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Another Problem With Big Bang?

BeAChooser

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I found this article interesting:

http://www.eurekalert.org/pub_releases/2007-08/cxc-dmm081607.php "Dark matter mystery deepens in cosmic 'train wreck, Public release date: 16-Aug-2007"

It states that

Astronomers have discovered a chaotic scene unlike any witnessed before in a cosmic “train wreck” between giant galaxy clusters. NASA’s Chandra X-ray Observatory and optical telescopes revealed a dark matter core that was mostly devoid of galaxies, which may pose problems for current theories of dark matter behavior.
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Then it notes two possible explanations.

Mahdavi and his colleagues have two possible explanations for their findings, both of which are uncomfortable for prevailing theories. The first option is that the galaxies were separated from the dark matter through a complex set of gravitational "slingshots.” This explanation is problematic because computer simulations have not been able to produce slingshots that are nearly powerful enough to cause such a separation.

The second option is that dark matter is affected not only by gravity, but also by an as-yet-unknown interaction between dark matter particles. This exciting alternative would require new physics and could be difficult to reconcile with observations of other galaxies and galaxy clusters, such as the aforementioned Bullet Cluster.
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If the second is what it takes, then the Big Bang menagerie of invisible particles, forces and interactions just keeps growing. :D
 
Strange universe, isn't it? Let's see how it all settles out. Nobody knows exactly what Dark matter is yet anyway.
 
While theories about dark matter are interesting, I can't see anything in that article that actually suggests any problem with the big bang.
 
Cuddles said:
I can't see anything in that article that actually suggests any problem with the big bang.
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Dark matter (along with dark energy, inflation, strings, black holes and other phenomena that may be nothing but mathematical constructs) are the foundations of the current Big Bang theory. If there's a problem with dark matter, there's a significant problem with Big Bang.
 
BeAChooser said:
Dark matter (along with dark energy, inflation, strings, black holes and other phenomena that may be nothing but mathematical constructs) are the foundations of the current Big Bang theory. If there's a problem with dark matter, there's a significant problem with Big Bang.
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Don't get too carried away. Strings, for example (be they cosmic strings or strings as in String Theory) are not at all necessary for the standard cosmological model.
 
Yllanes said:
Strings, for example (be they cosmic strings or strings as in String Theory) are not at all necessary for the standard cosmological model.
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But they are being used to address some of the problems observed with the standard model and domains where the standard models leaves off.

One problem is that the standard model requires lots and lots of parameters. It's VERY complex. Complex is often wrong.

Gravitational forces have not been successfully incorporated in the standard model. String theory is trying to address this.

The standard model describes low energy events but the Big Bang was a high energy event. String theory is an attempt to explain the physics of the Big Bang ... and perhaps what came before it, ASSUMING that it actually occurred.

Strings theory, via the movement of branes, is trying to explain inflation, a key ingredient of the Big Bang.

There is a theory that collisions between branes create Big Bangs.

There are even attempts to explain dark energy as a manifestation of strings.

So I wouldn't say that strings are unnecessary to the Big Bang theory.
 
BeAChooser said:
Or even if it exists.
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But I've seen pitchers!!!1!! :eye-poppi

Seriously, I'm no astronomer or physicist but Phil Plaitt has some pictures up on his weblog that he insists capture DM. Here's one of them.

Please let me know what you think of them. Is he wrong or is it just inconclusive?
 
Someone correct me, if I am wrong, but it seems that Dark Matter was really a work-around to reconcile the differences between what the Big Bang implies, and the observations made about celestrial objects.

If that is true, then a problem-with-dark-matter, once resolved, could actually help explain the Big Bang more accurately, rather than become "another problem" for it.
 
BeAChooser said:
If the second is what it takes, then the Big Bang menagerie of invisible particles, forces and interactions just keeps growing. :D
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I'm sorry, but can you explain how this proves problematic for the Big Bang Theory? The theory is not even mentioned in the article, and you do not articulate at all on it. Should I suggest why?
 
BeAChooser said:
So I wouldn't say that strings are unnecessary to the Big Bang theory.
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Cosmic strings and other topological defects such as magnetic monopoles or domain walls are possible explanations for very precise phenomena (ultra high energy cosmic rays, etc.)

You know what string theory is.

None of these things is needed by the current cosmological model, based on general relativity. This model explains with great accuracy everything that happened to the large scale structure of spacetime after the first 10-6 seconds (I don't care about the precise moment, some people are more optimistic and go to smaller fractions of a second). The things you are talking about would explain what happened before that.

When we talk about the Big Bang theory we usually mean what I mentioned in the last paragraph, not the Big Bang itself but what happened since a very short time after it. This is what I meant by the standard cosmological model, which doesn't need topological defects, etc. (but does need dark matter).

If you want to push our understanding beyond to a smaller fraction of a second maybe you need strings or loop quantum cosmology or whatever. But they are not an ingredient of our current theory and certainly not one of the foundations of it.
 
Slimething said:
I'm no astronomer or physicist but Phil Plaitt has some pictures up on his weblog that he insists capture DM. Here's one of them.

Please let me know what you think of them. Is he wrong or is it just inconclusive?
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They didn't actually "observe" DM. They inferred it must exist from some observations they otherwise couldn't explain using what they know about observable matter and gravity. And to explain it, DM has to have some rather amazing properties. And as you can see from what I posted at the start of this thread, even those properties may need to be even more amazing still. :)

It's important to realize that they first inferred the presence of dark matter in our galaxy in order to explain the rotation curve for the stars in our galaxy around its center. But there is another possible explanation in that case besides dark matter. One that the Big Bang community largely ignores. That is the one promoted by plasma cosmologists which can be demonstrated in the lab and in computer models using well understood physics.

The issue in your question is whether gravitational lensing can only be caused by dark matter. Some plasma cosmologists appear to question that notion too. For example, here are a couple sources that discuss alternative explanations and problems with the dark matter lensing notion:

http://www.thunderbolts.info/tpod/2005/arch05/050822lensagain.htm

http://www.holoscience.com/news.php?article=stb9s0ye

If you search around, you can find other discussions.

The examples that are being labeled as "proof of dark matter", such as the colliding galaxy observation by Clowe, make a major assumption ... that all of the baryonic, ordinary matter is in the form of hot plasma or bright stars in galaxies. But most of the mass of galaxies may well be in the form of dwarf stars. Several studies of galaxies have shown that they have ”red halos” that are mostly red dwarfs. Other studies have indicated halos filled with white dwarfs. In addition, there is evidence that a huge amount of mass may be found in relatively cool clouds of plasma.

I guess I believe the verdict is out and what makes me uncomfortable with Big Bang is that one phenomena after another is being explained only via bizarre particles, forces, energies and interactions that we haven't been able to demonstrate or see in a lab here on earth. At this point they are purely mathematical constructs. On the other hand, Plasma Cosmologists have a built a rather interesting theory that seems to explain many if not most of those observations with physics that can be duplicated in the lab. So I guess you will have to decide which you are more comfortable with.

By the way, there's another possible explanation for the lensing observations apparently ... that our theory of gravity is wrong: http://www.physorg.com/news85310822.html In fact, I read that Clowe himself says "I personally would prefer a pure modified gravity solution to the mass discrepancy question."
 
Thanks, BeAChooser, that's a lot of information and you went to a lot of trouble. As for me, I'm still too enthralled with the cosmos in general to really get into the nitty gritty but I do admire those who do. :)
 
strathmeyer said:
I'm sorry, but can you explain how this proves problematic for the Big Bang Theory?
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So you don't think a bunch of particle, forces, interactions and physics that have only been inferred from observations in distant galaxies, and that have not observed or reproduced in our labs is not problematic? What if one could offer an explanation for those observations that does not involve such particles, forces, interactions and physics, but instead is based on physics that has been observed, reproduced and studied in labs here on earth for decades? Maybe we should apply Occam's Razor?
 
Yeah, as others have pointed out, there is a difference between big bang theory and the standard cosmological model. The standard cosmological model is big bang+inflation+dark matter+dark energy. What makes/causes dark matter/energy or drives inflation is up for debate (somewhat), but this simple model describes an enormous amount of phenomena. Big bang describes the state of the early universe, inflation solves other issues, dark matter gives us the correct picture of structure formation, and dark energy...is...well, observationally unavoidable.

Now, the current Hot Topic is trying to figure what the heck dark matter/energy really IS. One possibility: the dark energy is caused by a slowly-rolling scalar field (quintessence, for you fans out there), and it might couple to a dark matter particle via a Yukawa interaction. This would lead to a 5th force among dark matter particles ONLY. Why would we care about this possibility? Well, 5th forces are in principle OBSERVABLE, so by searching for clues to a 5th force we can see if these kinds of ideas are on the right track. Essentially, we like theories that make 5th forces because they are falsifiable!

**begin shameless plug**
It's not like finding 5th forces are easy or anything. We have to look for subtle clues in, say, the evolution of structure, that would differ from the standard picture. Now, if only some forum member were engaged in exactly this sort of research....hrm....

http://arxiv.org/abs/0707.2968

Muhahahahahaha!
**end shameless plug**

If we do find strong evidence for a 5th force, it would in no way invalidate big bang theory, but it would modify our picture of the standard cosmological model.

As an interesting aside, Joel Primack has suggested calling it "double dark theory", but I think that's pretty silly.
 
From a page linked to in BeAChooser's link (http://members.cox.net/dascott3/index.htm):

"The 'Deep Impact' mission by NASA produced information that astounded the project cometologists, yet these key findings were predicted by the Thunderbolts group to which author/lecturer Donald Scott belongs."

Hahahahahahahahahaha. Bonus points for spotting the funny bit (and the point where I stopped reading).

Question for BeAChooser: If I were to say enough things, providing enough references and evidence, would you ever decide that the standard cosmological model is the current best way to describe the universe, and that the electric universe is..well...bunk? If you're preparing an essay reponse, note that I only need a yes/no answer.
 
Yllanes said:
the current cosmological model, based on general relativity. This model explains with great accuracy everything that happened to the large scale structure of spacetime after the first 10-6 seconds
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Only by inferring a bunch of forces, particles, energies, interactions and physics that so far no one has actually observed or reproduced in labs here on earth. Inflation, which is an essential part of the Big Bang theory at this time, is nothing more than a mathematical notion. You may claim that COBE proves it but plasma cosmology can also explain the COBE data. String theory is trying to explain how inflation occurred but strings themselves are something that some physicists will also admit may never be observable. They are again nothing more than mathematical abstractions at this point in time.

Yllanes said:
This is what I meant by the standard cosmological model, which doesn't need topological defects, etc. (but does need dark matter).
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Plus dark energy, magnetic monopoles, ubiquitous black holes, and I'm sure I've missed a few other ghosts that Big Bang astronomers have had to introduce to explain observations because of their insistance that gravity explain it all.

Why is it that I can pick almost any current book on the big bang and I will likely find hardly a mention of plasma and electromagnetism? Plasma comprises almost all of the matter in the observable universe and electromagetic fields are everywhere and demonstrably have a very powerful effect on plasmas (in fact, far more than gravity). Plasma cosmologists do not ignore gravity. Why is it that Big Bang cosmologists consistently ignore plasmas and the effect of electromagnetism on them? Is it because they are too invested in their *cool* mathematical ghosts?
 
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