On Sat, Jun 7, 2025 at 8:05 AM Alan Grayson <[email protected]> wrote:
*>> The James Webb telescope recently found a galaxy that had a red shift > of 14.44, from that number astronomers calculate that it took light 13.5 > billion years to reach us, so we're observing how that galaxy looked 13.5 > billion years ago. However during that 13.5 billion years the universe has > not only been expanding it's been accelerating, so back then the universe > was expanding slower not faster than it is now. Today that galaxy is not > 13.5 billion light years from us, it is 34.7 billion light years from us. > Even if we could travel at the speed of light we could never reach that > galaxy in a finite number of years, and any galaxy that has a red shift > greater than 1.8 is forever out of our reach.* > > *> You say we're observing how that galaxy looked 13.5 billion years ago,* > *Yes.* > *> but that the redshift being observed today, gives us the recessional > velocity today?* > *Not exactly. Velocity is about objects moving through space, but the redshift tells us how much space itself has been expanding. The movement through space can never be faster than the speed of light** nor can we communicate faster than the speed of light, but space itself is free to expand at any speed.* *> Seems contradictory. AG * > *It's not. 13.5 billion years ago when that light was emitted it was in the ultraviolet, but during its journey space has been expanding, so the wavelength of the light has been expanding, so now the light is in the infrared not the ultraviolet. * *John K Clark See what's on my new list at Extropolis <https://groups.google.com/g/extropolis>* -- 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/CAJPayv11gj1-fy%3DQsDvkjLLY_5_z-crbpCfvm%2BYpEPamhaB-9w%40mail.gmail.com.
