The End of Dark Matter?

If you've ever done some physics work with galaxies, you'll know a few things. One is that in a really cool twist of fate, Newtonian physics seems to be a very good approximation. And, let's face it, we've all heard of dark matter. A 'halo" of DM is usually given as an explanation for some of the erratic behavior observed in galaxies. From the aforementioned site:

Much of the evidence for dark matter comes from the study of the motions of galaxies. Many of these appear to be fairly uniform, so by the virial theorem the total kinetic energy should be half the total gravitational binding energy of the galaxies. Experimentally, however, it is found to be much greater: in particular, stars far from the center of galaxies have much higher velocities than predicted by the virial theorem. Galactic rotation curves, which illustrate the velocity of rotation versus the distance from the galactic center, cannot be explained by only the visible matter.

Well, maybe not anymore. The CERN newsletter reports on a group that redid the calculations with general relativity, NOT Newtonian physics, and found that there was no need for dark matter. In fact, it works perfectly.

This is because even for weak fields and slow speeds, well-known nonlinearities change the character of the solution dramatically. The success of Newtonian mechanics in situations like our solar system can be traced to the fact that in this case the planets are basically "test particles", which do not contribute significantly to the overall field. However, in a galaxy this approximation is not a good one - all the rotating matter is also the source of the gravitational field in which everything rotates.

Basically, the planets and all that extra stuff is usually ignored when the calculations are done, but when included they actually make a big deal. A pdf of their work is available. It'll require a strong background in physics for comprehension to even begin, but it's worth the read.

Personally, I find this fascinating. Not only that it was never done before, but that there's enough matter to make a difference. When you think about the amount of planets and what not there are compared to stars, and how massive they are compared to stars, it doesn't seem to fit. I'm skeptical, but CERN is CERN, and you don't say this meaning nothing. And, while I've understood dark matter, and the concepts behind it, it was just a little bit hokey, ya know? I'd actually be very glad if it turned out over the next few years Dark Matter could be done away with. Fuzzy physics, in my opinion...

I will wait to see if any rebuttal comes soon.

I'm still fairly sure there is matter out there we cannot see, for instance we all know that Gravity bends, twists and warps the fabric of spacetime. What is that fabric made out of? It's a legitimate question I feel has been pretty much ignored by quite a few theoretical phyisists.

The reason that that question has been ignored is because it is generally unanswerable.

It's empty space. That fabric of spacetime is just empty space - and despite the fact that emptiness having a deformable shape is a difficult concept to get around, it does. Outside of the deformable emptiness is irrelevant, because it simply doesn't exist.

So, we can't really look at what the very fabric of existence is made of - that's more a metaphysical discussion topic than a factual, explainable topic of science.

At least, we can't yet. The fabric of existence may come into the question in more major ways later in the life of science, and may lead to new modes of travel, and some massive paradigm shifts.

What about Dark energy or "Vacuum" energy which is thought to make up a much largersection of the universe then Dark matter? Empty space seems to not be empty and has some type of force that wants to push space apart. I thought that repulsive energy is the reason why the expansions of the universe is speeding up.

As far as I've heard, this recent paper has done nothing to Dark Energy.

Dark Energy is commonly lumped with Dark Matter because, well, they look and feel like they go together, but the don't particularly. I'm fairly sure that Dark Energy is in the same state as it was before this paper.

Originally posted by Viendin
It's empty space. That fabric of spacetime is just empty space - and despite the fact that emptiness having a deformable shape is a difficult concept to get around, it does. Outside of the deformable emptiness is irrelevant, because it simply doesn't exist.

"Empty" Space has to be made of something if it can be deformed, nothingness would not be deformable it just does not make sense. Disagree all you like but I'm sure any logical thinking will agree that the current explanation of the Vacuum is severly lacking.

The "emptiness" itself isn't what's being molded, what's deformable. What is deformed is spacetime. It is the universe itself.

I don't elabourate because I have fairly radical ideas on the subject, that build a bit on string theory, but I don't know nearly enough about String Theory to really make informed theories based upon it. It's also a very visually based theory, so, you'll have to either come to grips with a deformable reality (not the vacuum itself, the whole universe) or come up with your own way for it to work. I chose the latter.

Can you ever really have a vacuum? The theory of spacetime says gravity pervades all of space, and so at any given point there has to be energy.

Seems to me I read about large quantities of Mass being found in an area where there is no visible objects to be found. The asumption was that it might be a large quantity of Dark Matter, based on it's gravitation effects on ordinary Matter.

I've also seen Dark Matter maps made, that show possible Dark Matter not far from our local group of stars. How they figure this, I don't know.

Vacuum energy is definitely not the same as Dark Energy.
I don't think they have much of an idea what Dark Energy might be yet.
But vacuum energy, as best as I can say, is the "quantum jiggle" of the basic hydrogen the makes up the universe. It's everywhere. Zero vacuum empty space isn't empty, it's full of energy. That's their story.

And yes, modern improvements to Newtonian physics do quite well, compared to Einsteinian. Don't forget, orbital dynamics failed with Einstein's rules, but worked fine with Newton's stuff. We would never have made it into orbit or to the Moon. It's all about Gravity. I think one works better on sub-atomic particles (quantum), and the other on molecular. (large scale mass)

If Gravity is transmitted by "Gravitons" of a particular size, then yes.

Once you get below that threshhold, or, conceivably, a smaller one, if Gravitons are not the smallest-affecting particles present, (which they likely aren't, given their relative weakness, and likely low energy) then space at those intervals would be able to be, but not necessarily always be"empty", devoid of any energy, matter, or, well, anything.

I personally feel that Gravity is the indirect effect of a far stronger force. The curvature of spacetime is not an effect of gravity - well, not of the gravity we are familiar with - it is the cause of the gravity we are familiar with. The actual gravity that I think of exists to a great extent outside of the dimensions recognisable by human senses, and is, in actuality, interacting with other universal membranes nearby our own. But that's going into what I discussed before, and I'm really not schooled enough in String Theory to make realistic assertions and assumptions on it, so it stays my own thought.

Originally posted by ZPE StarPilot
Seems to me I read about large quantities of Mass being found in an area where there is no visible objects to be found. The asumption was that it might be a large quantity of Dark Matter, based on it's gravitation effects on ordinary Matter.

I've also seen Dark Matter maps made, that show possible Dark Matter not far from our local group of stars. How they figure this, I don't know.

Those massive areas were, for the greater part, not directly observed but indirectly expected, they were required in our equations. The required masses constitute the maps.

Originally posted by ZPE StarPilot
Vacuum energy is definitely not the same as Dark Energy.
I don't think they have much of an idea what Dark Energy might be yet.
But vacuum energy, as best as I can say, is the "quantum jiggle" of the basic hydrogen the makes up the universe. It's everywhere. Zero vacuum empty space isn't empty, it's full of energy. That's their story.

I agree, but only up to the extent I did in my earlier point - below a certain size, no actual energy must exist. In many areas, it does, but it doesn't necessarily. This is, of course, semantics, because at these sizes, vacuums are useless to us.

Originally posted by ZPE StarPilot
And yes, modern improvements to Newtonian physics do quite well, compared to Einsteinian. Don't forget, orbital dynamics failed with Einstein's rules, but worked fine with Newton's stuff. We would never have made it into orbit or to the Moon. It's all about Gravity. I think one works better on sub-atomic particles (quantum), and the other on molecular. (large scale mass)

I think you've mixed up your theories a bit, ZPE. First, recheck the first post. I'm fairly certain they had been using Newtonian Physics, and that was what resulted in the need for Dark Matter. The new, better research was done with actual General Relativity, and it proved itself far more competent and gave them answers that eliminated the need. So, it looks like the reverse from what you said: Einstein was right, Newton was wrong.

And, the theories you mixed a bit: General Relativity and Quantum Mechanics. Newtonian Physics was a predecessor to both, and modern-day String Theory is a hopeful successor. GR deals with the macro, and QM with the micro, and the strife of 20th century physics has been to unite the two, as they just don't seem to enjoy meshing together well enough to actually do it.


Sorry to have broken up your post, ZPE - I hate it when people do this, and find myself on the route.. But I feel it does work well with science-related subjects, when there are real facts being discussed. I'm more a hater of the many quote-reply post when discussing purely theoretical or philosophical material.

[edit on 11-10-2005 by Viendin]

Viendin, what you say sounds ok. I'm not a physics major... err... mechanical and electrical physics I've had, but not relativity or gravitational.

It does seem like physics has a ways to go before we have truely useful answers. I see first one theory, and then the other, providing the answers, and creating more questions. But as long as they keep trying, I'm happy.

It is a bit disturbing to see Einsteinian physicists saying "oh wait, let me change the numbers". There is truely a battle going on between the two camps. Neither will have a final solution anytime soon.

I've been following the theories of "The Electric Universe" for a little over a year now and I have to say that their observations seem to explain all of the phenomena that mainstream science cannot.

Where theories have to be reworked after each new observation, "The Electric Universe" has simple and elegant explanations which fits the observable proof. In addition their theories can be replicated in the laboratory as plasma phenomena are scaleable.

As I have seen on www.thunderbolds.info, see following links,

www.thunderbolts.info...
www.thunderbolts.info...
www.thunderbolts.info...
www.thunderbolts.info...

The electric power of a galaxy can and does hold it together, no dark matter needed.

I find the whole idea of dark matter and dark energy to be modern day magic.

The fact is their theory doesn't work and instead of looking at that theory and scrapping it, adjustments have been made, and made, and made, finally giving us this "Dark Matter".

Take a look at the EUT and see what you think.

Originally posted by ShadowXIX
What about Dark energy or "Vacuum" energy which is thought to make up a much largersection of the universe then Dark matter? Empty space seems to not be empty and has some type of force that wants to push space apart. I thought that repulsive energy is the reason why the expansions of the universe is speeding up.

Can you imagine being in a spaceship running from the bad alien guys trying to kill you, (or even your alien ex-wife wanting alimony), and suddenly find the "end" of the universe?

I wonder if that would suck....

[edit on 12-10-2005 by Shaker]

"Fuzzy physics, in my opinion... "

Many concepts are fuzzy - it's like many physicists before me have said, you can never truly appreciate the deepness of any physics without understanding the math behind it. I only quickly read over the paper, as I don't really have much time to sit down and grind out everything myself, but some of the math in there is quite fuzzy (I am a physicist btw). If the physics is truly fuzzy - it's the math that is fuzzy first, not the concept. But like I say, nothing should be taken as absolute fact in sciences, so anyone arguing a subject either solidifies a theory further, or reforms the theory, so it's good these arguments exist...

Dark matter has to exist, since I'm composed entirely of it. Dark matter, evil energy, ya know.

Originally posted by Nygdan
Dark matter has to exist, since I'm composed entirely of it. Dark matter, evil energy, ya know.

Thank NYGDAN,
that explains a heck of alot of questions that I have had about you Yuck, Yuck

Whoa there... not quite yet...

arstechnica.com...

However this claim is not without its detractors. Korzynksi's response claims that the Cooperstock and Tieu model is unphysical. Namely, that it includes a "fudge factor" in a shell of matter which isn't observed and seems to be little more than a mathematical artifact... one which skews the results of Cooperstock and Tieu.

Indeed, merely resolving galactic rotation alone is insufficient to dispense with the need for dark matter. Motions of galaxies themselves within clusters, as well as diffuse hot intergalactic gas, also require far more mass than is observed. The most direct observations we have made of dark matter, using gravitational lensing of more distant galaxies, also confirm that there is far more mass than we can see there.

Most clusters have their component galaxies at such high velocities that their observed masses would have the cluster flying apart in just a few hundred million years and hence there would be no clusters remaining today. Intergalactic gas is so hot that it, too, would rapidly escape the cluster if not for the presence of much more mass than we can see. The Cooperstock/Tieu model addresses neither of these problems.

So it looks like dark matter is here to stay for the time being.

That's what I thought, but didn't have a clue how to say it...

The original Cooperstock/Tieu model appeared on astro-ph without any kind of peer review. At least one error has been found in the model so far.
xxx.lanl.gov...

...it is not a physical model – it contains a physical singularity (which Cooperstock and Tieu write off as a mathmatical singularity, but not physical)....

Refute articles:
www.economist.com...
paste.exclaimindustries.net...