What Exists Beyond the Reach of the First Photon in the Universe?

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Discussion Overview

The discussion centers around the nature of the universe at the moment of the Big Bang and the implications for the first photon, including concepts of space, light, and the expansion of the universe. Participants explore theoretical aspects of special and general relativity, the conditions of the early universe, and the concept of "dark" regions in space.

Discussion Character

  • Exploratory
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant questions the nature of space at the moment the first photon began traveling, wondering what exists beyond its reach.
  • Another participant explains that the Big Bang occurred everywhere simultaneously, suggesting that there was no empty space at that time.
  • There is confusion regarding the implications of the speed of light as a universal limit, with one participant noting that general relativity allows for galaxies to recede faster than light due to cosmic expansion.
  • Some participants challenge the idea of "expanded areas" of the universe, arguing that space is not being created but rather that everything is moving away from everything else.
  • A participant mentions that descriptions of the Big Bang often refer to the observable universe, and highlights that light could not travel through the dense plasma of the early universe until about 380,000 years later.
  • There is acknowledgment that the conditions at the Big Bang are not fully understood, with models starting only moments after the event.

Areas of Agreement / Disagreement

Participants express multiple competing views regarding the nature of space and the implications of the speed of light, indicating that the discussion remains unresolved with no consensus reached.

Contextual Notes

There are limitations in understanding the early universe, including missing assumptions about the nature of space and time, and the dependence on definitions of "dark" regions and the expansion of the universe.

hypotemoose
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Dark "corner" of the universe

Hi all,

So I'm reading about special relativity and "c" and, go figure, I have a couple questions. But here's my first, most basic question. Forgive me for confusion of terms and noob questions.

I don't know "when" light was created (at BB or much later), but let's say that - if I can - that the very first photon, Photon Bob, started traveling at 'c' at 'second 0' and that we're in the vacuum of our universe without any gravity to bother us.

Apparently, light (this photon) travels at 'c' - 299,792, 458 metres/second. So, at Start time (Second 0), location of Photon Bob is at x 0, y 0 And it is traveling solely in the direction of y. So at End time (Second 1), Photon Bob is at X 0, Y 299,792,458 metres.

My question then, is WHAT, at that exact instant, Second 1, is at 299, 792, 459 metres? More space - space where light hasn't reached yet?


Sorry, I have no familiarity with physics/math notations to have made this shorter. But I really appreciate the help!

- Hypo
 
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The big bang occurred everywhere in the universe at the same time. The very early universe was filled with an extremely hot bath of hot particles and radiation, annihilating with themselves to make more particles and radiation over and over again. The key thing to understand is that there was no "empty space" anywhere in the universe at this time. The entirety of the universe was filled like this.
 


Thanks!

I'm confused b/c I'm reading "The God Problem" by Howard Bloom and he translates into layman's terms one of Einstein's findings that 'c' is a universal "speed limit" - nothing exceeds c.

But if speed is measured by distance/time, what is the location at which anything traveling at c will be located 1 unit of time later if it's already at the "sidelines/edge" of the universe and heading "out of bounds"?

However, it sounds like you're saying that, apart from black holes, there is no part of the universe that is "dark", including the expanded areas that weren't there when the universe was smaller?

Sorry, this is confusing stuff! Appreciate the help!
 


hypotemoose said:
I'm confused b/c I'm reading "The God Problem" by Howard Bloom and he translates into layman's terms one of Einstein's findings that 'c' is a universal "speed limit" - nothing exceeds c.

That's actually not true. The speed limit c is only for local areas of space where you can apply Special Relativity. General Relativity has no such limit and it is this fact which allows for galaxies to recede from us at a velocity greater than c due to cosmological expansion.

But if speed is measured by distance/time, what is the location at which anything traveling at c will be located 1 unit of time later if it's already at the "sidelines/edge" of the universe and heading "out of bounds"?

However, it sounds like you're saying that, apart from black holes, there is no part of the universe that is "dark", including the expanded areas that weren't there when the universe was smaller?

I'm saying that there isn't any "expanded areas" of the universe that wasn't there prior. That whole idea is incorrect. The universe is not expanding into anything else. Space is not being created where no space was before. Everything in the universe simply gets further away from everything else unless bound by gravity or another fundamental force like electromagnetism.

See the FAQ threads in this forum.
 


Very interesting. Appreciate it, Drakkith!
 


When you see descriptions about the big bang [BB]occurring at some 'point', they are referring to the observable universe, not the total cosmos. [I just saw an illustration in Wikipedia a few days ago, cannot find it now..]

'Dark' likely refers to the fact that until about 380,000 years after the BB no light could get through the initial charged plasma...photons [particles] of light were absorbed. So we could not 'see' anything had we been there.

At the BB and until some 380,000 years later, things were initially really dense...and very different from today...so much so that at the BB itself nobody knows exactly what was there...nor where it came from...our models actually start just moments after the initial bang.
 

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