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Could dark matter simply be the unobserved universe? Could dark matter simply be the unobserved universe?

05-09-2011 , 12:31 AM
Isn't it possible that all the light that we observe has yet to reach us? and could this unobserved part of the universe be responsible for what we call dark matter?
Could dark matter simply be the unobserved universe? Quote
05-09-2011 , 12:36 AM
Quote:
Originally Posted by Greeksquared
Isn't it possible that all the light that we observe has yet to reach us? and could this unobserved part of the universe be responsible for what we call dark matter?
No. Dark matter was first proposed (or at least was applied early on) to explain the rotational velocity of galaxies. Essentially, stars weren't going at the speed they 'should' if all the mass of a galaxy was visible matter.

Second, experiments on the CMB, using visible light (visible in the mechanical sense, not to the human eye) from just after the big bang shows evidence of dark matter. Though I'm not sure that's as convincing as the first.

Actually, this quote from Wiki pretty much summarizes things:

"Dark matter was postulated by Fritz Zwicky in 1934 to account for evidence of "missing mass" in the orbital velocities of galaxies in clusters. Subsequently, other observations have indicated the presence of dark matter in the universe; these observations include the rotational speeds of galaxies, gravitational lensing of background objects by galaxy clusters such as the Bullet Cluster, and the temperature distribution of hot gas in galaxies and clusters of galaxies."

All of these are indications of dark matter in the visible universe, and not something outside the visible universe.
Could dark matter simply be the unobserved universe? Quote
05-09-2011 , 12:52 AM
Maybe you are thinking of black holes?
Could dark matter simply be the unobserved universe? Quote
05-09-2011 , 01:01 AM
Hmmm...I initially read the OP to mean further away from us than the edge of the visible universe. I think I mostly got that from the 'yet' and from 'unobserved', but I will admit there might be the other reading of the OP.

If I remember right, a while ago (and maybe currently), black holes and brown dwarves (among other things) were considered for dark matter. I don't know if that's what you mean, OP.
Could dark matter simply be the unobserved universe? Quote
05-09-2011 , 01:02 AM
I have seen theories about dark matter being matter from different branes.

I think seeing a light that hasn't reached us might be a problem though.
Could dark matter simply be the unobserved universe? Quote
05-09-2011 , 01:34 AM
Perhaps if you could travel faster than the speed of light you could time travel, but maybe you would just be able to turn around and watch what happened but not influence it. I suck at staying on topic.
Could dark matter simply be the unobserved universe? Quote
05-09-2011 , 03:40 PM
Dark matter doesn't emit light at all. I'm sure it emits something, but it's nothing our five senses can perceive. But whatever it is I'm sure it's all very pretty to the Ubonong's in the Universe Next Door.
Could dark matter simply be the unobserved universe? Quote
05-09-2011 , 07:18 PM
Quote:
Originally Posted by Greeksquared
Isn't it possible that all the light that we observe has yet to reach us? and could this unobserved part of the universe be responsible for what we call dark matter?
No, it is almost impossible for matter in an unobserved part of the universe to create the effect that everybody thinks dark matter is responsible for. Given the specific anomalies we see, it is almost a sure thing that there is extra matter filling up the universe that does not interact with light.

EDIT: I think I answered a slightly different question than you were asking. But no, what you say is not possible because the dark matter emits gravitons which travel at the speed of light and cause regular matter to behave differently, which we observe by looking at photons they emit, which also travel at c. So if dark matter interacted with light, it could not be so far away that the light it emitted hasn't reached us yet, because this is the same amount of time that it takes for us to see the gravitational effect of dark matter.

I thought you were asking about a case where matter from a different brane causes the gravitational anomalies. Here, seeing the matter would be impossible no matter how long you wait because photons are confined to a brane while gravitons are not.

Last edited by Max Raker; 05-09-2011 at 07:27 PM.
Could dark matter simply be the unobserved universe? Quote
05-09-2011 , 07:21 PM
Quote:
Originally Posted by A_C_Slater
Dark matter doesn't emit light at all. I'm sure it emits something, but it's nothing our five senses can perceive.
It emits gravitons and (most likely) W and Z bosons.
Could dark matter simply be the unobserved universe? Quote
05-10-2011 , 08:07 AM
http://arxiv.org/PS_cache/astro-ph/p.../0203457v1.pdf

Also (to whoever interested in the dark matter puzzle) look here before above paper if not familiar already ;

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

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

Last edited by masque de Z; 05-10-2011 at 08:20 AM.
Could dark matter simply be the unobserved universe? Quote
05-11-2011 , 12:33 PM
Dark matter is just something that exerts gravitational influences on the matter that we can detect but it doesn't interact at all with light. It doesn't even block light. It is a misnomer since it is not dark, it is invisible. It should be called invisible matter.

It could be an exotic form of matter or it could be soemthing wrong with our understanding of gravity.
Could dark matter simply be the unobserved universe? Quote
05-11-2011 , 02:38 PM
ya gravitational lensings is probably the coolest way for us to "see" a direct effect of dark matter.
Could dark matter simply be the unobserved universe? Quote
05-11-2011 , 02:54 PM
Quote:
Originally Posted by Max Raker
It emits gravitons and (most likely) W and Z bosons.
does it also emit unicorns?

might as well
Could dark matter simply be the unobserved universe? Quote
05-11-2011 , 05:15 PM
Well, W bosons kind of look like unicorns if you squint your eyes a little.
Could dark matter simply be the unobserved universe? Quote
05-11-2011 , 05:50 PM
Quote:
Originally Posted by Max Raker
No, it is almost impossible for matter in an unobserved part of the universe to create the effect that everybody thinks dark matter is responsible for. Given the specific anomalies we see, it is almost a sure thing that there is extra matter filling up the universe that does not interact with light.
Could not dark matter just be regular matter existing on a seperate brane? I would think that if gravity interacted across branes then a galaxy on one brane would move as close as possible to a galaxy on another brane. Of course they could never come in contact except thru the exchange of gravitons. The matter is dark to us because photons(and other bosons except gravitons) do not move across branes.
Could dark matter simply be the unobserved universe? Quote
05-16-2011 , 12:49 AM
isn't dark matter just **** that doesn't emit light?
Could dark matter simply be the unobserved universe? Quote
05-16-2011 , 06:01 AM
What about particles that are not clustered and are simply roaming around on their on in space? You can't see a lone atom in space with or without light through a telescope.

If we go by the Big Bang I'm sure random particles are gonna go flying on their own?
Could dark matter simply be the unobserved universe? Quote
05-16-2011 , 09:16 AM
Quote:
Originally Posted by LUCIUS VARENUS
What about particles that are not clustered and are simply roaming around on their on in space? You can't see a lone atom in space with or without light through a telescope.

If we go by the Big Bang I'm sure random particles are gonna go flying on their own?
This is true, but if they're so sparse that we can't see them, then there won't be enough of them to make up for the mass that we believe should be there. On the other hand, if they were dense enough to represent the missing mass, then we should be able to see them.

Recall that it is estimated that there is 5 times as much dark matter as regular matter, so a few atoms here or there really won't do it.
Could dark matter simply be the unobserved universe? Quote
05-16-2011 , 10:19 AM
I know LV was talking about atoms (and I think LLY answered it well wrt baryons), but the idea isn't totally without merit. It has to be a different type of particle.

For instance, it is hypothesized that neutrinos have a (very small) mass, as evidenced by neutrino oscillation experiments. Those experiments can actually only give us a difference in the three flavors of neutrino mass (there's the electron neutrino, muon neutrino and tau neutrino).

These particles don't interact readily with matter to say the least--I'm going off memory, but I think one would need a thickness of lead measured in light years to have a 50% chance of stopping a neutrino. Because of this, they won't clump, and astronomers thought the neutrinos might be the source of the 'missing mass' or dark matter. I think the consensus has become that they contribute, but not nearly enough. I also think there were distributional problems as well--the rotational periods of galaxies were one of the first indications of dark matter, and if neutrinos don't clump, they won't explain that 'problem'
Could dark matter simply be the unobserved universe? Quote
05-16-2011 , 05:33 PM
this.

http://www.nasa.gov/home/hqnews/2006...rk_Matter.html

and dark matter's gravity can interact with light.
Could dark matter simply be the unobserved universe? Quote
05-16-2011 , 06:30 PM
Quote:
Originally Posted by R-A-I-N
this.

http://www.nasa.gov/home/hqnews/2006...rk_Matter.html

and dark matter's gravity can interact with light.
Do you have a paper or anything else that has documentation more than the link provided by these scientists claiming the observation of collisions (i didnt see anything in the linked page other than a broad news release description without data or images). I would love to see what it is they are observing. If you dont i will try to search for them later differently.
Could dark matter simply be the unobserved universe? Quote
05-16-2011 , 09:05 PM
Ok here is what i found after searching about that collision seen by Chandra;

http://chandra.harvard.edu/photo/2006/1e0657/index.html

and their paper;

http://iopscience.iop.org/1538-4357/...648_2_L109.pdf

Of course one needs to go over the paper to actually see if they agree with their interpretations. Interesting.
Could dark matter simply be the unobserved universe? Quote
05-17-2011 , 04:24 AM
Quote:
Originally Posted by masque de Z
Ok here is what i found after searching about that collision seen by Chandra;

http://chandra.harvard.edu/photo/2006/1e0657/index.html

and their paper;

http://iopscience.iop.org/1538-4357/...648_2_L109.pdf

Of course one needs to go over the paper to actually see if they agree with their interpretations. Interesting.

You have to accept this statement:

Quote:
Hot gas detected by Chandra in X-rays is seen as two pink clumps in the image and contains most of the "normal," or baryonic, matter in the two clusters
I do not.

They have shown that the gravitational field(based on lensing) is focused around the stars and galaxies in the clusters instead of with the gas clouds. This does not prove that the galaxies are surrounded by a cloud of dark matter.

epicycles, epicycles, and more ****ing epicycles

Nobody predicted super massive black holes at the center of every galaxy. Nobody predicted that there would be a direct correlation between the mass of these black holes and the sigma(average velocity) of the outer most stars in these galaxies and nobody knows why this correlation exists. We know that gravity is not yet understood on the quantum scale or at the center of a black hole. I firmly believe that when that is sorted out the source of the extra gravity will be accounted for. But that may never happen as long as the biggest clue 'way too much gravity' is considered solved by the addition of invisible, immeasurable, epicycles. My favorite guess, of several, is that the super massive black holes are actually orders of magnitude larger than can be measured by their 'local' gravity and that the same mechanism(whatever that may be, probably QM related) that prevents a singularity from being formed causes a large portion of the SMBHs gravity to behave differently. Almost like a shock wave of sorts.

http://mcdonaldobservatory.org/news/...2009/0202.html

Quote:
Their precision measurements of the brightnesses — that is, the number of stars — at various distances from the centers of elliptical galaxies allowed them to calculate much more accurately than previously the masses of stars that are “missing” in the centers of the biggest ellipticals. This revealed more surprises: The missing mass increases in lockstep with the measured masses of the central black holes. It was known that the two quantities are related, but it was not known that the correlation is so tight as to be within the margin of error. That is, the correlation is virtually perfect.

The missing mass also increases in lockstep with another galaxy property that is known to be tied directly to black holes, namely the speeds at which stars move far out in the galaxy where they cannot feel the black hole’s gravity.
Bad assumption IMO. Everything in their own study tells them that the SMBH and the gravity of the entire galaxy are related and they refuse to accept it.
Could dark matter simply be the unobserved universe? Quote

      
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