On Monday, July 13, 2020 at 5:19:30 PM UTC-6, Lawrence Crowell wrote: > > On Monday, July 13, 2020 at 4:42:24 PM UTC-5, Alan Grayson wrote: >> >> >> >> On Monday, July 13, 2020 at 1:42:49 PM UTC-6, Alan Grayson wrote: >>> >>> >>> >>> On Monday, July 13, 2020 at 11:57:50 AM UTC-6, Brent wrote: >>>> >>>> >>>> >>>> On 7/12/2020 11:50 PM, Alan Grayson wrote: >>>> >>>> There can be because it's consistent with the equations. A black hole >>>>> doesn't include any matter. General relativity is non-linear, that's why >>>>> there can be non-flat cosmologies that contain no matter. Of course >>>>> there >>>>> may be some different, better theory in which spacetime can't be curved >>>>> without matter...but it seems unlikely since we have good evidence that >>>>> gravitational waves exist. >>>>> >>>>> Brent >>>>> >>>> >>>> Yes, good evidence that gravitational waves exist, but as far I know >>>> they're always associated with material interactions such as collisions of >>>> black holes. In the case of EM waves, I'd be more receptive of your claim >>>> that they can exist independent of charges and/or currents, but as far as >>>> I >>>> know there's no evidence of that. AG >>>> >>>>> >>>> But a collision of black holes does NOT involve matter. Black holes >>>> (as far as the theory goes) are purely geometric things, i.e. made of >>>> empty >>>> space. >>>> >>>> Brent >>>> >>> >>> How then does the BH at the center of our galaxy weigh in at 4 million >>> solar masses? AG >>> >> >> It's measured by observing the rotation rates of stars near the galactic >> core, and not so small by comparison with other BH's at the center of >> galaxies, called Super Massive BH's. AG >> > > It is unfortunately apparent that you are pretty highly confused by some > of this. You need to sit down and read a comprehensive book or text on GR > and related subjects. It is not going to be possible to clear this up with > dozens of email posts. > > LC >
About the EP; I merely stated that it demonstrates that acceleration is locally indistinguishable from gravity, and then I stated what "locally" means. This is what Wiki and other sources say. Yet you say I am confused. How so? About masses of BH's, I watch documentaries which feature astrophysicists offering their opinions, and they *uniformly* claim that BH's have mass. How could it be otherwise if they're remnants of massive collapsed stars? Not one makes Brent's claim, that they're just geometric manifestations. AG -- 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 [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/everything-list/78f2531b-9fb5-43a9-bd44-9d7e00deb400o%40googlegroups.com.
