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THE UNIVERSE NOW-LITERALLY
Forum List | Follow Ups | Post Message | Back to Thread Topics | In Response To Posted by stelios on September 2, 2009 18:07:59 UTC |
We know telescopes provide a window to the past but the farther we go away (or back in time) the situation becomes pretty sticky. Consider "looking" (catching the light) from a space object (star, quazar, AGN, whatever) 47 billion years away (that's the farthest we've gazed so far, right?). The light actually left the object well before that time (has to be less than 13.7 billion years) and then it got stretched due to the expansion of space and reached us only today. Today, this object is not there anymore but its matter is somewhere in a different form or formation. So, where are today all those particles that took part in the reaction that produced the light that ultimately reached us? For as long as the object they were part of was alive, they should be moving farther away from us with it, so their light path received by us after all those years is the path of the object observed. Still, this path is 47 billion years away and less than 13.7 billion years back in time. On the other hand, the object (or its particles) could have moved away from us during all those years faster than light, so we we'll never catch a glimpse even if we wait forever. Whatever the case, everything we see today in the sky is not there anymore and they have moved away from us at some speed. Plus, almost everybody agree that there is no central point in the universe and all vantage points are equivalent. I suppose this holds if one takes for granted that any point in the universe has the same restrictions as we have, being able to see around it only the evolution of the universe but not the absolute present state of the universe, so this equivalence principle holds in somewhat different way for any given moment in time (like our absolute NOW or our absolute one hour later etc.). Equivalence of vantage points at any given moment still holds if indeed those points sit on the surface of the balloon, so any one point is no different than the others. But if there is ”something” inside the balloon (unlikely) equivalence breaks
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