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Author Topic:   Dark matter a dying theory?
tesla
Member (Idle past 285 days)
Posts: 1199
Joined: 12-22-2007


Message 31 of 113 (619192)
06-09-2011 2:49 AM
Reply to: Message 30 by PaulK
06-09-2011 1:51 AM


Re: Not so fast....
in general there have been positive results from other experiments.

well then, here is the update:
http://www.world-science.net/othernews/110607_darkmatter.htm

"Dark mat­ter is es­ti­mat­ed to ac­count for nearly 90 pe­r­cent of all mat­ter in the un­iverse, yet its ident­ity re­mains one of the big­gest mys­ter­ies of mod­ern sci­ence. Al­though dark mat­ter is in­vis­i­ble to tele­scopes, most as­tro­no­mers say they know it exists be­cause it ex­erts a strong gravita­t­ional in­flu­ence over ga­lax­ies that noth­ing vis­i­ble can ex­plain."

This paragraph sums up the evidence quite well:

In science language, I read : "strong (apparently) gravita­t­ional in­flu­ence"

and:

"noth­ing vis­i­ble can ex­plain."

If all the space dust in a galaxy is collected, what is its gravitational capability? or does that not matter either?


keep your mind from this way of enquiry, for never will you show that not-being is
~parmenides

This message is a reply to:
 Message 30 by PaulK, posted 06-09-2011 1:51 AM PaulK has responded

Replies to this message:
 Message 32 by PaulK, posted 06-09-2011 3:29 AM tesla has acknowledged this reply
 Message 33 by Panda, posted 06-09-2011 7:51 AM tesla has acknowledged this reply
 Message 34 by Percy, posted 06-09-2011 9:27 AM tesla has responded
 Message 50 by Taq, posted 06-09-2011 3:31 PM tesla has responded

  
PaulK
Member
Posts: 16629
Joined: 01-10-2003
Member Rating: 3.0


Message 32 of 113 (619194)
06-09-2011 3:29 AM
Reply to: Message 31 by tesla
06-09-2011 2:49 AM


Re: Not so fast....
So you agree that there is evidence ? Even your added words and omissions don't change that.

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 Message 31 by tesla, posted 06-09-2011 2:49 AM tesla has acknowledged this reply

  
Panda
Member (Idle past 2405 days)
Posts: 2688
From: UK
Joined: 10-04-2010


Message 33 of 113 (619216)
06-09-2011 7:51 AM
Reply to: Message 31 by tesla
06-09-2011 2:49 AM


Re: Not so fast....
tesla writes:

"noth­ing vis­i­ble can ex­plain."


"Fucking Magnets, How Do They Work?"

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Percy
Member
Posts: 19880
From: New Hampshire
Joined: 12-23-2000
Member Rating: 5.2


(1)
Message 34 of 113 (619230)
06-09-2011 9:27 AM
Reply to: Message 31 by tesla
06-09-2011 2:49 AM


Re: Not so fast....
Hi Tesla,

I think you're conflating two different things.

There is something we cannot see exerting a gravitational influence on galaxies. We don't know what is exerting this force, but we've given it a name: dark matter. We have very strong observational evidence of this phenomena.

What we don't have any good evidence for is the nature of dark matter. We don't know what it is. No one is claiming we know what it is. One cannot make claims based upon insufficient evidence.

There are a number of hypotheses about the nature of dark matter. Maybe one of them is right, maybe not. We don't know yet.

--Percy


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 Message 31 by tesla, posted 06-09-2011 2:49 AM tesla has responded

Replies to this message:
 Message 35 by tesla, posted 06-09-2011 11:17 AM Percy has responded
 Message 43 by slevesque, posted 06-09-2011 3:04 PM Percy has responded

  
tesla
Member (Idle past 285 days)
Posts: 1199
Joined: 12-22-2007


Message 35 of 113 (619278)
06-09-2011 11:17 AM
Reply to: Message 34 by Percy
06-09-2011 9:27 AM


Re: Not so fast....
There is something we cannot see exerting a gravitational influence on galaxies. We don't know what is exerting this force, but we've given it a name: dark matter. We have very strong observational evidence of this phenomena.

There is something we cannot see exerting emotional and behavioral influence on mankind. We don't know why this force has such influence, but we have given it names like "God" or "Belief structure". We have very strong observational evidence of this phenomena.

Do you see that this evidence is not really any evidence other giving a name to an unexplainable phenomenon?

What we don't have any good evidence for is the nature of dark matter. We don't know what it is. No one is claiming we know what it is. One cannot make claims based upon insufficient evidence.

That is exactly what everyone is doing though.

There are a number of hypotheses about the nature of dark matter. Maybe one of them is right, maybe not. We don't know yet.

Those entertaining the alternative hypotheses do not seem to be entertaining them here.

Edited by tesla, : missing quote box added.


keep your mind from this way of enquiry, for never will you show that not-being is
~parmenides

This message is a reply to:
 Message 34 by Percy, posted 06-09-2011 9:27 AM Percy has responded

Replies to this message:
 Message 36 by Percy, posted 06-09-2011 1:53 PM tesla has responded

  
Percy
Member
Posts: 19880
From: New Hampshire
Joined: 12-23-2000
Member Rating: 5.2


(1)
Message 36 of 113 (619329)
06-09-2011 1:53 PM
Reply to: Message 35 by tesla
06-09-2011 11:17 AM


Re: Not so fast....
tesla writes:

There is something we cannot see exerting emotional and behavioral influence on mankind. We don't know why this force has such influence, but we have given it names like "God" or "Belief structure". We have very strong observational evidence of this phenomena.

The problem with this analogy is your labels. "Dark matter" is a relatively neutral label that doesn't imply any particular conclusion about the nature of dark matter. "God" on the other hand is pretty specific about the nature of this influence. "Belief structure" is an improvement but still far too specific. But I think few would have much problem with this analogy if you were to choose a truly neutral term, maybe "psychology" for example.

Stating this another way, people's behavior and feelings and responses to stimulus are very real, but calling the phenomenon responsible "God" or "Belief structure" is to imply a specific answer where we don't really have one. "Dark matter" as it is interpreted within the physics community implies no specific answer at this time.

Or coming at this from yet another angle, when we say "dark matter" is responsible for keeping rotating galaxies from flying apart we haven't narrowed down the answer. It could be a form of matter that only rarely interacts with normal matter, or it could be objects that do not give off enough light to be detected, or it could be that we don't quite have the laws of physics correct yet, or it could be the influence of extra dimensions, or it be something else I haven't included here since this isn't a complete list, or it could be something no one has thought of yet.

But when you say "God" is "exerting emotional and behavioral influences on mankind" you're implying a very specific answer, one you have no evidence for.

--Percy


This message is a reply to:
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Replies to this message:
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tesla
Member (Idle past 285 days)
Posts: 1199
Joined: 12-22-2007


Message 37 of 113 (619338)
06-09-2011 2:13 PM
Reply to: Message 36 by Percy
06-09-2011 1:53 PM


Re: Not so fast....
But when you say "God" is "exerting emotional and behavioral influences on mankind" you're implying a very specific answer, one you have no evidence for.

Do you know anything at all about the history of mankind and mankind’s buildings of temples and cities in the name of God?

Or noticed 'In God we trust' on money?

Have you seen the joy in a person’s face in a church when they have prayed?

No evidence? The evidence of the influence on this mystery called "God" on mankind is so bold and evident you can only ignore it to not see it.


keep your mind from this way of enquiry, for never will you show that not-being is
~parmenides

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 Message 36 by Percy, posted 06-09-2011 1:53 PM Percy has responded

Replies to this message:
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slevesque
Member (Idle past 3332 days)
Posts: 1456
Joined: 05-14-2009


Message 38 of 113 (619344)
06-09-2011 2:33 PM
Reply to: Message 9 by cavediver
06-08-2011 4:24 AM


You are on a one-way trip to cranks-ville with this thinking. I'd get that out of your system now. If you think for one second that the cosmology world has not seriously looked at alternative explanations, you're an idiot.

I agree I worded that a bit poorly, I was speaking more of a serious consideration of alternatives particularly by those who have been searching for this dark for 20 years with little results.

I was referring that maybe it was time for a genuine paradigm shift in the way we approach this question.

We have high-confidence that dark-matter is real. High-confidence does not mean "this is the truth and we cannot possibly be wrong".

I just have a hard time seeing how such a high-confidence is merited.

Edited by slevesque, : No reason given.


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slevesque
Member (Idle past 3332 days)
Posts: 1456
Joined: 05-14-2009


Message 39 of 113 (619345)
06-09-2011 2:37 PM
Reply to: Message 13 by Percy
06-08-2011 8:25 AM


Yeah, you're right, even though a Nobel awaits the team that uncovers the nature of what we currently call dark matter, scientists march in lock step to their preconceptions and refuse to think outside the box. Over the past decade the articles I've read have described scientists who are confining themselves to only the most pedestrian of possibilities.

Yet undiscovered forms of matter? How boring is that!
Mini-black holes created during the big bang? Yawn.
Modified laws of physics? Snore.
Effects of extra dimensions? Soporific (look it up).

Read reply to CD for clarifications.

Also, only the first two here fall in the category of dark matter, and the first one insanely more popular then the second.

What I'm saying is that I see little basis for such a strong tendency to think unknown kinds of matter are responsible for what we see

PS I'm not talking about scientists not wanting to think outside the box, I'm not a conspirationist. But I realize that paradigms have much more influence then we usually acknowledge, and that this seems to me to be a textbook example.

Edited by slevesque, : No reason given.


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Percy
Member
Posts: 19880
From: New Hampshire
Joined: 12-23-2000
Member Rating: 5.2


(1)
Message 40 of 113 (619346)
06-09-2011 2:53 PM
Reply to: Message 37 by tesla
06-09-2011 2:13 PM


Re: Not so fast....
Okay, let me try another tack.

Let us grant for the sake of discussion that God is a proven and well identified phenomenon. In that case, "dark matter" fits into a different category because, unlike God, we have no idea what it is. "Dark matter" is merely a label for the unknown cause of the gravitational influence that prevents rotating galaxies from flying apart. The gravitational influence itself is well established, but the cause of that influence is not. We give the cause of this gravitational influence the name "dark matter."

--Percy


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 Message 37 by tesla, posted 06-09-2011 2:13 PM tesla has responded

Replies to this message:
 Message 45 by tesla, posted 06-09-2011 3:22 PM Percy has acknowledged this reply

  
slevesque
Member (Idle past 3332 days)
Posts: 1456
Joined: 05-14-2009


Message 41 of 113 (619348)
06-09-2011 2:57 PM
Reply to: Message 14 by NoNukes
06-08-2011 9:46 AM


I think the analogy is apt, but perhaps strained. The hypothetical Vulcan was merely difficult to detect. But there was no belief that it would be impossible to detect.

It may well be that dark matter is impossible to detect other than through its gravitational effect. There may never be anything other than highly circumstantial evidence for dark matter. Unlike the case of Vulcan, every failure to detect dark matter may mean simply dropping one particular dark matter hypothesis.

No analogies are perfect, but I think it is a good fit.

Both come from a difference between a predicted theoretical value and actual observation. In both cases, the ad hoc explanation was matter tha we could not see (vulcan was posited to be on the other side of the sun if I remember correctly) that explained the discrepency via it's gravitational effect.

Not there is nothing inherently wrong with this: Neptune's existence was predicted via this same reasoning


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PaulK
Member
Posts: 16629
Joined: 01-10-2003
Member Rating: 3.0


(1)
Message 42 of 113 (619350)
06-09-2011 3:02 PM
Reply to: Message 39 by slevesque
06-09-2011 2:37 PM


quote:

What I'm saying is that I see little basis for such a strong tendency to think unknown kinds of matter are responsible for what we see

PS I'm not talking about scientists not wanting to think outside the box, I'm not a conspirationist. But I realize that paradigms have much more influence then we usually acknowledge, and that this seems to me to be a textbook example.


Are you sure that your opinion is due to investigating the evidence or does it have more to do with the fact that many YECs oppose dark matter because it discredits one of their arguments ?

Here is what a professional astrophysicist wrote about the evidence for dark matter versus Modified Newtonian Dynamics (MOND) in 2008:


In summary, MOND explains galactic rotation curves better than dark matter does, and pretty much nothing else. Dark matter explains the cosmic microwave background, large scale structure, galaxy clusters, gravitational lensing, the Bullet cluster and the cluster Abell 520, and also is consistent with a host of cosmological observations (e.g., nucleosynthesis, supernovae data, cluster estimates of the matter density) that MOND isn't. All that really remains is to detect dark matter directly.

In summary, MOND explains galactic rotation curves better than dark matter does, and pretty much nothing else. Dark matter explains the cosmic microwave background, large scale structure, galaxy clusters, gravitational lensing, the Bullet cluster and the cluster Abell 520, and also is consistent with a host of cosmological observations (e.g., nucleosynthesis, supernovae data, cluster estimates of the matter density) that MOND isn't. All that really remains is to detect dark matter directly.
[/qs]

here

How many of these lines of evidence have you considered in your assessment of dark matter ?

And it is beginning to look as if we have direct detection too, now. At least two consistent positive results, and a real possibility of a third.


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slevesque
Member (Idle past 3332 days)
Posts: 1456
Joined: 05-14-2009


Message 43 of 113 (619351)
06-09-2011 3:04 PM
Reply to: Message 34 by Percy
06-09-2011 9:27 AM


Re: Not so fast....
There is something we cannot see exerting a gravitational influence on galaxies. We don't know what is exerting this force, but we've given it a name: dark matter. We have very strong observational evidence of this phenomena.

You are sort of begging the question here.

What we do observe is a difference between the theoretical mass a galaxy contains, nferred from it's rotating speed, and the observed visible mass it actually contains.

''Dark matter'' isn't the name being given to this phenomenon, it is the name of one of the explanation thought possible: that this indicates additional matter exists that has a gravitational influence. The terms dark matter therefore aren't as general as you say they are, and they certainly imply a certain amount of specificity contrary to what you say in your next message.


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 Message 34 by Percy, posted 06-09-2011 9:27 AM Percy has responded

Replies to this message:
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slevesque
Member (Idle past 3332 days)
Posts: 1456
Joined: 05-14-2009


Message 44 of 113 (619358)
06-09-2011 3:21 PM
Reply to: Message 42 by PaulK
06-09-2011 3:02 PM


Are you sure that your opinion is due to investigating the evidence or does it have more to do with the fact that many YECs oppose dark matter because it discredits one of their arguments ?

It has little to do with YECism, and more to do with discussions I have had and reading. I also don't pretend to have looked in depth into the subject either.

Also, YECist have no reason to reject dark matter nor dark energy that I know of. It would be interesting for you to point out which arguments you are referring to.

How many of these lines of evidence have you considered in your assessment of dark matter ?

I am definitely not leaning towards MON either, which seems to be the main concern of the astrophysicist you quoted. I can't comment on any points specifically because his comment was much too general.

And it is beginning to look as if we have direct detection too, now. At least two consistent positive results, and a real possibility of a third.

I agree the bullet cluster sutdy is interesting, but previous claims of direct detection have also come and gone before.


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tesla
Member (Idle past 285 days)
Posts: 1199
Joined: 12-22-2007


Message 45 of 113 (619360)
06-09-2011 3:22 PM
Reply to: Message 40 by Percy
06-09-2011 2:53 PM


Re: Not so fast....
We give the cause of this gravitational influence the name "dark matter."

I see nothing wrong with that. What I am pointing out is due to lack of evidence it might be wise to put alternative idea's into the foreground and keep dark matter a potential until proven otherwise.


keep your mind from this way of enquiry, for never will you show that not-being is
~parmenides

This message is a reply to:
 Message 40 by Percy, posted 06-09-2011 2:53 PM Percy has acknowledged this reply

Replies to this message:
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