Yesterday night, just before falling asleep, I started thinking a little bit about dark matter and how it could be related to a black hole. I come up with a Hypothesis.

What if dark matter is just wrapped space-time? ;)
What if vacuum actually has a very tiny mass, and when the vacuum is wrapped, you can get more of this "mass" in a smaller volume?

The universe is made mostly of vacuum. At the same time, the most common kind of matter is dark matter. If dark matter is actually the vacuum, than that would explain why we have more dark matter than normal matter. Also, closer to stars and closer to black holes, particularly beyond the event horizon, the vacuum would weight much more.

That means that the density of the dark matter would be defined by how much the space-time is wrapped in a given volume, and dark matter would become the primary cause of gravity (gravity=curvature of space-time/volume?)...

Does that make sense? Is there anything that I missed or interpreted wrong?
Please give me feedback. I'm curious about the universe... :D

Excuse me... I need a cup of coffee... ;)

The whole definition of 'vacuum' contains the fact that it cannot weigh anything. Dark matter is not the vacuum but it is mysterious if it exists.

The whole definition of 'vacuum' contains the fact that it cannot weigh anything. Dark matter is not the vacuum but it is mysterious if it exists.
How much does light weight?
And the definition of vacuum can very well change. Maybe the "vacuum" is not really a vacuum. Aren't there particles that just pop up from it? Doesn't that suggest there is something there?

How much does light weight?
And the definition of vacuum can very well change. Maybe the "vacuum" is not really a vacuum. Aren't there particles that just pop up from it? Doesn't that suggest there is something there?

Like has 0 mass, that is why it is able to go the speed of light.

Like has 0 mass, that is why it is able to go the speed of light.
How can something has 0 mass and still exist? How can it be different from the vacuum?

>How much does light weight?
And the definition of vacuum can very well change. Maybe the "vacuum" is not really a vacuum. Aren't there particles that just pop up from it? Doesn't that suggest there is something there

Light does couple to gravity, as does energy in general, but it does not have a weight due to rest mass.
Light will appear to bend towards a massive body, but not because it has a weight due to any rest mass, but it is following a straight line in spacetime which is curved by the massive body.
The vacuum can be viewed as consisting of virtual particle/anti particles pairs which can exist for the duration allowed by HUP and during their existence, they contain energy. They should also therefore couple to gravity.
But as for there ability to then curve spacetime in the same way that Dark matter is proposed to do- I doubt it very much.( Although it is claimed that light can curve spacetime in the same way that mass/energy density does)

If this were so, then our universe would not be flat, but very curved due to the energy contained in the vacuum. This is not observed.

How can something has 0 mass and still exist? How can it be different from the vacuum?Having mass just isn't a requirement for existence. I don't think that you would consider something to not be a vacuum just because it had light in it.

And the definition of vacuum can very well change. Maybe the "vacuum" is not really a vacuum. Aren't there particles that just pop up from it? Doesn't that suggest there is something there?

NO IT CAN'T! If we were to go around changing our definitions of things all the time then words would be meaningless and we couldn't communicate! Tha vacuum definition (although I won't pretend to know all of it) contains the fact that it must be DEVOID of matter (that with mass) and have properties such as zero pressure etc. It is a concept which may or may not exist out there. What most scientists agree on is that empty space is very nearly a vacuum. Now if u want to say that space is composed of dark matter then it is called dark matter but u can't say dark matter is a vacuum because they are two different things and u can't get one from the other!

If this were so, then our universe would not be flat, but very curved due to the energy contained in the vacuum. This is not observed.
Were the observation accurate? What was measured? Only the normal mass or both the normal mass and dark matter? Because if only normal matter was oberved, then we observed only 5% of all the matter in the universe. Than, we would have to add 95% and that would probably give you a more curved universe. If we obeserved both kinds of matter, than you might be right. ;)

NO IT CAN'T! If we were to go around changing our definitions of things all the time then words would be meaningless and we couldn't communicate! Tha vacuum definition (although I won't pretend to know all of it) contains the fact that it must be DEVOID of matter (that with mass) and have properties such as zero pressure etc. It is a concept which may or may not exist out there. What most scientists agree on is that empty space is very nearly a vacuum. Now if u want to say that space is composed of dark matter then it is called dark matter but u can't say dark matter is a vacuum because they are two different things and u can't get one from the other!
Not the definition, but our understanding on what we call "vacuum". We would probably have to call it something else if we would find that vacuum=dark matter... ;)

>>Were the observation accurate? What was measured? Only the normal mass or both the normal mass and dark matter? Because if only normal matter was oberved, then we observed only 5% of all the matter in the universe. Than, we would have to add 95% and that would probably give you a more curved universe. If we obeserved both kinds of matter, than you might be right.

Hi TruthSeeker,
when measurements were made by the boomerang experiment ( Balloon Observations of Millimetric extragalactic ANd geomagnetics ) from Antarctica, of the CMBR, the results were indicative of a flat universe to a high degree of accuracy.
The results include baryonic and dark matter, as well as dark energy.

>>Were the observation accurate? What was measured? Only the normal mass or both the normal mass and dark matter? Because if only normal matter was oberved, then we observed only 5% of all the matter in the universe. Than, we would have to add 95% and that would probably give you a more curved universe. If we obeserved both kinds of matter, than you might be right.

Hi TruthSeeker,
when measurements were made by the boomerang experiment ( Balloon Observations of Millimetric extragalactic ANd geomagnetics ) from Antarctica, of the CMBR, the results were indicative of a flat universe to a high degree of accuracy.
The results include baryonic and dark matter, as well as dark energy.
Ok then. So, does that mean that matter in the universe is evenly distributed? Or that is not taken into account or observed?

Not the definition, but our understanding on what we call "vacuum". We would probably have to call it something else if we would find that vacuum=dark matter... ;)

Still don't like this! We could never find that vacuum=dark matter as I have stated before but we could find that space is full of dark matter instead of a near vacuum theory. Either way, a vacuum will always be a vacuum and such a concept is important and highly applicable in physics/astronomy.

Still don't like this! We could never find that vacuum=dark matter as I have stated before but we could find that space is full of dark matter instead of a near vacuum theory. Either way, a vacuum will always be a vacuum and such a concept is important and highly applicable in physics/astronomy.
Wheter vacuum=dark matter or vacuum is full of dark matter, it seems that that would be just a matter of perspecive. I mean.... you still have lots of dark matter wherever there is space... :bugeye: ;)

It is like the difference between looking at a glas full of water or just the water by itself. :)

I know what u are trying to say: that instead of empty space being a vacuum, it could be dark matter. I just didn't like your wording:)

So the crux of your argument is basically that empty space itself might (and/or must) have mass. Is that right? Im sure there is hard evidence out there to refute this but i do think dark matter may exist out there IN empty space.

I know what u are trying to say: that instead of empty space being a vacuum, it could be dark matter. I just didn't like your wording:)

So the crux of your argument is basically that empty space itself might (and/or must) have mass. Is that right? Im sure there is hard evidence out there to refute this but i do think dark matter may exist out there IN empty space.
Yes, you understand me... ;)

Even if there is a lot of evidence against my claim, think for just a while. Isn't it weird that 95% of the universe is made of something that we can't see, and at the same time 95% of the universe is "empty" space? Wouldn't they seem to be the same or extremely related? If the dark matter is evenly distributed all around the "empty" space in the universe, wouldn't the universe actually be flat? Because if the matter would be evenly distributed, then there wouldn't be a curvature such as an sphere. So a flat universe can be seen as an universe with lots of empty space, or an universe with lots of matter evenly distributed. In this case, we wouldn't be a ble to consider "empty" space as empty, because there is "something" there. Do you follow me?

If the dark matter is evenly distributed all around the "empty" space in the universe, wouldn't the universe actually be flat? Because if the matter would be evenly distributed, then there wouldn't be a curvature such as an sphere.

No, all cosmological models take matter to be evenly distributed (this is called homogeneous) and yet, the universe is not flat.

No, all cosmological models take matter to be evenly distributed (this is called homogeneous) and yet, the universe is not flat.

Yes but only on a large enough scale. It is more of a statistical (random) thing really. Anyway......

Isn't it weird that 95% of the universe is made of something that we can't see, and at the same time 95% of the universe is "empty" space?

So this is where u are coming from, where it all started eh? :)

No I don't think its weird. U have to look at the facts. It is quite likely that the dark matter is simply hydrogen or helium since these are the most abundant elements in the universe. They are dark because they have not enough thermal (or nuclear) energy to emit light yet. It is also possible that there is other even more dense matter out there that is unlike any element. I think looking at these two theories is probably a little better than jumping to the conclusion that space is matter etc!

Dark matter is not hydrogen or helium; they do not exist in interstellar space in sufficient quantities to explain the orbital characteristics of galaxies, nor the observed mass distribution in groups and clusters of galaxies,

Dark matteris not likely to be a component of the vacuum, however, as it definitely seems to be loosely associated with galaxies, and to be missing from large volumes of intergalactic space.

Just to confuse you, dark energy on the other hand may well turn out to be associated with empty vacuum, as it is present everywhere, and increases per unit volume as space expands.

But, as I have said many times before, don't get dark energy and dark matter confused; they are entirely different things. One (dark matter) has positive energy and mass and is concentrated around galaxies, the other has negative energy and repulsion force and is everywhere.

The only thing they both have in common is that they cannot be observed.

No, all cosmological models take matter to be evenly distributed (this is called homogeneous) and yet, the universe is not flat.
Wait a minute. Is the universe flat or not!?!? There has been a lot of discussion about that already here and in other places. Everyone say it is flat. Now you say it isn't!?!? :eek: :confused:

Dark matter is not hydrogen or helium; they do not exist in interstellar space in sufficient quantities to explain the orbital characteristics of galaxies, nor the observed mass distribution in groups and clusters of galaxies,

Dark matteris not likely to be a component of the vacuum, however, as it definitely seems to be loosely associated with galaxies, and to be missing from large volumes of intergalactic space.

Just to confuse you, dark energy on the other hand may well turn out to be associated with empty vacuum, as it is present everywhere, and increases per unit volume as space expands.

But, as I have said many times before, don't get dark energy and dark matter confused; they are entirely different things. One (dark matter) has positive energy and mass and is concentrated around galaxies, the other has negative energy and repulsion force and is everywhere.

The only thing they both have in common is that they cannot be observed.
Ok. I got them completely confused!!! :D
Yes, I guess the right term for what I'm talking about would be dark energy. I was thinking about the one that is everywhere and that is associated with vacuum... :D

That's nice. I got to the same conclusions all by myself... :)

So. What are the properties of dark energy? If it expands space, what is the difference between dark energy and anti-gravity?

Wait a minute. Is the universe flat or not!?!? There has been a lot of discussion about that already here and in other places. Everyone say it is flat. Now you say it isn't!?!? :eek: :confused:

Where did you hear that it is flat?

Dark matter is not hydrogen or helium; they do not exist in interstellar space in sufficient quantities to explain the orbital characteristics of galaxies, nor the observed mass distribution in groups and clusters of galaxies,

How do u really know that?

And what might u think dark matter is?

Where did you hear that it is flat?
The boomerang experiment or something like that. Someone cited it before...

The boomerang experiment or something like that. Someone cited it before...
You are right, I'll correct what I said earlier:

No, all cosmological models take matter to be evenly distributed (this is called homogeneous) and yet, the universe is not flat.

No, all cosmological models take matter to be evenly distributed (this is called homogeneous) and yet, the universe is not necessarilly flat.

No, all cosmological models take matter to be evenly distributed (this is called homogeneous) and yet, the universe is not necessarilly flat.
Which is what I was saying in the beginning... :rolleyes: :D

So my question for you would be: why do you think that the universe may be not flat eventough matter is evenly distributed? ;)

>>No, all cosmological models take matter to be evenly distributed (this is called homogeneous) and yet, the universe is not necessarilly flat

Yes, but it has been measured to be flat to a high degree of accuracy.
The combined effect of mass ( all mass) distribution, the expansion and dark energy all account for this.

So my question for you would be: why do you think that the universe may be not flat eventough matter is evenly distributed? ;)
Because all the cosmological models of the universe take as assumptions that matter is evenly distributed. If the density is larger than a critical density, the universe has positive curvature, if it is less, it has a negative curvarture, and if the density of matter equals this critical density, it will have zero curvature, i.e., it will be flat. Again, all these solutions are under the assumption that matter is evenly distributed (this is one of the so called cosmological principles).

Because all the cosmological models of the universe take as assumptions that matter is evenly distributed. If the density is larger than a critical density, the universe has positive curvature, if it is less, it has a negative curvarture, and if the density of matter equals this critical density, it will have zero curvature, i.e., it will be flat. Again, all these solutions are under the assumption that matter is evenly distributed (this is one of the so called cosmological principles).
Ok, I didn't take into account any "critical density". What do you mean by that, and why it would curve the universe?

Ok, I didn't take into account any "critical density". What do you mean by that, and why it would curve the universe?
Matter causes the space to be curved. The fact that matter is evenly distributed makes this curvature constant. So all spaces in the cosmoligal models are space of constant curvature. This curvature depends on the density. This density is a parameter in Einstein's equations. According to this density, the solutions of the equations give a closed space, a flat space or an open space.

Matter causes the space to be curved. The fact that matter is evenly distributed makes this curvature constant. So all spaces in the cosmoligal models are space of constant curvature. This curvature depends on the density. This density is a parameter in Einstein's equations. According to this density, the solutions of the equations give a closed space, a flat space or an open space.
But if the matter is evenly distributed, wouldn't the density be also evenly distributed?

But if the matter is evenly distributed, wouldn't the density be also evenly distributed?
yes.
If the density is evenly distributed, the curvature of space will be constant. This is what happens in all cosmological models. If this constant density is high enough, space is closed, if it is low, space is open. When we say high or low, in fact it is with respect to some critical density. If the density equals this critical density, space is flat

yes.
If the density is evenly distributed, the curvature of space will be constant. This is what happens in all cosmological models. If this constant density is high enough, space is closed, if it is low, space is open. When we say high or low, in fact it is with respect to some critical density. If the density equals this critical density, space is flat
Ok... now I'm grasping the idea... ;)

But what if the matter is not evenly distributed? I mean... the big bang was in a single point right? So wouldn't the "edge" of the universe be more dense, where the space-time is still "unfolding" and expanding?