Recent content by Cerenkov

Are you aware of this story, YH5598? https://en.wikipedia.org/wiki/Nightfall_(Asimov_novelette_and_novel) Living in the perpetual light of the six suns in their system the humanoid inhabitants of Lagash have never experienced true darkness. So if they were exposed, even for a short time, to...

Hello. I've been reading about the Lagrange points... https://en.wikipedia.org/wiki/Lagrange_point ...and also about Pluto and its moons. Having discovered that the barycentre of the Pluto - Charon system lies at a point in space between the dwarf planet and its major moon Charon a number of...

Ok, that seems reasonable. And it agrees with what I understand about Relativity. Specifically, that no observer occupies a special or privileged location or viewpoint. Therefore, observers located on their own particular worldlines experience their own Proper Times, each being as valid as...

Thank you, Peter. I will do that, see what I can see and get back to you with my findings. Ok, so you've used the terms Comoving Distance and Comoving Time today. Also Proper Distance and Proper Time. Comoving Distance I now begin to understand. Based upon your comments above, would Proper...

I see. And so this addresses the point we discussed earlier about this whole scenario being dynamic. The light left these worldline locations, took time to reach the periphery of our light cone. And that elapsed time has to be factored in when calculating the redshift values. The system is...

Thank you so much for this help, Peter. I shall return to this thread tomorrow (getting late here) and respond.Cerenkov.

Currently observable light that has been travelling towards us since the beginning of the universe, was emitted from comoving positions that are now 46 Glyr from us. Yes. Our light cone grows at the speed of light allowing us to see further and further into space and back in time and this...

Ah, thank you. That would have been one of my questions. You pre-empted me. In a nice way. :smile:

Ok, looking closer, here's what I see. The dotted lines flanking our central worldline represent the worldlines at redshift values of 1, 3, 10 and 1,000. These worldlines are also physically removed from us through space by certain Comoving distances values, expressed in Giga light years...

I have that on my screen, Peter. Yes, I think I see it now. Here's what is immediately apparent to me. The central vertical axis represents 'here' and where the horizontal 'now' line crosses it is where we are, here and now on planet Earth. There's a light cone extending from us downwards...

I'm looking at figure 1 of the .pdf of the Davis Lineweaver paper right now phyzguy. The catch is that I cannot look at it with the eyes of understanding that you, Peter Donis and phinds can. The meaning of those curved lines, numbers and shaded areas are no doubt obvious to you guys. Not so...

Thanks phinds. Yes, I'm aware that it is the expansion of space that is carrying the galaxies along for the ride and not the galaxies themselves moving through space. Hence there is no violation of relativity. Nevertheless, it is sometimes difficult for a layman like myself to get the...

That's another error on my part Peter. Treating the cited values as if they existed in a fixed and static universe. Hence the mistake about treating time and distance as equivalent. I must try to get my head around the fact that what we are discussing here is a dynamic system. That space is...

I think I can see what I did wrong Peter. I conflated Siegel's values of distance with time, figuring (wrongly) that since light takes one year to travel one light year, time and distance were therefore equal and interchangeable. So when he talked about that critical distance of 13 to 15...

Hello. I have visited this site recently... https://lco.global/spacebook/light/redshift/ ...and was wondering at what value of z in the table below would galaxies appear to recede at superluminal velocities? z Time the light has been traveling Distance to the object now 0.0000715 1...