What are your thoughts on dark matter?

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Elimentals

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What if there is no inflation?

and everything is just getting smaller, from the forces to the particles as the strings vibrations become less.

Kind of like how dust settles after an explosion :)
 
Knyro

Knyro

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Dark matter may have not been detected directly but there is quite a bit of evidence suggesting it's existence so it's not really just a convenient cop-out to explain why galaxies don't fly apart. See gravitational lensing.
 
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Elimentals

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Knyro said:
Dark matter may have not been detected directly but there is quite a bit of evidence suggesting it's existence so it's not really just a convenient cop-out to explain why galaxies don't fly apart. See gravitational lensing.
Click to expand...

That explains Dark Matter, and actually has no bearing on why they don't fly apart(gravity does that), it explains the spin.

Dark energy on the other hand is the reason for inflation ie: why the galaxies move away from each other, so its a different story.
 
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demiurge

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Swa said:
Not really a true comparison. You know there is an object and it makes a sound. Dark matter makes no sound and can't be observed.
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We can't see dark matter, but we can detect it by its effects on normal matter through gravity and by the X-rays emitted by hot, dark matter.

Two options:
1. Something is fundamentally wrong with our understanding of gravity and rotation. Unlikely as this has withstood many tests for centuries
or
2. Galaxies and galactic clusters must contain dark matter and far more of it than light matter.
 
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Humberto

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Can one instead say that galaxies are held together not by "dark matter" but by "fairy dust" and "ogre snot"?
 
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demiurge

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Why do people find it so hard to believe that there is stuff in the universe which our mammalian eyes and brains cannot see?
We can detect dark matter and it makes sense given what we already know.
 
Knyro

Knyro

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Elimentals said:
That explains Dark Matter, and actually has no bearing on why they don't fly apart(gravity does that), it explains the spin.

Dark energy on the other hand is the reason for inflation ie: why the galaxies move away from each other, so its a different story.
Click to expand...

From my understanding, galaxies do not have enough gravity themselves from visible objects (stars, planets, black holes etc.) to keep themselves together. This is consistent with computer simulations on the subject. Dark matter has gravitational pull as well, hence providing the extra gravitational force to keep galaxies from flying apart.
 
isie

isie

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Knyro said:
From my understanding, galaxies do not have enough gravity themselves from visible objects (stars, planets, black holes etc.) to keep themselves together. This is consistent with computer simulations on the subject. Dark matter has gravitational pull as well, hence providing the extra gravitational force to keep galaxies from flying apart.
Click to expand...
from my understanding the theory of dark matter came about when measuring the mass of galaxies, they have two equations, luminous mass (mass of visible objects in a galaxy) and rotational mass (mass measured using rotation of a galaxy with newtons laws and or Einstein theories depending on speed) in theory both calculations should pretty much be the same, however rotational mass comes allot more more then luminous so either newtons laws and Einstein theories are wrong or there is much more matter then what is visible.



This is my understanding so I know I'm missing allot of finer details
 
Unhappy438

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demiurge said:
Why do people find it so hard to believe that there is stuff in the universe which our mammalian eyes and brains cannot see?
We can detect dark matter and it makes sense given what we already know.
Click to expand...

This

Humans five senses reveal little about the universe, we require apparatus to further investigate most things like gamma rays, xrays, ultraviolet, microwaves, or radio waves. I would hardly find it surprising if we just currently lack the technology to view dark matter.
 
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zippy

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Swa said:
Not really a true comparison. You know there is an object and it makes a sound. Dark matter makes no sound and can't be observed.


Always love the rhetoric of how scientists acknowledge mistakes and science correcting itself. No it's usually other scientists that correct something and not science that corrects itself but people that correct it. Often the very people that opposes it. It's a valid criticism that prevailing ideas are not always correct or accurate.


And using Newton's laws there has to be other stuff pushing and pulling on solar systems. Yet that was not what was proposed or if it was then the people that proposed it were wrong, but instead general relativity was developed and it dealt with the discrepancies in Newtonian physics very well. Why is it so inconceivable that general relativity breaks down on an even larger scale instead of some unobservable mysterious substance that nobody can detect?
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My point is that it's a process. There was a time that Newtonian physics was regarded as THE theory. Even now there is no single theory of everything. That doesn't mean that current theories are wrong. They are incomplete. Newtonian physics isn't wrong. It explains things at relatively low speeds quite well. Newtonian physics is part of the journey. Just as quantum physics is part of the journey. And general and specific relativity.

It's a work in progress. Has been for centuries and will continue to be for centuries to come.

Edit: Newtons Third Law is used to help find and verify exo planets.

http://freevideolectures.com/Course/2254/Introduction-to-Astrophysics/8#
 
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Geriatrix

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zippy said:
It's a work in progress. Has been for centuries and will continue to be for centuries to come.
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Until society collapses because of some disease and we all start hitting each other to death with sticks again, arguing about what happens to us afterwards. But more on that later.
 
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Devill

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Geriatrix said:
Until society collapses because of some disease and we all start hitting each other to death with sticks again, arguing about what happens to us afterwards. But more on that later.
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No no no, there will be one religion first, then it will devide into many.....
 
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Geriatrix

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