How can we accurately determine the expansion rate of the Universe?

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The discussion centers on the complexities of determining the expansion rate of the Universe, questioning whether it is expanding or accelerating. Observations and scientific papers are referenced to support various viewpoints, particularly regarding dark energy's role, which is suggested to constitute about 75% of the Universe. The conversation also touches on the distribution of dark matter and energy, emphasizing the need for precise definitions and models in cosmology. Additionally, the impact of cosmic inflation on the Universe's expansion is highlighted, with a consensus that further understanding is required. Overall, the thread underscores the ongoing debate and uncertainty in cosmological measurements and theories.
  • #91
Hello

The observable universe does not show expansion or acceleration one way or another.

It does show a clustering affect.

The clustering produces areas of high density such as large galaxies and centres of clusters of galaxies that produce extremely large jets and Star that produce extremely small jets. This process of ejecting matter and reforming star and galaxies is a main player in the universe.


A Jet is a Jet, Big or Small: Scale Invariance of Black Hole Jets
http://www.mpa-garching.mpg.de/HIGHLIGHT/2003/highlight0308_e.html


The blowtorch jet in the radio galaxy NGC 6251
http://www.astr.ua.edu/keel/agn/ngc6251.html

One important lesson from radio galaxies is that the central engine continues to eject material in nearly the same direction for at least several million years, based on the fact that the tiny parsec-scale jets in the core regions point in the same direction as the very extended radio structure which may stretch several million light-years (and thus took at least that many years to form).

Photo Release - heic0804: Gargantuan galaxy NGC 1132 - a cosmic fossil?
http://www.spacetelescope.org/news/html/heic0804.html

The Origin of the Brightest Cluster Galaxies
http://www.cita.utoronto.ca/~dubinski/bcg/

Giant Galaxy's Violent Past Comes Into Focus
http://chandra.harvard.edu/press/04_releases/press_051004.html

and

Spectacular X-ray Jet Points Toward Cosmic Energy Booster
http://chandra.harvard.edu/press/00_releases/press_060600pic.html

M87:
Chandra Reviews Black Hole Musical: Epic But Off-Key
http://chandra.harvard.edu/photo/2006/m87/

The processes show a two part one part contracting pulling in star matter into dense regions and the other part ejecting the matter back into space reforming not just star areas but galaxies afar.
 
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  • #92
Sundance said:
Hello

The observable universe does not show expansion or acceleration one way or another.

It does show a clustering affect.
And your evidence for this is? Because nothing you posted after this has any relevance whatsoever to any of these claims you have made.
 
  • #93
G'day Chalnoth

I have given you information and you come back with such a statement.

The question is do you want to understand what's happening?

If you do than start reading

This topic, it has the key to many issues.


Magnetic Reconnection
http://arxiv.org/find/all/1/all:+AND+Magnetic+Reconnection/0/1/0/all/0/1

If you do not read it so be it.
 
  • #94
Sundance said:
G'day Chalnoth

I have given you information and you come back with such a statement.

The question is do you want to understand what's happening?

If you do than start reading

This topic, it has the key to many issues.


Magnetic Reconnection
http://arxiv.org/find/all/1/all:+AND+Magnetic+Reconnection/0/1/0/all/0/1

If you do not read it so be it.
I suspect I understand the issues at hand much better than you do. It is not enough to simply throw a few papers out there and claim that they support your case. Make your case, and I will respond.
 
  • #95
Hello Chalnoth

You said

I suspect I understand the issues at hand much better than you do. It is not enough to simply throw a few papers out there and claim that they support your case. Make your case, and I will respond.

Its OK, do not worry about. You know all.
 
  • #96
Sundance said:
Its OK, do not worry about. You know all.
No, I don't. I'm just saying I am likely aware of a fair fraction of the evidence you are presenting. At least as it relates to cosmology. So make your case already. Why, specifically, does this evidence endorse your view?
 
  • #97
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  • #98
Sundance said:
Hello Chalnoth

My view is not that important. It's what science can prove and give us some understanding of the working parts of the universe.
Okay...

Sundance said:
I keep on reading knowing that I know very little and yet what I know tells me that you lack understanding of critical issues.
But you keep throwing out stuff about the astrophysics of particular objects in the universe. The astrophysics of these objects has no direct bearing upon cosmology. So why do you think these are 'key' issues? What makes them key? Why are they important?

Because as far as I'm concerned, I'm really only interested in understanding astrophysics so far as it helps me to understand cosmology. Cosmology is what interests me the most. And you haven't even attempted to draw a logical line between the astrophysics of these particular objects and cosmology. So what are you trying to say?
 
  • #99
G'day Chalnoth

Those topics are Key topics. I think you missed the boat in understanding astrophysics and cosmology.

Understanding the parts that make up the larger parts is quite important.

What triggers a Supernova?

What triggers a Jet small or large?

What evolution path do galaxies take?

How do galaxies form small or large?

Since you find no value in those topics so be it.
 
  • #100
Sundance said:
G'day Chalnoth

Those topics are Key topics. I think you missed the boat in understanding astrophysics and cosmology.

Understanding the parts that make up the larger parts is quite important.

What triggers a Supernova?

What triggers a Jet small or large?

What evolution path do galaxies take?

How do galaxies form small or large?

Since you find no value in those topics so be it.
There is value in these topics, to be sure, but they're not things I personally find interesting.

Except perhaps for the supernova part. At least for Type IA supernova, the supernova occurs when a white dwarf that is accreting matter exceeds the Chandrasekhar limit. I like to have at least some understanding of these as they directly impact cosmology (as they're used as distance measures).

The other points you bring up are, as yet, very poorly-understood. Many astrophysicists are extremely interested in those questions. I am not. I'm interested in the large-scale behavior of the universe, not the details of objects within it. And none of these topics are key topics for understanding the large-scale behavior.
 
  • #101
G'day from the land of ozzzzzz

At the door step we have our Sun with quite important activities that we can study and learn how the parts of the universe work.

Magnetic reconnection is a most important process that allows matter to be broken up into Neutrons and compacted if the evironment allows for the confinement.

The following images show the Sun and the magnetic reconnection causing jet streams.

http://74.125.153.132/custom?q=cach...n+spots&cd=7&hl=en&ct=clnk&client=google-coop


http://74.125.153.132/custom?q=cach...n+spots&cd=3&hl=en&ct=clnk&client=google-coop
 
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  • #102
Too many unclear facts concerning expanding Univerce, what force and conditions...doubtedly...
 

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