Cosmological terminology

[toucana]

[ split from glossary of apologetics thread ]

Faradave wrote

Further, "expansion of space" (any particular simultaneity) over time suggests independence of space from time, if one presumes a flat geometry. This cannot be the case in view of invariant speed (i.e. space/time ratio) limit c, which indicates a dependence.

Why on earth would anyone make such an assumption as “if one presumes a flat geometry” when discussing the universe or cosmology ?

You have presumably heard of Minkowski Space, Riemann Manifolds and other types of non-Euclidean differential geometry routinely used in discussions of General Relativity and the mathematics of the space-time continuum ?

[toucana]

Faradave

I think the nuance between the words Cosmos and Universe that you are trying to promote corresponds to the distinction between synchronic and diachronic modes of analysis in linguistics.

Cosmos —> synchronic —> (from Greek συν- "together" and χρόνος "time”)
Universe —> diachronic —> ((from δια- "through" and χρόνος "time")

https://en.wikipedia.org/wiki/Synchrony_and_diachrony

This distinction was first proposed by the pioneering Swiss linguist Ferdinand de Saussure (1857-1913) in his posthumously published Course In General Linguistics (1916) - in which he argued in favour of the primacy of synchronic analysis of languages in order to understand their inner functioning, as opposed to a diachronic approach which typically tends to emphasise etymology.

The only problem with this cosmological usage is that it appears to be subjective and personal to you, and is unknown to any other lexicographer of scientific terminology that I can find.

[Faradave]

...google it. Which dictionaries contradict each other over meanings for universe?

Though not dictionaries per se, the links in my post above conflate "cosmos" with "space" in "cosmic inflation". "Universe" is defined as "all space and all time". So, there's a potential conflict in equating "cosmos" with "universe". That's why I encourage defining terms explicitly, which I think we all agree on.

Here's another reason. Referring to a drawn triangle, I might say it widens from vertex to base. But does it? It's a static drawing. By contrast, if you place two adjacent fingertips on a desk they form the sides of a triangle. Now, if you slide those fingers apart, that triangle is actively widening. The difference is usually obvious from context but sometimes not.

"Cosmic inflation" by the balloon analogy, suggests an individual 3-sphere (i.e. the "balloon") which actively expands. However, 4D spacetime suggests to me, a better onion analogy, in which worldlines extend outward through successive layers of space which coexist along time. The latter is a more passive, deterministic view of expansion.

In a curved-space, radial-time model, "space" is any concentric 3-sphere enclosing the big bang (BB). Euclidean interval-time coordinates are physically realized at every event (4D location), except possibly the central BB singularity. Local flatness makes a spatial arc indistinguishable from it chord (∆x).

[bangstrom]

4D spacetime suggests to me, a better onion analogy, in which worldlines extend outward through successive layers of space which coexist along time. The latter is a more passive, deterministic view of expansion.

A 4D hypersphere expanded into 3D space has the form of a torus and several multiverses that cyclically expand and contract and expand again can be strung together inside the volume of a toroidal universe where the center of the torus is the common Big Bang-Big-Crunch beginning and end of all the universes.

An observer located at a point within the torus that appears to be rotating away from the Big Bang center would see his part of the torus as an expanding universe while an observer in a part of the torus that is rotating back to the center would be in a contracting universe.

Rudy Rucker’s model for visualizing a continuous 4D universe starts here.

http://www.rudyrucker.com/geometryrelativity&4D/#chap-7

[Dave_Oblad]

I might disagree with Bangstrom about the shape of the 4D Universe.

An expanding 3D Sphere would look like an Ice Cream Cone composed of each iteration (snapshot) of the expanding Universe. The image Faradave posted above would be like looking at the Ice Cream Cone from the top and the cone part is solid, static and hidden.

The actual shape would be more like the typical Cosmic Expansion model backed to the Big Bang point in time/history. We always exist on the latest iteration of this next hyper sphere. Each 3D iteration is a Planck Interval in thickness along the 4th axis. When folks ask where the edge of the Universe is located.. we ARE on the edge. Literally.. the edge of New Creation. We can't see this edge because we can only see information in 3D.

Like a flatlander can only see radially around him.. but Time for such a being is the 3rd Dimension. This flatlander can't see behind (history) or in front of himself (future) along his 3rd axis of Time. Each iteration of temporal length (Planck length) allows the Geometry of Matter to write the next Geometry onto the newly created blank space grid. By using the Geometry of History, particles can maintain information regarding next position and velocity for every new point of sub-matter created that allows the Block Universe to be both Static and Dynamic at the same time. The Dynamic part is the on going creation of New Space and the imprinting of previous Matter Geometry on each new layer of 3D space.

In other words, the Big Bang is still an ongoing process. New Matter is constantly being created for each new 3D slice of Space. Since New Matter would have a slight constraining effect on the Planck Length of New Space, the Planck Length growth would be somewhat inhibited near Matter, unlike the Space between Galaxies.

Depending on the Gravitational Field (Variable Planck Length grid field density) Matter is forced to take on a slightly different Geometry to accommodate the differential in Planck Lengths over it's size. Lucky for us the alternate Geometry to accommodate a variable density space grid field is the same Geometry matter must accept/convert to.. to accommodate motion. Exposure to a Space Grid Field Density Differential forces Matter Geometry to be the same as the Matter Geometry of Acceleration.

And that, of course, is Gravity.

My two cents as always... Couldn't resist.. lol.
Best wishes,
Dave :^)

[Dave_Oblad]

Hi Bangstrom, sorry I jumped the gun a bit. I clicked on the link you provided and found some good stuff, including what I was saying about the 4D shape being conical. I will have to go back and read more than just chapter 7.

A quick point in regards to Relativity: It should be possible to make an instrument that quickly outputs its Velocity through Space with no outside references. How? Remember the Centrifuge Experiment with 2 clocks, 1 on the Arm and 1 at the center. These two clocks will run at different rates. If one can mathematically remove the temporal effect of being a clock that is under rotational acceleration (which would be a constant if the whole experiment was not accelerating) then the difference between the two (atomic) clocks would produce a value that can only occur at 1 specific velocity.

Because the equation for Time Dilation is non-linear, there can only be one place on that curve where both clocks agree about their relationship. That place on the curve is the actual velocity of the instrument through Space. Clever physics folks would probably be able to find a better more compact design that yields faster results.

Later all...
Dave :^)

[bangstrom]

I clicked on the link you provided and found some good stuff, including what I was saying about the 4D shape being conical. I will have to go back and read more than just chapter 7.

As I recall, the 3D shape is conical when going from the bottom to top or more like a hemisphere when expanding- and like the top of a sphere when contracting. The end result is a complete sphere or Faradave's layered onion.

I added the link to Rudy Rucker’s model because I find it to be a possible extension of Faradave’s onion model where the onion represents one cycle of time from Big Bang to Big Crunch. If the onion rebounds from its Big Crunch the result would be a new Big Bang and the creation of a whole new universe with possibly little resemblance to the previous cycle.

The second universe could collapse and rebound into a third universe and the cycles could continue ad infinitum with a series of universes connected by a single timeline. Rucker calls this a “string of pearls model” or, with Faradave’s onion, a “string of onions.” This is a linear 3D understanding of how our universe may be part of a continuous cycle of universes rather than a one-time event.

The timeline of a “string of onions” can be joined into a continuous circle within a 3D torus to represent a never-ending circle of possible universes going around and around. This is Rucker's model of a torus-shaped multiverse that contains all possible universes... past present and future. He simplifies this model as a single 4D hypersphere since a torus in 3D space becomes a 4D hypersphere when rotated through one more dimension just as a 2D circle becomes a 3D sphere when rotated through one more dimension. This is Rucker’s idea of the universe as a 4D sphere but he describes it as a torus because a torus is easy for us Spherlanders to visualize.

I like to imagine Rucker’s model as a washing machine with an agitator in the center and the universes are like articles of clothing going around and around. They expand as they move to the outside and contract as they move to the center and, at the very center, is the Big Crunch-Big Bang where everything dies and is reborn.

In Rucker’s model, an observer’s location in the greater of a 4D spacetime determines whether their universe appears to be either be expanding or contracting. Any motion away from the center expands and any motion back to the center contracts but there is no actual expansion or contraction of the 4D sphere itself. There are just different densities depending on their distance from the center where everything contracts to a point.

I like to imagine Rucker’s model as a washing machine with an agitator in the center and the universes are like articles of clothing going around and around. They expand as they move to the outside and contract as they move to the center and, at the very center, is the Big Crunch-Big Bang where everything dies and is reborn.

In Rucker’s model, there is no need for dark energy to accelerate the expansion of space because the expansion of space is an illusion and it takes no energy to accelerate an illusion. The 4D hypersphere that contains our universe neither expands nor contracts.

Rucker's 4D model is a timeless hypersphere using Block Time but his writing was before the term "Block Time" became popular.

A quick point in regards to Relativity: It should be possible to make an instrument that quickly outputs its Velocity through Space with no outside references. How? Remember the Centrifuge Experiment with 2 clocks, 1 on the Arm and 1 at the center. These two clocks will run at different rates. If one can mathematically remove the temporal effect of being a clock that is under rotational acceleration (which would be a constant if the whole experiment was not accelerating) then the difference between the two (atomic) clocks would produce a value that can only occur at 1 specific velocity.

Because the equation for Time Dilation is non-linear, there can only be one place on that curve where both clocks agree about their relationship. That place on the curve is the actual velocity of the instrument through Space. Clever physics folks would probably be able to find a better more compact design that yields faster results.

The two clocks on the centrifuge could be synchronized so they both read the same time but the problem remains that there is no way of knowing the absolute velocity of the clock in the center. The measured difference in time would be relative to the center clock and the center clock’s absolute velocity relative to the universe is a big unknown.

I don't see how a calculation could be done to give you the absolute velocity of the center clock.

[Dave_Oblad]

Hi Bangstrom, in regards to your last statement:

Bangstrom wrote: I don't see how a calculation could be done to give you the absolute velocity of the center clock.

Both clocks have traveled for the same period of time per distance of the test. Both clocks will be dilated. The arm clock will be more dilated (slower) by a specific amount. Since the formula for computing Dilation vs Velocity is nonlinear, then visualize a graph plotting Velocity vs Dilation.

Above graph is for all velocities using the formula:

On this graph above must be two points representing the center clock and the arm clock.

Imagine the arm clock is exactly 20% slower than the center clock. There should be only one place on that nonlinear curve where the difference is exactly 20%.

Imagine the device is slow.. then the dilation difference could be very low.. say 0.1%
Imagine the device is pretty fast.. then the dilation difference could be medium.. say 5%
Imagine the device is really fast.. then the dilation difference could be great.. say 50%

See: The dilation difference as a percentage can only be fit to the graph at one exact point. The fastest clock indicated on the graph as being the actual velocity through local space of the device as per the graph.

One might argue that for every lower point on the graph (faster clock) there is a point further up that is exactly (say) 20% differential (slower clock). However we know the exact ratio of distance traveled between the two clocks. This would eliminate all potential candidates except the one that maintains the distance traveled ratio between the two clocks as being valid.

We are taking advantage that Dilation vs Velocity is a nonlinear relationship and that both clocks are constrained as one device for an accurate measure of differential clock rates vs actual distance both clocks have traveled relative to each other.

Again: There can only exist 1 place on the graph where the known ratio of distance traveled for both clocks match the dilation ratio of both clocks.

This help?

I haven't given much consideration to the effect on this device near a star etc. adding gravity effects.

Best to ya,
Dave :^)

[Dave_Oblad]

Also, a quick note about the 4D shape of the Universe.

It can't be a simple symmetrical hyper-sphere. The 4th dimension is a direction that all points on the 3D surface must agree upon. Note that two points located on opposite sides of the sphere would be pointing at each other, direction wise, if pointing in the direction of history. Only a cone made of spheres can have all points per sphere agree on the same direction (axis) we define as history.

Later Friends,
Dave :^)

Ps. Sorry, didn't mean to derail this thread, but it caught my eye.

[bangstrom]

In other words, the Big Bang is still an ongoing process. New Matter is constantly being created for each new 3D slice of Space. Since New Matter would have a slight constraining effect on the Planck Length of New Space, the Planck Length growth would be somewhat inhibited near Matter, unlike the Space between Galaxies.

Depending on the Gravitational Field (Variable Planck Length grid field density) Matter is forced to take on a slightly different Geometry to accommodate the differential in Planck Lengths over it's size. Lucky for us the alternate Geometry to accommodate a variable density space grid field is the same Geometry matter must accept/convert to.. to accommodate motion. Exposure to a Space Grid Field Density Differential forces Matter Geometry to be the same as the Matter Geometry of Acceleration.

And that, of course, is Gravity.

I don’t know if yours is the same view as mine but it appears similar.
I see gravity as shorter-space-and-slower-time which is just another way of saying gravity, when mapped on a grid, is curved spacetime. As the universe grows less dense, our surrounding gravitational field (the Space Grid) expands, Plank lengths grow longer and time quickens.

These are the same changes a test particle experiences as it emerges from a gravity well. Longer distances and quicker time. So the expansion of the universe is essentially the same as emergence from a gravity well with the Big Bang condition as the bottom of the well.

Hi Bangstrom, in regards to your last statement:

Bangstrom wrote: I don't see how a calculation could be done to give you the absolute velocity of the center clock.

Both clocks have traveled for the same period of time per distance of the test. Both clocks will be dilated. The arm clock will be more dilated (slower) by a specific amount. Since the formula for computing Dilation vs Velocity is nonlinear, then visualize a graph plotting Velocity vs Dilation.

The outer clock should spin faster and indicate a slower time but how would the two clocks detect local acceleration? When accelerated, the rotated clock would move faster in the forward direction but slower in the reverse and cancel any difference. Both clocks are moving together so the acceleration for both should be the same.

You could forget about the rotating clock and measure the speed of the centrifuge rim in the forward direction and compare that with the rim speed in the reverse. Or for greater sensitivity, you could compare the speed of a forward-moving beam of light with the speed of reverse beam and look for phase shifts but that has been done with the MM-X with disappointing results. I don’t see how the centrifuge experiment would work.

Also, a quick note about the 4D shape of the Universe.

It can't be a simple symmetrical hyper-sphere. The 4th dimension is a direction that all points on the 3D surface must agree upon. Note that two points located on opposite sides of the sphere would be pointing at each other, direction wise if pointing in the direction of history. Only a cone made of spheres can have all points per sphere agree on the same direction (axis) we define as history.

In Rucker’s model, the direction of history is circular away from the center of the 4D hypersphere and then back to the center for another round as a totally new universe. Our universe is limited to a small portion of the total volume of the hypersphere.

Our 3D visible sphere has three axes all at right angles to each other. The 4th dimension is the fourth axis in the direction of our motion through time. All axes in a 4D hypersphere lie at right angles to each other so the direction of time is at right angles to all three axes of our 3D space. The fourth axis of time lies at right angles each of our 3 axes of space and that is the part of 4D space that we Spherelanders can’t visualize. Our motion through time first appears locally and then retreats radially in all directions into invisible history.

[Dave_Oblad]

Hi Bangstrom,

Your last paragraph is correct. If I had a 4D hand, I could point at the center of the Universe by pointing in the direction of History. If I pointed in the opposite direction, I would be pointing at the edge of the Universe, and beyond that edge is non-existence, not some weird sort of alternate volumetric space. Literally, the edge of the Universe.

As far as Time goes, I don't believe in Time or that Time exists. I do believe in Sequence without Time.

That's almost as hard to grasp as the shape of a 4D object. See, I remember long ago seeing the idea expressed that an object falling into a Black Hole would appear to freeze and suspend in place as viewed from an outside observer. That's ridiculous. If that ship had a giant sign showing the Time of Day, yes, it would appear to be running slower and slower the closer it got to the Black Hole. Not because Time is slower but because Matter and Energy has become more complex, or extended internal atomic sequences.

So Clocks run slower as they are made of Matter and Energy. But actual Time around the Black Hole is not changed. That ship will disappear into the Black Hole super Fast, even as its clocks slow down. For example, two Black Holes colliding registered on our instruments in Milli-secs and not Years.

My Mental Model of the Universe indicates it must be Grid-like or Cellular. Scale between objects is always locally consistent. Chemistry wouldn't work if atomic scales weren't absolute. Ie: Big and small hydrogen atoms. So, my model is based on a Cellular Automaton and our existence is purely defined by just a set of Rules. There are an infinite set of such Universes, each with its own set or rules. None of which occupy any more real space than the value of Pi. Real space doesn't exist except within each virtual construct.

In my Model: History is not erased but is required as part of the whole, specifically to define the geometry that must follow into the future. The Quantum operates at infinite speed (because Time doesn't exist) and any sampling of Matter or Energy is just a snapshot of the sequence and thus appears to have random elements that follows the rules of probability, even though everything is absolutely hard determined by the previous existing state(s).

If our reality was only based on the single previous moment, then there would only be two speeds, still and speed of light. If reality only had three layers, there would only be three speeds possible, etc. Thus the speed of matter is totally dependent on a real existing depth of many temporal layers. Once one accepts that Temporal Thickness must exist.. then.. without some weird eraser (Langoliers?) then History is a solid object back to the start of everything. Since it is based on rules.. if an element of geometry is somehow broken, back say 1000 years, that break will propagate instantly to what/where we call now. But.. it will also be repaired instantly by its own history and we will never detect such a break.

Anyway, if New Matter propagated onto the next Temporal Layer (with geometrical alterations as needed) has a restrictive effect on Growth of the Planck Length, then Matter basically prevents the Planck Length from increasing in size as a copy of the previous space cells. Out in deep space, minus Matter, Cells can grow as the natural result of building layers on a growing sphere.

Matter moving at one speed has a different Geometry than the same type Matter moving at a different speed. In order for Matter to Move, it must be the result of certain rules. Once Matter has a specific Geometry, that Matter will continue moving at that constant speed (until altered). If one tries to change the speed of Matter faster than it can Change its Geometry of accommodate the new speed, then said Matter will shatter. Speeding up Matter changes its Geometry to a higher level of complexity (due to the speed of light limitation) and thus slows down its internal cycles. So clocks don't measure Time, they measure Matter Complexity vs Velocity.

Oh, the Geometry of Accelerating Matter is different than Matter coasting. Space Geometry that has a Planck Length Differential (Gravity Well) forces Matter to copy itself to new Temporal Layers with the Geometry of Acceleration towards Smaller Planck Lengths. So, of course Matter tries to Accelerate Downwards. That's Gravity of course.

Ok, not sure if I responded to your observations adequately, but I have to get back to my duties now. Back in a few days to see what's happening here.

Be safe and well..
Dave :^)