Another Hijack from Philosophy, Science & Reality

[beecee]

 

But take a field like cosmology, where we are so insulated by immense space and incredibly long time periods, that the models can not be fully vetted. Here Professor Krauss can tell us what the universe must look like to a scientist 600 billion years from now...and we have absolutely no way to empirically check on the reality of his claims.

 

 

No he tells us what the Universe will probably look like, based on past observational and present data, and extrapolating that forward...as these theories stand the test of time, they become "more certain" but never really proven, a word you seem preoccupied with. eg: Before the advent of the HST, scientists theorised that the probable formation of the solar system was caused by a cloud of gas and dust in space, that started to collapse.....With the HST, we have now seen this methodology in action in other distant solar systems.....so our theory has gained in certainty.....we are also pretty certain that the mechanism for stars is nuclear fusion, but we have not really ventured to the surface of star, taken a sample and tested it.

Edited June 23, 2017 by beecee

[tar]

BeeCee,

 

Understood, but probable observations of a scientist 600billion years from now, is not something sensibly forecast. We have very little information about the large scale dynamics of the universe, how one galaxy feels about another, and what information is exchanged between the two, and so on. What are voids about, what is the great attractor about, how big and long lived will scientists in 600 billion years be? He has no information about how big the universe is, and since we are just now seeing areas of space that just became transparent to photons 13.7? billion years ago, the boundaries of our observable universe are not yet reached. The wavelengths of electromagnetic waves coming to those future scientists from the limits of their observable universe may be way too long for us to see, but those future scientists would have evolved in such an environment, where maybe their information gathering facilities will be way different than ours. Evolutionarily they likely fit better than we do to that long wavelength environment, and technology wise they had perhaps 600billion years of advancements in science to work with, and perhaps they even would have record of our observations of the CMB. Dr. Krauss believes the scientists of that era will just see a few gravitationally bound galaxies, and will have no way to figure the big bang occurred. I think the Dr. is being very short sighted. If we learned so much since HST was put in orbit, extrapolate that capability and knowledge gain out 600billion years, and tell me again what scientists will and will not be able to witness.

 

Regards, TAR

Perhaps a scientist in 2037 will have the output from 12 LIGO experiments wirelessly transmitted to receptors along her optic nerve, and she will be able to see gravity waves passing through Earth. That is only 20 years away.

[beecee]

BeeCee, Evolutionarily they likely fit better than we do to that long wavelength environment, and technology wise they had perhaps 600billion years of advancements in science to work with, and perhaps they even would have record of our observations of the CMB. Dr. Krauss believes the scientists of that era will just see a few gravitationally bound galaxies, and will have no way to figure the big bang occurred. I think the Dr. is being very short sighted. If we learned so much since HST was put in orbit, extrapolate that capability and knowledge gain out 600billion years, and tell me again what scientists will and will not be able to witness.

 

Regards, TAR

Perhaps a scientist in 2037 will have the output from 12 LIGO experiments wirelessly transmitted to receptors along her optic nerve, and she will be able to see gravity waves passing through Earth. That is only 20 years away.

 

 

Gravity and expansion are shaping our Universe.....as ignorant as we are to the exact causes of both, we do know what the results are.

Over large scales, expansion will as Professor Krauss has noted, see distant galaxies move beyond our observable universe.

Gravity over smaller scales will see the MW and Andromeda and our local group and beyond merge.

Large scale maps of the universe, formulated by info from WMAP and other probes tell us this.

What the Professor says is that the evidence we currently have for the BB, maybe largely unobservable in 600 billion years.

Do you have any other explanation?

We are also pretty certain that our solar system only has another 5 billion years left. Are you arguing against that diagnosis also?

As a lay person, I'm reasonably confident that our cosmologists are not dragging theories out of their butt...they observe, they experiment, they then theorise.....they continually test those theories...they test them again, and again.....GR for example has made predictions that have finally been verified.

Again, any "reality" or "truth" that philosophers may be obsessed with, is not really the goal of science....if by chance they stumble on truth, then all well and good.

Theories and models based on experiment and observation, are tested all the time.....they also gain in certainty over time.

[tar]

BeeCee,

 

"Over large scales, expansion will as Professor Krauss has noted, see distant galaxies move beyond our observable universe.​"

 

 

Well yes, I think that is not the proper way to think about the data. Just because the wavelengths of light coming in from far away (the CMB) are redshifted a 1000 times does not make them unobservable, just moves red to violet light out of the visible spectrum. Actually the same shift would move X-ray emissions closer to visible wavelengths. So the areas of space, currently beyond the CMB, in terms of our ability to receive the electromagnetic radiation they put off, are actually parts of space we will see later at longer wavelengths, not areas of space that have moved outside our observable universe. What I mean is that the areas of space that we currently witness as cosmic background radiation, in the radio wavelengths, are right now today probably developed star systems that maybe have gone through 3 generations of star development and they themselves are so far away that due to the expansion of space, light they put out today will never reach us, ever, we know that we can currently see that area of space when it was very young and that we will be able to see it forever, because as it ages, in terms of our view of it, the wavelengths it is putting out will be increasingly red shifted and thereby we will see the system in slower and slower motion and redshifted to a larger and larger degree, but we know we will NEVER see it as a 13.8 billion year old system, because the one instance of that system that exists has moved out of reach. So we will never see that system as a 13.8 billion year old system, but we have no way to lose sight of it as a younger than 13.8 billion year old system.

 

Regards, TAR

What Professor Krauss does not know is when the farthest back we can see will show us areas of space older than "soon after the big bang". If we could see such areas of space, we could see an outside edge of the universe and start to form an idea of the shape and size of the place and our position in it. And the vision of places in space as far as we can see in a certain direction being older than soon after the big bang, would, as time went on, surround us more and more, until no CMB was observable, and ALL directions had areas of space older than slightly after the big bang old.

So given the 600billion year timeline, I would say chances are good we will be able to see the outside reaches of our universe, and thereby have more knowledge of the place, not less.

Edited June 23, 2017 by tar

[beecee]

BeeCee,

So given the 600billion year timeline, I would say chances are good we will be able to see the outside reaches of our universe, and thereby have more knowledge of the place, not less.

No, again the Professor is correct. While over time the CMBR will certainly approach absolute zero, the universe is also accelerating in its expansion rate. Galaxies beyond our observational horizon are apparently moving away at FTL.

As galaxies approach this horizon where recessional speeds approach and exceed "c" galaxies will be shifted beyond our viewing capabilities.

This is what Professor Krauss is referring to.

According to current cosmology and GR, there is no center, no edges, and no universal horizons to speak of, other then those centered about us here on Earth and our observable/particle horizon centered about us, and the fact that the same situation/s would be evident for any other beings anywhere in the universe.

Edited June 24, 2017 by beecee

[tar]

BeeCee,

 

I understand what he is referring to, and you and he are not thinking it through. We never in our lifetimes will see any area of space further than 100 lyrs away, as a star system as old as our own. That does not put such systems out of our observable universe. If a system should move out of range, as per radiation from it, today not being able to reach us, that means we will never see that system as a 13.8 billion year old system. It does not preclude us from seeing it as a 12 billion year old system or an 8 or a 2 or a 1 billion year old system, or as it was, when we see it tonight in our skies. For instance the GW we saw a couple of years ago was a system that was 12.5 billion years old at the time we saw it. If something we see at 900z was a billion years old when we look at it now, it will be closer to 2 billion years old, when we look at it in a billion years. How old do you figure it will look when we see it in 600 billion years? Your answer has to be less than 613.8billion and greater than 2.

 

Regards, TAR

Edited June 24, 2017 by tar

[beecee]

And again just quickly, the universal speed limit, "c" applies only to anything with mass: Spacetime is not curtailed by this limit.

BeeCee,

 

I understand what he is referring to, and you and he are not thinking it through.

Quite possible with regards to myself...But I aint a professional, and neither are you...Professor Krauss and most mainstream cosmologists/astrophysicists are though.

As I said somewhere else, these people are at the coal face everyday, studying many aspects of observational evidence from many state of the art probes such as Planck, WMAP, etc etc, as opposed to lay people like you and I that frequent science forums, open to any Tom, Dick and Harry, speculating all we like, sometimes in ignorance.

[tar]

"Galaxies beyond our observational horizon are apparently moving away at FTL."

 

But there are NO galaxies ON our observational horizon, so there is no chance of any moving beyond it.

[beecee]

http://www.pbs.org/wgbh/nova/blogs/physics/2012/10/how-large-is-the-observable-universe/

 

 

extract:

"Interestingly, as the universe expands, the size of the observable portion will grow—but only up to a point. Gott and his colleagues showed that eventually there will be a limit to the observable universe’s radius: 62 billion light-years. Because of the accelerating expansion of the universe, galaxies are fleeing from us (and each other) at an ever-hastening pace. Consequently, over time, more and more galaxies will move beyond the observable horizon. Turning once again to our relay race analogy, we imagine that if the players get faster and faster as the race goes on, there will be more and more who were so far away when they first threw the ball that the light would never have had time to reach us".

>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>

 

http://www.scienceforums.net/topic/106042-philosophy-science-reality/page-7

A:

"Not like “winking out of existence as you watch”, but yes - in the long run (very long run - billions of years), distant galaxies that we can see now will become undetectable, because the light from them will be unable to reach us.

Actually, some of the galaxies we can still see are probably already “out of range”, it's just that the light that left them back when they were still “in range” is still making it's way towards us. But the last light we'll ever see from those galaxies is already “in flight”, and once the last of that light reaches us, there will never be any more.

Eventually, everything except the “local cluster” of galaxies (our milky way, Andromeda, and a few more) will be out of range. The universe will be a lonely place. But that's not going to happen for trillions of years, so it's nothing to worry about - odds are we'll be long dead from any of a million other fates long before that happens".

[tar]

we have not witnessed the furthest we can see yet

[beecee]

"Galaxies beyond our observational horizon are apparently moving away at FTL."

 

But there are NO galaxies ON our observational horizon, so there is no chance of any moving beyond it.

https://en.wikipedia.org/wiki/Observable_universe

https://en.wikipedia.org/wiki/List_of_cosmological_horizons

https://en.wikipedia.org/wiki/Particle_horizon

[tar]

so if there are areas of space beyond the CMB, I could imagine that there may be some that we would never see the first light from, but everything between us and the CMB we have already seen the first light from, so there is only the second, third, fourth and 13.8billionth light that we will see from those areas of space. There is not a reason for their light to all of a sudden not be able to reach us, it is already on its way and it can only get longer in wavelength it can not decide not to get to us

[beecee]

we have not witnessed the furthest we can see yet

Yep, we are finding new galaxies everyday, but in time, they will also move beyond our observation/s.

so if there are areas of space beyond the CMB,

The CMBR pervades all of our universe.

 

I could imagine that there may be some that we would never see the first light from, but everything between us and the CMB we have already seen the first light from, so there is only the second, third, fourth and 13.8billionth light that we will see from those areas of space. There is not a reason for their light to all of a sudden not be able to reach us, it is already on its way and it can only get longer in wavelength it can not decide not to get to us

Recessional velocity at or greater then "c" will see them in time, disappear.

There is not a reason for their light to all of a sudden not be able to reach us, it is already on its way and it can only get longer in wavelength it can not decide not to get to us

 

 

When recessional velocity exceeds "c" no light will reach us.

This is the same reason why light cannot escape the EH of a BH.

[tar]

"While we will continue to receive signals from this location in space, even if we wait an infinite amount of time, a signal that left from that location today will never reach us. Additionally, the signals coming from that location will have less and less energy and be less and less frequent until the location, for all practical purposes, becomes unobservable."

 

​Which is what I understood. It does not mean the image ever stops coming. It just gets slower and weaker. What is practical in 600 billion years may be impractical at the moment.

Edited June 24, 2017 by tar

[beecee]

Tar:

Firstly from my observation, we maybe getting off topic...maybe more cosmology than the thread title.

As a lay person, I will always support what I have claimed, and as I have done in this thread, with appropriate links.

While sometimes those links maybe pop science oriented, they may possible also be misleading, although so far, in this thread, I don't believe so.

I also welcome any correction to any incorrect interpretation of mine.

I don't believe that you have yet offered any link supporting your interpretation.

Thinking for ones self is admirable to say the least, but so also is the realisation that sometimes one still needs expertise within that discipline.

Your posts at times, also seem mildly confusing and mixed up, but perhaps that's just me.

 

​Which is what I understood. It does not mean the image ever stops coming. It just gets slower and weaker. What is practical in 600 billion years may be impractical at the moment.

If the light source is beyond where the recessional velocity of the object is "c" then I believe no light at all will reach us.

Again, the same reason light does not get out of a BH.

[tar]

BeeCee,

 

On topic because we are talking about the reality of the universe...in 600billion years. Hardly realistic. And exactly as accessible to philosophy as it is to science. Even the scientific claims of possible reality in 600billion years admit that the Solar system and maybe even the Galaxy will not be the same by then...so it is very far from being empirically testable today, and whether my take is reasonable or logical to the same or lesser extent than a scientist's take, we are both getting about 600billion years ahead of our selves and we are talking about a universe that is quite huge, as if it is all happening at once, which it obviously is not.

 

So a scientific model would have the whole universe behaving according to a simple gas law and some principles of Newton's and Einstein's. A philosophical model would have the whole universe behaving as the universe behaves, and the important bits would be what we experience of it, not what it is doing right now a ly from here, but what light and energy from everywhere is hitting the planet now.

 

In someway the second take is more empirically based than the first.

 

So is reality what we know must be the case, or what we experience. That is, when we see the Mars Rover about to run into a hidden ditch, the Rover has actually already been in the ditch for some amount of minutes. Which take is real?

 

Regards, TAR

I was watching the Yankees live yesterday and at the same time watching live stats on my Yahoo Fantasy league. I watched a homerun and looked down to see my hr total increment, and it was already incremented. I guess there is a several second delay in the broadcast to give the station time to bleep out an inappropriate comment, whereas the stat feed beat the TV broadcast to my family room.

my daughter, unknown to me, was actually at the game several rows back from where the homerun landed which I did not know until after I had texted her a comment about the game

She actually had experienced the hr firsthand before even the stat feed was informed.

last football season my now PhD daughter at VT would watch a game off the internet while I was watching it on ESPN. I learned to not text her congratulations on a VT score, because she had not seen it happen yet, since the internet feed was behind the ESPN feed

while when she was at a game, she could text me a happening before I saw it on ESPN

Edited June 24, 2017 by tar

[Mordred]

Yep, we are finding new galaxies everyday, but in time, they will also move beyond our observation/s.

 

The CMBR pervades all of our universe.

 

Recessional velocity at or greater then "c" will see them in time, disappear.

 

 

 

When recessional velocity exceeds "c" no light will reach us.

This is the same reason why light cannot escape the EH of a BH.

I need to interject here. What you described is the Hubble horizon. Recessional velocity is not a true velocity. It is a consequence of separation distance applied to

 

[latex]V_{rec}=H_o d [/latex] In other words it depends on the distance of the observer.

Locally per Mpc the rate of expansion is only 70 km/s/Mpc at the leading edge of the signal. The light beam has no problem overcoming expansion at that leading edge.

 

It can literally overcome the recessive velocity from our local observer point as the light beam lead edge is a different event coordinate. Our measure of recessive velocity cannot apply to that event coordinate. ( lead edge light beam).

 

Hence the observable universe is far greater than the Hubble Horizon.

[tar]

we are basing the idea of an accelerating expanding universe on what of it we see at the moment

 

That is looks like it is expanding now, could mean it was expanding before, and now it is not, or it could be contracting now, and we would not know about that until evidence arrived, which given the size of the place, could take a while to get here.

[Mordred]

we are basing the idea of an accelerating expanding universe on what of it we see at the moment

 

That is looks like it is expanding now, could mean it was expanding before, and now it is not, or it could be contracting now, and we would not know about that until evidence arrived, which given the size of the place, could take a while to get here.

That is studied by using the late integrated Sache-Wolfe effect.

 

The FLRW metric equates the dynamics your referring to. The calculator in my signature can graph each event horizon. Under expansion history according to LCDM and based on current data can make a predictive model up to 88 Billion years into the future.

 

Assuming the current values for lambda/matter and radiation continue the same ratio of change or constant for lambda.

 

For example rate of expansion was slowing down from CMB to age roughly 6.8 Gyrs. This is the end of the matter dominant era. The radiation dominant was BB to CMB surface of last scattering. Now we are in the Lambda dominant.

 

Lambda dominant is the accelerating portion to expansion. During matter dominant this isn't true as it was decelerating.

Edited June 24, 2017 by Mordred

[tar]

or lets say a phase transition normally happens to universes of our type when they are 100 billion years old and something quite different starts happening everywhere

 

local stars would look the same as always for 3 years at least, and then one by one close stars would exhibit the new behavior,

 

Stars everywhere else in the galaxy would look the old way for up to 100,000 years, and still after they changed appearance the rest of the galaxies local to us, would look like nothing new happened.

 

I think it is safe to say, philosophically, that the universe has not yet done what it is going to do.

while everything we see the universe do is something that it already did a long time ago

Edited June 24, 2017 by tar

[Mordred]

Any observer effect surprisingly shows up in redshift and thermodynamic data.

 

You measure a star then you want to measure a known wavelength baseline. Hydrogen has a well known spectrographic signature. So we can measure this wavelength and look for redshift influences on the lightbeam.

 

The real physics of cosmology is studying the expansion history via its influences on light beams via redshift. This is actually where universe curvature comes into play. If the universe is contracting the lightpath would be curved for example.

 

Cosmologist must consider observer influences at every stage. The models would not work as they do if they didn't.

 

We can compare temperature measurements and spectography under redshift to eliminate observer offsets. Thats the first couple of years training in cosmology. Lol that topic used to drive me crazy come exam times lol.

 

The best quantity to bring the discussion back to science, philosophy and reality to describe reality with the greatest accuracy via physics is the invariant quantities. These are the quantities that all observers can agree on. Under physics its about the closest to being definable as a real measurement as opposed to an observer variant measurement. (side note also convenient to use in symmetry relations under translations).

 

When you get down to it the variations from those invariant quantities provides incredible insights into how our universe evolved over time. It is of paramount use in Cosmology.

Edited June 24, 2017 by Mordred

[Strange]

What Professor Krauss does not know is when the farthest back we can see will show us areas of space older than "soon after the big bang". If we could see such areas of space, we could see an outside edge of the universe and start to form an idea of the shape and size of the place and our position in it.

 

 

The furthest / earliest we can ever see is 380,000 years after the big bang. Before that the universe was opaque.

 

As far as we know, there is no edge to the universe.

I have reported your hijack of this thread with your misunderstandings of cosmology. You should have started your own thread for this.

"Galaxies beyond our observational horizon are apparently moving away at FTL."

 

But there are NO galaxies ON our observational horizon, so there is no chance of any moving beyond it.

 

 

There are galaxies within our observable universe that are receding at more than c. We can see galaxies that are receding at more than c.

we have not witnessed the furthest we can see yet

 

 

Yes we have. The CMB is the furthest it is ever possible to see.

BeeCee,

 

On topic because we are talking about the reality of the universe...in 600billion years. Hardly realistic. And exactly as accessible to philosophy as it is to science.

 

 

Nonsense. Philosophy cannot say anything realistic about the future state of the universe (except by echoing the results of science).

[beecee]

I need to interject here. What you described is the Hubble horizon. Recessional velocity is not a true velocity. It is a consequence of separation distance applied to

 

[latex]V_{rec}=H_o d [/latex] In other words it depends on the distance of the observer.

Locally per Mpc the rate of expansion is only 70 km/s/Mpc at the leading edge of the signal. The light beam has no problem overcoming expansion at that leading edge.

 

It can literally overcome the recessive velocity from our local observer point as the light beam lead edge is a different event coordinate. Our measure of recessive velocity cannot apply to that event coordinate. ( lead edge light beam).

 

Hence the observable universe is far greater than the Hubble Horizon.

 

Accepted....

Thanks for that......Obviously I have my horizons mixed up somewhat.

 

Nonsense. Philosophy cannot say anything realistic about the future state of the universe (except by echoing the results of science).

Bingo!

Edited June 24, 2017 by beecee

[Mordred]

No problem.