We can see to the edge of the universe.

[rockman]

Tar, my understanding of expansion is primitive, so I'm not expecting anyone to agree. I do try to learn though and I do apreciate this forum, and hopefully you guys don't run me off.

 

I do have a few questions though.

 

If I'm understanding Sisyphus right, the universe is expanding faster than the speed of light. Is this right? And I should look at the expansion similiar to an expanding balloon with points on it, except there really is no surface like such a balloon has.

 

The problem I'm having a hard time grasping here, is that from my searches online space is basically defined as nothing, except for photons, energy, etc., that exist within it.

 

So how does nothing expand?

 

It is not hard to grasp an explosion (big bang) flinging matter across space-nothing. Which is incorrect. And it is not hard to grasp expansion, where there is no motion, only expansion, if we have "something" that is expanding.

 

Hopefully my idiot questions don't have the effect of moving the thread to P&S

[tar]

Pangloss,

 

I am disappointed that you want to run me off. If my questions are inappropriate for this area of the board, I understand. But where else, better than here to test my hypothesis, and its consequences? I am afraid that if you send Rockman and me to the speculation and psuedoscience section, we will just muck about, with no adult supervision. On the other hand, I can't answer Rockman's questions without using the model of the universe I am constructing, which seems to me to fit together well, but which evidentally is invalid because it challenges some widely held beliefs. And I don't want to make it sound like science, since it is not tested, but I would still like the opportunity to find out where my model diverges from known science.

 

I think I have some valid, important, useful insights to add to our understanding of the universe. If they have already been had, then they have not been had by everyone because people believe stuff that is not possible to fit into what we know are facts.

 

For instance here is a piece of the Wiki article on "observable universe size."

"This means the universe has expanded to 1292 times the size it was when the CMBR photons were released. Hence, the most distant matter that is observable at present, 46 billion light-years away, was only 36 million light-years away from the matter that would eventually become Earth when the microwaves we are currently receiving were emitted."

 

Is it not obvious that photons emitted from matter 36 million light-years from the matter that would become Earth would make the trip, even through expanding space, in under 40million years? Therefore, those cannot be the photons we are seeing now 13.7 billion years later, those photons passed this way 13.7 billion years ago.

 

There is a frame shifting error there somewhere, and I am trying to sort it out, with the help of the minds and knowledge that frequent this board.

 

I am not engaging in psuedo science and speculation.

 

Please don't move this thread. Help me sort it all out, so it all fits together, without breaking the laws of physics and logic.

 

Regards, TAR

[Pangloss]

Nothing personal, TAR. What often happens, and all science-related forums deal with this, is that people learn a few things about a subject, then decide that they know what's really happening. We don't mind straightening out misconceptions, but when your idea is challenged, if you react by rejecting critical information you've overlooked, we pretty much lose interest. We're not here to help you challenge science with unsupported claims. Our interest is in the dissemination and education of what's actually been demonstrated and supported.

 

But if you're looking for a little support, by all means, I wish you the best of luck! Thinking about new ideas and looking at problems in a different way is a hallmark of science. Just remember what Isaac Newton said: "If I have seen further it is by standing on the shoulders of giants." First give every bit of thought to ALL the work accomplished by those who came before you. Then consider the possibility that you might be able to see a little farther.

[tar]

Pangloss,

 

OK, I fullfill all the critera of a psuedo-scientist. Send my two threads, this one and my hypothesis:all space is causally linked, to the speculation section. I will continue to think about it, and read, and try and put 2 and 2 together. I admit that the chances of me seeing it right and you seeing it wrong are very very slim.

 

But I would like a last word, a summation of my thoughts, which I still believe are consistent with observation and fact and the Big Bang Theory.

 

WMAP after they released the 5 year survey, gave us a powerful amount of new information about our Universe. We have only had a year or two to study it, and think about it and fit it into our model of the universe. Much of the "fitting" that is being done is based on our previous notion that the background radiation was the left over heat, from the big bang. Hence it must be an image of the surface of the last scattering, that is just getting to us now. I do not think that forcing our recent findings into that mold is correct. It doesn't work out. We were AT the surface of the last scattering when it happened, 13.7billion years ago. We can't just be seeing it now, we already saw it. The furthest matter from us could only have been 84,000,000lys away at a maximum and we would have seen that matter by the time we were 100,000,000years old. And once we see some matter, it has no physical way to leave our view. Space can expand all it wants, as fast as it wants and we are forever linked to that matter by the stream of photons it is emitting. That matter can congel, form stars, a galaxy, a quasar, but still it continues to send out an unbroken stream of photons. The stream of photons can be stretched from gamma rays to radio waves, it can become less and less luminous, the angular size can lessen, the photons can arrive at longer and longer intervals, but no physical law in the universe will remove that piece of matter from it's radial position in our skies. Once we see it, we will always see it (and it, us,) till it stops putting out photons, and even then the photons will continue to arrive at our location for 10s of billions of years.

 

So we see the whole universe, every light emitting part of it. But we see NONE of the current universe, and none of the universe as it looked to us, in our past. We only see every part of the universe, as it looks to us now.

 

Regards, TAR

[Spyman]

For instance here is a piece of the Wiki article on "observable universe size."

"This means the universe has expanded to 1292 times the size it was when the CMBR photons were released. Hence, the most distant matter that is observable at present, 46 billion light-years away, was only 36 million light-years away from the matter that would eventually become Earth when the microwaves we are currently receiving were emitted."

 

Is it not obvious that photons emitted from matter 36 million light-years from the matter that would become Earth would make the trip, even through expanding space, in under 40million years? Therefore, those cannot be the photons we are seeing now 13.7 billion years later, those photons passed this way 13.7 billion years ago.

Ok, let's assume that the expansion was an average constant for simplicity and then make rough estimates in steps of million years. We are going to get a false answer since the expansion of the universe changes over time and it was extreamly rapid during the early stages of BB, but it might give you some insight...

 

1292 times 36 million lightyears in 13.7 billion years gives an expansion of ~3.395 million lightyears each million years. So when the photon has travelled 1 million lightyears from the emitter towards the receiver, the total distance between the emitter and the reciever has expanded with 3.395 million lightyears and the photon's position has been displaced with the same rate as it's original position in proportion vid total distance.

 

The photon's position is at (36-1)/36 percent of the distance, but because of the expansion it would now be displaced with (36-1)/36 = 97.2% of 36 + 3.395 million lightyears, witch is at 38.3 million lightyears away from the receiver.

(The photon has been pushed back to a farther distance due to expansion.)

 

After 2 million years the total distance has expanded with 2*3.395 million lightyears and the photon has been pushed back by expansion to a distance of (38.3-1)/(36+1*3.395) * (36+2*3.395) = 40.5 million lightyears.

 

After 3 million years the total distance has expanded with 3*3.395 million lightyears and the photon has been pushed back by expansion to a distance of (40.5-1)/(36+2*3.395) * (36+3*3.395) = 42.6 million lightyears.

 

.

.

.

 

After 40 million years the total distance has expanded to 171.8 million lightyears and the photon has been pushed back by expansion to a distance of 90.8 million lightyears.

(The photon still has a very long way to travel before it can reach us.)

 

.

.

.

 

After 46 million years the total distance has expanded to 192.2 million lightyears and the photon has been pushed back by expansion to a distance of 95.2 million lightyears.

(By now it has passed the midpoint between the reciever and the emitter.)

 

.

.

.

 

After 101 million years the total distance has expanded to 378.9 million lightyears and the photon has been pushed back by expansion to a distance of 111.4 million lightyears.

(From now on the trip is downhill and it actually starts to approach the reciever.)

 

.

.

.

 

After 291 million years the total distance has expanded to 1027 million lightyears and the photon has been able to outrace the expansion and reach a distance of 0.26 million lightyears.

(Finally the photon can reach the reciever sometime within the next million years.)

[StringJunky]

Thinking about new ideas and looking at problems in a different way is a hallmark of science. Just remember what Isaac Newton said: "If I have seen further it is by standing on the shoulders of giants." First give every bit of thought to ALL the work accomplished by those who came before you. Then consider the possibility that you might be able to see a little farther.

 

Pangloss, I think these words and quote should, somehow, be integrated into the forum's advice section to new posters with regard to presenting new 'theories' or hypotheses. Being new to this forum and learning to conform to the level of scientifc discipline required here, I find these words very illuminating and concise.

 

Sorry to distract, but I was moved enough to comment.

[tar]

Thankyou Spyman,

 

That was instructive. I think I was moving the photon too far before I expanded the space, and I was not expanding the space fast enough. If the integral was smaller than a million years and you performed the same excercise (understanding its a false result since we evened out the rate) would the time the photon takes be longer with smaller integrals? Would the result be different if you expanded the space, and then moved the photon or moved the photon and then expanded the space? Or did your example simulate moving the photon effectively along with the expansion?

 

Regards, TAR

[Spyman]

In my example I move the photon first as if space didn't expand and then I streach space, it's only a rough approximation because in reality space expand while the photon travel through it, but with small enough steps the result will get very close.

 

With smaller steps of 100 000 years, the trip takes ~304 million years, with steps of 10 000 years ~305.33 million years and with 1000 years ~305.28 million years.

 

If you expand space first, then in the first step the photon would be brought back to 36+3.395 before it travels forward to 39.395-1 witch brings it to 38.395 instead of the 38.3 million lightyears in my example. One could probably calculate it that way too and also get a rough result.

 

[EDIT]

When space expands it streatches the light rays within it and creates a cosmological redshift, witch we can measure in light from distant stars.

 

Here is an link to a Cosmos Calculator: http://www.uni.edu/morgans/ajjar/Cosmology/cosmos.html

 

You are supposed to put in Omega=0.27, Lambda=0.73 and Hubble=71 to get values corresponding with our Universe.

 

Then you can put in different values for the redshift and it will calculate how far the object was when the light was emitted, how far it really is now, how fast it was moving away then due to expansion and how fast it is receding now.

Edited August 27, 2009 by Spyman
Adding Morgans Cosmos Calculator

[tar]

Spyman,

 

I have played with that calculator a little. It doesn't go above redshift 6. I am interested in what the formulas say about regions of space we might 'see' at redshift 15.

 

Also I am not 100% sure of what is meant by distance now and distance then. Are we talking about distance to the object or distance to the image, and does "now" mean when both regions of space, are 13.73 billion years old? And does "then" mean when both regions of space were (ie.) 6.7 billion years old?

 

Regards, TAR

[Spyman]

Those values are only recommended, I think it's because our equipment wasn't technically able to observe objects with higher redshift when the calculator was created. But you can theoretically put in any redshift, for instance a redshift of 1090 is supposed to be for the CMBR, (Cosmic Microwave Background Radiation).

 

Distance "Now" is the actual distance to the object, when the image it emitted reaches us. Like if we could pause the universe and pull out a large meterstick and measure the real distance between us and where it is right now.

 

Distance "Then" is the past distance to the object, when the image was emitted towards us. Like if we could go back in time with our meterstick and measure the real distance between us and where it was then, when the image started it's journey.

 

It doesn't calculate the distance the image has travelled, but since the image propegates with the speed of light, one can simply subtract "Age of Universe Then" from "Age of Universe Now" to get how much time and space the photons has moved through before it reached us.

 

The photons travel distance is most commonly used in popular science articles, for example it could be stated that "Biggest Ever Cosmic Explosion Observed 7.5 Billion Light Years Away". When we put in that particular GRBs, (Gamma Ray Burst), redshift of 0.94 in the calculator, we can find out how far the object was when the burst took place, (5.32 bly), and how far the remnants are today, (10.32 bly).

( Statement quoted from: http://www.internationalreporter.com/News-3384/biggest-ever-cosmic-explosion-observed-7-5-billion-light-years-away.html )

[tar]

Spyman,

 

Thanks again for helping me get the conventions straight. Some of my confusion has come from not properly parsing the meaning of then, and now, and currently and really, when the universe is talked about. And I still think, that I am not the only one that frame shifts when talking and thinking about the universe.

 

For instance, if the universe started at a point, where time, space and matter and energy came into existance, and inflated, had the last scattering, expanded rapidly at first light, and have continued to expand to the present day universe, then ALL regions NOW, regardless of how far away they are, or how old they look to us, are, in the current universe, ALL 13.73 billion years old. This would be true even if some regions of space are outside of our "observable" universe. Those regions NOW, would be what ever 13.73 billion years of development made them.

 

Is this a correct understanding of the conventional meaning of the universe now?

 

Regards, TAR

[Spyman]

Yes, at least from my understanding, I would say that it's very close.

 

The Universe comprises by definition: "everything that physically exists: the entirety of space and time, all forms of matter, energy and momentum, and the physical laws and constants that govern them."

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

 

The Copernican Principle states that: "the Earth is not in a central, specially favoured position. More recently, the principle is generalised to the relativistic concept that humans are not privileged observers of the universe."

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

 

The Cosmological Principle states that "all points in space ought to experience the same physical development, correlated in time in such a way that all points at a certain distance from an observer appear to be at the same stage of development. In that sense, all spatial conditions in the Universe must appear to be homogeneous and isotropic to an observer at all times in the future and in the past."

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

 

Timeline of the Universe:

 

 

But I would also like to add:

 

- The Cosmological Principle may still be challenged and shot down.

 

- There are different models about the actual Ignition, starting the BB, we don't know if the Universe suddenly came into existance or if it has always been here, some newer models predict that the Universe was contracting before the BB event.

 

- We calibrate our cosmological time to zero against the BB ignition, but that doesn't mean that there wasn't any "time" before that.

 

- The size and contents of the Universe is also highly debatable, we don't know how big the outside of our observable part is and what properties it has, all we have is the clues we manage to extract from the remnants we can measure.

[tar]

Spyman,

 

Thanks for the response and the thoughts. Very nice.

I took a little break from the forum to do some more reading, and try to get a better picture of where I am getting it wrong. I still do not see my mistake. Something doesn't add up in my model, but it doesn't seem to add up in the accepted model either.

 

Perhaps you can help me sort it out.

 

There seems to be several "starting" points we have to deal with.

 

One is the "moment" of the big bang, when all the space and time and matter and energy, that ever has, or ever will directly effect our instruments or senses, began.

 

Shortly after this moment, an exponential inflation of space occurred, moving regions of space far out of causual connection with each other. No gravity, or light could communicate the state of one region to a widely separated one. After this inflationary period however, a second starting point seems to be suggested, where antigravity was mostly cancelled out by gravity, leaving just some gravity around. At this "second starting point" gravity, whose influence moves at the speed of light, could begin to relink one region to another. Even though photons were still being scattered at this point, gravity, being something somehow related more to the mass of somethings, than the electromagnetic wave/particle nature of photons, did not have to wait for the last scattering to begin relinking regions.

 

Then a "third starting pont" around 379,000 years after the first starting point, occurred at the "last scattering" when photons were free to travel.

 

The region of space, that is now the milky way, was present in the universe, at each of these "starting points".

At the moment gravity gained its footing, the amount of space, causually linked by gravity to the region of space that would become the milky way, could be thought of as zero, but the sphere of gravitational influence, would from that moment, expand at the speed of gravity. The "observable" universe, that is the regions of space whose gravity affects us, or, regions of space affected by our gravity, could be determined from that starting point.

 

Likewise, at the moment of the last scattering, our Milky Way region of space, was causally connected to zero other regions by photons(light), but our region's photons began at that point to enlarge a sphere, at the speed of light, of our "visable" universe. Regions of space, coming into our view, because their photons had the time to reach us, where simultaneously receiving our first photons. We each "saw" each other, as 279,000 year old regions of space.

 

Here is where our earlier (false result) excercise, of determining how long it would take photons to traverse a percentage of that earlier, smaller, but expanding, universe, comes into play. The false results of that excercise, indicated, that electromagnetic images of widely separated regions, could reach each other, after million or billions of years. What percentage of the universe could thusly be linked is obviously at question, depending upon the size of the universe at last scattering, and the rate of expansion, at that time. However, the important concept to me, is the fact that the arrival of the "image" denotes the actual causal connection. The photon from one region, has reached the other, and relayed the information of the "state" of that distant region of space (at the time the photon was released).

 

If we "see" a region of space, then it must be causally linked to us. It's photons have reached us, and ours have reached it. If gravity causally linked us to that region, before light did, it seems to follow that that region's mass, the region associated with that visual image, should have been "felt" by our region of space, earlier than the arrival of the visual image. Meaning, for instance, that the gravitational image of that region of space, would not be the same apparent size, or the same calculated age, or the same calculated distance, as the photon image.

 

So, in April we found a gamma ray burst at Z=8.2 (GRB 090423) figured to be an image from a 630 million year old universe, the light having taken over 13 billion years to get here.

 

Yet we figure the background radiation to be the image of the surface of last scattering, at the limits of our observable, visible universe at Z=1000+ at the age of 379,000 years the light taking 13.73 billion years to get here.

 

There seems to be a very large percentage of our visible universe left to be discovered. Those images between Z=8.2 and Z=1000. Images we would see as regions of space as they were between the age of 379,000 and 630,000,000.

 

Regards, TAR

[Spyman]

If we "see" a region of space, then it must be causally linked to us. It's photons have reached us, and ours have reached it. If gravity causally linked us to that region, before light did, it seems to follow that that region's mass, the region associated with that visual image, should have been "felt" by our region of space, earlier than the arrival of the visual image. Meaning, for instance, that the gravitational image of that region of space, would not be the same apparent size, or the same calculated age, or the same calculated distance, as the photon image.

The image from distant objects reaches us syncronised with the gravitationally attraction as it was, at the same time as the image was transmitted.

 

I try to imagine gravity like a deformation of space that propagates like a wave with the speed of light, but one could also view it like a graviton moving through space. Since the photon and the graviton both starts at the same time and point, travels with the same speed and traverses the same path, they must also both arrive at the same time.

 

Eg. if there is two movie projectors, showing the same movie in parallell, and one of them has the lens blocked in the opening of the movie, they would still be in sync, on the screens, when the lens cover is removed.

 

So even if gravity is able to traverse the early Universe when light is blocked by matter, when the path is cleared light will be able to race through space, side by side with the gravity wave that is emitted at the same time as the photons, and reach the finish togheter.

[tar]

Spyman,

 

"So even if gravity is able to traverse the early Universe when light is blocked by matter, when the path is cleared light will be able to race through space, side by side with the gravity wave that is emitted at the same time as the photons, and reach the finish togheter."

 

Granted. This would have to occur. But I was trying to visualize the "event" as occuring in a particular "region" of space. The light and the gravity from the event would arrive here synchronized. We see the light image, and feel the gravitational image of the event, at the same time.

 

But, although it makes no sense, the gravity from that "region" also reached the milky way region, earlier. In terms of causal connectivity, that is. So is there somehow a "double" image of gravity we could observe, and use to help determine the distances to events?

 

Or conversely, do we "feel" the gravity from a distant region in space in a manner, that would not precisely coincide with the light image, in terms of distance, apparent size, and age? Not that some aspect of gravity does not arrive bringing information about the event, at the same time as the photon arrival, but that gravitational information about that region of space has been available, or is available, based on a different "starting point", which would place the importance, or gravitational effect of the mass of that region of space, (on the milky way region,) at a closer range, than the photon, graviton, image would report.

 

Regards, TAR

Edited September 7, 2009 by tar
added "graviton"

[Spyman]

The light and the gravity from the event would arrive here synchronized. We see the light image, and feel the gravitational image of the event, at the same time.

The thing here is that they are both snapshots of the event, if you want a movie you need a stream of images and if you want to continue to feel the gravity it needs to be updated.

 

When the Moon orbits Earth, the gravity interaction gets updated continually and causes tidal forces as can be seen in the tides.

(The speed at which the updates or wave propagates is with light speed.)

 

The gravity wave that reached our area earlier, doesn't stick around any more than light does, it continues outward.

 

So when light reaches us it is togheter with fresh and accurate gravity syncronized with the light.

(Like the example with the two movie projectors.)

[tar]

Spyman,

 

"The gravity wave that reached our area earlier, doesn't stick around any more than light does, it continues outward."

 

Thanks for that. I think that was my problem, I had gravity sort of sticking around, or building up, or something. I am not quite sure, what I was doing, but I am more better now.

 

Regards, TAR

 

PS Thanks for helping me along. I still am adding things up and coming up a bit short or long, but nothing that probably won't work out when I see it right.

---

Merged post follows:

Consecutive posts merged

Spyman,

 

Need your help again.

 

If the visible universe is figured to contain around 80 billion galaxies and it is a sphere that is 95 billion ly in diameter now, and was 84 million ly in diameter at the time of the last scattering, how do we visualize, from the minds eye, the matter of those 80 billion galaxies, in the 380,000 year old uninverse?

 

I thought I might figure that early universe about 5,400 galaxies in diameter.

 

(4/3 times pi times 2700 cubed=82,447,957,600.)

 

However, dividing the diameter of that early universe (84million lys) by 5,400, I get regions of space containing a galaxy worth of matter, 15,555 ly wide. Meaning in my imagination, that the matter of the milkyway should have been causally connected by photons by year, lets say 396,000 or so with only 2,699 galaxies worth, to go, to the edge of the milkyway centered visible universe.

 

Can I proceed in this manner?

 

Regards, TAR

[Spyman]

I don't think it's any good to measure distances in the early universe in the term of galaxies, since they are so small compared to the large distances between them and when the universe was ~0.4 billion years old, matter had not yet even started to compact enough to form stars, it was probably more like a soup of Hydrogen and Helium atoms.

 

"The observable universe contains about 3 to 7 × 1022 stars (30 to 70 sextillion stars), organized in more than 80 billion galaxies, which themselves form clusters and superclusters."

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

 

"Most galaxies are 1,000 to 100,000 parsecs in diameter and are usually separated by distances on the order of millions of parsecs (or megaparsecs)."

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

(1 parsec is about 3.26 light-years.)

 

Clusters contain from 50 to 1000 galaxies with even larger separation and they in turn, are grouped in superclusters with very large voids in between.

 

 

 

About the causally connected distances:

 

It might be possible to trick Morgans calculator to show how far away our area could be reached by light when the universe was ~0.4 billion years old. The Hubble constant changes with time and the calculator uses it among other things to keep track of time. But I am not sure if it will yield correct values or not by changing the Hubble value...

 

If you still want to try it out, here is how:

- First, here is the link again: http://www.uni.edu/morgans/ajjar/Cosmology/cosmos.html

- Put in the values: Omega=0.27, Lambda=0.73, Hubble=71 and change the redshift until you reach 0.4 billion years in age Then.

- It will tell you how large the Hubble constant was back Then, take that value and put it in for Hubble and the calculator will assume that the redshift you put in are if we where back in that time.

- Now you need to find the redshift that lets you see the farthest distance away. Start with a low value for z and increase it until the distance Then stops increasing and start to decrease with higher z.

- The distance Then, at the turning point, should theoretically be the farthest distance that light could have reach us from, at that time.

[tar]

Spyman,

 

Thanks. I tried it. Got 3.66Billion lyrs. But am not clear on what that is telling me.

 

Regards, TAR

[Spyman]

Sorry, I managed to mess things up...

 

1) Somehow I misinterpreted the age of 396 000 years as 0.4 billion years, when it really is 0.4 million years or 0.0004 billion years.

(Must have been very tired.)

 

2) Morgans Calculator don't show age values lower than 0.01 billion years and can't handle values higher than 1000 for Hubble.

(Didn't have the ability to check it, at that time.)

 

Closest I can get with the calculator, are with Hubble=970 and z=1.7, that takes us back to the age of 1.0 billion years and the larges distance light was able to reach us from, at that time, was 0.42 billions lightyears.

[tar]

Spyman,

 

I just thought you knew the calculator wouldn't take us back to the last scattering, and you were giving me an idea of what kind of speeds away, and distances we were talking about at 400,000,000 years. Still learned some stuff, but don't really trust the calculator, cause I don't know if its talking about what I think its talking about.

 

For instance.

 

"Closest I can get with the calculator, are with Hubble=970 and z=1.7, that takes us back to the age of 1.0 billion years and the larges distance light was able to reach us from, at that time, was 0.42 billions lightyears."

 

In a billion years, light can travel 1 billion light years, so why couldn't light from 1 billion lys away reach us? Can never figure out, which people are talking about...how far the object was...how far the image traveled...length measured Then...length measured Now...length measured in a variable fashion, taking into consideration that space was stretching as light was traveling through it...?

 

In the reading and picture, model looking at, that I have been doing over my lifetime, and more intensely in the last month or two, I am never sure, what has been taken into account, what assumptions are being made, and what is left to figure out.

 

A few of the big issues I have.

 

People talk about the universe Now, as this web of interlaced clumps and strings and walls of galaxies stretching out forever in all directions. There is no perspective in the universe, that would see this picture, other than a human's mind's eye model. There is nothing "real" about this model. There is no impact, that a 13.73billion year old galaxy, 45 billion lys away, would have on us, now, and no place in the universe, where our galaxy, and that galaxy could be seen, both, as they are, today. The impact that that galaxy has on us today, is the photons and gravity that are reaching us today, from that region of space. What stage of development that region of space was at, and how long the light and gravity eminating from it, that are affecting our present, have traveled, are the important questions. The causal connection. The photons and the gravity that are striking our world, now, that is what we see, that is what we feel, that is what we observe, that is what is creating and affecting our reality.

 

The Cosmic Microwave Background Radiation, is talked about, as leftover heat from the big bang. It is understood, but not often mentioned that the regions of space eminating this radiation are the same regions of space that Now, in the minds eye model of the current universe, are housing 13.73billion year old Galaxies or strings of Galaxies, 45 billion light years away. The photons and gravity from those regions of space are only in reality, affecting our reality in one way, from one perspective. Our perspective, now.

 

Not that models of the entire universe, at different stages of its development, can not be imagined. But that our real universe consists of all the photons and gravity, that are reaching us today. Other perspectives are imaginary in nature, and subject to imaginary errors, introduced when all the facts are not known or properly integrated into the picture. The truest picture is the one we (and our instruments) see and feel. It can not lie, it cannot be wrong, and it is sure to fit exactly with reality.

 

I am often confused by pictures and models that are presented to me, because I do not know what has been assumed, what imagined perspective has been taken, what things have been enhanced, subtracted or added, or figured out for me in advance.

 

For instance. Pictures of deep field objects are often colorized, using schemes to bring infrared or ultraviolet info into the visible spectrum. Pictures of deep field objects are often pieced together, over hours or days, one photon at a time. The resulting image is not a "real" image. That is to say, that you can not look at it, and draw useful conclusions from it, concerning the way those regions of space actually are affecting us, now. You have to be able to subtract everything that was added, add everything that was subtracted, slow down everything that was speeded up, and speed up everything that was slowed down, and comprehend and agree with all the assumptions that were made, to put the image together.

 

And often in models and descriptions, a few dimensions have been manipulated in one manner or another, to make things easier to visualize, or to fit onto a two dimensional media.

 

I am not complaining. I am not saying that the work already done for me in presenting pictures and models, is not welcomed. I am just mentioning why I am often confused, not knowing what has already been done, and is already known, and what is left to do, notice, fit together, and discover.

 

Regards, TAR

[Spyman]

In a billion years, light can travel 1 billion light years, so why couldn't light from 1 billion lys away reach us?

OK, lets make an simple analogy:

Imagine a large rubber band, 100 centimeters long, firmly attached in the end and the start is in your hand. Place a fast ant, with a top speed of 1 centimeters per second, on the band close to your hand. When the ant starts to run towards the end, you play a trick on the ant and start to streach out the band while it is running. Since you are much bigger than the ant, you are able to streach the band with 100 centimeters per second.

 

Now, lets ask your question again, but slightly reformulated:

 

In 100 seconds, the ant can travel 100 centimeters, so why couldn't the ant from 100 centimeters reach the end, (in 100 seconds)?

 

How long do you think it would take for the ant, if you could continue to streach the rubber band forever?

(Think about it before you read this thread: http://www.scienceforums.net/forum/showthread.php?t=24039)

 

Now, to answer the quoted question, the light couldn't reach us at the available time because space was expanding to fast. But depending on the dynamic of the expansion it might be able to reach us at a later time.

Edited September 12, 2009 by Spyman

[tar]

Spyman,

 

But, after a hundred seconds the ant is more than 100cm from your hand. After a billion seconds it will be much more than a billion cm from your hand. My question is not how long it would take the ant, at this point, to turn around and come back. My question pertains to the marks we made on the rubber band before we starting stretching it. After a billion seconds, the ant is at one of those marks, one of those regions in space. If we would take note of that mark, and repeat the experiment, this time placing a second ant at that mark, and point him/her/it toward our hand and begin the stretching again, the second ant would arrive at our hand, at exactly the same moment as the first ant reached the mark.

 

Regards, TAR

[Spyman]

If the two ants starts at the same time, traverses the same path and distance, with the same speed, then they also arrive at their respective goals at the same time. It makes no difference if they are going in opposite directions or not.

[tar]

Spyman,

 

Well then, how come we are just seeing the surface of the last scattering now, coming from so far away, in all directions?

 

Yes I know, inflation. The photons started out, coming toward us at the speed of light, but were not making any progress, and were actually getting farther away as space was expanding so fast that the distance between the photon and us was actually increasing.

 

Fine, I can accept that, seems reasonable, seems real, seems true.

 

But the number of galaxies in the universe seems to have been carefully figured out to be 80 billion galaxies. 80 billion, in an infinite universe, would make no sense, so the number must be either 80 billion in the observable universe, 80 billion in the visible universe, or 80 billion in a finite universe that we are able to see the photons from a certain percent of.

 

Do you know which the 80 billion is referring to?

 

Regards, TAR

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I see it says observable, but I am trying to subtract the 2% to get visible, and I am not sure what to take the 2% from.