On May 18, 4:37 pm, Brad Guth <bradg...@gmail.com> wrote: (snipped) > > Your interpretation that 400 million light years is the optical limit > of seeing other more distant stuff is perhaps not taking into account > those extremely long time exposures of extremely sensitive CCDs > gathering photons and thousands of frame stacking methods applied.
Well thanks for keep pushing me to make more clear.
One of the nasty problems of astronomy is a blizzard of terms for which seem like appropriate but not actually the concept involved. For example astronomy has these terms:
What I am after, is the concept that says that light turned on at distance x, can only travel so far before it is too attenuated that it cannot be seen anymore. Even a supernova that goes off, has a distance limit to where it is no longer able to be seen.
So let me put out an analogy. A shotgun with its thousand pellets. As you shoot the gun the pellets are together closely and as they travel meters they start to widen out and not so together and nearby. With increasing distance of travel there is only 3 pellets per cubic meter. With further distance, there is 1 pellet per cubic meter.
Light from a star, from a galaxy, from a supernova is much the same as those pellets of a shotgun. At some distance, there are so few light waves of that star, or galaxy or supernova so that the observer can no longer see the object. I believe this upper limit is 400 million light years, whereas astronomers mostly believe it is infinity.
Now I am looking at some old supernovae in human history-- such as the 1604 Kepler's supernova which was 20,000 (alleged) light years away. So comparing the light of that supernova with its distance we can sort of arrive at a upper limit of light travelling before a supernova is no longer able to be seen due to sheer distance.
-- More than 90 percent of AP's posts are missing in the Google newsgroups author search archive from May 2012 to May 2013. Drexel University's Math Forum has done a far better job and many of those missing Google posts can be seen here: