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Author Topic:   Dark matter a dying theory?
Taq
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Posts: 8482
Joined: 03-06-2009
Member Rating: 6.1


Message 85 of 113 (619552)
06-10-2011 11:18 AM
Reply to: Message 74 by slevesque
06-09-2011 10:27 PM


Re: Not so fast....
I guess you could call it a verified educated guess.

Who is playing word games now?

But if, by putting a kettel of water on the stove, I hypothesise that it will boil eventually, then whether it turns out to be true or false the fact remains that it was an educated guess.

I am 37 years old. Once I was just 6 months old. At one time I was a baby. Does that mean I am still a baby?


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 Message 90 by slevesque, posted 06-14-2011 1:42 AM Taq has not yet responded

  
Taq
Member
Posts: 8482
Joined: 03-06-2009
Member Rating: 6.1


Message 104 of 113 (621751)
06-28-2011 3:54 PM
Reply to: Message 97 by slevesque
06-14-2011 2:02 PM


Re: Not so fast....
I did read your message, but it does not contain the answer to this specific quesiton, simply because it contains an example of an educated guess (predicting where your wife will be) and a fact (looking on the gps), but it failed to highlight the supposed substantial distinction between eduacted guess and hypothesis.

The difference is right there in your description. The difference is the testable nature of the proposal, and then the test itself. A hypothesis is a TESTABLE PROPOSAL, not an educated guess.

I repeated many times that saying a hypothesis is an educated guess isn't a negative thing, so I am not tryign to denigrate anything.

It isn't accurate, either. If they are one in the same in your eyes then why not use the term that all scientists use: hypothesis.

As to dark matter, scientists are proposing testable explanations, and then testing those explanations. That makes it a scientific hypothesis.


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Taq
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Posts: 8482
Joined: 03-06-2009
Member Rating: 6.1


Message 105 of 113 (621752)
06-28-2011 3:58 PM


It would seem to me that supermassive blackholes at the center of galaxies suffer the same "problems" that dark matter suffers from. You can't directly observe a black hole because they do not radiate light. However, they do have a strong gravitational field. When you map the movements of stars in the center of the Milky Way they are all orbiting around a single point, but no luminous matter can be observed at this single point. When you calculate the mass needed to produce these orbits you find that only an object with several million solar masses can produce the observed orbits.

So would those who argue against dark matter being actual matter also argue against supermassive blackholes (also the result of matter) for the same reasons?


  
Taq
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Posts: 8482
Joined: 03-06-2009
Member Rating: 6.1


Message 112 of 113 (621953)
06-29-2011 5:20 PM
Reply to: Message 110 by SecondPeterThreeFive
06-29-2011 5:08 PM


Not at all. I do not denegrate faith in God one bit.

You denigrate faith by using it as an insult.

Actually, the ancient age of the universe is the dogma being clutched to.

The age of the universe is a conclusion drawn from evidence, not a dogma. If you want to dispute the age of the universe then please put forth data that contradicts the current calculated age.

There is little differential speed observed in the arms of spiral galaxies, a fact that would be impossible if the universe was 20-30 billions of years old.

Evidence please.

The "answer" is that there must be a "sphere" of matter around the plane of the visible arms to account for the observed rotation. This matter must be "dark matter" to explain why we cannot see it.

Actually, we can see it. We can see it through gravitational lensing as discussed in this article:

http://home.slac.stanford.edu/...sreleases/2006/20060821.htm

Scientists are actively mapping the distribution of dark matter using gravitational lensing.

If you can entertain for one second the possibility of a young universe, then the rotational speed of spiral arms offers no puzzle at all, and is even consistent with the hypothesis.

In a young universe we should not even be able to see these galaxies due to the fact that they are millions of light years away.


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