Finite Universe: Light speed and the Earth's distance/time from event

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Discussion Overview

The discussion revolves around the apparent contradiction between the age of the universe, estimated at 13.75 billion years, and the observation of objects that are over 13.75 billion light years away. Participants explore concepts related to the observable universe, the implications of light travel time, and the nature of the universe's expansion and structure.

Discussion Character

  • Exploratory, Debate/contested, Conceptual clarification

Main Points Raised

  • Some participants question how we can observe objects over 13.75 billion light years away if the universe is only 13.75 billion years old, suggesting that light from these objects must have traveled for longer than the universe's age.
  • Others argue that we cannot see further than the age of the universe and propose that objects observed at such distances are now much further away due to the expansion of the universe.
  • One participant challenges the assumption that we are at the center of the universe, stating that if we were, the distances to objects would be more uniform.
  • Another participant asserts that the universe is isotropic and homogeneous at large scales, implying a consistent structure, which contradicts earlier claims about non-uniformity.
  • There is a discussion about the shape of the universe, with one participant suggesting a non-trivial topology, while another counters that this is not supported by current experimental or theoretical evidence.

Areas of Agreement / Disagreement

Participants express differing views on the nature of the universe's structure and the implications of light travel time, indicating that multiple competing perspectives remain without consensus.

Contextual Notes

Some statements made in the discussion rely on assumptions about the universe's topology and structure that are not universally accepted or supported by evidence. The discussion also reflects varying interpretations of cosmological principles.

rationalist76
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This may not be the correct Forum to post this Thread, but i thought i might as well. I was just wondering: if the matter in the Universe is assumed to be 13.75 billions years old, why is it that we can witness things over 13.75 billion light years away? I came across this Wikipedia article on the Observable Universe, and i was curious how it could have occurred before the Big Bang. Because it takes the light to travel, let's say, 15 billion light years to reach our telescopes, would that not mean the event had to take place 15 billion years ago? And would that not contradict the fact that the event took place before the Big Bang? Thank you to all of the answers
 
Astronomy news on Phys.org
welcome to pf!

hi rationalist76! welcome to pf! :wink:

see the cosmology faq at https://www.physicsforums.com/showthread.php?t=506987" :smile:
 
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tiny-tim said:
hi rationalist76! welcome to pf! :wink:

see the cosmology faq at https://www.physicsforums.com/showthread.php?t=506987" :smile:

thank you! sorry, i am new and am not extremely aware as to how to find things yet, bu ti believe that will obviously help
 
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rationalist76 said:
This may not be the correct Forum to post this Thread, but i thought i might as well. I was just wondering: if the matter in the Universe is assumed to be 13.75 billions years old, why is it that we can witness things over 13.75 billion light years away? I came across this Wikipedia article on the Observable Universe, and i was curious how it could have occurred before the Big Bang. Because it takes the light to travel, let's say, 15 billion light years to reach our telescopes, would that not mean the event had to take place 15 billion years ago? And would that not contradict the fact that the event took place before the Big Bang? Thank you to all of the answers

Since you didn't give a reference to the article, I can't comment directly. However we definitely cannot see further than the age of the universe. The only thing that might make sense is that something we see that far back in time is presumably now much further away.
 
rationalist76 said:
This may not be the correct Forum to post this Thread, but i thought i might as well. I was just wondering: if the matter in the Universe is assumed to be 13.75 billions years old, why is it that we can witness things over 13.75 billion light years away? I came across this Wikipedia article on the Observable Universe, and i was curious how it could have occurred before the Big Bang. Because it takes the light to travel, let's say, 15 billion light years to reach our telescopes, would that not mean the event had to take place 15 billion years ago? And would that not contradict the fact that the event took place before the Big Bang? Thank you to all of the answers

You are assuming that we are in the center of the universe. (An old mis-information.)

From the center of the universe, light/matter has been expanding for about 14 billion years.

If the expansion was consistent, that would allow for about 30 billion light years from end to end. If we were in the center, anything would about the same distance away. But there are couple of factors.

1. We are not in the center.
2. The universe is not consistent.
3. The universe is not the shape it seems. Our universe (as we perceive it) is sort of like a fried skin of a donut. Things sort of travel in loops. In other words, if you threw a ball in one direction, (given a little patience) it would come about and hit you in the back of the head. So distance can be tricky.
 
Lord Challen said:
2. The universe is not consistent.
3. The universe is not the shape it seems. Our universe (as we perceive it) is sort of like a fried skin of a donut. Things sort of travel in loops. In other words, if you threw a ball in one direction, (given a little patience) it would come about and hit you in the back of the head. So distance can be tricky.

Both of these statements aren't really true.

2. The universe, at a large scale is isotropic and homogenous, meaning there is no "preferred direction in space" and each point in space looks roughly like any other point. Therefore it is roughly "consistent."
3. Your assuming the universe has non-trivial topology. This is most certainly not supported experimentally or theoretically (see Topological Censorship Conjecture).
 
Lord Challen said:
1. We are not in the center.
This one is not true either since the http://en.wikipedia.org/wiki/Observable_universe" is light travel time).
 
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