On 8/16/2025 4:37 PM, Alan Grayson wrote:
Suppose you and a pro-baseball pitcher are standing alongside a road playing catch. When you catch his fastball it has an energy of 70J and stings thru you glove. Now his throw is little off and instead going to you, it is caught by a kid in a passing car going the same direction as the throw. But when the kid catches it bare handed it doesn't even hurt because it's only got an energy of 2J. How did the ball loose energy?On Saturday, August 16, 2025 at 12:56:53 PM UTC-6 Brent Meeker wrote: On 8/16/2025 12:27 AM, Alan Grayson wrote:On Monday, August 11, 2025 at 10:21:16 PM UTC-6 Alan Grayson wrote: On Sunday, August 10, 2025 at 8:23:53 PM UTC-6 Alan Grayson wrote: On Sunday, August 10, 2025 at 5:51:31 AM UTC-6 John Clark wrote: On Sun, Aug 10, 2025 at 6:01 AM Alan Grayson <[email protected]> wrote: On Saturday, August 9, 2025 at 5:45:01 AM UTC-6 John Clark wrote: *Until very recently the most distant object our telescopes can see had a redshift of about 14, but very recently there are reports that the James Webb telescope has seen point-like objects that seem to have a redshift of 25! Whatever these objects are they contain little or no dust as you'd expect because dust requires elements other than hydrogen and helium which need to be made in stars, but if we really are looking at an object that has a red shift of 25 then we're looking at something that existed before stars did. If confirmed that would be a pretty profound discovery, and about the only thing that could explain them are Primordial Black Holes created during the first nanosecond after the Big Bang.* ** *JWST Found Objects at Insane New Distances (Redshift of 25?!)* <https://www.youtube.com/watch?v=saL_1R1WitA&t=797s> */> How is the red shift related to the velocity of light? How large must it be to equal c? TY, AG /* *Because space is expanding and accelerating, galaxies that have a redshift greater than about 1.7 are today moving away from us faster than the speed of light, so we can never reach them or even send a message to them, they are beyond our causal horizon; however today we can still see them because at the time the light from them was emitted the galaxy was closer to us than it is now, and back then it was receding away from us slower than it is now, slower than the speed of light. For the same reason today we can even detect the Cosmic Microwave Background even though ithas a redshift of about 1100, but we could never send a message or influence anything that happens that far away.* *John K Clark See what's on my new list at Extropolis <https://groups.google.com/g/extropolis>* TY. If it's not too much trouble, can you show me how you do that calculation? AG What is the physical interpretation of the huge red shift of the CMB? It can't mean extreme recessional velocity since it's here, everywhere, in every direction. AG Since the CMB isn't receding, what is the physical interpretation of its huge red shift? AGIt's all relative. We're receding, if you insist on "somebody is receding". The bit of the CMB we see is a further away bit every day. Its photons have traveled to us thru space that has been expanding as they traveled. BrentSince I am free to choose any observer is receding, I did. But more important is your model of the photon. Since the wave property of light is an ensemble property, what allows you to claim they lose energy as the universe expands? AG
Brent -- 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 visit https://groups.google.com/d/msgid/everything-list/574dbe44-43f5-4bbb-a50c-da92f6de7d00%40gmail.com.
