Z
zeestephen
Guest
I do not understand why an observer on Earth can point a telescope in ANY direction and find radiation from the earliest galaxies and from the Big Bang.<br /><br />Unless the Earth is at the "center" of the universe, it seems like the view from Earth should be lopsided.<br /><br />I do not understand how a "flat balloon" or a "flat saddle" shaped universe solves this problem.<br /><br />For example, let's say the Andomeda Galaxy is 12.5 billion years old. All but 2.5 million years of its radiation would have passed by Earth and disappeared forever. Under this hypothetical, if we look "past" Andromeda, why isn't there a big blank nothingness "behind" it since no galaxies existed before 12.5 billion years ago?<br /><br />I have the same question about the CMB. How is it that ALL the CMB radiation is arriving from ALL directions at the same moment? Why are there not big blank spots in the sky where the CMB has already reached Earth, and passed it, and disappeared forever? <br /><br />And here's an easy question. The "thickness" of the Milky Way is about 1000 LY. What is Earth's relative position, in light years, to the "top" and "bottom" of the Milky Way?<br /><br />Thanks to all for helping!