Why is matter unevenly distributed in space?

James R said:
It is my understanding that the universe is homogeneous at large scales, in the sense that if you pick two large-enough chunks of the universe at random, each one will contain approximately the same amount of matter, the same number of galaxies, and so on.

However, on the largest scales, the universe seems to consist of a cosmic "web" in which the "strands" contain lots of galaxies and matter, but the strands are separated by large voids. So, in that sense, the universe doesn't look homogeneous.
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I couldn't argue with that, except to say at what scales we are actually talking about.eg: I'm more or less focusing on the observable universe scale, and I picture a state as detailed in post
DaveC426913 said:
It is a bit of an ambiguous phrase, depending on the scale we look at. There are a few ways of interpreting it.

There is a question of why the entire universe isn't perfectly uniform, since we believe it expanded from a volume smaller than an atom, and there is no known reason why there would by any variation at all in that initial bubble.

But this is what we think it looks like now at the largest scale.

View attachment 7060

Sure, gravity pulled matter into clumps and tendrils, but where did those first inhomogeneities originate?

We sort of have to define the question first: at what scale are we talking about uneven distribution? Unfortunately, we can't leave that clarification to the OP who asked the question since they are not familiar with modern cosmology, or, apparently, physics.
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Roosters for ever said:
I couldn't argue with that, except to say at what scales we are actually talking about.eg: I'm more or less focusing on the observable universe scale, and I picture a state as detailed in post
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I would probably speculate also, as time marches on with expansion and gravity acting universally and continually, that the homogenity shown in that illustration will change. eg: solar systems, galaxies, groups of galaxies, galactic walls and webs, will continue to merge, leaving larger regions of empty space and smaller denser regions.
 
Wizard of Whatever said:
It could be in the initial structure of the big bang, in that it didn't bang in all directions equally or in all directions at all.
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It wasn't a "bang" as in an explosion. It was simply an evolution of space and time, (as we know them) from a hot dense state. The observational data shows that all galaxies in all directions, are moving away from us, and the further away, the faster the expansion observation. Also the observed 2.73K of the CMBR at this time, in all directions is fair confirmation.
 
DaveC426913 said:
But this is what we think it looks like now at the largest scale.

View attachment 7060

Sure, gravity pulled matter into clumps and tendrils, but where did those first inhomogeneities originate?

We sort of have to define the question first: at what scale are we talking about uneven distribution? Unfortunately, we can't leave that clarification to the OP who asked the question since they are not familiar with modern cosmology, or, apparently, physics.
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NASA has a great video of flying through the Cosmic Web.
Better than those old screen savers of stars shooting from the centre.
 
DaveC426913 said:
This is a hard science forum, not a religion or fringe forum. Shoulder angels and sky daddies are not valid sources. If you have a belief you can't possibly defend, please take it up in a more appropriate forum.
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While we're on the subject, I'm still waiting for WoW's answers here and here.

When do you think you might get around to addressing those outstanding issues, Wizard?

I'll add post #46 to the list...
 
sculptor said:
I do not agree that matter is unevenly distributed in space.
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The other answer besides the anisotropies diagram I posted is the view from your telescope.
What do you see? Another earth? No you see a moon smaller than earth and a quarter of a million miles away so that is an uneven distribution of matter.
You also see the sun (don't use the telescope) far greater than earth but 93 millions miles away.
So really it's stuff all over the place with a range of masses and distances, by definition that is not uniform, locally.
On large scales things even out a bit more but only in the same way every male in the UK is about 5 feet ten.
 
James R said:
Please do not make pseudoscientific claims in our Science subforums again.

Thanks.
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Perhaps he is talking about this....
“The Angel Nebula, cataloged as NGC 2170, is a reflection nebula located in the constellation Monoceros, approximately 2,700 light-years from Earth, where interstellar dust scatters and reflects the blue light from nearby hot, young stars, creating its ethereal glow. (google) Just trying to give him the benefit of the doubt.
 
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