Author: Dave Gomboc
Date: 15:31:23 11/28/99
Go up one level in this thread
On November 28, 1999 at 18:00:25, Eelco de Groot wrote: > >On November 28, 1999 at 02:04:09, KarinsDad wrote: > >>Eelco, >> >>Not to belabor this a lot, but the entire issue is one of 90 to 99% of "matter" >>is dark matter (according to the theorists). However, it only affects two known >>light phenomena in space out of dozens (and only one of these is via fairly >>direct gravitational effect, the other is pure mathematics based on a theory). > >You are right, KarinsDad, I was using the term dark matter somewhat liberally. >The reason was that I was mentally including some things I had read about (see >Scientific American January 1999 for instance). There were some new >developments: observations of supernovae at far distances seem to indicate that >they are not moving away from us as fast as their distance, measured by their >specific brightness, would predict. In other words expansion in the early >universe was less rapid, but I admit the evidence is just one lightphenomenon >again. But if true that would be evidence for a type of antigravitation, or an >effect similar to what Einstein described as his "cosmological constant". This >could be seen as a form of "dark matter" that is actually a form of energy and >is present even in the vacuum of space. > >That would give the following list: > >Type Likely composition Main Evidence > >Visible matter Ordinary matter Telescope observations > visible in stars etc. > >Baryonic Ordinary matter Big bang nucleosynthesis >dark matter but too dim too see calculations,deuterium abundance > >Nonbaryonic Various exotic Orbital speeds of stars and galaxies >dark matter particles too high > >Cosmological Energy of empty Microwave background observations, >"dark matter" space Supernovae > > >The expansion of the universe might even be accelerating if this is true. >That would make life in the very, very distant future difficult. > >>For example, scientists cannot find out if neutrinos have mass at all, but >>consider them to be a main candidate for some major fraction of dark matter. >>Does it not seem strange that scientists can measure the mass of a proton, but >>not the mass of a neutrino when neutrinos should outnumber (in quantity) normal >>protons by a billion to one? One would think that if there are so many of them, >>that the mass could be measured via quantity somehow. > >That would probably due the fact that neutrinos are very hard to catch, I >believe I read somewhere they can fly through lightyears of lead without being >stopped. They interact very little with other matter so measurements are very >difficult. Another thing is that there are various forms of neutrinos, some even >harder to measure than others and they may even interchange. > >> >>The entire thing is just an attempt to keep the big bang theory (or even the >>inflationary universe theory) alive (via mathematics) and to give people >>something to write their PhD thesis' on in physics. It is extremely difficult to >>remove a theory that held sway for such a long time. Look how long it took for >>the solid state theory to go away. > >Maybe but there aren't many good candidates to replace it. But true, there are >many variants of the Big Bang theory that people test against observations. > >> >>If you are interested, you can read the following web page on dark matter and >>mysticism. It will show you the level at which people will believe almost >>anything (even PhDs). >> >>http://www.thuntek.net/sumeria/cosmo/darkmatter.html >> >>Finally, consider the following. If scientists are merely deluded into thinking >>that the universe is really expanding (similar to how scientists one day thought >>the earth was flat or the center of the universe), then if the universe is not >>really expanding (just appears to be expanding), then dark matter (and the big >>bang theory) is a total sham based on a false premise. In our arrogance, could >>it be that we have created the 20th century version of the flat earth theory? > >There would have to be another explanation for the universally observed >redshifts then and that would have to give rise to completely new theories >about that I think. > > > >> >>KarinsDad :) >> >>PS. I haven't had a good off topic discusion since I became moderator. I felt >>like loosening my collar for a change. I used to post a few off topics a month. >> >>PSS. Although dark matter theories have been around for years, the quantity of >>dark matter is not only an estimate, but that estimate has been changing every >>time they come up with a different size of the universe > >It is more the density of dark matter that is important. If it isn't high enough >the universe will keep expanding indefinitely > >I think only the observable universe is important for the calculations. The size >depends on the calculated age of the universe for instance, estimates vary. > >> (which probably doesn't have a set size, or at least not a measurable one). >This is what I meant by >>bleeding edge in my previous message. The theory changes everytime a >>technological advance puts a better telescope up. > >That's why they put them up :) > >Eelco > >Sorry for late response, apart from the two of us is anybody still following >this by the way? :) Completely spaced out thread this. I'm reading. I don't have anything to contribute, though. Dave
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