On Friday, January 19, 2018 at 9:38:32 AM UTC-7, agrays...@gmail.com wrote: > > > > On Thursday, January 18, 2018 at 4:24:43 PM UTC-7, Lawrence Crowell wrote: >> >> >> >> On Thursday, January 18, 2018 at 4:04:17 PM UTC-6, agrays...@gmail.com >> wrote: >>> >>> >>> >>> On Thursday, January 18, 2018 at 3:49:15 AM UTC-7, Lawrence Crowell >>> wrote: >>>> >>>> >>>> >>>> On Thursday, January 18, 2018 at 1:44:00 AM UTC-6, agrays...@gmail.com >>>> wrote: >>>>> >>>>> >>>>> >>>>> On Wednesday, January 17, 2018 at 3:45:25 AM UTC-7, Lawrence Crowell >>>>> wrote: >>>>>> >>>>>> On Tuesday, January 16, 2018 at 4:35:36 PM UTC-6, agrays...@gmail.com >>>>>> wrote: >>>>>>> >>>>>>> >>>>>>> >>>>>>> On Sunday, January 14, 2018 at 9:57:14 AM UTC-7, John Clark wrote: >>>>>>>> >>>>>>>> On Sun, Jan 14, 2018 at 5:17 AM, <agrays...@gmail.com> wrote: >>>>>>>> >>>>>>>> > >>>>>>>>> I recently viewed a documentary on Quasars. IIRC, they are >>>>>>>>> interpreted as immense BH's with inflowing matter of galactic size to >>>>>>>>> account for their brightness, and their redshift, applying Hubble's >>>>>>>>> Law, >>>>>>>>> indicates they are far removed, closer to the BB than any galaxies >>>>>>>>> within >>>>>>>>> our observable universe. Question: did galaxies form that early after >>>>>>>>> the >>>>>>>>> BB to account for the huge inflows of matter and brightness? TIA, AG >>>>>>>>> >>>>>>>> >>>>>>>> Quasars formed very soon after the Big bang, almost embarrassedly >>>>>>>> soon. A recently discovered quasar called J1342+0928 is 13.1 billion >>>>>>>> light >>>>>>>> years away and was formed just 690 million years after the Big Bang, >>>>>>>> and >>>>>>>> yet it is powered by a Black Hole of 800 million solar masses. >>>>>>>> Astronomers >>>>>>>> have trouble explaining how a Black Hole could get that big that >>>>>>>> fast >>>>>>>> by conventional stellar evolution, but if from day one the universe >>>>>>>> already contained 100 solar mass Black Holes that would help a lot in >>>>>>>> explaining how that could happen and maybe give us a hint at what >>>>>>>> Dark >>>>>>>> Matter is too. >>>>>>>> >>>>>>> >>>>>>> *Hard to believe it formed that soon and so huge. For it to be that >>>>>>> bright, how much mass must be inflowing per unit time, say per second >>>>>>> or >>>>>>> year? Is that mass speculated to be from an already formed galaxy? >>>>>>> TIA, AG* >>>>>>> >>>>>> >>>>>> From the perspective of classical gravitation it might be thought >>>>>> that the initial singularity fragmented into singularities of black >>>>>> holes >>>>>> in the emergent cosmology. If we think of singularities as topological >>>>>> objects, then their generation or destruction means topology changes. We >>>>>> might then think of the demolition of the initial timelike singularity >>>>>> at >>>>>> time t = 0 and the generation of spacelike singularites in Schwarzschild >>>>>> black holes or mass-inflation singularities as an operation that changes >>>>>> topology. Quantum gravity is then a theory described by cobordism. >>>>>> General >>>>>> relativity does not permit this. So it is possible that black holes >>>>>> emerged >>>>>> in the first few Planck units of time in the generation of this >>>>>> cosmology. >>>>>> >>>>> >>>>> *What's the difference between a timelike and spacelike singularity? >>>>> Also, these BH's are not the result of collapse of massive stars, since >>>>> stars didn't exist at that time. What is the speculation of the cause of >>>>> these BH's? And why are they so bright without any infalling matter? AG* >>>>> >>>> >>>> *A spacelike singularity is on a spatial surface, such as with a >>>> Schwarzschild black hole. Such singularities are spatial, occur in the >>>> future of geodesics and do not propagate information into the future. A >>>> timelike singularity is a one dimensional curve that has no spatial >>>> extent. >>>> They do propagate information into the future or local future in the >>>> timelike interior of a KN black hole. The singularity that generated a >>>> cosmology may be timelike within some other space or they may be spacelike >>>> as the boundary of the cosmological spacetime. * >>>> >>> >>> *As far as I know, spacelike and timelike apply when comparing TWO >>> events, whether or not they're causally connected. I don't see how these >>> concepts can apply to a single event, such as a BH. AG * >>> >> >> Think of points on a Schwarzschild singularity as having a spacelike >> separation. The Kerr singularity has points separated by time, and the >> geometry is a ring. >> > > *This is for Brent. Do you understand LC's explanation of a singularity (a > single event) being spacelike or timelike? I thought spacelike and timelike > refer to whether TWO events are causally connected. How can a single event > be spacelike or timelike? TIA, AG * >
*LC refers to "points on a singularity". But a singularity IS a point! Of course, if Brent is right, there are no singularities in GR since the theory breaks down at the center of a BH. In sum, I don't grasp LC's argument. What are we trying to figure out here? How massive BH's might have formed in the very early universe? What could they form FROM if there were few if any stars? How could they be so bright without massive inflows of matter into their accretion disks? AG* > >> >>> >>>> The black holes may have been generated in the big bang. The are not >>>> bright in of themselves; they are black holes after all. >>>> >>> >>> *I know. But they become bright due to infalling matter in accretion >>> disk. Did galaxies form within the first billion years of the BB and then >>> infalling to account for their brightness? Seems unlikely. AG* >>> >> >> So far it appears that primordial galaxies appeared before 1 billion >> years after the BB. There are signatures of PopIII stars prior to these as >> well. These might have spawned large black holes. The origin of such early >> black holes is unknown. >> >> LC >> >> >>> >>> >>>> Quasars are extreme active galactic nuclei of young galaxies we observe >>>> in the past. >>>> >>>> LC >>>> >>> -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to everything-list+unsubscr...@googlegroups.com. To post to this group, send email to everything-list@googlegroups.com. Visit this group at https://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/d/optout.
