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Noteworthy
Sophyphile


Registered: 10/05/08
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Dark Matter
#14871988 - 08/04/11 12:11 PM (12 years, 9 months ago) |
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Shouldnt it be called 'invisible mass'???
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Noteworthy
Sophyphile


Registered: 10/05/08
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or 'discrepancy between brightness data and motion data'?
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DieCommie

Registered: 12/11/03
Posts: 29,258
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What is in a name? That which we call dark matter by any other name would still be dark.
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audiophoenix
Find Peace



Registered: 08/28/09
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Loc: Upstate NY
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does dark matter actually have mass, by conventional definitions? I am a bit ignorant in the matter... (pun intended)
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DieCommie

Registered: 12/11/03
Posts: 29,258
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Quote:
audiophoenix said: does dark matter actually have mass, by conventional definitions? I am a bit ignorant in the matter... (pun intended)
Yea, mass/energy - that is how it is able to exert gravitational pull. It reacts very weakly or not at all with the electromagnetic field.
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Noteworthy
Sophyphile


Registered: 10/05/08
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Last seen: 11 years, 3 months
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Quote:
DieCommie said: What is in a name? That which we call dark matter by any other name would still be dark.
because a lot of people look towards science for understanding without fully understanding it. In order to convey the correct meaning to the masses, it is good to have words that appropriately convey meaning.
The most correct notion of dark matter is not that it is dark (because something black is dark and can be detected) but that it has no colour or brightness qualities at all.
Also, the word matter suggests that dark matter is composed of particles. However it could be anything really. We have very little data on it other than in the discrepencies of various models.
The discrepancy is a mass calculation.
To help the science enthusiast understand, it may be useful to paint a true picture rather than try to impress them with the most contemporary buzz words and theoretical descriptions.
So perhaps it would be best to say to them:
The theory of general relativity has been incredibly useful in predicting the motion of heavenly bodies. In order for us to see a heavenly body, it must reflect or emit electromagnetic radiation.
So if we use general relativity to calculate the speed of stars around galaxies we find that the visible heavenly bodies do not account for the information needed to make General Relativity an accurate model.
On the other hand, if scientists add a lot of mass to a galaxy, the calculations become accurate. So all the added mass is called Dark Matter.
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DieCommie

Registered: 12/11/03
Posts: 29,258
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Quote:
So perhaps it would be best to say to them:
The theory of general relativity has been incredibly useful in predicting the motion of heavenly bodies. In order for us to see a heavenly body, it must reflect or emit electromagnetic radiation.
So if we use general relativity to calculate the speed of stars around galaxies we find that the visible heavenly bodies do not account for the information needed to make General Relativity an accurate model.
On the other hand, if scientists add a lot of mass to a galaxy, the calculations become accurate. So all the added mass is called Dark Matter.
Yes, this is how Dark Matter is usually described to the layman.
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Noteworthy
Sophyphile


Registered: 10/05/08
Posts: 5,599
Last seen: 11 years, 3 months
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so why would you still call it dark matter when it is neither dark nor matter...
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DieCommie

Registered: 12/11/03
Posts: 29,258
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Quote:
Noteworthy said: so why would you still call it dark matter when it is neither dark nor matter...
Because I followed your description...
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to see a heavenly body, it must reflect or emit electromagnetic radiation. ... we find that the visible heavenly bodies do not account
So its dark.
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if scientists add a lot of mass to a galaxy, the calculations become accurate.
So its matter.
Easy.
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Noteworthy
Sophyphile


Registered: 10/05/08
Posts: 5,599
Last seen: 11 years, 3 months
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dark things absorb light, matter refers to certain types of substances that can produce solid objects. You might think 'matter' just means 'substance'. But then why use a confusing word like matter, which makes people think of solid stuff with physical boundaries?
It seems like you are resisting the fact that the words are bad, because you don't see the point in changing them?
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DieCommie

Registered: 12/11/03
Posts: 29,258
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Quote:
dark things absorb light
Darkness is the absence of light. This is the context that 'dark' is used. Like a dark room, a dark room doesn't absorb light - it has an absence of light.
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why use a confusing word like matter, which makes people think of solid stuff with physical boundaries?
Because its hypothesized to have just as much of a physical boundary as 'regular' matter (like atoms and neutrinos).
I think the words are fine. They quickly and succinctly convey the key properties of the 'stuff'.
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ChuangTzu
starvingphysicist



Registered: 09/04/02
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Probably 95% of scientific terms are at least somewhat misleading to a non-scientist. The other 5% are completely nonsensical to a non-scientist. Call it whatever you want, it doesn't confuse anyone except those bound to be confused...
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Noteworthy
Sophyphile


Registered: 10/05/08
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Yes because most people just swallow the ideas as if they are an answer.
But they arent an answer. It doesnt answer anything to say that some scientist hypothesises dark matter to be like normal matter. There is no way to falsify this hypothesis (at present) so should it even be considered a scientific hypothesis?
Why isnt it valuable to seperate well defined, well verified scientific concepts from those imaginative paradigms used by theoretical academics?
The value of the imaginative paradigms is high, but it is different to the value of verified paradigms.
Why not care about the ability to convey science to the less-science-literate? Why not care about having a transparent, honest rapport between the scientist, the journalist, and the audience?
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DieCommie

Registered: 12/11/03
Posts: 29,258
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Quote:
Why not care about the ability to convey science to the less-science-literate? Why not care about having a transparent, honest rapport between the scientist, the journalist, and the audience?
We do care about the ability to convey to the lay public. But science, and particularly physics, is highly mathematical and most people are mathematically illiterate. So you have to translate for them, and you simply cant convey the same ideas in english as you do in mathematics (if you could we wouldnt need math). Its like a language, no matter how hard somebody tries to explain Don Quixote to me - If I cant speak spanish I will never be able to absorb it as it was written. If you cant speak mathematics, you will never be able to absorb physics as it is.
We could be more accurate, and instead of calling it dark matter call it , but that better description is meaningless to non-scientists.
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Sophyphile


Registered: 10/05/08
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or you could call it a discrepancy.
It is a big deal, imo, that 90% of the apparent gravitational effects are not accounted for by verifiable causes.
Dont you think there is value in separating good, repeated, confirmed science from the popular theoretical stories that get told amongst intelligensia?
Or do you think that there is no clear line to be drawn and everything that physicists discuss is just as legitimate?
or perhaps is all science just as questionable when it is contemporary?
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DieCommie

Registered: 12/11/03
Posts: 29,258
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Quote:
Dont you think there is value in separating good, repeated, confirmed science from the popular theoretical stories that get told amongst intelligensia?
Yea, there is value in that. And I think that the scientific community does a fine job of it.
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ChuangTzu
starvingphysicist



Registered: 09/04/02
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Quote:
DieCommie said:
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Dont you think there is value in separating good, repeated, confirmed science from the popular theoretical stories that get told amongst intelligensia?
Yea, there is value in that. And I think that the scientific community does a fine job of it.
I agree.
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