How is the Universe Expanding?

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    Expanding Universe
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Discussion Overview

The discussion revolves around the concept of the expanding universe, exploring whether it is more accurately described as expansion or stretching. Participants examine implications of general relativity on the nature of space and its relationship to galaxies and atoms, while also questioning the effects of cosmic expansion on different scales.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • One participant suggests that the universe is not expanding into anything but is instead stretching, proposing that the space between galaxies is increasing over time.
  • Another participant clarifies that the term "stretching" is synonymous with expansion in cosmology, emphasizing that the mathematical expressions of these theories are what matter, not the terminology.
  • Concerns are raised about whether the expansion of space affects atomic structures, with speculation about the potential for the universe to disrupt the fabric of matter.
  • A later reply points out that the expansion of space does not impact small-scale structures, as they are held together by gravity.
  • There is a caution against posting personal theories without grounding them in widely accepted models, suggesting that participants should familiarize themselves with established cosmological frameworks.

Areas of Agreement / Disagreement

Participants express differing views on the nature of the universe's expansion, with some favoring the idea of stretching while others adhere to the conventional understanding of expansion. The discussion remains unresolved, with multiple competing perspectives present.

Contextual Notes

Participants note the importance of definitions, such as what is meant by "stationary," and highlight the need for clarity in discussing personal theories versus established models. There are references to prior discussions and resources that may provide additional context.

Who May Find This Useful

This discussion may be of interest to individuals curious about cosmology, the nature of the universe, and the implications of general relativity on cosmic structures.

Alonzo.nieves
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Hello all. I'm quite new to this forum. I was wondering about the expanding or stretching universe. Can someone please tell me if my thoughts are correct and if not please correct me.

The expanding universe. A common definition of the universe is everything. But if the universe is expanding it has to be expanding into something. Expanding into a larger universe maybe? But I believe that a more accurate description of the universe is stretching. You can see the universe as a collection of galaxies a certain amount away from each other. A theory I have developed is that maybe the universe is just stationery. But as time passes the space between each galaxy and celestial bodies slowly move away, this shows the stretching of the galaxy. According to Einstein's theory of general relativity we have to think of space as a much more complex entity not just a vast amount of nothingness. Incorporating his theories of general relativity space should be capable of "bending" and "stretching".


If the space between celestial bodies are moving then what about the atoms, the building blocks of all matter. Maybe the spaces between them too are moving apart from each other. Or maybe its just the larger objects. Is the universe really powerful enough to rip the very fabric of everything we know into nothing? Does anyone know any recent research on this?
 
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Hi Alonzo, welcome to PF.

Alonzo.nieves said:
The expanding universe. A common definition of the universe is everything. But if the universe is expanding it has to be expanding into something. Expanding into a larger universe maybe? But I believe that a more accurate description of the universe is stretching. You can see the universe as a collection of galaxies a certain amount away from each other. A theory I have developed is that maybe the universe is just stationery. But as time passes the space between each galaxy and celestial bodies slowly move away, this shows the stretching of the galaxy. According to Einstein's theory of general relativity we have to think of space as a much more complex entity not just a vast amount of nothingness. Incorporating his theories of general relativity space should be capable of "bending" and "stretching".
No, it doesn't have to expand into something else. What you describe as "stretching" is actually what the expansion is. You might not like the name, but that's how it's used in cosmology. The actual theories are expressed mathematically, and what anybody calls the results is just a matter of semantics.

Alonzo.nieves said:
If the space between celestial bodies are moving then what about the atoms, the building blocks of all matter. Maybe the spaces between them too are moving apart from each other. Or maybe its just the larger objects. Is the universe really powerful enough to rip the very fabric of everything we know into nothing? Does anyone know any recent research on this?
Expansion of space does not affect small scale structures(up to and including galaxies). They're held together too strongly by their gravity.

This type of questions would fit better in the cosmology section of the forum. There's a bunch of sticky threads in there that you might find interesting, inluding the FAQ. A forum search might net you a few interesting threads tackling the very same questions you asked.
 
Thank you for that. Next time I will post in the Cosomology section. By the way I'm quite new to this here, I just started High School.
 
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You can see the universe as a collection of galaxies a certain amount away from each other.

This sounds like the observable universe...the tiny part we can observe.

http://en.wikipedia.org/wiki/Observable_universe


A theory I have developed is that maybe the universe is just stationery. But as time passes the space between each galaxy and celestial bodies slowly move away, this shows the stretching of the galaxy.

How do you define 'stationary'.

Be careful about posting personal theories here. Not allowed. Much better to study generally accepted models first and then ask questions about those if there are parts you don't understand.

In the most popular cosmological model, the 'FRW lambda cdm cosmological model', distances over intergalactic distances expand over time...but the movement at increasingly large distances is not 'slow'.

overview here: http://en.wikipedia.org/wiki/Lambda-CDM_model

and as already noted, lots of prior discussions available in these forums...
 

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