Early Universe: Closer Galaxies, Big Bang Visibility?

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Discussion Overview

The discussion revolves around the appearance of galaxies in the early universe, specifically whether they seem closer together as one looks back in time, and the visibility of the Big Bang itself. Participants explore theoretical implications, observational limitations, and the nature of time and light in cosmology.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Some participants propose that galaxies appear closer together when looking back into the early universe, suggesting a more compact arrangement.
  • Others argue that while it is impossible to see the Big Bang directly, if it were possible, one might observe it in every direction due to the spherical expansion from a singular point.
  • A participant mentions that the universe was not transparent until 380,000 years after the Big Bang, limiting visibility to what was directly in front of an observer during that time.
  • Some participants discuss the implications of being at the "edge" of the universe, with differing views on what that means in terms of dimensionality and observation.
  • There is a suggestion that every observer in the universe perceives the past, creating an illusion of being at the center of the universe.
  • One participant questions the nature of time flow, proposing that an observer experiences time differently based on the distance of objects in the universe.
  • Another participant notes that light from distant galaxies represents a view into the past, as the photons received were emitted long ago.

Areas of Agreement / Disagreement

Participants express multiple competing views regarding the visibility of the Big Bang and the implications of being at the edge of the universe. There is no consensus on the nature of time flow or the interpretation of being at the universe's edge.

Contextual Notes

Limitations include assumptions about the nature of visibility in the early universe, the definition of the universe's edge, and the implications of time as experienced by observers.

binbots
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When we look back into the early universe do the galaxies appear to be closer together? My logic is that the closer we go back to the big bang the more compact everything would be. I also would like to know if it was possible to see the big bang (I am aware it is not possible) would be see it in every direction we look?
 
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binbots said:
When we look back into the early universe do the galaxies appear to be closer together?
Yes.
I also would like to know if it was possible to see the big bang (I am aware it is not possible) would be see it in every direction we look?
The universe was not transparent until 380,000 years after the big bang, so like being inside a fog, you could only see what is right in front of you. After the universe became transparent, you'd still be able to see this brightly illuminated fog in all directions, but it would move away from you as the universe expanded, getting more and more red-shifted until today it would just be dim radio waves... aka the CMB.
 
A neutrino telescope would allow you to look back very close to the big bang. They are, however, highly impractical. A gravitational wave telescope is an entirely different matter. We have one up and running [LIGO] and another in the works [LISA].
 
So if we could we would see the big bang in every direction? The same event happening every in the universe. Hard to wrap your head around.
 
binbots said:
So if we could we would see the big bang in every direction? The same event happening every in the universe. Hard to wrap your head around.

That would make sense considering it was all originating from one point and exploded outwards in a spherical movement. But, to actually see the big bang would in fact be impossible, as it is the edge of a rapidly expanding universe. You would have to be relatively near to the edge, which would expand quicker than you could travel towards it.
 
We already are at the edge.
 
Chronos said:
We already are at the edge.

An edge defines a point in which a dimensional change occurs. To say we were at an edge of the universe would be a ridiculous claim to make, as we can see other objects away from the Earth at a full 360 degrees. We might be, as some have claimed if you travel through the universe in one direction, you might end up back where you started, but it would be nigh on impossible to prove.
 
Permit me to clariy, we are at the temporal edge of the universe - the most ancient observable region. We see the past in every direction.
 
Chronos said:
Permit me to clariy, we are at the temporal edge of the universe - the most ancient observable region. We see the past in every direction.

Isn't that true at any other point in the universe? Even on Earth we are looking very slightly in the past when we see with our eyes. Wouldn't your comment imply that we are close the "point" the big bang occurred? Or am I missing the point entirely?
 
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  • #10
It is true every other observer in the universe sees the past in every direction. It is also true every other observer in the universe has the illusion they are virtually at its center.
 
  • #11
So can one say that I (observer) am the only thing that is present and the further something is away from me the further back in time it is? Time flows out of me while light travels to me?
 
  • #12
Not sure about the time flow thing, but, yes, everything you see is as it was in your past due to the finite speed of light. Most of the photons we currenty receive from galaxies at z~1 were emitted by stars that have since 'died'.
 

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