07-24-12, 04:54 PM #21
07-24-12, 06:03 PM #22
post #5, AlphaNumeric clearly explains that dark matter does not interact much according to observation other than with gravity. This leaves open that it might interact via the weak force -- like neutrinos which only interact via the weak force and gravity. But AlphaNumeric also clearly explains that he thought he was told that neutrinos have been discarded as the main constituent of dark matter. The reason why is because they are too light and therefore don't clump as required by cosmological models.
If dark matter is WIMPs then you can never collect it because no material walls would impede it. It would be like trying to box up a sample of helium when all you have for the container is chicken wire mesh.
Current evidence strongly supports the hypothesis that most galaxies (including ours) have higher-than-average dark matter densities. A recent study of local stars showed evidence that there is about as much local intragalactic dark matter as predicted by the best models.
Ask Google what 0.3 GeV/cm^3 times the volume of the Earth is.
07-25-12, 06:56 PM #23
07-25-12, 07:29 PM #24
I shall answer assuming you meant "Is the assertion that massless phenomena are associated with a source of gravitation consistent with General Relativity."
Yes, because the Einstein curvature tensor is proportional to the stress–energy tensor which has terms for momentum density, so that massless phenomena with momentum density like electromagnetic waves are associated with non-zero curvature.
07-25-12, 07:30 PM #25
Having massless particles in a field theory does not cause a problem for general relativity. The mass given by the Higgs mechanism is not the same as gravitational mass. I've already explained this. Are you bothering to read what people say? This is your usual tactic of asking what you think are questions which lead to some conclusion you think proves something in the mainstream wrong. It never does but that doesn't stop you doing it. Thus far in this thread all your questions have done is show you don't know basic physics, you don't bother to find out what the Higgs mechanism involves before dismissing it and you're willing to ignore people you quote. Multiple times.
If you have some point to make then make it. If not please crawl back under whatever rock you reside beneath and let people who actually want to learn and understand things talk in peace.
07-30-12, 07:05 PM #26
Now, what massless particle is sufficient to stimulate gravity according the stress energy tensor that is sufficient that explain the 70-90% of the gravity stimulation in the universe that is not explained by mass.
We must remember, this particle does not couple with the electro-weak force, nor the strong nuclear force.
We have already demonstrated this particle must be massless because it would cause at least cause electron instability because of its mass.
Therefore, we must be able to supply parameters to the stress energy tensor that are sufficient to describe dark matter.
May I please see these parameters?
Thanks in advance.
07-30-12, 08:09 PM #27
You make nonsensical assumptions in the process of asking a question and as a result, I lack confidence that you are working from empirical facts. Why do you say massless when the evidence points to about 23% of the missing mass as cold dark matter which by definition is fairly massive as particles go? You have made no argument as to why it should be massless and ignored my calculations. The remaining approximately 70% is called dark energy but corresponds closest to the "lamdba" term in Einstein's equation at the heart of general relativity.
Why do you say it cannot interact via the weak force? I expect to see a calculation based on empirical observations or a scientific citation.
07-30-12, 09:59 PM #28
I have bolded and underlined that part of your post which I want to ask you about.
Can you explain what that electron instability would be that you allude to? By what mechanism would the instability be manifest between such 'massed' particles and the electron as you put it?
07-31-12, 06:52 PM #29
There's plenty of freely available lecture notes on the MSSM. Go find one using Google, read it and then come back if you're unsure about something. I doubt such a procedure will lead to fruitful discussion but hope springs eternal.....
08-02-12, 07:07 PM #30
08-02-12, 11:56 PM #31Non-massless dark matter will attack electrons and render them unstable.
08-03-12, 04:09 AM #32
Oh and since I probably shouldn't assume you know what MSSM means, it stands for Minimally Supersymmetric Standard Model.
/edit later that day....
This morning, while thinking about this, I couldn't think of any viable model of particle physics which has the electron being unstable. The motivation for calling into question even the very concept is decays typically split things down into their constituents (ala proton decay), along with a possible transmuting of a piece, or they convert a particle into it's lighter relative (ala muon to electron decay). Decays stop and the particle becomes stable when the sequence of decays reaches the lightest particle consistent with whatever symmetries are involved. In the case of the electron you have electromagnetic charge conservation so the electron would have to decay in something with electromagnetic charge. But it is the lightest electromagnetically charged particle, even allowing for quark masses (about 1MeV compared to the electron's 0.5MeV, ignoring strong force effects). But since I'm not infallible and various exotic particle models are always being proposed and falsified I asked someone I work with who happens to have a PhD in supersymmetric dark matter physics and he had the same thoughts, namely what would the electron decay into? Models of cold dark matter, such as various incarnations of supersymmetric extensions of the Standard Model, have the electron as being stable even in the precense of dark matter particles (typically the lightest supersymmetric particle). Supersymmetry allows certain types of decays to occur which wouldn't otherwise occur in the Standard Model but the instability of the electron is not one of them in any one put forth so far.
As such chinglu's claim is falsified, in the sense that he asserts it is an inevitability for any model to have an unstable electron if it includes cold dark matter. This is not so in the case of the MSSM so chinglu is mistaken. Of course this doesn't mean it's impossible to construct a dark matter model which does make the electron unstable but the instability would have to be extremely weak as we have experimental data which shows the typical life time of an electron is at least something like years. This is because we'd done experiments looking for proton decays to test some GUT models like ones with an SU(5) gauge group (as this is the simplest one which contains the Standard Model group ) and no detection of decays implying electron instability (since it is measured in the same way) were made. Thus even if chinglu can provide a model which allows the electron to be unstable in the presence of dark matter his assertion such thing is a necessity is false.
Last edited by AlphaNumeric; 08-03-12 at 05:34 PM.
08-05-12, 08:10 PM #33
If it does not, it needs to write equations for the energy stress tensor sufficient to implement the gravity stimulation necessary to implement the 70+% dark matter observed in the universe. Note, I am refuting RPenner's assertions on the dark matter compositions.
Now, can you write said equations or no.
Next, since these equations are not possible, we must assume dark matter has mass.
If it has mass, then any reasonable person would conclude if is occupies 70% of gravity, then it certainly exceeds the mass of an electron.
That proves if dark matter is true, it would disrupt the electron which is a contradiction, because the electron is stable.
Last your worthless belief in MSSM asserts the following,
"The only unambiguous way to claim discovery of supersymmetry is to produce superparticles in the laboratory. Because superparticles are expected to be 100 to 1000 times heavier than the proton"
Show me anything in nature as a particle that produces these masses for particles.
Otherwise, my argument holds true.
08-05-12, 11:01 PM #34
Chinglu has twice demonstrated that he cannot even read wikipedia articles on cosmology, let alone have a meaningful fact-based reasonable discussion.
Here Chinglu is twice corrected on the difference between "Dark Matter" (暗物质 roughly "dark/concealed/secret substance") and "Dark Energy" (暗能量 roughly "dark/concealed/secret energy"). Confusing these two is unacceptable.
08-06-12, 03:47 AM #35
I'm going to ask you one last time before I consider your posts little more than trolling..... please provide any model of particle physics which has an unstable electron when massive (100+ GeV) particles are involved. Please demonstrate the logical impossibility of such things as the MSSM, which have massive particles and a stable electron. If you fail to show you have grasped there's a difference between dark matter and dark energy then I'll conclude you aren't really bothering to look anything up, you're just making assertions without due consideration. If you want to do that go to the pseudoscience forum, such posts aren't for this forum. If I have to enforce that I will.
08-06-12, 08:03 PM #36
My posts have centered around gravity stimulation.
For every gram of glowing material we can detect, there may be tens of grams of dark matter out there.
Now, you claimed dark matter is able to stimulate gravity through the stress energy tensor.
I want to see your proof with the equations in order to prove the total amount of gravity stimulation in the universe.
Can you do this yes or no?
Once you do this, I want to see that your dark matter candidate does not make the electron unstable since it has mass.
Can you do this yes or no?
08-06-12, 08:09 PM #37
If this is even true, this does not have any effect on the dark matter particle(s).
These particle roam freely whereas bosons are constituent particles.
You are comparing apples and oranges.
If these dark matter particle(s) are free to roam, then they will interact with electrons. Otherwise, prove free neutrons will not interact with electrons.
08-07-12, 02:02 AM #38
www.arxiv.org for papers on dark matter and supersymmetry. You demand people provide a dark matter model with a stable electron, I say to look at the MSSM and you just ignore it. You have been given the information you need to answer your question. If you're unwilling to go read books or articles and demand everyone types out everything here for you then you're trolling.
08-07-12, 07:09 PM #39
You folks are wondering in fields of the illogical.
The entire issue here is what is the nature of dark matter if it is viable.
First, I suggested that dark matter must have mass. AN claimed that is false.
Then, I challenged AN to provide gravity stimulation that is equal to the dark mass with mass itself. The reason? Any mass running around the universe at the dark mass concentration would render the electron unstable because it would interact with the electron with its mass which is obviously not seen in nature.
AN and RPenner claimed the stress energy tensor can describe the gravity stimulation. Yet, dark matter does not interact with the weak nor strong nuclear forces. So, there is no stress energy tensor. Since energy it not emergent under the rules of physics, their argument completely fails.
That is where we are in this debate.
So, you 2 need to up the game a bit.
08-07-12, 07:27 PM #40
I think it's time to for the moderators to appeal to the admins for chinglu's final disposition. We rate him pants on fire.
By madanthonywayne in forum General Science & TechnologyLast Post: 07-22-12, 04:14 PMReplies: 64