Dark Matter Exploration of Chinese satellite DAMPE

Mar 2019
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"Why is indeed the question that underpins all physics.
There is an English saying "why has a long tail" (or should that be tale?)
If you answer one why, it always leads to another.
The answer at the end of the tail is always going to be "We don't know".
I suspect that we can delve into the mysteries of the universe for millions of years, and still find "we don't know" at the end of the tale."
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@ Woody:
The most horrible attitude might be to keep the dead rule for ever and reluctant to change the mind.
The most vivid archetype worldwide in 21th centry might be some of my former classmates in No.1 middle school of Xinhui (新会一中). Given without their connivance and even support, I think the local dark lord (江门地方黑恶势力钟永康) can not be so arrogant...
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I like to try to push one step forward even sometimes the "harmoneous tones" seems not so good.
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I think the down trend hints: at least the mass of the visible world is not infinite...
 
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Rabbit htam9876 @ neila9876:
I think that if you were in Omarha beach, you have at least 1 percent probability of survival. 呵呵
你江门地方黑恶势力钟永康及新会一中九一四班全世界打靶啦
 
Jun 2016
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687
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The idea of the possibility of links between Dark Energy and Dark Matter is very attractive,
and I have seen several articles about studies within in which this possibility was being very seriously explored,
however they all admit that no obvious evidence of any such link has yet been found, either experimentally or theoretically.
 
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Rabbit htam9876 @ Professor woodpecker:
There might be a bit confusing above, I think.
Since the terminology "dark energy" has been occupied by the "authentic hole" for other purpose, I should use another "eccentric" term: "dark light".
We can see "dark light", so I have no idea how to do such experiment...
Theory? Oh, I have deposited it in Mendeley...
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Neila9876 @ Rabbit htam9876:
You playboy, don't come causually to my thread and play...otherwise I will make you as dead as a Dodo.
 

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Oct 2017
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Rabbit htam9876 @ Professor woodpecker:
There might be a bit confusing above, I think.
Since the terminology "dark energy" has been occupied by the "authentic hole" for other purpose, I should use another "eccentric" term: "dark light".
We can see "dark light", so I have no idea how to do such experiment...
Theory? Oh, I have deposited it in Mendeley...
The term "Dark", when describing dark matter or dark energy, are just names for things that are unknown. Rotation curves of galaxies suggest that there's more mass than the one which is shining and can be observed by telescopes, so this "missing" mass is termed "dark matter". Supernova 1a distance measurements seem to suggest that the Universe is accelerating, which requires additional energy in inflationary cosmological models. This "missing" energy is called dark energy.

So, if you want different names, maybe consider "missing matter" or "missing energy"?

Also, dark matter cannot be seen... that's the point. If it's observable, it's no longer missing (when we observe it) and therefore not dark matter... if we observe some new component of matter that was previously not observed, the amount of dark matter gets reduced.

Neila9876 @ Rabbit htam9876:
You playboy, don't come causually to my thread and play...otherwise I will make you as dead as a Dodo.
That's mean...
 
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Oh, rabbit omitted a "not".What he said should be "we can not see dark light..." , I think. That's mean he often drunk...
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" ... Rotation curves of galaxies suggest that there's more mass than the one which is shining and can be observed by telescopes, so this "missing" mass is termed "dark matter". "
Yes. Good.
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Also, dark matter cannot be seen... that's the point. If it's observable, it's no longer missing (when we observe it) and therefore not dark matter...
Yes. Good.
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"So, if you want different names, maybe consider "missing matter" or "missing energy"?"
Not appropriate.
Theorectically, dark light exist in cosmos, not missing, just we can not see it.
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" Supernova 1a distance measurements seem to suggest that the Universe is accelerating,"
More details, please. You are always doing well in this respect. Thank you.
 
Oct 2017
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"So, if you want different names, maybe consider "missing matter" or "missing energy"?"
Not appropriate.
Theorectically, dark light exist in cosmos, not missing, just we can not see it.
Okay. I suppose there's no reason why you couldn't call unobserved radiation "dark light", but it's a strange term because usually the term "dark" is used when there is some kind of missing puzzle piece in an otherwise acceptable theory. The question is, then, what theory requires more light than is observed?

If you're not sure what I mean, consider dark matter. Historically, it was suggested that one solution to the galaxy rotation curve problem was to account for objects that are not readily observed, such as dust clouds, planets, asteroids, comets, brown dwarfs, etc. After all, over intergalactic distances, these sorts of celestial objects are so distant and faint that it's impossible to observe them. However, one can estimate the total mass budget of a galaxy by (for example...) estimating the numbers of these components and seeing if the estimates are quantitatively comparable to the amount of missing matter. Unfortunately, even with very liberal estimates, the budget comes up short. Something is very, very wrong. This has led to the desire for studying Modified Newtonian Dynamics (MOND) and the search for exotic dark matter particles in the lab as possible solutions instead.

The term "dark matter" has consequently come to mean the component of matter that would then resolve the galaxy rotation profiles problem, rather than just being a name for unobserved matter because it is too faint to see with telescopes. Dark matter might not even be a single thing, it might be a combination of many different effects that all add-up to the missing component of mass required to solve the galaxy rotation profiles problem.

To make things even more confusing, some galaxies or galactic systems seem to be fully explained (i.e. their dynamics understood) without the need for dark matter at all. It's an extremely confusing and difficult problem. We may never see a solution to it in our lifetimes.

" Supernova 1a distance measurements seem to suggest that the Universe is accelerating,"
More details, please. You are always doing well in this respect. Thank you.
No problem. I'm not particularly knowledgeable about it, so perhaps try reading one of the original papers: https://arxiv.org/pdf/astro-ph/9805201.pdf
 
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Mar 2019
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@ benit:
"Okay. I suppose there's no reason why you couldn't call unobserved radiation "dark light",..."
It's very complicated and a bit subtle. Not appropriate topic in PHF, perhaps.
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"...dark matter.Historically, it was suggested that one solution to the galaxy rotation curve problem..."
I mainly use it to solve the problem of "how big is cosmos / what's outside the visible world". I have talked about that in the thread "tramp and electron"...
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No matter scientists originally used the word "dark" to denote what meaning, seems that they used the right word.
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I will shift the topic of Supernova 1a distance measurements to the lounge later because it might be a bit off topic here. Thank you.
 
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Dark matter doesn't emit anything that we can see,
however it might emit something we can't see...
(or perhaps we just don't know we should be looking for it, or how to look for it).

If dark matter does emit something, what should we call it?
perhaps dark light?
 
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