Astrophysicists unwind 'Cold Dark Matter Catastrophe' conundrum

Jan 14, 2010

For nearly twenty years scientists have been trying to resolve the discrepancy in the cold dark matter paradigm - the so-called "Cold Dark Matter catastrophe". Recently an international research group including physics professor Lucio Mayer from the University of Zurich has succeeded in unraveling this paradox in a simulation of bulgeless dwarf galaxy formation.

Cold Dark Matter - present day science is still in pursuit of a proof of its existence. Numerous are only explainable by assuming its existence: the Cold Dark Matter (CDM) paradigm accounts, for instance, for the distribution of galaxies and of standard matter in the universe on large scales, i.e. on the order of billions of light years, and including the nature of the relic microwave background radiation from the Big Bang.

However, when applied to individual galaxies - dimensions of hundreds to ten thousand light years - the model breaks down, leading to inconsistencies with the observations of astronomers.

Predictions by the model suggest that the central regions of galaxies should rotate at greater speed than is effectively indicated by astronomical measurements. As a result, the model implies a significantly higher density of CDM at the than allowed by measurements. For nearly two decades astrophysicists, particle physicists and astronomers have struggled to resolve this «Cold Dark Matter catastrophe», as this discrepancy is called among specialists, and to propose an convincing explanation for the varying behavior of DM at different scales. To date all attempts at explanation have fallen short or led to further irresolvable discrepancies. An international research group including Professor Lucio Mayer of the University of Zurich as one of three project leaders has now succeeded in unraveling this conundrum using a highly sophisticated supercomputer simulation.

Simulation of standard matter

Mayer and his colleagues simulated the formation of disc dwarf galaxies, for which the "Cold Dark Matter catastrophe" is particularly severe. In contrast to their predecessors, for the first time they modeled not only the behavior of CDM as influenced solely by gravitation, but also the highly complex behavior of baryonic matter, as normal, visible matter is also called, down to the scale at which star clusters form. At 83 percent, DM composes the vast majority of a galaxy, but is nevertheless also influenced by baryonic matter, as the researchers could now demonstrate in their publication in Nature.

Thanks to the high resolution simulations, which required the use of various supercomputers including one from NASA, Mayer and his colleagues could show with their model that during supernova explosions not only the interstellar gas but also CDM is pushed away from the core of a galaxy. In explosions of supernovae large quantities of normal, visible matter are removed from the galactic core in one blast: DM responds to the sudden change of the gravitational field by expanding away from the center and its density decreases. As a result the rotational velocity of the declines. Thus for the first time the simulated CDM paradigm and the nature of dwarf galaxies are in harmony - the apparent paradigmatic discrepancy is thereby resolved and the "Cold Dark Matter catastrophe" disappears.

Consequences for astrophysics and particle physics

These new findings bear consequences for particle physics and some of the methods employed for detecting DM particles. Among others the approach for demonstrating the presence of DM particles by means of their disintegration into gamma radiation is based on the density of DM in the core of galaxies. The simulation now predicts a significantly lower density of CDM than previously assumed at the core of dwarf galaxies, one of the targets of detection experiments. The anticipated radiation signals would therefore have to be weaker than formerly expected, requiring detectors of correspondingly greater sensitivity.

Lucio Mayer, who holds an assistant professorship at the University of Zurich endowed by the Swiss National Science Foundation, will continue to work on the topic of "The Formation of Galaxies" in the future: one of his doctoral candidates, Simone Callegari, is already occupied with modeling the formation of  massive disc galaxies resembling our own Milky Way galaxy.

Explore further: Superstring theorist at University of Florida wins 2015 Heineman Prize

More information: F. Governato, C. Brook, L. Mayer, A. Brooks, G. Rhee, J. Wadsley, P. Jonsson, B. Willman, G. Stinson, T. Quinn and P. Madau: Bulgeless dwarf galaxies and dark matter cores from supernova-driven outflows, Nature, 14. January 2010

Provided by University of Zurich

4.4 /5 (8 votes)

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User comments : 18

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Nik_2213
3.7 / 5 (3) Jan 14, 2010
Could our Solar System's position in 'Local Bubble' blown by a supernova contribute to our physicists' problems detecting CDM ?

With the other stuff absent, our local laws may be 'Strictly Einsteinian'...

Uh, how does that affect everything ??
El_Nose
2.3 / 5 (8) Jan 14, 2010
Anyone ever stop and think about how rare(people get touchy about intellegent design -- and I use that phrase loosely) how rare Earth really is and has to be.

1) Earth is a rocky planet
a)Has a good deal of mass, enough to keep an atmosphere
b) its surface is mostly covered in water
i) scientists are saying couldn't've formed on this planet, but was from comets
c) Not only rocky, but has a hot, metallic core this produces a magnetic field to shield us
d) exists in the life zone
2) Had to come from a 1st generation ( or 3rd i always forget which ) star that had metals and other heavy elements
3) crust is mostly carbon and oxygen
4) Our Local cluster just happened to be ripped away from whereever we were and set adrift in a very unpopulated portion of the galaxy that is safe from supernova and intense radiation,
5) we have the oort cloud for extra protection

This doesn't even address life forming -- we are lucky indeed -- and we are probably surrounded in DM
Quantum_Conundrum
3 / 5 (2) Jan 14, 2010
Earth is obviously extremely unique.

So far, nothing even remotely resembling the earth has been found and published by anyone.

There are a few "super earths" that have been discovered, but even these are so vastly different from "Earth" that they may not even be rightly called "Super Earths". More likely "super-mercury" or "mini-neptune" would be better terms.
jonnyboy
1 / 5 (1) Jan 14, 2010
El Nose, what you describe as rare covers over 90 % of our galaxy. Quit believing in luck and start believing in probability.

malapropism
5 / 5 (2) Jan 14, 2010
Apologies for the pedantry but there are no "degrees of uniqueness" - something is either unique or it is not. (It's a common grammatical error that just happens to irritate me... no offense intended.)
GrayMouser
5 / 5 (1) Jan 14, 2010
Earth is obviously extremely unique.

We don't have a sample size to justify that statement. The extra-solar planets that may, or may not, have been spotted are a hypothesis to explain certain observed phenomenon that may be artifacts created by experimental instruments operating near or beyond their limits of reliability.
Even if the observational data is good, we still don't have enough observed planets to make such a statement. It reeks of hubris.
PinkElephant
5 / 5 (2) Jan 14, 2010
@El_Nose,

Earth isn't as unique as you think, and as time goes by it will become less unique still (as increasingly metal-rich stars and solar systems continue to form.)

There are other ways to get shielded by a powerful magnetic field; for example look at the satellites of Jupiter.

By the way, we are not in a "safe" location. As we complete an orbit of the galactic center every 230 million years, we repeatedly pass through the galaxy's arms -- where interstellar medium is dense, more new stars form, and supernova explosions are more frequent. We just happen to be between-arms at the moment, but this wasn't always so.

Oxygen and Carbon are some of the most common byproducts of supernova explosions, so lots of planets will have crusts rich in these. Water is a very common substance throughout the galaxy.

As for how (un)likely formation of life is, given a hospitable environment, be honest -- we really don't know at this moment.
Objectivist
4 / 5 (2) Jan 15, 2010
@El_Nose,

Anybody blabbering about ID has no understanding of physics and is disgustingly anthropocentric. The universe would have worked in any composition, however in another composition where life hadn't existed there wouldn't be idiots thinking they're some center of the universe, and it still would have been unique. Still on a big scale it's not your fault for misusing your brain for illogical behavior, the chain of events prior to and during your existence has unfortunately carved this fate on your forehead and the writing of this comment on mine.
VOR
not rated yet Jan 16, 2010
Indeed I find organic life no more or less remarkable than the inorganic natural universe, in the context of it all being 'natural', not 'supernatural'. The development of life is likely no more, or less, inexplicable or out of place than the development of say, a solar system. This is not to say every solar system has life, but the percentage is not important for the sake of this idea. The point is that earth and its life are less common but certainly not 'special' or solely unique. 'Disgustingly anthropocentric' seems to sum things up well. Im glad to see we are not ALL fools. Too bad those of us with a cold, rational, accurate view seem to be 'less common'. The whole unique idea is like thinking there's something 'special' about the first diamond you found before you found more. Nature isnt miraculous or beautiful or ugly, etc. THOSE ARE EMOTIONAL RESPONSES THAT SHOULDN'T BE CONFUSED WITH RATIONAL THOUGHT.
KBK
2 / 5 (4) Jan 16, 2010
If one is curious enough to try this, they will get quit interesting results. Gather together two 'psychics'. Get two scientists. Get two excellent regression hypnotists.

Hypnotize the two psychics, but at different locations. Far from one another. Make sure the the two scientists are present for each given situation in it's entirety. Ask the two hypnotized psychics to pass information along to and from each scientist until they are satisfied that the communications are real and are actual 'spooky action at a distance'.

the frightening thing for the scientists, is that this will work, and work perfectly as a trans or superluminal communication system, that passes through anything.

This experiment can be carried out quite simply and inexpensively. And it works every time!

Now what does that say about your 'dark matter?' That is a question, isn't it?
Scryer
2.3 / 5 (3) Jan 16, 2010
Dark Matter is simply a way for Astrophysicists to fail at doing their job correctly. Make up something without a mere basses then itself and an inexplicable observation?

What's so hard with going back to the root of the problem and changing the hypothesis of our elements. what's worse is that no scientist can say for certain where gravity gets it's potential, and yet we continue to agree that it is common in all things with no regard to it's cause in actuality.

These failings of science must come from the root, from all of science that can not explain the problem nor the cause. One effect may have many causes, one effect may not create an immediate cause, if everything is relative based yet upon that which you agree, then science is no closer to answering a question about the universe then you or me.
Nik_2213
5 / 5 (1) Jan 17, 2010
At risk of getting off-topic, KDK...
"This experiment can be carried out quite simply and inexpensively. And it works every time!"

Show me.
NeptuneAD
5 / 5 (1) Jan 17, 2010
Dark Matter is a hypothesis to explain certain phenomena, so far it seems to be the best explanation, just remember that people at one time thought the earth was flat and scoffed at the idea that the earth was round and revolved around the sun.

As far as whether the earth is unique or not, perhaps you should refer to the Drake Equation and the Fermi Paradox.
Viictor
2.3 / 5 (3) Jan 18, 2010

Gravitational interaction, the foundations of cosmology.
http://viictor-vi..._13.html
flaredone
not rated yet Jan 19, 2010
The problem in the explanation presented in the above article is, it considers dark matter outside of galaxy, because matter was blown away by pressure of radiation during galaxy formation, OK? But now the matter is concentrated in the center of galaxies again - so no reason for such dark matter distribution exists anymore.

In my opinion the correct explanation of dark matter distribution arises rather from supersymmetric nature of dark matter - instead of massive bodies itself it's attracted to gradient of their gravitational field.
StillWind
1 / 5 (1) Jan 21, 2010
Funny how fear + ignorance = arrogance. All someone has to do is point out that the current paradigm is total crap, and the insults fly.
flaredone
1 / 5 (1) Jan 21, 2010
..current paradigm is total crap, and the insults fly...
This is just an arrogant insult of current paradigm...>;-) The key is in more simple & universal explanation of it - not the denial of it. With such approach we would repeat old mistakes again. Dense aether theory has no problem with dark matter concept - it's a common dispersion phenomena, which occurs at the water surface. It could be explained both by deformation of space, both by particle stuff, trapped into it. These explanations just differ by their observational perspective in similar way, like quantum mechanics differs from relativity.
StillWind
1 / 5 (1) Jan 21, 2010
Its kind of hard to take the current paradigm seriously when, like the current AGW hoax, it based entirely on mathematic equations and computer sims, and there is so much wrong with it, and they had to come up with such an enormous fudge factor to make it fit with observed phenomena.
Heck, we don't even have a handle;e on our own Star, let alone the universe, and for those arrogant enough to think that we do is simply an illustration of how truly ignorant that they are.
For them to further insult another because the other suggests that they aren't god-like in their understanding, illustrates my point.
Time to start over and simply be honest that we don't really know anything, and try to stick to observed phenomena, then in a couple of centuries, we might have the basics down so that we might actually start thinking of a theory.
Right now, we might as well be baboons on the plain, except that they aren't arrogant enough to think that they know it all.