DM Candidate?
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From: dlzc on 16 Mar 2010 18:38 Dear Simple Simon: On Mar 16, 4:17 pm, "Simple Simon" <pi.r.cubed-nos...(a)gmail.com> wrote: > dlzc wrote: > > On Mar 16, 1:46 pm, "Simple Simon" <pi.r.cubed-nos...(a)gmail.com> > > wrote: > >> Is it possible that some of the dark matter > >> is simply matter that is outside of our past > >> light cone but gravitationally bound to > >> objects within it? > > > No. Dark Matter is essentially equidistant > > to the "bound normal matter", to first > > approximation. Examples are spiral galaxies, > > whose Dark Matter has the same gravitational > > center, but more of a torus or crushed sphere > > than a flat lens. > > > Direct counter example to your posit, is that > > eventually you'd expect to encounter light > > from that normal matter, which must occur > > unless it is FTL. We have new objects being > > discovered for sure, but not "adjacent" to > > known matter. Just "improved imaging > > techniques". > > I gather from your response that it is > "possible" that there is such matter > (that is, nothing about space-time precludes > such a condition from existing) but that the > dark matter necessary to account for > observation must be distributed otherwise. Yes. It must be on our past light cone, it must be non-lumenous, it must be frictionless, and it must be massive. Whether it be stuff, or "field" remains to be revealed. > If that is correct, then I would expect > that it is "necessary" for there to > be such "ordinary" dark matter since there > is nothing to preclude it and it is frame > dependent. Is mass frame dependent? No wait, I don't want to go there. The lumenous matter we see, for a large part, is moving 300 km/sec give or take 2x. "Frame" considerations really don't need to be part of your logic chain. The Dark Matter appears to be "in orbit" around a common mass center, so "frame adjustments" to the lumenous center, adjust to the Dark Matter center of that local collection too. > Additionally, one would expect the > preponderance of such "ordinary" dark matter > to be a predictable extension to the existing > distribution and to inversely increase with > the square root of the temporal distance (as > does the inverse of the area of the spatial > (simultaneity) cross section of of the past > light cone) assuming a circular light cone. > Is that accurate? No. Dark Matter is not distributed that way spatially, except (roughly, I think it is roughly linear) within a spiral galaxy. There is not more / less Dark Matter at earlier ages, except adjunct to lumenous matter. If you want to include expansion, then sure, Dark Matter density per cubic "light century" goes up as you go back in time. Just as more ancient objects appear larger, since they subtended a bigger portion of a smaller Universe... David A. Smith
From: eric gisse on 16 Mar 2010 19:41 Simple Simon wrote: > Is it possible that some of the dark matter is simply matter that is > outside of our past light cone but gravitationally bound to objects within > it? No.
From: Tom Roberts on 16 Mar 2010 23:26 Simple Simon wrote: > Is it possible that some of the dark matter is simply matter that is outside > of our past light cone but gravitationally bound to objects within it? No. It is not possible for such matter to REMAIN outside our past lightcone. Tom Roberts
From: BURT on 16 Mar 2010 23:37 On Mar 16, 8:26 pm, Tom Roberts <tjroberts...(a)sbcglobal.net> wrote: > Simple Simon wrote: > > Is it possible that some of the dark matter is simply matter that is outside > > of our past light cone but gravitationally bound to objects within it? > > No. It is not possible for such matter to REMAIN outside our past lightcone. > > Tom Roberts No. The reason we don't see it is because it isn't there. Mitch Raemsch
From: "Juan R." González-Álvarez on 17 Mar 2010 06:20
Simple Simon wrote on Tue, 16 Mar 2010 12:46:06 -0800: > Is it possible that some of the dark matter is simply matter that is > outside of our past light cone but gravitationally bound to objects > within it? No. -- http://www.canonicalscience.org/ BLOG: http://www.canonicalscience.org/publications/canonicalsciencetoday/canonicalsciencetoday.html |