A very fine presentation indeed!

actual talk begins at 4:27.

23-4.08.2015 Interesting presentation. Prof. John Barrow: 1.1. (No outside, no edge, no center, explanation with a model of 2-dimensional surface.) 1.2. Quote "The next interesting point to make about the expansion is that it is not an explosion. The Universe is not expanding into anything. There is no outside. There is no edge to the expansion. And there is no center. So the fact that everything is expanding away from us does not mean that we are (in) the center of the Universe. Well, it`s easy to say that simple to understand it ... from the case the Universe is infinite. If the Universe is infinite, then there is clearly no edge. But there is also no center. ... all these distances would expand and the network would appear to expand away from you as though you are in the center of the network, the same in every direction. So, every point acts as though it is a center...the concept that space is not fixed and flat, but it can be curved and dynamical and changeable. And if we have a surface which is 2-dimencional but not like this piece of flat paper, but curved like a surface of a ball, than you can see that if you are in this 2-dimensional Universe whose space is this curved surface, you could walk around on this surface and you could never arrive to an edge. If you inflate the balloon then if you mark these galaxies out on it ... then these points move away from one another and whichever point you sit on you will see the others moving away from you as though you are in the center. So the curvature of this space allows us the have no boundary, no edge. To expand but yet not have a center of expansion on its surface of space." Unquote; 2.1. (The visible Universe, 14 billions old Universe, 14 billions light years distance, horizon of our visible Universe.) 2.2. Quote "... that is the greatest distance from which light would have time to travel since the expansion began. That`s not the edge of the Universe but it is our horizon. We haven't had time to collect light from anywhere further away." Unquote; 3.1. (Accelerating expansion in the last 4-5 billions years, smaller horizon of visible Universe in the far future, no possibility to make cosmological observations.) 3.2. Quote "And eventually it will create an environment where there is the horizon and all the other galaxies will pass beyond that horizon around us which is much much smaller then it is today. And all the other galaxies will pass beyond that horizon and we will no longer in the far far future be able to make any cosmological observations anymore. We will not be able to determine that the Universe is expanding." Unquote; So the problem that disturbs me is: Observing with a telescope distant galaxies and objects we see them in the state as they have been in the past, when light began its travel. This means, we see in the past of our Universe. It is popular understanding that more distant objects we see more in the past of our Universe we see, close to its origins (for example quasars). But there is the horizon. The horizon is not the edge of the Universe. The visible Universe is not the existing Universe. There is no center. We are not in the center. Space is curved and expanding in every direction. We see a mixed image of our Universe as it (the objects, galaxies, stars etc.) has been at different distances from us in the different time periods in the past. We see only a very mixed image, picture, which is not equal to the real state of our Universe in its different regions and at all the distances in this concrete moment. In the same time science says that may be "we haven`t had time to collect light from anywhere further away" then 14 billions light years. Could expanding speed of Universe, relatively to the distance between us and the more distant objects, accumulated till now, including in the period of possible inflation, (the resulting speed of expansion of the space between us and the more distant objects - the speed of extension of the distance between us and the objects near the horizon or may be not so distant) be overpassing the speed of light? Has light from the beginning of our Universe, when Universe became transparent and light began to travel, already reached and overpassed during the inflation or later that region of the Universe (although the Universe has no center) where then or later our Solar system had to be created or has already been created and existed, or this light and images from this first period when the Universe has become visible has not reached us and is beyond the horizon of the visible Universe? If so, how this light has traveled in the "small" Universe in the period of inflation, if there is no edge and no outside, what has happened with the light and images from the beginning of the visible Universe, how this light has traveled in our curved space without edge if its speed has been obviously higher than the speed of expansion even during the inflation? I hope that this light of the beginning of the transparent and visible Universe and the images of the first objects, clouds, stars etc. is not absorbed by the different cosmic objects or reduced to the observable today microwave radiation... But how this light has traveled in this "small" curved space without edge, light with higher speed could obviously not overpass the expansion of the curved space and could obviously not go "outside" or create a new "front". So, if not reduced or absorbed, and in relation to that region (in the expanding in the past Universe where our Solar system had to be created) in our actual Universe where our Solar system is now situated, and in relation also to the speed of expansion (the final speed of expansion of space between the different objects - accumulated speed at the different distances of space between the different objects) and the speed of light itself, has it for ever already overpassed us (the image of this primordial transparent universe) or we have to wait in the future in order to be able to collect this light and see these images? (Could be possible that accumulated speed of expansion between distant object in our Universe is higher than the speed of light, if so, could this mean that these distant objects move one from another relatively with a speed higher than the speed of light, and if so, in relation to the Relativity of Einstein, could we speak about two different types of movement - movement of objects through the space and relative change of the distance between them, and relative movement of the objects and change of the distance between them in result of the expansion of the space itself, and if so what makes the difference, what is there in the "structure" of space which make difference when objects pass through it, through its "structure".) So my question is: Where exactly is the horizon of our visible Universe? And what is it depending on? Only on the age of our Universe? On the past 14 billions years and the logical relative distance of 14 billions light years? Is it connected with the fact that "we haven't had time to collect light from anywhere further away", or there are other reasons and we would never be able to see anything more from the past of our Universe with curved expanding space? Are the distant objects we can see the edge of what is ever possible to see from the past of our Universe, taking into consideration all the above? And if there is no center, have these distant quasars and objects been in the past situated "in the heart" of our then much smaller and expanding inflationary Universe? (And may be meanwhile the expansion has created this distance of 14 billions light years between this "heart" of the then expanding Universe and our present days Solar system, although we are now not in the center of our Universe and there are in the deep space such distant object on the other side of the sky, i.e. at a distance of other more 14 billions light years in the opposite direction of our visible Universe? May be our 3-dimensional space (or if somebody prefers 4-dimensional space-time) is simply a curved entity like the 2-dimensional surface of the balloon. But there is something in the balloon situated in our 3-dimensional space. So if we use such analogy we could ask what is inside the 4-dimensional curved entity of our Universe, may be situated in some other multidimensional entity.) 1. Where exactly is the horizon? 2. Which is the reason for the horizon (the premises for the distance to it/its "location'')? 3. Will we ever be able to see something more from the past and origins of our Universe?

I don't really care for his voice and presentation style... I'm sorry Mister Barrow - I'm reading your Book ' The Book of Universes ' and as a student of Astrophysics at Indiana University ( second year ) I read quite a lot and made a commitment to read at least one Book per week so I can gain knowledge that falls outside the standard study requirements... You're Book is great and full of historical accurate information on theoretical models of Universes by Dirac, Einstein, Schrödinger etc...I also will obtain the Book you wrote with Joseph Silk, who I respect and meet twice in person. So, while your Book is written in a entertaining and informative style your presentation is rather dull and without emotions. I respect the information presented here but im not surprised that there aren't many videos with Mister Barrow...his voice is monotonous, his style boring & emotional a bore.