Expanding time?

The point is, the sphere is not expanding...

The spacial dimensions are increasing, as predicted by cosmological models that are generally put under the umbrella of 'big bang'. The 'big bang' is not an explosion that provides impetus, the 'big bang' is just the expansion of space during the early universe through time. Modern cosmology has this early period of expansion as being extremely rapid.So no, the 'big bang' isn't dead. This is the big bang. The balloon analogy has only one purpose - to represent how distance between things can increase without those things moving (by expanding what's between them...in the balloon analogy it is rubber, in cosmology it is space). It is not intended as a complete analogy that describes spacetime. Don't get the actual model used confused with various analogies used to explain certain phenomenon within the model.The balloon analogy represents how space acts through time. The globe analogy represents spacetime as a whole. Edited by Modulous, : No reason given.

OK, say you are standing at 89 degrees latitude (almost completely south) on a perfectly spherical globe. In this thought experiment you can only travel east or west. The circumference for you would be how long it takes travelling east before you get back to where you started. You measure it to be about 1100 metres.If you lived in this universe where you could not see north or south, only east and west, you'd reckon the universe to be about 1100 metres in length.This universe has a twist, however, as time passes you inevitably travel north. Later you measure it again, and this time you find the answer to be 10,000 metres in length!This would be mysterious to you, from your east/west only perspective. However, if we take a 'step back' we can see the globe. You see yourself standing at 89 degrees and walking around and around with a gradual movement north. Travelling north represents forwards in time (south would be backwards in time) and east/west represents movement in space. It seems like the universe is expanding, the length is increasing as time passes!Our universe is much more complicated than the surface of a globe with a single spacial dimension and a single time dimension. It looks more like this - although that doesn't account for all those pesky extra space dimensions either.Here is our problem. In our example we have a single space dimension and a single time dimension and to represent them we need a model which seems '3d'. Obviously we don't use the radius of the globe (depth), but it's there anyway. Topology is a confusing subject, and I get lost a lot - but it is fascinating. Anyway, as you can tell from these complications, trying to represent a four dimensional universe would require an extra hypothetical dimension to represent them in. Since imagining a hypothetical five dimensional object with a four dimensional topology floating within it is fanatically difficult (though I believe some people have managed to get the knack), we simplify to the globe analogy. The expansion isn't the sphere, the sphere represents everything to do with the universe. The past present and future. We have reduced our three dimensions to just one for ease of explanation.Once you can understand this simplified (and I appreciate that simplified seems like a misnomer ), universe the rest follows. I don't want to patronize you so I won't presume what is over your head. Unfortunately it is a simple fact that the answers you are looking for are going to require a lot of thought. The best way I can help is to give you the example of pac-man universe. In this universe pacman can walk off one side of the screen and appear on the opposite side. Thus, the left side is connected to the right side. Imagine curving the screen into a cylinder shape. Do the same for up/down and you end up with a doughnut type shape. Pacman's universe is 2d (ignoring time to keep it very simple), but the representation of Pacman's universe is a doughnut - a three dimensional object (mathematicians like to call it at torus - but that's mathematicians for you).Confusing, I know, and I've probably given you more questions than answers. The cold sweats and headaches are normal, it only gets stranger I'm afraid so if you are an earnest seeker of the mysteries of the universe you're going to have to be content with a lot of states of confusion.It is beautiful though, even just a glimpse of it.

Yes, time flies like an arrow.
Fruit flies like a banana. It isn't expanding into space. Remember how to represent our 2D pacman world we needed a '3 dimensional' model - the torus. There is no 3rd spacial dimension in which it exists.You're going to have to get used to the 'universe as a whole' idea. Look at that picture, and for convenience imagine that time stops 100 years from now. That picture represents our entire universe, past and present and short future. It is that shape, period. It doesn't expand, it's just that shape. There is no expansion whatsoever from this perspective. Expansion is only what we perceive to happen as we travel through time - but time is integral to the diagram. Time, and its existence, are real. That most life forms, do not perceive it to the level we do does not influence it. The universe has four dimensions as part of its existence (maybe more), that's just the way it is. Some animals have evolved not only the awareness of the spacial dimensions, but they are also aware of the time dimensions. They neither measure space nor time (they have built in tape measures too).Why does time exist? Why don't we just have four spacial dimensions? That's a big question, a really big one. Its beyond the scope of this thread which is just discussing what spacetime actually is and what it means for space to be expanding and whether or not time is also expanding.Edited by Modulous, : No reason given.

I warned about getting confused between the two different perspectives. One must be very careful here. The universe is expanding if we look at how space changes over time.Look at the wmap diagram. Keep looking. See how it doesn't expand? It remains the same shape no matter how long you look at it because time is part of the diagram. The diagram is that of space and time. If we made a diagram that changed through time, then it would appear as if the universe was expanding over time, but we could represent it as a 4d object that simply exists.Think about a 1d universe, which is closed and flat. Let us call this a circular universe. Now imagine adding a second dimension (which we'll call time). This universe does not change shape as time progresses, so what happens if we take a circle and extend it into a second dimension where the first space dimension doesn't change?We get a cylinder right? A circle with a 'height' dimension that we use for convenience to represent time. Now, if the universe did expand over time we'd end up with a cone instead of a cylinder, right? If the universe was not expanding in a constant fashion, this cone might look a little like the wmap diagram - correct? Correct, the space expands through time.But the initial confusion was not about space changing through time, but about what happens to spacetime. Nothing happens to space time, just like nothing happens to our cone, our cylinder or our wmap diagram. It just is - it's just a certain shape of x dimensions. There is definitely a dimension called time. Of course, one could resort to the Cartesian demon idea and say that everything but 'I' could well be an illusion but that isn't productive discussion. So yes, time exists. Our perception of it, is quite different from our perception of space and it seems that time works slightly differently than space. Why this should be the case is something of a mystery. And one that is not really the topic here - I wouldn't dream of attempting to answer the question. Perhaps you'd be better off if you read What is Time and Space?

The origins of time aren't relevant here. Hawking has done some work on describing a universe where time was once space-like and there was a transition as it became less space-like. It's all very confusing, and it is unclear how similar our universe is to the one Hawking described. No.

Right, it being time. We didn't create it ourselves. It's origins are not really on topic here, and as I have said several times, I'm not the person to attempt to answer that question. Once again, one must be careful: 'Where' implies a spatial question but we are talking about the time dimension, and whilst it might make sense in a certain context - it can quickly lead to massive amounts of confusion.

I wouldn't go so far as to suggest that spatial dimensions are a physical thing, no.

Increasing through time, there's more space now, than there was when you wrote your post. Space. I think thinking of them as 'physical' puts us in danger of thinking about them in the wrong way. I'll just provide a quote, since in this topic I defer to the experts:

In the same way length is real and exists. No. I'd wager it was closer to 'a structural quality of the [gravitational] field.' What exactly does that mean - I can't accurately report. I am not a physicist and I know how easy it is to get it wrong so I generally refrain from getting into that level of detail. North-South and East-West are just convenient analogous names for the possible directions in a two dimensional universe. I mean by 'see' that if you were to look at the world you inhabited everything would either be east or west of you. There would be nothing above or below you, noting north or south of you, at least that is how it would appear to you as a naive observer existing at 89 degrees latitude. Humans experience space and time in different ways. We can travel in both directions in space with some element of freedom, but our travel through time is more constrained in a specific direction. Yes, that's all very nice. However, that doesn't give us any understanding about the hows and whys of time dilation. How can different observers be observing one thing but each seeing different things happening over different time periods with the same end result? How does one explain the twin paradox? How is it, if time isn't anything but a concept of relationships/perceptions of motion, how can this concept be seemingly altered and changed depending on whether the perceiver is either strongly or weakly affected by gravity?That's the problem, if time is not an entity how can a non-entity warp or vary?

Apologies for the delay. Is the height, breadth, length and age of a tree unreal? Or are they real, but its only the units we choose to describe them in that are conceptual? Right, and length is not a physical thing existing on its own. Yet it is a property that all things seem to have. It is one of at least three dimensions of an object. I'm suggesting that these properties exist and that man has discovered ways to measure them. The measurements are arbitrary and convenient. They measure things which change predictably over a period of time. A rule measures the distance between two points in space, a clock measures the distance between two points in time. In simple terms. Simple thought experiment. Take two batches of radioactive atoms. We empirically know that in any given batch, after 1 hour, half of the atoms will have undergone decay. Let's use a large number so that we can rule out statistical fluctuations. Let us say there are n molecules in each batch (a million, a billion, a godzillion whatever).With batch 1, we leave them just sitting in their box. With batch 2 we speed them up to near the speed of light. We wait 1 hour. We measure batch 1 and learn that 50% of them have decayed. We measure batch 2 and learn that only 10% have decayed.We stop batch 2 from their high speed jaunt. There are now 0.9n undecayed atoms. We'll say that 0.9n=m. If we now wait 1 hour and measure batch 1 we find that another 50% have decayed leaving n/4 undecayed atoms (only a quarter left since we've halved twice). We measure batch 2 and we find we have m/2 atoms left (ie since we last measured 50% have decayed).That's a simple start, how can this be, unless time is a property that objects have that can be measured differently depending on the relative speed of the measurement device and the thing being measured (in this case the clock was travelling at 0 relative to batch 1).

And you know that objects have a beginning and end in height (top to bottom), width (left to right), depth (out to in) and time (start to finish). That is where times fits into the properties of an object - in describing its dimensions.Objects aren't made out of length, but combining atoms together can create atoms of x length. Those atoms will exist in that configuration for y amount of time, but time is not a constituent in the same way electrons are. Unless we are talking really fundamental physics. No. Not unless length is a physical thing, an energy.

As far as I am aware it would measure greater than previously. Space has expanded, but physical objects in space maintain the same dimensions (the forces holding them together ensure this). I might not be the perfect candidate for book recommendations on this topic. You might find Brian Greene's The Fabric of the Cosmos rather good, I know I did with a similar length of background in electronic engineering and physics.

I think it might have an effect on vacuum energy/vacuum energy density. I don't think anyone has a definitive answer as to what that effect is at this time. I don't think it is simply analogous to the way other diffusion processes works I'm afraid - since I think space and the vacuum energy have an intimate relationship of sorts.