TalonD said: are a few questions from an entry level layperson acceptable here? if not then remove this post.

1. we are stationary but with the universe is expanding, the distance between us and distant galaxies is increasing due to expansion, so does that mean that the distance between us and the cmb is also increasing?

2. the cmb is 45b lyrs away, is that actual distance right now? the light we get from it was emittied 13.7 b yrs ago, was the cmb 13.7b light yrs away from us when that light was emitted?

3. we cannot say that space is a physical thing like the rubber of the baloon. We can only say that distance is increasing?

4. if distance is increasing does that mean that the three dimensional volume of the univers is increasing?

5. is the cmb analagous to the horizion that you would see if you were standing on the surface of the baloon?

this is exactly the most helpful kind of feedback. something like this draft essay on what you can learn from the balloon analogy has to go thru editing and revision. questions like this are exactly what are needed to help guide revision.3. what space is, physically, is something that physicists are working on---have a look at Frank Wilczek's new book Lightness of Being which is about the leading edge understanding of empty space. make your local librarian order the book. the link is in my sig. also read the SciAm article by Loll about the emergence of spacetime from a kind of chaos at the microscopic level---this is an unproven interesting conjecture which they simulate on the computer. we don't know yet what empty space is. but we do have a mathematical model for the increasing distances---that has to do for now.4. yes, the instantaneous 3D volume of space can be defined and estimated in the case that it is finite, and recent satellite data gives a lower bound on the volume, and it is increasing in a perfectly normal way as the cube of the scale factor.Of course if the 3D volume of space is not finite then it becomes more complicated to talk about it increasing. But if it is finite then we have this lower bound and it is easy to discuss. If you want a link to a reference, or simply to know the volume in cubic lightyears, please let me know.5. what passes for the LOCATION OF THE CMB ORIGIN is a large spherical surface called thewhere the stuff is that emitted the light we are now getting.In the past we were getting CMB light from other stuff that is nearer, but that light has already gone by us.In the future we will be getting CMB light from other stuff that is out beyond our current surface of last scattering---but that light is still on its way and has not reached us.All the matter in the universe, including the matter we are made of, participated in radiating the CMB light. The CMB light that our matter emitted is now 45 billion away from us, where other people can catch some if they make antennas. Every patch of matter made CMB, it is just a question of TIMING to say where the matter is whose light you are currently receiving at this moment.So your image of ahas some degree of rightness about it. Not a perfect analogy but it does tell the listener to focus not on the material stuff but on the mathematical object (the spherical surface, like the crcle of horizon on earth). there was a momentary onetime event when expansion was 380,000 years old and the glowing hot fog became transparent, and released its somewhat reddish orange light. Each photon of that light is now 45 billion lightyears from its point of origin.1. you ask is the distance to the CMB increasing? the distances between all widely separated stationary things are increasing by Hubble Law, so the distance between us and the matter which sent us the CMB light we got yesterday is increasing as part of that general process. two approximately stationary patches of matter, their distance apart increases 1/140 percent every million years.but something else is happening. the distance to the surface of last scattering is increasing in a more serious way. we only get the CMB light from some particular batch of matter once. it passes by. tomorrow we will get light from matter that is farther away than that batch whose light we got yesterday.Question 2 was your best question of all.==quote==2. the cmb is 45b lyrs away, is that actual distance right now? the light we get from it was emittied 13.7 b yrs ago, was the cmb 13.7b light yrs away from us when that light was emitted?==endquote==No, the matter that emitted the CMB light which we are now getting was, when it emitted the light, at a distance of 41 MILLION lightyears from our matter.You should get this number for yourself by going to Ned Wright calculator and putting in z = 1090. this is the redshift of the CMB light. It says that while the light has been traveling towards us the universe has expanded by a factor of 1090 (and the wavelength of the light increased by the same factor)Since both our matter and the matter that emitted the light are stationary, and the distance between is NOW 45 billion, it must be that the distance THEN was 45 billion divided by 1090!If you divide 45 billion by 1090 you will get 41 million.therefore the distance to the matter then, when it emitted the light, was 41 million lightyears.that's a pretty condensed explanationdon't be discouraged if it doesn't satisfy you, keep asking, thanks for the above questions.