The Universe and expansion.

[Jzz]

I have just been reading some interesting facts by someone who went to the trouble of actually doing some calculations. It is well known that according to the Big Bang Theory the Universe expanded extremely fast but exactly how fast was that expansion? The Universe went from smaller than an atom to the size of our solar system in less than a billionth of a second.

If the maths is done it turns out that in the first billionths of a second of the Big Bang, the Universe was expanding at the rate of 5,000,000,000,000,000,000 (5 quintillion) miles per second. Dividing by the speed of light gives the answer that at the beginning of time, the universe was expanding at 26,881,720,430,107 times the speed of light.

In actual fact these figures mean very little because in the very first billionths of a second of the Big Bang none of the elements needed to establish physical laws were in existence.

I suppose the theory is that if it could happen once; it could happen again.

 

[Catastrophe]

"none of the elements needed to establish physical laws were in existence"

Interesting point Jzz. I have often wondered whether there was some time "modification", such that these so-called billionths of a second would actually correspond to much larger time intervals in "new money". Time dilation or contraction?

After all (no pun intended) how can you compare conditions during inflation to current time measurements. There were no seconds, no hours, no clocks to compare the time planet Earth would take to rotate billions of years in the future. And how can you compare a definition based on the speed of light when, according to modern physics, no material object can exceed the speed of light? Was the entire Universe not material? Space, maybe. But another idea suggests that everything is travelling through SpaceTime at the speed of light. How would that affect the calculations? Pick and choose "facts" according to how one wants the answer to turn out?

If anyone wants to be scientific about it, perhaps they can suggest a method to go back to the "BB" and measure it.

Your calculations make worries about division by zero, and the misuse of the mathematical concept of infinity, pale into insignificance.

Cat

 

[Jzz]

After all (no pun intended) how can you compare conditions during inflation to current time measurements. There were no seconds, no hours, no clocks to compare the time planet Earth would take to rotate billions of years in the future. And how can you compare a definition based on the speed of light when, according to modern physics, no material object can exceed the speed of light? Was the entire Universe not material? Space, maybe. But another idea suggests that everything is travelling through SpaceTime at the speed of light. How would that affect the calculations? Pick and choose "facts" according to how one wants the answer to turn out?

Very nice Cat I am truly tempted to sit back in my rocking chair with a blanket across my knees, puffing away at a meerschaum pipe in deep contemplation of the connotations of all that has been said. Seriously, all these considerations do bring about a very philosophical bent of mind. What more can be said!

 

[Catastrophe]

Always the philosopher, me.

Well, it should be: "I" really, but that sounds a bit OTT.

Cat

 

[Catastrophe]

" Dividing by the speed of light gives the answer that at the beginning of time, the universe was expanding at 26,881,720,430,107 times the speed of light."

We are currently saying that matter cannot exceed the speed of light. So is it a consequence that energy can expand at over 26 million million light speed? And if some energy becomes matter (E = mc^2), does it suddenly stop, or reduce to c? How do we fit mass/energy into this situation? Are we saying that our edict on the speed of light being non-exceeded did not apply during inflation? What about all these assumptions that our laws of physics apply in all locations at all times?
There is something wrong here?

Cat

 

[Helio]

We are currently saying that matter cannot exceed the speed of light. So is it a consequence that energy can expand at over 26 million million light speed?

It's common to think of the Bang itself as an explosion, especially since explosions make bangs. But it wasn't a bang it was amore of an incredible swoosh of space. The energy (think photons) and elemental particles (quarks, once formed) were floating in this tiny space and simply got carried outward in all direction, though not from any center. Like the dots on the surface of a balloon analogy, they just separated at rates unimaginable for that short burst of time.

That's my understanding, fwiw. [I'm curious what Dr. Joe is going to say if he responds to my question related to this.]

 

[Catastrophe]

Helio, I know all that standard line stuff, and the confusion between space and SpaceTime et cetera. Been there- done that - wrote the book! I find the whole thing (basically BBT is consistent > t = 0 but otherwise) crumbling into uncertainty.

All stand and salute Heisenberg! There is no agreement AT t = 0. I am sorry to say that I shall not be asking any more questions in a certain direction. 'Singularity' is the gospel truth, but who wrote the gospel? Ah, well, we know nothing about t = 0, but we can't dump the 'singularity' and even consider something equally fictitious, because the 'singularity' was once part of the (holy cow) 'scientific' fiction. Now it is in question, but we can't let go of it, because it was once part of the 'scientific belief'. Many before, including Galileo, Copernicus and Newton would recognise what I am saying.

OK. End of rant for today!

Cat

 

[Helio]

I do find it interesting, nevertheless, that some seem capable of applying GR math to t=0 and before. So I must concede some credit.

 

[Catastrophe]

You never saw me do that!


Cat

 

[Helio]

You never saw me do that!


Cat

I forgot that you eschew the phew of the supposed singularity.

 

[Catastrophe]

Sorry, I forgot the

 

[Unclear Engineer]

It seems to me that the distinction has always been that nothing can exceed the speed of light through space - but that space, as measured in dimensions, can somehow be enlarged faster than the speed of light, e.g., the "inflation" of the "Big Bang".

On the other hand, when we look at the changes in space that we call "gravity waves", aren't we seeing those waves travel at only the speed of light?

 

[Helio]

I assume gravity waves, like gravity as we tend to think of it, is constantly interacting with space, not dissimilar to ocean swells. Hence limited to c.

 

[Unclear Engineer]

I assume gravity waves, like gravity as we tend to think of it, is constantly interacting with space, not dissimilar to ocean swells. Hence limited to c.

Yes, we think of waves traveling through a medium by physically displacing the medium against some force, such as gravity for ocean waves, compression waves against molecular repulsion, etc.

So, if we think of gravity waves as moving space itself, aren't we thinking of space being moved at the speed of light, or less?

And, if that is the case, then how did inflation move space at more than the speed of light?

And, if "dark energy" (or whatever) could do that long ago, why not now?

 

[Helio]

So, if we think of gravity waves as moving space itself, aren't we thinking of space being moved at the speed of light, or less?

And, if that is the case, then how did inflation move space at more than the speed of light?

Great question. I’ve suspected expansion isn’t any sort of stretching of existing space, but new space flowing into existing space. With less and less mass density with time would allow more influx of fresh green() space causing accelerated expansion. I’m guessing and playing with this. I look forward to the real answer, with breath not on hold.

 

[Catastrophe]

I am not saying that I subscribe to this notion, but there is an idea which tries to reconcile space and time dimensions, and that is that we are all travelling through SpaceTime at the speed of light. Just thought I would mention it.

Cat

 

[Unclear Engineer]

That is what I mentioned previously somewhere in these cosmology threads: that if we are traveling in some dimension at the speed of light, would we be able to even perceive that dimension?

Going to the analogy of flatlanders living on a sphere without the ability to perceive its curvature, and not realizing that the expansion they can perceive is driven by expansion of the radial dimension they cannot perceive, I sometimes wonder if what we observe and extrapolate backward and forward in time, to think of as infinitesimal progressing to infinite, is perhaps really not extrapolatable that far in either direction of time. For instance, what if those flatlanders were on the surface of a sphere that is ringing like a bell, with its radial dimension expanding and contracting cyclically, without that unperceived radial dimension ever going to zero or infinity. If the length of time during which observations were obtained was tiny with respect to the frequency of the oscillation, would those flatlanders be able to tell the difference between a cyclic environment and a once-and-done existence?

 

[Catastrophe]

It was in the "Hidden in Plain Sight" Series; I am not sure which one. The 4th dimension was unified in length as It involved the four coordinates x, y, z and ct.

 

[lanzu]

I think the universe could be collapse and be inflation again.it just like a big rebound.Our universe is just be the one of the multivariate universe.

 

[Catastrophe]

I could understand this, if, in a cyclic system, there are phases which are involved, most definitely avoiding words like universes, multiverses, and anything else which contradicts the definition of Universe, as being all there is.

I am not supporting the idea of a cyclic Universe. I am discussing an imaginative, unproven idea which, nevertheless, is just as worthy of consideration (if not more worthy) as the fictional idea of a singularity. Maybe a 'singularity' is 'really' a nexus between 'phases' in a cyclic universe. This is no more than a purely imaginative, unsupported idea.

Cat

 

[Greenlight]

I think the problem lies in perception of time flow. Space-time is inseparable. Yet we always just say space expanded, we never mention the time side of the equation. If nothing moves faster than light it obviously must be the time factor that changed instead of space factor.

 

[Catastrophe]

It is not space which expanded, but SpaceTime. SpaceTime may represented graphically by showing time as the vector ct, i.e., km per sec x sec (time) = km = distance. So, graphically, you have coordinates x, y, z and ct. From this it follows that (putting x, y, z = 0) that everything is travelling through SpaceTime at c, the speed of light.

I am just recounting one idea I have come across, but do not necessarily subscribe to. But it is interesting.


Cat :