From my extrapolation of what I’ve read, our observable universe (as opposed to other universes and dimensions seriously proposed by others) derived from one central point 13.8 billion light years away and in the past (a light year is both a measure of distance and time). This was inexpertly termed “The Big Bang,” when it should have more accurately been called “The Sudden Expansion/ Dispersal” perhaps. To think of the event in terms of an explosion leads to faulty understanding about the clues of what happened. Extrapolating from that, we are seeing half way to the origins point, which means if it expanded in a globular fashion, this universe is also at least 13.8 light years on the other side of the origins point making a total of at least 27.6 billion light years in diameter. I caution with “at least” because I have seen nothing saying the Milky Way Galaxy is at the outer limits of the expansion, which would necessarily mean an even larger universe. Our current best telescopes are said to be able to discern objects ~13billion light years away and back in time, therefore close to the center/point of origin. They cannot see any part of the other side of the expansion. If you think of our universe as a giant globe or ball,we can see almost to the center, but not to any part beyond that. A caution: I recently have read articles graphically depicting our universe more as a tubularlike cone expanded from the origin point, but I have found no explanation for that configuration as opposed to the 360 degree expansion in all directions I postulated above.
One oddity in current theory which had troubled my understanding is that the original sudden expansion dispersed matter virtually instantaneously to the edges in contravention of the speed of light limitation (186,000 m/p/s) which applies to every other thing in the universe and that allows us to see “back” as light catches up at light speed. Before that theory caught up with me I always wondered how we could see back if we were expanding at the same speed of light. It is all quite bewildering, and I gather from reading, I am not much behind our best theoretical physicists in their befuddlement.
Back to the question posed, as you can see 150 million light years away in a 27 billion light year universe qualifies as a near neighbor.
Last edited by wacojoe; 06-15-2018 at 06:46 PM.
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“You can vote your way into socialism, but you have to shoot your way out.” — Too fundamental to have an attribution