Substitute to Dark Matter?

[fatty_ashy]

hahaha...a cool thought just entered my mind when i was on the metro (trains, or MRT if u're singaporean). the rate in which the universe is accelerating right? now, the faster someone is going, the higher the inertia thus the higher the mass right?
that means the faster the expansion of the universe, the more mass the universe has! in which case, the "open" universe state isn't very realistic now is it

[Roberto]

The problem of the missing mass of the universe is more subtle, it arises from the fact that there is not enough matter, based on galaxy models, to hold the visible galaxies together. Even if you added the extra mass from the relativistic effects, you would have the same problem, because all the mass in the galaxy would be accelerating equally.

But the problem is worst. The galaxies are not truly accelerating because of the expansion of the universe. What we think it´s happening is that more space is being created and this rate is increasing, so you see the galxies becoming more distant without being truly accelerated. Weird, isn´t it?

[wavelength?]

Is it possible that dark matter could be made up of gravitons? My theory is that gravitons are pulled from space by the celestial bodys mass. For example on earth the gravitions are pulled in by earths mass and the closer they get to earth the faster they go thus increasing the gravity that we feel and keeping us on the surface. In space they would not be in motion and have no effect on us since we have very little mass.

[Roberto]

In fact, due to the characteristics of the gravitational interaction, gravitons are massless and always travel at the speed of light. So, the solution to the dark matter problem cannot be the gravitons.

[nick33]

The universe will expand for ever and its mass will become infinite, which makes no sense.
something is wrong with the accelerated expansion.

[Tormod]

nick33, you obviously have not read much about the big bang theory. Mass will not become "infinite". All matter has a half-life (even the fundamental particles) which means that everything breaks down into energy. The universe has a finite amount of energy, and as the universe expands this energy is spread over vast amounts of space. So it dilutes into nothing.

If the universe is not as flat as it is observed to be, then it may not be able escape it's own gravity and would eventually start contracting.

But neither way, the energy level in the universe is finite (at least in the observable universe).

But please - provide proof for your argument that there is something wrong with accelerated expansion. Or did you forget to read our FAQ?

Anyway, in our reviews section you will find a review of the book "Five ages of the Universe" which discusses what will happen if the universe expands forever.

http://www.hypography.com/Article.cfm?id=29590


Tormod

[nick33]

Thank for your comments Tormod. I appreciate your perception that universe has to be finite.
The point is how it remains always finite in a self-consistent way. This has nothing to do with calculations. This is much more basic than any mathematics. This is simple logic generated from one fractal like 3D-spiral structure as shown in the link below.

http://www.world-mysteries.com/toi_esavov.htm


To understand the universe we have to remove the singularity in the universe beginning.

[CD27]

if i may, i would like to comment on my own idea of what "dark matter" is. if i am wrong wiht the definition, please correct me. dark matter is matter that is "missing", right? an example. let's say you're looking at a planet. for some reason this planet is revolving around, well, nothing. you can't find what it's revolving around. if that's the case, the solution is simple. perhaps the "missing matter" is in another dimension. perhaps our dimension and that other dimension are temporarily/permanently connected through some sort of bridge. and if that "star" that this planet is roting around is in the other dimension, it would not be visible to us, and thus would be "missing matter" or "dark matter" as some may call it.

am i correct?

[CD27]

to comment on nick33,

if the big bang is true, which i belive in it because it has great evidence and nothing tells me that it is wrong, then eprhaps the universe is still expanding. it is in one of two stages, which is yet unknown to us. 1)it is still accelerating from the initial blast of the big bang, 2) it is slowing down from the initial blast of the big bang. eaither way, i simply don't see how dark matter could be connected with any of that. it is much deeper than that, something we as humans have not grasped yet.

[Bo]

Some remarks: the increase of mass by accelaration isn't correct here; that is because not the particles in the space are accelarating, but space itself. Then there are no effects like the increase of mass. (i hope this sounds sinsible; it's late here in holland and i dont know of a nice analogy at the moment).
further: there are 2 concepts used not always correctly in the above discussion: Dark matter is a 'sollution' for the apparently missing matter in the gravitational attraction in galaxy's (there are other sollutions like Modified newtonian dynamics: http://www.astro.umd.edu/~ssm/mond/astronow.html Dark Energy Is used for the extra repulsive force present in the universe that causes the current accalaration of the univers (which is not understood by normal general relativity)
There are models in String theory That predict that although normal matter is confined in our normal 4D world, the gravitons can travel to these extra dimensions (at large scales) This oss of gravitons is effectivly seen as a repulsive force, thus taking the dark energy into account. I once read something that on smaller scales this process could explain the dark matter problem; but i forgot how.
Bo