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> 8.5 billion lights years away—more than halfway across the universe Why is it halfway across? The universe's diameter is 93 billion ly. Shouldn't 8.5 billion

• anotheraccount9 4y ago
  (I'm not an astrophysicist). They possibly are referring to the initial age of the universe times the speed of light (13.8 billion light-years), as if it was static. Like you infer, "[...] stuff is everywhere, light goes at c, stars and galaxies move, and the Universe is expanding." https://www.forbes.com/sites/startswithabang/2018/02/23/if-the-universe-is-13-8-billion-years-old-how-can-we-see-46-billion-light-years-away/?sh=494c7e2d1303 https://www.forbes.com/sites/startswithabang/2018/02/23/if-t...
  • nicksrose7224 4y ago
    I think it's more likely they got it wrong and are referring to what they assume the size of the universe is. It's hard to grasp why the observable universe is 92 billion ly in diameter
• yayr 4y ago
  universe is a relative word, and typically treats us at being at the center (which in the whole of reality is somewhat unlikely). So it only describes that part of reality observable by us. 8,5 bn ly refers to roughly half distance to all of the observable events in that observable reality at the time these events occured. Since 3D space presumably expands, it would now take much more time for any event in our observable "universe" to reach from one end of the observation limit to the other... by the way - if you want to go down further that rabbit hole a good place to start is to search for "levels of multiverse"