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Simple Alternative to Dark Matter: Challenging Newton and Einstein

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posted on Jan, 15 2007 @ 11:01 AM
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I'm not sure how many of you read Discover Magazine, but I was going through my stack at home and came across something published in August of last year that was extremely interesting. Dark Matter is sometimes used as a sort of "fudge factor" to explain strange events, like the observation that outer stars in a galaxy don't move slower than the inner stars, something that contradicts Newton's laws. To fix the error, scientists just assumed that every galaxy must have a surrounding halo of dark matter. The problem is that Newton's laws work well for our solar system, but fail to accurately describe motion in something as large as a galaxy. To fix this, Newton's laws were tweaked, Einsten was challenged on relativity, and the resulting theory was more natural, logical, and didn't require "halos" of dark matter to work. It's a long article, but I cut out a few important pargraphs to make it easier to read:


Faced with flat rotation curves that seemed to flout Newton's laws, astronomers assumed the existence of a halo of dark matter around every spiral galaxy. Whatever the stuff was, it did not emit light, but it did exert a gravitational pull. The dark matter tugged on the stars, cranking up their speeds and creating the flat rotation curves. Milgrom decided to retrofit Newton…If you took high school physics, you may remember having Newton's most important equation pounded into your head:

F = ma. With this simple formula, known as Newton's second law, Newton forever linked forces (F) to their action on mass (m) in the form of acceleration (a). We all experience the relation between force and acceleration whenever we're in a car. As the car accelerates, we're forced back in our seats; when it decelerates, we're forced forward. Milgrom found that the best way to resolve the problem of the flat rotation curves was to modify this hallowed equation.

"I assumed that when the accelerations due to gravitational forces became very small, the formula changes to F = ma²/a0," Milgrom says. According to Milgrom, this change holds only when accelerations fall below one 10-billionth of a meter per second every second. Not only does this modification work best with the data, he adds, but the new constant, a0, may be of cosmological significance: Accelerating at this rate will take you from a resting state to the speed of light in the lifetime of the universe. Otherwise Newton's law operates as usual. So with MOND, stars in the outer reaches of galaxies move faster than expected, not because of the influence of some invisible matter but because Milgrom's amended version of Newton's second law increases the force acting on them.

To make MOND a serious alternative to dark matter, Milgrom's inspired guess needed to mature into a true theory, with a firm foundation in modern physics. And that meant confronting not just Newton but his wild-haired offspring, Einstein. It was Einstein who divined the interconnections between gravity, space, and time. For MOND to make headway in the field, someone was going to have to find a way to reconcile it with Einstein's masterpiece, the theory of general relativity.

On March 25, 2004, a paper from Physical Review Letters D appeared on the Los Alamos preprint server, a Web site where physicists post their newest articles. The paper, titled "Relativistic Gravitation Theory for the MOND Paradigm," was written by Jacob Bekenstein, Milgrom's collaborator since the 1980s. Building on earlier attempts, Bekenstein was finally able to generate a MOND theory that Einstein might have loved. The new theory was called TeVeS, an acronym for tensor, vector, and scalar—mathematical terms that describe how matter and energy interact with space and time in general relativity.

"TeVeS does everything," says Mario Livio with enthusiasm. A self-described agnostic in the MOND debate, but one with an obvious love for the underdog, Livio says that Bekenstein's work is "a phenomenal paper." In TeVeS, he adds, all the right things happen. Its results mesh with what physicists know about gravity from Einstein, and when gravity is very weak, it reduces to the behavior Milgrom envisioned in his first MOND papers. "With Bekenstein's theory we should now be able to explore all aspects of relativistic behavior," Milgrom says, unable to hide his pride. "This includes the bending of light by gravity, and in principle, the new theory should be OK for galaxy formation"… TeVeS has already passed a crucial first test, Milgrom says, because it can be used to explain the phenomenon of gravitational lensing, a cosmic optical illusion in which matter bends light. It's one of the stranger predictions of general relativity, and astronomers have confirmed it many times over.


www.discover.com...




posted on Jan, 15 2007 @ 11:18 AM
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I have a Discover subscription, and enjoy reading the magazine.

Einsteins' theories will eventually be molded, or changed all toghether. I remember reading in the magazine awhile ago about some (MIT I think) students, who had slowed light down to almost a complete stop.

I think I also read in January's edition, an article about a high-school science teacher and a couple of his students, who created a test, which made sound travel faster than light. I'll try and dig it up. I may have read about it here.

Well, skimming throught the January copy, It's apparent the article is not in there, but I did come across an article from 2006 sometime (January is a compilation of best stories of 2006), that supports Dark Matter.

www.discover.com... "Cosmic Collisions"



posted on Jan, 15 2007 @ 11:48 AM
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Stopping light was done using a new state of super-cooled matter called "bose einstein continuum" I believe. The researcher were actually able to bring light to a stop, then "release" it again after a short time. Is this what you're referring to?

Dark Matter and MOND theory are both supported by solid theories and observations that are predicted by each theory's respective equations, so right now I think it's a matter of what makes the most sense to you. Of course I have absolutely no expertise and my opinion is worth jack, but I just personally like the simpler explanation over the more exotic one, especially since Dark Matter has never been harvested.

(by the way, unrelated question, but I haven't posted on ATS for years...is there are way to delete the tags under your name without spending points? What I have now was meant to be funny when I made it, but now it just seems kind of presumptuous)



posted on Jan, 16 2007 @ 02:31 AM
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Very interesting idea, zhangmaster, and one which I, like you, find a lot more attractive than the dark matter hypothesis.

I'd love to read a bit more about this. Any online sources you can recommend? I already found the following:

1. A 2003 interview with the originator of the MOND hypothesis


Q: It's been said that dark matter theory is beginning to resemble the celestial mechanics of Ptolemy, who continually added epicycles to his models as the observations failed to conform to a geocentric universe. What would it take for scientists to abandon dark matter?

A: DM is encountering difficulties in the face of observations, and people keep inventing new DM with new properties to try and circumvent these difficulties. Over the years I have refrained from attacking DM, but others have started finding faults with it and that trend is increasing.

He sounds like a sensible, levelheaded fellow who deserves to be taken seriously.

2. A recent New Scientist article that reviews the theory seriously and sympathetically


The theory has recently overcome some serious problems that had plagued it since its inception - such as how it fits with general relativity - and it is now able to make surprising predictions about the evolution of the universe.

What has made people sit up and take notice is a 2004 paper by Jacob Bekenstein of the Hebrew University of Jerusalem in Israel (New Scientist, 22 January 2005, p 10). His paper, the culmination of a 20-year quest to reconcile MOND with relativity, seems to have stood the test of time and has convinced several other groups to work on the theory and test its predictions. Their results suggest Bekenstein is on to... a theory of gravity that preserves the best aspects of relativity, but with modifications that could make dark matter obsolete.

This article contains a thought that I, too, had when I read your original post:


Where do you go to look for modified Newtonian dynamics (MOND)? Try our own solar system. Since the early 1980s, NASA's Pioneer 10 and 11 space probes have been coasting away from the sun in the outer solar system. Puzzlingly, they have been decelerating more quickly than Newton's law of gravity would predict. The cause of this "Pioneer effect" is hotly debated, but the rate of deceleration is about what you would expect if Jacob Bekenstein's theory were correct.

3. A PhysicsWeb article about problems with the dark matter hypothesis


Despite decades of searching, the "dark matter" thought to hold galaxies together is still nowhere to be found... Some physicists think it makes more sense to change our theory of gravity instead.


I found all of these by following the links at this page, which brings together serious MOND literature from all over.

Any other stuff worth looking at? A few scientifically kosher MOND-debunking sites would be good.



posted on Jan, 16 2007 @ 11:34 AM
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I just finished reading through your links. Very interesting stuff and thanks for posting the information. I was able to find one detailed paper on MOND that you can buy, one paper that claims to prove the existence of dark matter although it might be too difficult to understand, and a more simple article that highlights what it says is an observation of dark matter.

Like I said before, I'm not an expert on dark matter theory but like the interviewer mentioned in your first link, the scientists that support this view are beginning to sound like Ptolemy who kept inventing "fudge factors" to account for the discrepency between his theories and observations. Dark Matter theorists invent neutralinos, axions, warm and cold DM, halos around galaxies...etc and although no dark matter has ever been detected, like followers of a religion the scientists label disbelievers "heretics" for their views. I understand that both theories "work", but knowing that I'll never be able to understand both sides well enough to debate with authority, I'd have to choose MOND and TeVeS on faith because of their simplicity.

Paper on MOND (purchase)
scitation.aip.org...

Paper on Dark Matter (intense)
arxiv.org... (paper on dark)

Article on Dark Matter Observation
today.slac.stanford.edu...

[edit on 16-1-2007 by zhangmaster]



posted on Jan, 17 2007 @ 05:01 AM
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Originally posted by zhangmaster
I'm not sure how many of you read Discover Magazine, but I was going through my stack at home and came across something published in August of last year that was extremely interesting. Dark Matter is sometimes used as a sort of "fudge factor" to explain strange events, like the observation that outer stars in a galaxy don't move slower than the inner stars, something that contradicts Newton's laws. To fix the error,
"TeVeS does everything," says Mario Livio with enthusiasm. A self-described agnostic in the MOND debate, but one with an obvious love for the underdog, Livio says that Bekenstein's work is "a phenomenal........




hello


i am sorry but MOND theory is not required.also no theoretical reason for these modifications at all.

MOND theory is a fudge factor to replace the Dark Matter fudge factor..


why you ask?

because your above observations have already been explained by established physical laws.

in detail

astronomers ONLY EVER use gravity to explain motion in the universe.

yet it is the MOST weakest force!!

the above observations can be explained by simple electromagnetic forces and this has been done
and fits with experimental observations:-

here is the link;-

www.electric-cosmos.org...

www.electric-cosmos.org...


if you read carefully ALL THE PAGES it explains observations with established theory.

it works as per the scientific method.


members.cox.net...




www.the-electric-universe.info...



no requirement to add on fudge factors at all.


public.lanl.gov...

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Edn

posted on Jan, 17 2007 @ 07:46 AM
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Maybe I read your post wrong zhangmaster but you just said

etc and although no dark matter has ever been detected

Then you post a link to the article that proves dark matter exists.
today.slac.stanford.edu...



posted on Jan, 17 2007 @ 10:50 AM
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Edn, I won't be entirely convinced that it exists until they detect in using the Large Hadron Collider to be completed this year. I've read that this may be one of the best opportunities to actually produce the stuff and study it in depth.


[edit on 17-1-2007 by zhangmaster]



posted on Jan, 17 2007 @ 06:27 PM
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Dark matter is still the preferred theory on account of a significant amount of astrophysical observations.

More and more recent observations and computations support it, and axions, a potential dark matter particle were now experimentally detected.

The real problem is "Dark Energy".

I like investigation of non-standard physical theory---as such is clearly needed for Dark Energy, but I think dark matter is real---there are enough distributional density fluctuations and specific anomalies that seem to indicate some truly dynamically active 'stuff' independent from the visible hadronic matter.

The alternate physics could be simultaneously real.




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