time. It will proceed with the same speed of light and propagate through the same expanding space that the photons from the halfway galaxy will. It will reach us, as surely as the photons from the halfway galaxy. The only difference will be the redshift. What ever redshift would have been detected at the halfway galaxy, plus whatever redshift we detect coming from the halfway galaxy.

 

We can still see the darn thing.

 

Regards, TAR2

Edited October 19, 2012 by tar

[Iggy]

(bolded mine)

You mean velocity (of a photon) is constant.

You're equivocating. I refer you to my previous answer:

 

"constant velocity" means constant relative to any observer. It doesn't mean constant relative to a local penny.

 

Pennies, like galaxies and the people in them, don't expand.

The grid on the rubber sheet, like intergalactic distance, does expand.

 

Light acts like a bug that is capable of crossing a penny in one second. That is how fast its feet will carry it. Set the bug on the rubber sheet and let it go. Stretch the sheet. The bug will cross its local penny in one second, but the distance between the bug and a distant penny will change by much more than the width of a penny in one second.

 

If velocity "has absolutely nothing to do with the scale factor", then it has nothing to do with the scale factor. Point.

Velocity cannot in the same model be influenced by the scale factor in such a way that "Photons are not able to reach us when space between them and us is expanding faster than they can propagate".

More equivocation. The velocity of the photon relative to the emitter at the time of emission is the same as the velocity of the photon relative to the observer at the time of observation. That is what I said, and it absolutely does not imply that the velocity of the photon relative to the observer is constant between emission and observation. I suspect you are intentionally missing the distinction.

[EquisDeXD]

I like your post and the quandary I believe it identifies. Looking at galaxies as they were billions of years ago does make me stop and think what's really going on now? Additionally, I wonder about theories that involve things we can't see. Some scientist think the have seen what is probably the black hole at the center of the Milky Way. Maybe so, but the theories poping up about what can or cannot escape the black hole, what really happens at the event horizon? We can't see it really, nor can we see dark matter/force/energy, and now some are talking about Boson field/energy. Sure you can measure around the black hole and conclude that must be the black hole causing that wobble, but still, how many light years ago did that wobble happen?

No real scientist claims to have ever directly observe a black hole, they can accurate use infrared telescopes to directly see the gas and stars surrounding it, and with regards to dark matter, it is confirmed that we cannot see the mass required for galaxies to form. While there could be an astoundingly large number of black holes that we can't, that would not only make the current rate of star formation a lot harder to achieve and devour more stars than we see right now, it would also mean there would have had to of been that much more matter in the early state of the galaxy to create all those super massive stars that become black holes, and of course if supernova were that common Earth would have been sterilized. Instead, scientists think that there is matter which doesn't interact with the electro-magnetic force or also perhaps the strong and weak force, just gravity, which is similar to what is scientifically confirmed to be the neutrino, though it was discovered because it does in fact have a very very weak interaction with the EM and strong force. You can't see air can you? Well that's because of the lack of electro-magnetic interaction for it's energy state that make not dense enough to be directly observable, but we still know there's air.

at greater than C

Stop right there, nothing accelerates to above the speed of light, and matter itself can't even go at the speed of light, and this is because the relative distance between measurements of points decreases proportionally to the speed of an object. The expanding of space does not cause anything to be measured at greater than c, it simply creates the relativistic effect of light's frequency stretching out along with space. This problem was actually worked on around a 100 years ago, and shortly after that, Lorentz' equations and the Lorentz transformation were derived which describe the time dilation and length contraction as an object relatively approaches the speed of light.

Edited October 19, 2012 by EquisDeXD

[tar]

So consider another Galaxy, whose recessional speed, has "just now" exceed C. Now consider a hydrogen atom in that Galaxy, that has been in existence for 13.7 billion years. It has emitted photons, depending on its temperature, over the entire 13.7 billion years. Like a heartbeat, continually for 13.7 billion years. Currently we hear the heartbeat from when that hydrogen atom was only a few billion years old, and it sounds a bit slower than a local hydrogen atom would at that temperature. As we continue to listen it gets slower and slower and fainter and fainter, but ALL the beats, up to and including its last beat, before its galaxy's recessional speed exceeded C, can and must reach us. All of future time will include a possible photon, of appropriate wavelength, from that hydrogen atom, reaching the Milky Way. Just really really low frequency (slow beats) the further out in time you place the Milky Way in.

[EquisDeXD]

So consider another Galaxy, whose recessional speed, has "just now" exceed C.

There is no scientific evidence to support that any matter has been observed to travel at or above C.

 

 

 

 

Now consider a hydrogen atom in that Galaxy, that has been in existence for 13.7 billion years. It has emitted photons, depending on its temperature, over the entire 13.7 billion years. Like a heartbeat, continually for 13.7 billion years. Currently we hear the heartbeat from when that hydrogen atom was only a few billion years old, and it sounds a bit slower than a local hydrogen atom would at that temperature. As we continue to listen it gets slower and slower and fainter and fainter, but ALL the beats, up to and including its last beat, before its galaxy's recessional speed exceeded C, can and must reach us. All of future time will include a possible photon, of appropriate wavelength, from that hydrogen atom, reaching the Milky Way. Just really really low frequency (slow beats) the further out in time you place the Milky Way in.

Light takes time to travel, it's not already at what some guy says should be it's location from the moment it's emitted. As galaxies move away at a greater speed, their length contraction will become greater which will proportionally account for keeping the speed of light constant.

Edited October 19, 2012 by EquisDeXD

[zapatos]

So I am not concerned with such a point in time, when said galaxy's photons can no longer reach the Milky Way. I am leary of there being such a point in time.

The concept is exceedingly simple. The fact that you acknowledge that a photon cannot exceed c, and that you acknowledge that recessional speeds do exceed c, leads me to believe that you are being purposely obtuse and wasting the time of those explaining it to you. I cannot imagine why you are doing so.

 

There is no scientific evidence to support that any matter has been observed to travel at or above C.

He didn't say matter has been observed to travel at or above c. He said a galaxy can have a recessional speed exceeding c, for which there is scientific evidence.

[Spyman]

The expanding of space does not cause anything to be measured at greater than c, it simply creates the relativistic effect of light's frequency stretching out along with space. This problem was actually worked on around a 100 years ago, and shortly after that, Lorentz' equations and the Lorentz transformation were derived which describe the time dilation and length contraction as an object relatively approaches the speed of light.

No, in modern cosmology the expansion of space can and does cause us to measure receding speeds greater than light.

 

There is a distinction between a redshift in cosmological context as compared to that witnessed when nearby objects exhibit a local Doppler-effect redshift. Rather than cosmological redshifts being a consequence of relative velocities, the photons instead increase in wavelength and redshift because of a feature of the spacetime through which they are traveling that causes space to expand. Due to the expansion increasing as distances increase, the distance between two remote galaxies can increase at more than 3×10⁸ m/s, but this does not imply that the galaxies move faster than the speed of light at their present location (which is forbidden by Lorentz covariance).

http://en.wikipedia.org/wiki/Redshift#Expansion_of_space

 

While special relativity constrains objects in the universe from moving faster than the speed of light with respect to each other, there is no such theoretical constraint when space itself is expanding. It is thus possible for two very distant objects to be expanding away from each other at a speed greater than the speed of light, and this is true for any object that is more than approximately 4.5 gigaparsecs away from us.

http://en.wikipedia.org/wiki/Metric_expansion_of_space

[michel123456]

No, I am not contradicting Iggy, YOU are the one claiming that velocity is influenced by the scale factor in the model, NOT Iggy and me.

(Velocity has nothing to do with the scale factor, however distances are determined by it.)

(bolded mine)

Yes you do.

Taking as granted that C is NOT influenced by the scale factor:

how is it possible to state that "Photons are not able to reach us when space between them and us is expanding faster than they can propagate"I'll let you think more about this point.

I'll do the same.

I quit

this thread for a while.

Edited October 19, 2012 by michel123456

[tar]

The concept is exceedingly simple. The fact that you acknowledge that a photon cannot exceed c, and that you acknowledge that recessional speeds do exceed c, leads me to believe that you are being purposely obtuse and wasting the time of those explaining it to you. I cannot imagine why you are doing so.

 

 

He didn't say matter has been observed to travel at or above c. He said a galaxy can have a recessional speed exceeding c, for which there is scientific evidence.

 

Zapatos,

 

I am not trying to be obtuse. I am trying to be logical, and work with the things we know, and the things we see.

 

We don't see what any galaxy is doing right now, what is pertinent to us is what we see the galaxy doing right now. The "events" we witness are 100% real. They fully account for that particular Galaxy's existence to us. It is, as far away and dilated as it is. And there is, in the universe, only one instance of said Galaxy. From a shifting perspective we can imagine observers between us and said galaxy, and what they must be witnessing in terms of photons from said galaxy. This requires that photons from said galaxy are both arriving now, and some very many more are on the way.

They will not be currently present to us, until they get here, but one can take a Godlike view, not bound by the speed of light, and fix the location and expanse of each and every one of those photons, within the framework of a universe that is 13.7 billion years old, and of a hypothetical size, that a universe that looks like it does, here and now, to us, must be, from a Godlike view, not bound by the speed of light.

 

But translation back to our here and now view is required at every step, to predict how each of the "in transit" photons will appear to us, when they get here.

 

With the Galaxy that is "currently", from the Godlike view, reaching a recessional speed of C from the Milky Way, its future appearance to us, is ALREADY in transit, and mappable on the Godlike grid between. Each of the events that occurred in that Galaxy between the events that we see now, and the events that occurred in the billions of years between what we see happening there now, and what the Godlike view, sees happening there now, as its recessional speed reaches C, have already informed the godlike grid of their presence. We have been informed of events happening at that galaxies location for many billions of years, since the Milky Way received its first photons from it. We are being informed currently of its presence in the universe, and we will in the future continue to be informed.

 

Logically, since the information is coming in, at the speed of light, and the godlike grid is already loaded with the information, it must continue to arrive, without end. Being that a finite amount of events, a finite amount of hydrogen beats are loaded already into the grid, and they must last, as information to us, for an infinite amount of time, the only solution is for each beat to get slower, so that as time passes regularly at the galaxy, it appears to us dilated, almost but not quite, standing still, as the 100s of billion years pass. Practically frozen in space, as we see it age to a 13.7 billion year old Galaxy, some time 100s or 1000s of billions of years in our Milky Way's future.

 

Regards, TAR2

[Iggy]

No, I am not contradicting Iggy, YOU are the one claiming that velocity is influenced by the scale factor in the model, NOT Iggy and me.

(Velocity has nothing to do with the scale factor, however distances are determined by it.)

(bolded mine)

Yes you do.

Taking as granted that C is NOT influenced by the scale factor:

how is it possible...

The speed of light is locally measured at c and is not locally influenced by a change in scale.

 

Please stop mischaracterizing what I said!

 

If leaving the thread is the only way for you to do that then please leave and don't return.

[Spyman]

No, I am not contradicting Iggy, YOU are the one claiming that velocity is influenced by the scale factor in the model, NOT Iggy and me.

(Velocity has nothing to do with the scale factor, however distances are determined by it.)

(bolded mine)

Yes you do.

Taking as granted that C is NOT influenced by the scale factor:

how is it possible to state that "Photons are not able to reach us when space between them and us is expanding faster than they can propagate"I'll let you think more about this point.

I'll do the same.

I quit

this thread for a while.

No, Michel you are mistaken, I don't see any contradiction with what Iggy has said or what I am saying.

 

Maybe you are reading something into my words that I didn't intend to say or you could possibly be misinterpreting Iggy.

[EquisDeXD]

No, in modern cosmology the expansion of space can and does cause us to measure receding speeds greater than light.

 

There is a distinction between a redshift in cosmological context as compared to that witnessed when nearby objects exhibit a local Doppler-effect redshift. Rather than cosmological redshifts being a consequence of relative velocities, the photons instead increase in wavelength and redshift because of a feature of the spacetime through which they are traveling that causes space to expand. Due to the expansion increasing as distances increase, the distance between two remote galaxies can increase at more than 3×10⁸ m/s, but this does not imply that the galaxies move faster than the speed of light at their present location (which is forbidden by Lorentz covariance).

http://en.wikipedia....ansion_of_space

 

While special relativity constrains objects in the universe from moving faster than the speed of light with respect to each other, there is no such theoretical constraint when space itself is expanding. It is thus possible for two very distant objects to be expanding away from each other at a speed greater than the speed of light, and this is true for any object that is more than approximately 4.5 gigaparsecs away from us.

http://en.wikipedia....ansion_of_space

 

Well I guess it's a tricky situation, because I suppose even I myself cited in some thread that it could mathematically be possible (though I still didn't know "why" it was possible) for matter to do so through expansion, but as the article states "but this does not imply that the galaxies move faster than the speed of light at their present location (which is forbidden by Lorentz covariance)."

 

But just to be sure, there wouldn't happen to be any direct evidence where astronomers measured the location of a galaxy, then the next day found that it was somehow further away than light could have traveled either? Otherwise it seems like it's saying "oh yeah, there're expanding faster than C, trust me, but you can't see it because something to do with light taking time to travel". Where do you define why you don't measure the objects traveling at C and proving that they are actually traveling faster than C? If the space is expanding faster than C and the matter is following it faster than light, how could you have a length contraction past 0 to cancel it out in measurements? A negative number would essentially be like taking a square and then collapsing it until the bulk of it "swung around" to the other side from a line your collapsing it to, which by then you'd still have physical or absolute area.

Edited October 20, 2012 by EquisDeXD

[tar]

Well I guess it's a tricky situation, because I suppose even I myself cited in some thread that it could mathematically be possible (though I still didn't know "why" it was possible) for matter to do so through expansion, but as the article states "but this does not imply that the galaxies move faster than the speed of light at their present location (which is forbidden by Lorentz covariance)."

 

But just to be sure, there wouldn't happen to be any direct evidence where astronomers measured the location of a galaxy, then the next day found that it was somehow further away than light could have traveled either? Otherwise it seems like it's saying "oh yeah, there're expanding faster than C, trust me, but you can't see it because something to do with light taking time to travel". Where do you define why you don't measure the objects traveling at C and proving that they are actually traveling faster than C? If the space is expanding faster than C and the matter is following it faster than light, how could you have a length contraction past 0 to cancel it out in measurements? A negative number would essentially be like taking a square and then collapsing it until the bulk of it "swung around" to the other side from a line your collapsing it to, which by then you'd still have physical or absolute area.

 

EquisDeXD,

 

Yes. A tricky situation.

I was admonished earlier, that the universe does not "know" anything.

Not completely convinced of this fact myself. After all, we are 100% universe material ourselves, and we know something.

So set theorywise I would say that at least some part of the universe is capable of knowing something. Which would indicate that when taken as a whole, there is some "knowing" that the universe can do. So the universe does know something.

 

Information, by the construction of the word, indicates that an outside form is internalized. One part of the universe, informing another of its form or presence. That you and I know the universe exists, is because it informed us of its presence.

 

I throw in this philosophical type approach here, because it is central to the thread, as to the differences and similarities between our internal model of the universe, and the universe itself. The universe itself exists with or without our model of it. Our model would not exist if not for the information presented by the universe, to us. Our model reflects the universe. The universe need not comply with our model. What is possible in our heads, as we collapse a square and swing it around to the other side of a line, may not be something the universe itself would accomplish in the same fashion. We would have to try it out, and see if this activity would actually work in the world. There is bound to be some component of the operation that really doesn't work that way. Works in the imagination, but does not fit reality.

 

This is my caution to Krauss (and to myself), to give the universe the benefit of the doubt in all regards. It is always the thing we are in and of, and the thing we know. Our knowledge of it, can never be greater than it. There is always, much more that other portions of the universe have been informed of, than what a single human has been informed of. And likewise, an entire university of scientists, with records from thousands of years of human attention to incoming information.

 

There is plenty of room, to ask the question, "Is Krauss looking at this, right?"

 

Regards, TAR2

Edited October 20, 2012 by tar

[EquisDeXD]

EquisDeXD,

 

Yes. A tricky situation.

I was admonished earlier, that the universe does not "know" anything.

Not completely convinced of this fact myself. After all, we are 100% universe material ourselves, and we know something.

So set theorywise I would say that at least some part of the universe is capable of knowing something. Which would indicate that when taken as a whole, there is some "knowing" that the universe can do. So the universe does know something.

The universe as in random chunks of matter and energy which it mostly consists of scientifically does not know or think in any way, and I don't see how space expansion is evidence of that.

 

 

 

I throw in this philosophical type approach here, because it is central to the thread, as to the differences and similarities between our internal model of the universe, and the universe itself. The universe itself exists with or without our model of it. Our model would not exist if not for the information presented by the universe, to us. Our model reflects the universe. The universe need not comply with our model. What is possible in our heads, as we collapse a square and swing it around to the other side of a line, may not be something the universe itself would accomplish in the same fashion. We would have to try it out, and see if this activity would actually work in the world. There is bound to be some component of the operation that really doesn't work that way. Works in the imagination, but does not fit reality.

Well yeah, but our current models, the universe could exist without our models of it, but our knowledge of it is still only modeled by our scientific understanding of it.

 

This is my caution to Krauss (and to myself), to give the universe the benefit of the doubt in all regards. It is always the thing we are in and of, and the thing we know. Our knowledge of it, can never be greater than it. There is always, much more that other portions of the universe have been informed of, than what a single human has been informed of. And likewise, an entire university of scientists, with records from thousands of years of human attention to incoming information.

There is plenty of room, to ask the question, "Is Krauss looking at this, right?"

There is a bunch of room to ask questions, but there's no point investigating anything if you can easily have 0 confidence it's correct. And in science, you don't throw away previous models that use to work, you build off of them and revise them.

 

 

[tar]

The universe as in random chunks of matter and energy which it mostly consists of scientifically does not know or think in any way, and I don't see how space expansion is evidence of that.

 

 

 

 

Well yeah, but our current models, the universe could exist without our models of it, but our knowledge of it is still only modeled by our scientific understanding of it.

 

 

There is a bunch of room to ask questions, but there's no point investigating anything if you can easily have 0 confidence it's correct. And in science, you don't throw away previous models that use to work, you build off of them and revise them.

 

EquisDeXD,

 

Well, points taken. Except for the random chunks of matter thing. We would both agree that a hurricane has no brain, or purpose in mind. It is just a bunch of air and H2O heated up by the Sun's energy. But some characteristics emerge, that give the hurricane an identity and a direction, and powers to saturate stuff and blow stuff down and around. There is a definite non-randomness when a huge thing with a shape and a name is headed for your city. Random? Not exactly. There is a season for hurricanes, and they are somewhat predictable. They have a way about them, all their own, that no other random chunks of matter seem to emulate. Except perhaps a spiral Galaxy on some much much huger scale.

 

So, what do you think about enities? Are they random chunks of matter? The Sun? Is the Sun not a completely different type of random chunks of matter, than a rack of billiard balls? Are you not a completely different collection of random chunks of matter, than an earthworm? Is an apartment building a different type of random chunks of matter than a beehive?

 

I tend to give myself characteristics given to me, by the universe, and thusly consider myself a reflection of the universe. A creation of the universe, if you will. That the universe is capable of such a thing, is obvious, because here we are, with no other possible source, but the universe. And proof beyond any possible argument, that the universe knows how to create a TAR. And I am, in my own estimation, NOT just a random bunch of matter. And I tend to give every other entity in the universe equal footing, as NOT just random bunches of matter.

 

Regards, TAR2

[michel123456]

No, Michel you are mistaken, I don't see any contradiction with what Iggy has said or what I am saying.

 

Maybe you are reading something into my words that I didn't intend to say or you could possibly be misinterpreting Iggy.

 

Maybe the point of misunderstanding:

From the right beginning, I am speaking about velocity of light in the expanding space (in the gap between the "local pennies"), NOT about velocity as measured inside the penny, or received at the penny.

[Iggy]

This is my caution to Krauss (and to myself), to give the universe the benefit of the doubt in all regards. It is always the thing we are in and of, and the thing we know. Our knowledge of it, can never be greater than it...

 

There is plenty of room, to ask the question, "Is Krauss looking at this, right?"

Are these the remarks from Krauss that you're talking about?

 

And it should put us, give us some kind of cosmic humility, which is the other thing that should be characteristic of science.

 

Humility: The recognition that we don't understand everything. Bill Maher talked about it last night. What pompous assholes like Rick Warren, who claim to understand everything, are antagonistic to science. We should realize that there's more we don't understand about the universe than we do. And I wanna give you an example of this.

 

The far future. What's gonna happen in the far future? Remeber 100 years ago we thought we lived in a static eternal universe. The amazing thing is for civilizations that live in the far future, what will they see? Well, the universe is accelerating. That means all the distant galaxies are going to be carried away from us and eventually they will move away from us faster than the speed of light. It's allowed in General Relativity.

 

They will disappear. The longer we wait, the less we will see. In 100 billion years any observers evolving on stars (and there will be stars just like our sun in 100 billion years)... any observers in civilizations evolving around those stars will see nothing except for our galaxy, which is exactly the picture they had in 1915.

 

All evidence of the Hubble expansion will disappear. Why, because we won't see the other galaxies moving apart from us. So they will have no evidence in fact of the Big Bang. They wont see the Hubble Expansion. They won't even know about dark energy. They wont know about the cosmic microwave background -- it will disappear too. It will red-shift away and it turns out for fancy reasons, this plasma in our galaxy, when the universe is 50 times its present age, the microwave background won't be able to propagate in our galaxy. All evidence of the Big Bang will have disappeared.

 

And those scientists will discover quantum mechanics, discover relativity, discover evolution, discover all the basic principles of science that we understand today, use the best observations they can do, with the best telescopes they will build, and they will derive a picture of the universe which is completely wrong!

 

They will derive a picture of the universe as being one galaxy surrounded by empty space that is static and eternal... Falsifiable science will produce the wrong answer.

If you heard Krauss say that and then you thought "Careful, Krauss, we can't know everything about the universe. Science can be wrong"... that just doesn't make sense. Something seriously doesn't add up.

 

I understand that you don't like the model, but I can think of no more salient example to make the point that you and Krauss both seem to be making. The same model that predicts that there was a big bang also predicts that the evidence for the big bang will disappear in the future. There is no reason to think, in other words, that the universe willingly cooperates with us to answer the questions we have about it. The more we learn the more evident it is that the universe isn't interested in explaining itself to us.

 

You made clear that you don't like the model -- that you'd rather think of the universe as eternal and unchanging. I can only imagine that is the basis of your objection and not really anything to do with the hubris you accuse Krauss of having for using the model as an example. Because, if those are the remarks you're talking about then it is extremely strange to hear them then caution Krauss that we can't know everything about the universe. Extraordinarily strange.

[EquisDeXD]

EquisDeXD,

 

Well, points taken. Except for the random chunks of matter thing. We would both agree that a hurricane has no brain, or purpose in mind. It is just a bunch of air and H2O heated up by the Sun's energy. But some characteristics emerge, that give the hurricane an identity and a direction, and powers to saturate stuff and blow stuff down and around. There is a definite non-randomness when a huge thing with a shape and a name is headed for your city. Random? Not exactly. There is a season for hurricanes, and they are somewhat predictable. They have a way about them, all their own, that no other random chunks of matter seem to emulate. Except perhaps a spiral Galaxy on some much much huger scale.

Hurricanes are distinguishable from rocks. How does that mean they can think?

 

So, what do you think about enities?

Depends on how you define them. I don't think gravity can think.

 

 

I tend to give myself characteristics given to me, by the universe, and thusly consider myself a reflection of the universe. A creation of the universe, if you will.

Everything in the universe is a byproduct of the universe, so what?

 

That the universe is capable of such a thing, is obvious, because here we are, with no other possible source, but the universe. And proof beyond any possible argument, that the universe knows how to create a TAR. And I am, in my own estimation, NOT just a random bunch of matter. And I tend to give every other entity in the universe equal footing, as NOT just random bunches of matter.

I'm still not understanding why you think the universe in any way consciously does things. Scientifically, any form of thinking in any way has only been observed only in living things, which the universe has no apparent reason to be.

If you play the "well science doesn't know" card, then you need to be prepared for the counter of "so then why can't you be completely wrong?". If the whole of science can be wrong, and what your saying is outside of evidence, how is there any scientific justification that you aren't making it up?

 

Besides, we're suppose to be talking about expanding space, there's no such evidence that constitutes that galaxies can "know" anything.

Edited October 20, 2012 by EquisDeXD

[tar]

Iggy,

 

Yes, those are the remarks upon which I base Krauss' huberis. How exactly does one say at the beginning of ones remark how silly it is for someone to act as if they know everything, and then by the end of the remark say with certainty, what the universe will look like, from the Milky Way in 650 billion years? And not only that, but claim to know what future scientists can and can not find out about the universe? It struck me at the viewing as an extreme contradiction. It is exactly why I started this thread. If one is to believe there is more we do not know, than know, then claiming understanding of the conditions present in the universe, and what of it will be available for unknown entities so incredibly far into the future, is crazy talk. There is no way to even guess at such a thing. And absolutely no reason to, either. We will not be there to verify, or care. It could be wonderful, it could be horrible, it could be the majority of the Milky Way, with its future scientists, are crushed together in the black hole at the Milky Way's center, or the Milky Way could lose its current form and become something else. Like a hurricane, loosing its fury when it moves over land, or away from the warm waters that generate its character.

 

I in no way consider the universe static and unchanging. Quite the opposite. And if it came up with life on Earth, I am rather sure it is capable of all sorts of configurations, great and small. A scientist must take the universe as if galaxies are like gas molecules, subject to the same laws and equations. And no where in such equations, can you derive life, or peanut butter cups. If the equations cannot predict peanut butter cups, than I have no faith, what-so-ever, in their ability to predict what an entity in this region of the universe, can and will be informed of in 650billion years. It certainly will be different, but it probably will not look anything like, anything we can imagine.

 

And if our current observable universe is limited to 13.7 billion lys, the observable universe at the time of Krauss' prediction will be fifty times as large. And if at first, after the big bang there was inflation, incredible inflation, and then there was expansion, and then the expansion accellerated, the universe is capable of not just doing one thing forever. It's "current" accelleration, might not continue, the same way it appears locally to be acting.

 

If the said galaxy we were talking about was actually right now, heading toward us, we would not even see it slow and make the turn back, for billions of years. Why could not the universe be currently engaged in huge circulations and eddies, the scope and nature of which, we have not had the time, to notice?

 

Regards, TAR2

Edited October 21, 2012 by tar

[Iggy]

Iggy,

 

Yes, those are the remarks upon which I base Krauss' huberis. How exactly does one say at the beginning of ones remark how silly it is for someone to act as if they know everything, and then by the end of the remark say with certainty, what the universe will look like, from the Milky Way in 650 billion years? And not only that, but claim to know what future scientists can and can not find out about the universe?

It's like hearing Einstein say "I don't know what weapons will be used in world war three, but in world war four people will use sticks and stones" and thinking "My God, how could Einstein be so arrogant to think he can predict the weapons used in the fourth world war... It contradicts his admission that he can't predict the weapons of the third world war. It's hubris".

 

Or, imagine if I were explaining length contraction and I said "an alien ship approaches earth at some fraction of the speed of light and the alien pilot sees the earth as an oblate spheroid".

 

Your answer might be, "Length contraction, HA! I seriously doubt it. How can you know there are alien civilizations? You can't know how an alien's eyes work or even if they have eyes!"

 

By making an extremely literal reification of a rhetorical example you've missed the point completely.

[Spyman]

Well I guess it's a tricky situation, because I suppose even I myself cited in some thread that it could mathematically be possible (though I still didn't know "why" it was possible) for matter to do so through expansion, but as the article states "but this does not imply that the galaxies move faster than the speed of light at their present location (which is forbidden by Lorentz covariance)."

 

But just to be sure, there wouldn't happen to be any direct evidence where astronomers measured the location of a galaxy, then the next day found that it was somehow further away than light could have traveled either? Otherwise it seems like it's saying "oh yeah, there're expanding faster than C, trust me, but you can't see it because something to do with light taking time to travel". Where do you define why you don't measure the objects traveling at C and proving that they are actually traveling faster than C? If the space is expanding faster than C and the matter is following it faster than light, how could you have a length contraction past 0 to cancel it out in measurements? A negative number would essentially be like taking a square and then collapsing it until the bulk of it "swung around" to the other side from a line your collapsing it to, which by then you'd still have physical or absolute area.

When distant objects gets carried away by expansion of space they are NOT considered traveling through space.

 

Here is a list of current observational evidence we have of space expanding, as have been said already, there is no theoretical constraint in general relativity for space to expand faster than light. If you want to question relativity or space expansion then I suggest you make a new thread for that.

 

Observational evidence

 

Theoretical cosmologists developing models of the universe have drawn upon a small number of reasonable assumptions in their work. These workings have led to models in which the metric expansion of space is a likely feature of the universe. Chief among the underlying principles that result in models including metric expansion as a feature are:

 

• the Cosmological Principle which demands that the universe looks the same way in all directions (isotropic) and has roughly the same smooth mixture of material (homogeneous).
   
  
• the Copernican Principle which demands that no place in the universe is preferred (that is, the universe has no "starting point").
  

Scientists have tested carefully whether these assumptions are valid and borne out by observation. Observational cosmologists have discovered evidence - very strong in some cases - that supports these assumptions, and as a result, metric expansion of space is considered by cosmologists to be an observed feature on the basis that although we cannot see it directly, scientists have tested the properties of the universe and observation provides compelling confirmation. Sources of this confidence and confirmation include:

 

• Hubble demonstrated that all galaxies and distant astronomical objects were moving away from us, as predicted by a universal expansion. Using the redshift of their electromagnetic spectra to determine the distance and speed of remote objects in space, he showed that all objects are moving away from us, and that their speed is proportional to their distance, a feature of metric expansion. Further studies have since shown the expansion to be extremely isotropic and homogeneous, that is, it does not seem to have a special point as a "center", but appears universal and independent of any fixed central point.
   
  
• In studies of large-scale structure of the cosmos taken from redshift surveys a so-called "End of Greatness" was discovered at the largest scales of the universe. Until these scales were surveyed, the universe appeared "lumpy" with clumps of galaxy clusters and superclusters and filaments which were anything but isotropic and homogeneous. This lumpiness disappears into a smooth distribution of galaxies at the largest scales.
   
  
• The isotropic distribution across the sky of distant gamma-ray bursts and supernovae is another confirmation of the Cosmological Principle.
   
  
• The Copernican Principle was not truly tested on a cosmological scale until measurements of the effects of the cosmic microwave background radiation on the dynamics of distant astrophysical systems were made. A group of astronomers at the European Southern Observatory noticed, by measuring the temperature of a distant intergalactic cloud in thermal equilibrium with the cosmic microwave background, that the radiation from the Big Bang was demonstrably warmer at earlier times. Uniform cooling of the cosmic microwave background over billions of years is strong and direct observational evidence for metric expansion.
  

Taken together, these phenomena overwhelmingly support models that rely on space expanding through a change in metric. Interestingly, it was not until the discovery in the year 2000 of direct observational evidence for the changing temperature of the cosmic microwave background that more bizarre constructions could be ruled out. Until that time, it was based purely on an assumption that the universe did not behave as one with the Milky Way sitting at the middle of a fixed-metric with a universal explosion of galaxies in all directions (as seen in, for example, an early model proposed by Milne). Yet before this evidence, many rejected the Milne viewpoint based on the mediocrity principle.

 

The spatial and temporal universality of physical laws was until very recently taken as a fundamental philosophical assumption that is now tested to the observational limits of time and space.

http://en.wikipedia.org/wiki/Metric_expansion_of_space#Observational_evidence

 

-----

 

Maybe the point of misunderstanding:

From the right beginning, I am speaking about velocity of light in the expanding space (in the gap between the "local pennies"), NOT about velocity as measured inside the penny, or received at the penny.

This is what you said:

I don't think it is that simple.

 

When the road grows by 2 inches, it means that there is scale factor of 2. When the scale factor is applied to space, it is applied also to any velocity (because velocity is spce/time), and thus it is applied to C also.

That's why we observe galaxies receding at apparent speed multiple of C.

 

Or:

if the road is 10 inches long, one inch travel is 10% of the road.

 

When suddenly the road extends to 20 inches long (by scaling), then one "scaled-inch" still is 10% of the length, or 2 inches. The important thing is that for the same time, the distance as measured in the new space system (the scaled-space) remains constant: that's the main property of C.

and it is wrong, when distances increase due to expansion it takes longer time for light to traverse this new distance.

 

-----

 

I am not trying to be obtuse. I am trying to be logical, and work with the things we know, and the things we see.

After 9 pages and 175 replies your claim to be in pursuit of logic and knowledge is wearing pretty thin.

 

When comparing to other large threads in this particular area of the forum, one specific similarity emerges: someone continues to repeatedly make claims against conventional wisdom and dodges any replies that point out flaws or tries to explain why those claims are wrong.

 

From my experience people searching for knowledge and understanding, ask questions instead of repeating the same inaccuracies.

 

It is evident that we have failed miserably in our attempts to explain for you, a model in which space can be expanding such that it can bring current visible objects beyond a horizon from where they can't be observed anymore, such that you can understand it and take it to your heart.

 

The burning question is IF you want to learn and understand or if you simply will reject any explanations that challenges your current belief?

 

I don't see any point in continue and debate with you if you refuse to try to understand, I gave you the benefit of a doubt but it is fainting fast.