If the light of all the galaxies in the cosmos reached us simultaneously how bright would the night sky be?

I mean, if light travelled instanteously rather than at the speed of light -- and we could see the whole universe as it exists right now simultaneously -- would the night sky appear as a solid blaze of stars and galaxies?





E.g. if we gaze 15 billion light years into deep space, there is nothing but blackness, because the stars did not exist 15 billion years ago, and light from that region would take that long to reach us. But in reality that distant reach of space should currently be filled with galaxies, even though we can never detect them.

If the light of all the galaxies in the cosmos reached us simultaneously how bright would the night sky be?
I AM NOT SURE WHERE YOU ARE GOING WITH THIS QUESTION...





LIGHT FROM ALL THE STARS IN ALL THE GALAXIES WITHIN THE UNIVERSE IS PRESENTLY COMING TO THE EARTH ALL THE TIME...





Simultaneously is a rather vague term when applied to light rays.





When objects emitting light rays are a LONG distance away, the intensity of the light rays is GREATLY diminished, but they are still coming to us all the time.





When you look out into deep space, you can see the light from "some stars." If you change the way you are looking at the stars by adding binoculars or a telescope, you can see "even more stars." If your telescope is a good one, you can see other galaxies which contain billions more stars but they are so far away that you can only see the light from the grouping, not from individual stars within those galaxies. Essentially the issue that you face is one of collecting enough of the light to see them. That is done using a large telescope with a big lens or a big mirror inside of it that collects the light and delivers it to your eye.





I have never found a situation where when I looked out into space I found nothing but blackness. Stars are out there "all around us." Certain parts of space are not as densely packed with stars as others are, but there are thousands and thousands of stars in even the most thinly populated regions.





I also think you are somewhat confused by the issue of distance and what is out there...The Universe does not end at 15 Billion Light Years distance. Scientists using "Radio Telescopes" have detected objects in deep space at distances of up to 40 Billion Light Years in all directions from Earth. That is indeed an impressive distance if you consider that one Light Year is roughly six trillion miles.
Reply:the light u see is a function of time... to alter the light element wud alter how time itself is perceived... alter the way light in space travels and you wud also alter the way it travels on earth. when u look at your mother all the visual wud scrunch to gether and u wud have no way of telling if your mother was standing near or far from u... because u receive all the perceptions at the same time. It wud kill you... because your brain if it received and processed the information... would be in sensory overload.
Reply:You wouldn't know.





YOU'D BE BLIND!
Reply:NO.





Yes, you could be correct (we don't really know) that certain areas are too far away to see stars yet. But on the other hand, lots of stars we DO see have since died out. Since entropy exists, I would guess less light rather than more.
Reply:It wouldn't be much brighter, assuming the 1/r^2 intensity law was still in effect.





There would be no red shift for faraway galaxies, since the Doppler effect wouldn't exits, so some galaxies whose light is removed from our visual range would become visible.
Reply:They would still be far away. Whether the light reaches us instantly or takes 15 million years, the same amount of light reaches us.
Reply:Presuming the Universe is infinite and static a straight line in any direction would intercept a star. Thus the sky would uniformly and brightly lit. And the earth would also be incredibly hot and irradiated by cosmic rays!





The fact that this is not so is called "Olber's Paradox" among other names. There have been a few explanations, some more convincing than others.





http://en.wikipedia.org/wiki/Olber's_par...





http://www.mathpages.com/home/kmath141/k...
Reply:nothing would really change except our understanding of the universe we might even see another starin the sky(not) did you ever see a galaxy that is lets say 11 billion ly away


can you see it with your naked eye i know that i cant





you answer: the sky would not be brighter at all (if you look with the naked eye)





example:the light from the andromeda galaxy doesnt affect the brightness of things here on earth and its our closest cousin so think of a galaxy 15billion ly away:Nothing would happen





hope this helps