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Author Topic:   Dark matter a dying theory?
Taq
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Posts: 9973
Joined: 03-06-2009
Member Rating: 5.7


Message 17 of 113 (619122)
06-08-2011 4:54 PM
Reply to: Message 15 by tesla
06-08-2011 3:14 PM


Re: Not so fast....
You know, It could be a problem with the math.
Let's examine this posibility as well:
Lat's say a spinning mass is off balance. take a beach ball, and in the center attach a metal core, one half iron, the other half aluminum. In a free spin (in space), will it travel?
I am assuming that you are referring to the spin rates of galaxies. If not, then the rest of this post will be more for general knowledge.
The first hint that dark matter existed was that galaxies were spinning too slow as measured by the luminous mass of the galaxy. However, this isn't the only evidence for dark matter. Gravitational lensing offers the best evidence for dark matter. We know from relativity that mass distorts spacetime, therefore dark matter should do the same even if it does not reflect, absorb, or emit light.
Secondly, dark matter does not seem to interact with luminous matter, something akin to neutrinos. This is why dark matter is often referred to as WIMP's (weakly interacting massive particles).
The perfect place to put these two characteristics to the test is in galactic collisions. When two galaxies collide the luminous matter interacts. This slows the luminous matter. However, the dark matter does not interact and moves right through. This should leave 4 different areas of mass, two for luminous matter from each colliding galaxy and two further away on each side for the dark matter. So how do we look for these areas of mass? Gravitational lensing of light from background galaxies. So what are the results? Exactly as predicted. The picture below maps the luminous matter in red and the dark matter in blue:
Read more here:
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So not only is the math correct, we can now map the distribution of dark matter around galaxies. I would say that dark matter is not a dying theory.

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 Message 15 by tesla, posted 06-08-2011 3:14 PM tesla has replied

Replies to this message:
 Message 20 by tesla, posted 06-08-2011 5:07 PM Taq has replied

  
Taq
Member
Posts: 9973
Joined: 03-06-2009
Member Rating: 5.7


Message 19 of 113 (619125)
06-08-2011 4:58 PM
Reply to: Message 18 by tesla
06-08-2011 4:54 PM


Re: Not so fast....
No real point other than what is stated. I’m aware that for every action there is an equal and opposite reaction. So if a massive earthquake, or an asteroid impact can modify the behavior of a mass, a solar flare could move a star etc., then perhaps the behaviors are being affected by interaction forces (unseen matter in a standard sense) instead of invisible matter.
How does this produce gravitational lensing of light?
Or maybe the unseen matter is just too small to see, like a group of asteroids.
This would dim the light coming from background galaxies which would be detectable. Dust particles much smaller than asteroids blocks our view of our own galactic core (which is very bright), as a counter-example.
It could just be variations in spins and balance because the 'evidence' is strong for spiral galaxies.
Again, this does not explain gravitational lensing where no luminous mass is observed.
I'm simply suggesting there are other possibilities besides invisable matter. I'm not a scientists, so You can take what ya want or leave it all at that.
Those other possibilities have to take all of the observations into account, not just the spin rate of galaxies.

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 Message 18 by tesla, posted 06-08-2011 4:54 PM tesla has replied

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 Message 21 by tesla, posted 06-08-2011 5:22 PM Taq has replied

  
Taq
Member
Posts: 9973
Joined: 03-06-2009
Member Rating: 5.7


Message 22 of 113 (619132)
06-08-2011 5:25 PM
Reply to: Message 21 by tesla
06-08-2011 5:22 PM


Re: Not so fast....
You know, light can do some funny things, because it will take the quickest path. We can only guess at what is between us, and what we are looking at over very long distances.
We don't have to guess. We can directly measure it. When measured, light is being bent by gravity produced by non-luminous mass.
"There are ongoing searches to use lensing to find a type of dark matter called MACHOs (massive compact halo objects). Although MACHOs, as dark matter, cannot be seen themselves, if they pass in front of a source (e.g. a star nearby), they can cause the star to become brighter for a while, e.g. days or weeks. This effect has been observed, but determinations of the dark matter are not yet conclusive."
How does this explain the observations made in the bullet clusters discussed in my post above?

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 Message 21 by tesla, posted 06-08-2011 5:22 PM tesla has replied

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 Message 25 by tesla, posted 06-08-2011 5:55 PM Taq has replied

  
Taq
Member
Posts: 9973
Joined: 03-06-2009
Member Rating: 5.7


(1)
Message 24 of 113 (619135)
06-08-2011 5:30 PM
Reply to: Message 20 by tesla
06-08-2011 5:07 PM


Re: Not so fast....
This to me is propaganda; scientists have to believe in dark matter to have funding for science in their field.
False. Scientists have to back their claims with evidence. Period. Scientists who claim that dark matter exists have backed this claim with experiments and evidence. What is not tolerated is people sitting in the back row taking potshots at a theory they never intend to test.
If anything, scientists who vehemently disagree with the current consensus are more strongly tolerated within science than in other professions. Fred Hoyle was famous for staunchly rejecting the Big Bang theory, yet he was kept around just because he disagreed. More importantly, Hoyle at least tried to produce a competing theory. He was wrong, but at least he was spectacularly wrong.

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 Message 20 by tesla, posted 06-08-2011 5:07 PM tesla has replied

Replies to this message:
 Message 26 by tesla, posted 06-08-2011 5:58 PM Taq has replied

  
Taq
Member
Posts: 9973
Joined: 03-06-2009
Member Rating: 5.7


(1)
Message 27 of 113 (619140)
06-08-2011 6:01 PM
Reply to: Message 25 by tesla
06-08-2011 5:55 PM


Re: Not so fast....
I'm simply pointing out that light can be tricky. All our stellar observations are of very old light (distance of a million light years means we see what that looked like one million years ago, not in current time)
Every single observation we make anywhere is of old light. You seem to be throwing up arbitrary distances so that you can ignore the evidence.
I'm saying: nobody truly knows, and there are still a lot of other potentials besides invisible matter to explain the behavior. We don't know, everyone is guessing.
Scientists aren't guessing. They are creating hypotheses and testing those hypotheses (the bullet cluster example I mentioned is a perfect example). So far, dark matter has passed those tests.
For a similar theory in science perhaps you should do some research on neutrinos. These are weakly interacting particles that were used to explain missing energy in supernovae explosions. It has a lot of parallels with our current discussion on dark matter.

This message is a reply to:
 Message 25 by tesla, posted 06-08-2011 5:55 PM tesla has replied

Replies to this message:
 Message 29 by tesla, posted 06-08-2011 6:16 PM Taq has replied

  
Taq
Member
Posts: 9973
Joined: 03-06-2009
Member Rating: 5.7


Message 28 of 113 (619141)
06-08-2011 6:03 PM
Reply to: Message 26 by tesla
06-08-2011 5:58 PM


Re: Not so fast....
And so far they have failed to do that.
Quite the opposite. They have tested their hypotheses and they have passed testing. The bullet cluster collision above is a perfect example.
The data has to be interpreted. It doesn’t mean initial interpretations are correct.
Can you please show why the interpretations are wrong?

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Taq
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Posts: 9973
Joined: 03-06-2009
Member Rating: 5.7


Message 47 of 113 (619364)
06-09-2011 3:28 PM
Reply to: Message 29 by tesla
06-08-2011 6:16 PM


Re: Not so fast....
Initial post. That site [The initial analyses] is from: is dedicated to new science. I'm pointing out there is not any evidence.
What are you trying to say here?
LMAO an 'educated' guess is still a guess !
A verified hypothesis is not an educated guess. Do you even understand how science works?

This message is a reply to:
 Message 29 by tesla, posted 06-08-2011 6:16 PM tesla has replied

Replies to this message:
 Message 48 by tesla, posted 06-09-2011 3:31 PM Taq has replied
 Message 49 by slevesque, posted 06-09-2011 3:31 PM Taq has replied

  
Taq
Member
Posts: 9973
Joined: 03-06-2009
Member Rating: 5.7


Message 50 of 113 (619368)
06-09-2011 3:31 PM
Reply to: Message 31 by tesla
06-09-2011 2:49 AM


Re: Not so fast....
If all the space dust in a galaxy is collected, what is its gravitational capability?
The sum of the mass is the gravitational capability. This sum is much less than the amount of gravity that galaxies are producing as observed by spin rate and gravitational lensing.
"nothing visible can explain."
Yep, matter that does not absorb, reflect, or emit light. What is wrong with that?

This message is a reply to:
 Message 31 by tesla, posted 06-09-2011 2:49 AM tesla has replied

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Taq
Member
Posts: 9973
Joined: 03-06-2009
Member Rating: 5.7


Message 51 of 113 (619369)
06-09-2011 3:35 PM
Reply to: Message 49 by slevesque
06-09-2011 3:31 PM


Re: Not so fast....
Try not to play on words. You did say ''creating a hypothesis'', which is pretty much making an educated guess.
I have always found you to be a pretty honest person, so I will assume that you are making an honest mistake here. Let's see what I actually said:
"Scientists aren't guessing. They are creating hypotheses and testing those hypotheses."
You only quoted the creating part and left out the rest. Most would consider that to be a quote mine. A hypothesis that is tested and passes those tests is a verified hypothesis, not an educated guess.

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 Message 49 by slevesque, posted 06-09-2011 3:31 PM slevesque has replied

Replies to this message:
 Message 57 by slevesque, posted 06-09-2011 3:49 PM Taq has replied

  
Taq
Member
Posts: 9973
Joined: 03-06-2009
Member Rating: 5.7


(1)
Message 52 of 113 (619370)
06-09-2011 3:39 PM
Reply to: Message 48 by tesla
06-09-2011 3:31 PM


Re: Not so fast....
A verified hypothesis is not a hypothesis.
I never said that it was. What is so hard to understand here? This is Science 101.
I posted a picture and posted a link describing research into dark matter. I described how it tested for the presence of dark matter, and how dark matter was verified. How is this an "educated guess"? Most would call it strong evidence, and most astronomers do.

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 Message 48 by tesla, posted 06-09-2011 3:31 PM tesla has replied

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Taq
Member
Posts: 9973
Joined: 03-06-2009
Member Rating: 5.7


Message 53 of 113 (619371)
06-09-2011 3:41 PM
Reply to: Message 45 by tesla
06-09-2011 3:22 PM


Re: Not so fast....
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.
What is wrong with the explanation that this gravitational influence is due to matter that does not absorb, emit, or reflect light as well as having very weak interactions with luminous matter? What do you find so objectionable? It fits the data perfectly.
Edited by Taq, : No reason given.

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 Message 45 by tesla, posted 06-09-2011 3:22 PM tesla has seen this message but not replied

Replies to this message:
 Message 60 by Percy, posted 06-09-2011 4:20 PM Taq has replied

  
Taq
Member
Posts: 9973
Joined: 03-06-2009
Member Rating: 5.7


Message 54 of 113 (619374)
06-09-2011 3:45 PM
Reply to: Message 39 by slevesque
06-09-2011 2:37 PM


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
Astronomers are able to map where dark matter is in the universe, and yet you think there is little basis for its existence. Perhaps the problem isn't with the evidence?

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 Message 39 by slevesque, posted 06-09-2011 2:37 PM slevesque has not replied

  
Taq
Member
Posts: 9973
Joined: 03-06-2009
Member Rating: 5.7


Message 59 of 113 (619384)
06-09-2011 4:15 PM
Reply to: Message 57 by slevesque
06-09-2011 3:49 PM


Re: Not so fast....
It's that I think that what Tesla calls an 'educated guess' is the ''creating a hypothesis'' part of how scientists work.
So what shall we call the verified hypothesis? Still an educated guess?
I'm pointing out that he is right: it is an educated guess, and scientists continually work on educated guess with an increasing level of confidence the more it is tested and verified. Nonetheless, he is right on that.
They did work on it, and it passed testing. So what do we call it now? And no, tesla is not right. I distinctly stated that it was a tested hypothesis, one that passed testing. He called this an educated guess, which it is not.

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 Message 57 by slevesque, posted 06-09-2011 3:49 PM slevesque has replied

Replies to this message:
 Message 74 by slevesque, posted 06-09-2011 10:27 PM Taq has replied

  
Taq
Member
Posts: 9973
Joined: 03-06-2009
Member Rating: 5.7


Message 62 of 113 (619394)
06-09-2011 4:35 PM
Reply to: Message 60 by Percy
06-09-2011 4:20 PM


Re: Not so fast....
The term "dark matter" no longer encompasses only possibilities that are matter.
That, in itself, would be a very tortured discussion. Matter and energy are interchangable, and forces are the result of the interchange of particles. Even more, if my understanding is correct String theory proposes that matter is made up of extra dimensions rolled up into strings. It would be one of those discussions where the colloquial and scientific uses of words form a Gordian knot.

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Taq
Member
Posts: 9973
Joined: 03-06-2009
Member Rating: 5.7


Message 64 of 113 (619398)
06-09-2011 4:39 PM
Reply to: Message 58 by slevesque
06-09-2011 4:13 PM


But I also do keep in mind what Einstein said to Heisenberg: it is the theory which decides what we can observe.
That probably needs some context. For Heisenberg's uncertainty principle it is certainly true. The theory states that one can observe the momentum or the location of a particle, but not both. For Einstein, one can observe the particle or wave characteristics of light, but not both at the same time.
If you really search for something long enough, you'll find it, even if it's not there.
Which is why phlogiston theory is so popular in science. Oh, wait . . .

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