Is the Expansion of Space/Time a Result of Object Motion or Framework Growth?

  • Thread starter Thread starter thetexan
  • Start date Start date
  • Tags Tags
    Expansion
AI Thread Summary
The discussion centers on whether the observed expansion of space/time is due to the framework itself expanding or if objects are moving apart within that framework. It is suggested that the current cosmological model supports the idea that the metric space expands, while objects can also exhibit proper motion, although this is less significant on a cosmic scale. The concept of a "big crunch" is debated, with the assertion that it would not involve a deflation of space/time but rather gravitational attraction within the expanded framework. The relationship between matter and the space/time framework is questioned, particularly regarding the implications for a potential rebang following a big crunch. Ultimately, the conversation highlights the complexity of understanding cosmic expansion and the dynamics of objects within the universe.
thetexan
Messages
269
Reaction score
13
I know expansion explains the size of the space/time framework. Is the "expansion" we see between objects relative to each other (objects seem to be getting farther away in all directions) due to continued expansion of space/time or is there also an inter-framework explosive (for lack of a better word) expansion going on. I know I'm not being too clear so let me ask this.

I am not sure about the status of 'the big crunch' as a theory anymore but let's talk about that since it helps me to explain the above. When people talk about the big crunch I believe they were talking about an eventual universal gravitational attraction between objects bringing them together into a single point. To me that would mean that the gravitational attraction going on there would be working within the entire space/time framework in its expanded state...not the framework itself. In other words the big crunch would not be a deflation of space/time (opposite to what happened originally with expansion) but rather a simple gravitational attraction of the objects with the expanded space/time. But then the possible resulting big REBANG would be contained within the already expanded space/time from the previous big bang.

So this means to my weak analysis that the only way to get to a REBANG and have it be a true repeat of the previous big bang space/time would have to deflate somehow thus requiring a new expansion with the rebang.

I know it appears now that none of this will happen since it is still accelerating which brings me back to the question. Is this expansion an expansion of space/time only or objects that are truly moving away from each other as a result of an explosive component to the big bang sans the expansion component.

In other words if the apparent expansion is due to space/time expansion then is there any actual motion of the objects within the framework or is everything stationary within the framework and just the framework is expanding.

Using the balloon analogy...the dots on the balloon move away from each other as a result of the expansion of the framework (surface of the balloon) but are the dots themselves also moving within the framework along the surface away from each other? This would be measured positionally as the relative position of an object to its proper position within space/time as if expansion was not occurring.

Wow. I hope someone can understand what I'm asking.

tex
 
Astronomy news on Phys.org
thetexan said:
I know expansion explains the size of the space/time framework. Is the "expansion" we see between objects relative to each other (objects seem to be getting farther away in all directions) due to continued expansion of space/time or is there also an inter-framework explosive (for lack of a better word) expansion going on

As far as the currently widely accepted cosmological model is concerned (ΛCDM + inflation), it is the metric space that expands.

thetexan said:
So this means to my weak analysis that the only way to get to a REBANG and have it be a true repeat of the previous big bang space/time would have to deflate somehow thus requiring a new expansion with the rebang.

This is not scientifically justified.

thetexan said:
In other words if the apparent expansion is due to space/time expansion then is there any actual motion of the objects within the framework or is everything stationary within the framework and just the framework is expanding.

There is actual motion of the objects, but the recession of galaxies is due to expansion.

thetexan said:
Using the balloon analogy...

I recommend this

http://www.phinds.com/balloonanalogy/

I also recommend reading the Wikipedia page about current cosmological model

https://en.wikipedia.org/wiki/Lambda-CDM_model
 
thetexan said:
In other words if the apparent expansion is due to space/time expansion then is there any actual motion of the objects within the framework or is everything stationary within the framework and just the framework is expanding.
It's closer to the second, the framework is expanding.
https://en.wikipedia.org/wiki/Metric_expansion_of_space
However objects can also have 'proper motion', relative to each other, but that's not really relavent on the scale of the universe as a whole.
It's relavent for nearby objects though, the Andromeda galaxy is actually getting closer to the milky way despite the overall cosmic expansion.
 
Last edited:
Is the space/time framework dependent on mass inside of it for its existence? If, in a thought experiment, we could snap our fingers and all matter disappears, is the framework still there? In other words is the space/time independent of the matter it contains or is it the matter that establishes the framework. The reason I ask is this...how could you have a big crunch followed by a rebang unless the framework deflates also during the big crunch bringing us back to a similar starting point.

I guess I'm confused on this point...I think of space/time as it expanded as an expanding container in which matter coalesced...the two being different, one a container and the other the stuff in the container. As the container expanded the stuff in the container also expanded.

tex
 
TL;DR Summary: In 3 years, the Square Kilometre Array (SKA) telescope (or rather, a system of telescopes) should be put into operation. In case of failure to detect alien signals, it will further expand the radius of the so-called silence (or rather, radio silence) of the Universe. Is there any sense in this or is blissful ignorance better? In 3 years, the Square Kilometre Array (SKA) telescope (or rather, a system of telescopes) should be put into operation. In case of failure to detect...
Thread 'Could gamma-ray bursts have an intragalactic origin?'
This is indirectly evidenced by a map of the distribution of gamma-ray bursts in the night sky, made in the form of an elongated globe. And also the weakening of gamma radiation by the disk and the center of the Milky Way, which leads to anisotropy in the possibilities of observing gamma-ray bursts. My line of reasoning is as follows: 1. Gamma radiation should be absorbed to some extent by dust and other components of the interstellar medium. As a result, with an extragalactic origin, fewer...
This thread is dedicated to the beauty and awesomeness of our Universe. If you feel like it, please share video clips and photos (or nice animations) of space and objects in space in this thread. Your posts, clips and photos may by all means include scientific information; that does not make it less beautiful to me (n.b. the posts must of course comply with the PF guidelines, i.e. regarding science, only mainstream science is allowed, fringe/pseudoscience is not allowed). n.b. I start this...
Back
Top