Does dark matter come in two types?
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From: Yousuf Khan on 30 Jun 2010 16:45 On 6/26/2010 7:40 AM, eric gisse wrote: > Yousuf Khan wrote: >> Atoms are some of the most flexible particles we have been given in >> nature. These particles are lower than atoms, they do not exist not as >> flexibly. >> >> Let me put it to you in ways even you should be able to understand. You >> can't build a Lego house or a Lego car with a single Lego brick. Atoms >> are our Lego houses or Lego cars, these particles are just our Lego >> bricks. > > There are massive, stable particles that are not atoms. > > I am repeating trivial points because they seem to be not sinking in on your > end. Yeah? What are they, can you name one? What's the biggest, most stable subatomic particle in existence? The neutron, while it's inside a nucleus of course. But that's a pretty bog standard particle. Can you think of something more exotic that's also stable? >>> No, I'm sticking with what I said. Your babble about 'signal to noise >>> ratio' is just silly and stunningly ignorant. Ask a particle physicist if >>> my assessment is unkind - there are a few around here. >> >> No honest particle physicist would disagree with anything I've said. I > > That particular union just leaves behind the group of stupid particle > physicists. So you're saying that all particle physicists need to be liars and scoundrels? It certainly explains your case well enough. But I somehow don't think you represent them though. >> bring up the word "honest" very deliberately, to mean those particle >> physicists who are not involved in the search for further funding >> requests for newer, more powerful accelerators. > > No, what you say is stupid for a handful of reasons less what I'm not > mentioning. > > 1) higher power accelerators have higher luminosity. look up the term. <snip> The point that's not getting through to you is: what if there aren't any more particles left to discover? Why would that happen? No SUSY, maybe no Higgs. Because maybe particle physics took a wrong turn when going beyond the Standard Model. Maybe they're betting on the wrong horse entirely. You can have all of the luminosity you like, but you're just going to be discovering the same particles over and over again. But will they ever realize that they've bet on the wrong horse, or just keep waiting for that horse to show up? Will they keep asking for higher luminosities to coax that horse to show up? >> We now have a 7 TeV accelerator at the LHC. Supposedly created entirely >> to search for a supposedly sub-200 GeV theoretical particle. What if > > The accelerator wasn't built just to look for the Higgs. Do some research > before spouting. They really have no idea what they're going to look for beyond the Higgs. They're hoping after they discover the Higgs, that other new particles might pop out with it. In other words, they are hoping that the Higgs will define their next mission statement. The Higgs is the gateway from the Standard Model to SUSY: if they don't find the Higgs, then they won't find anything from SUSY either. Even if they find the Higgs, SUSY is still not guaranteed. >> that particle doesn't show up under 200 GeV? Are they going to keep >> looking for it at the same accelerator at higher and higher energy >> levels? They will upto a certain point, but at what point will they >> decide that they need the next generation 14 TeV accelerator, > > The collisions are {to be} 14 TeV. > > 7 + 7 = 14 > >> to keep >> searching for it? The signal-to-noise ratio will just keep growing > > Stop using the term 'signal to noise'. You do not know what it means. I know it perfectly fine. Do you know anything about thermodynamics? It doesn't look like it considering what you say below: >> Obviously you don't know what you're talking about as you can't produce >> any sources to back you up. You're covering your ignorance with posturing. >> >> And beyond that, your understanding of the cosmological constant as >> being "negative energy density" is all wrong anyways. The cosmological >> constant is described as caused by positive energy density, with >> negative pressure. Here's even a source just for giggles, since it >> obviously doesn't stop your posturing. > > Energy = pressure / c^2 > > Negative pressure means negative...energy? Oh really? Genius! I'm sure every automotive manufacturer since the invention of the piston engine would be thrilled to find out that their engines have actually been producing negative energy on each downstroke of the piston. Forget about thermodynamics, that's so 19th century, they're now using cosmological energy! They can add it to their marketing literature. >>>> You're the only one saying vacuum energy is producing the expansion, >>>> while at the same time you're saying vacuum energy gravitates; in case >>>> it isn't completely obvious to you, energy gravitating and producing an >>>> expansion are direct opposite statements. >> >>> http://www.astro.ucla.edu/~wright/cosmo_constant.html >> >> He said exactly what my previous link said, "it's a positive energy >> density, but a negative pressure". > > http://hyperphysics.phy-astr.gsu.edu/hbase/press.html > > He mentions a positive _cosmological constant_, which corresponds to > _negative_ energy density. The placement on the left hand side of the field > equations is relevant. What are you smoking? There's no mention of a cosmological constant, let alone negative energy in there. This is a link to basic fluid mechanics. >> That's not energy gravitating, that's >> energy anti-gravitating. > > The term gravitation does not mean attraction only. Do not abuse the > language. You mean abuse it more than "negative energy density"? >>> "Local dark matter and dark energy as estimated on a scale of ~1 Mpc in a >>> self-consistent way", A. Chernin et.al., A&A 507-1271-1276 >>> >>> My notes as written, as I don't have A&A in front of me : >>> >>> "Estimating the mass of the local group to ~10^12 M_sun using >>> observations that show the gravitational radius of the system >>> 3.1< M< 5.8 x 10^12 M_sun. Consistent with other observations. >>> The local value for dark energy is 0.8< rho_local< 3.7 >>> rho_global, where rho_global is the global value for dark energy >>> density. Dark energy provides a correction to the system's >>> effective mass via virial theorem estimates" >>> >>> So much for your guess. >> >> It won't convince anyone because that's just an energy *calculation*. In >> other words, it's not an actual energy *measurement*. These are >> theoretical calculations not empirical measurements. >> >> It's an impossible task right now to measure actual vacuum energy (even >> locally), as we haven't invented the equipment yet. So theoretical >> calculations is what we have to live with right now, but don't fool >> yourself into thinking that any of those calculations have any basis in >> reality. >> >> Yousuf Khan > > You didn't even look. > > Don't draw conclusions from things you did not read and did not make any > effort in understanding. So you're saying that book from /A. Chernin et al./ says they've _actually measured_ the vacuum energy? With an instrument? Really, that's the story you're going to tell me? What instrument would that be? Did they borrow it from Doctor Who? Don't tell me it's a telescope, as that's not going to give you a direct result. Yousuf Khan
From: Raymond Yohros on 1 Jul 2010 21:55 On Jun 24, 12:43 am, Yousuf Khan <bbb...(a)spammenot.yahoo.com> wrote: > On 6/24/2010 7:28 AM, eric gisse wrote: > > > Yousuf Khan wrote: > > > [...] > > >>> Define what dark matter 'should' predict here. > > >> Quite simple really, Dark Matter should predict all of the Dark Matter > >> remains attached to only the galaxies in the cluster, it should go > >> nowhere else -- ever. > > > Wrong. Dark matter will keep going through a shock while the baryonic matter > > is slowed down. That's what was seen in the bullet cluster, if you actually > > look at the picture. > > You'll have to be more specific than that. Which baryonic matter? The > galaxies or the intergalactic gas? Dark Matter will stay with the > galaxies, but it doesn't care if intergalactic gas collides or not. It's > not galaxies that are colliding in the Bullet Cluster, it's just gas. > why you say that? do you really think dark matter stay with the galaxy? wimps may not exist at all! neutrinos may not be the kind of dark matter everyone expects but they move and spread out like light! almost nothing stops them r.y
From: Yousuf Khan on 2 Jul 2010 07:47 On 7/2/2010 7:55 AM, Raymond Yohros wrote: > On Jun 24, 12:43 am, Yousuf Khan<bbb...(a)spammenot.yahoo.com> wrote: >> You'll have to be more specific than that. Which baryonic matter? The >> galaxies or the intergalactic gas? Dark Matter will stay with the >> galaxies, but it doesn't care if intergalactic gas collides or not. It's >> not galaxies that are colliding in the Bullet Cluster, it's just gas. >> > > why you say that? > do you really think dark matter stay with the galaxy? Yes, that is their only purpose in life: to beef up the mass of galaxies. Intergalactic gas is actually more massive than the galaxies, but not very dense. Dark Matter is supposed to stay with the dense regions that are galaxies. > wimps may not exist at all! We're pretending here, for argument's sake. That's all. > neutrinos may not be the kind of dark matter > everyone expects but they move and spread out > like light! > > almost nothing stops them That's why they were known as the "hot" dark matter candidates, since they are relativistic. Yousuf Khan
From: Raymond Yohros on 2 Jul 2010 14:18 On Jul 2, 6:47 am, Yousuf Khan <bbb...(a)spammenot.yahoo.com> wrote: > > do you really think dark matter stay with the galaxy? > > Yes, that is their only purpose in life: to beef up the mass of > galaxies. Intergalactic gas is actually more massive than the galaxies, > but not very dense. Dark Matter is supposed to stay with the dense > regions that are galaxies. > but that beefing up comes from baryonic matter and gravitation observation shows that stars do not move faster near the centers of galaxies all the times and thats when people start speculating about intergalactic dark matter. > > > wimps may not exist at all! > > We're pretending here, for argument's sake. That's all. > yes but for how long will this go on? not even the LHC has shown any sign that this particles may exist > > > neutrinos may not be the kind of dark matter > > everyone expects but they move and spread out > > like light! > > > almost nothing stops them > > That's why they were known as the "hot" dark matter candidates, since > they are relativistic. > maybe there is no such thing as cold dark matter just normal hot and cold matter and a huge load of neutrinos! r.y
From: BURT on 2 Jul 2010 18:06
On Jul 2, 4:47 am, Yousuf Khan <bbb...(a)spammenot.yahoo.com> wrote: > On 7/2/2010 7:55 AM, Raymond Yohros wrote: > > > On Jun 24, 12:43 am, Yousuf Khan<bbb...(a)spammenot.yahoo.com> wrote: > >> You'll have to be more specific than that. Which baryonic matter? The > >> galaxies or the intergalactic gas? Dark Matter will stay with the > >> galaxies, but it doesn't care if intergalactic gas collides or not. It's > >> not galaxies that are colliding in the Bullet Cluster, it's just gas. > > > why you say that? > > do you really think dark matter stay with the galaxy? > > Yes, that is their only purpose in life: to beef up the mass of > galaxies. Intergalactic gas is actually more massive than the galaxies, > but not very dense. Dark Matter is supposed to stay with the dense > regions that are galaxies. > > > wimps may not exist at all! > > We're pretending here, for argument's sake. That's all. > > > neutrinos may not be the kind of dark matter > > everyone expects but they move and spread out > > like light! > > > almost nothing stops them > > That's why they were known as the "hot" dark matter candidates, since > they are relativistic. > > Yousuf Khan Dark matter is wrong because it would be everywhere with an origin with normal matter gravitationally coallescing. It would make up most of everything including the Sun and solar sytem. But it does not. There is a better explanation than dark matter for what we see. Mitch Raemsch |