What is seen from the farthest star?

In summary, the conversation discusses the concept of the universe having an edge and whether a star can exist at this edge. It also explores the idea of the universe being part of a larger multiverse and whether the observable universe is all that there is to see. The conversation concludes that the universe is likely infinite in size and that the big bang did not occur at a single point in space.
  • #36
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  • #37
Excuse me for my ignorance. I have been referring to implications of Gravity's Rainbow which is a recently added experiment at CERN.
If you are not familiar with it then of course you would not understand my posts.
 
  • #38
IGBY International said:
Excuse me for my ignorance. I have been referring to implications of Gravity's Rainbow which is a recently added experiment at CERN.
If you are not familiar with it then of course you would not understand my posts.
I don't see how the rainbow gravity theory would affect light geodesics on cosmological scales (maybe to a minor degree close to massive objects), especially to this extent:

IGBY International said:
Light circulates within creating a multitude of past "Light" objects that are observed as further and further away. Reflections, duplicates of our past existence.
 
  • #39
lifeonmercury said:
It's possible the edge of the observable universe is actually the edge of the entire universe. We can't see any further than 46 billion light years in any direction and really don't know for sure what's behind this horizon. However, the consensus is that we wouldn't find anything special out there.
Why would the edge of the seeable universe be the edge of the whole universe? Is the horizon the edge of the earth?
 
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  • #40
IGBY International said:
According to the general theory or relativity light bends. A universe is a closed system nothing gets out, nothing comes in. Light circulates within creating a multitude of past "Light" objects that are observed as further and further away. Reflections, duplicates of our past existence.
IGBY International said:
Excuse me for my ignorance. I have been referring to implications of Gravity's Rainbow which is a recently added experiment at CERN.
If you are not familiar with it then of course you would not understand my posts.
How does the gravity rainbow theory state that light circulates and gives us "duplicates of our past existence"? From my understanding, gravity rainbow theory states that gravity has different effects on different wavelengths of light and that the Big Bang never actually happened. What is the relation?
 
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  • #41
Jason R Carrico said:
If I'm on the surface e of the balloon and look up, what do I see?

Under the balloon analogy you can't look up because you are a two dimensional being on a universe expanding into the 3rd dimension. The real universe is expanding into a fourth spatial dimension (not time) that you can't see because you are three dimensional.
 
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  • #42
Algr said:
Under the balloon analogy you can't look up because you are a two dimensional being on a universe expanding into the 3rd dimension. The real universe is expanding into a fourth spatial dimension (not time) that you can't see because you are three dimensional.

Hmmm. It never occurred to me before that expansion might imply a 3d surface embedded in a 4d space. Does expansion imply a 4th spatial dimension, or is that carrying the balloon analogy further than is meaningful?
 
  • #43
Sounds like an infinite stack of turtles to me.
 
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  • #44
Grinkle said:
Hmmm. It never occurred to me before that expansion might imply a 3d surface embedded in a 4d space. Does expansion imply a 4th spatial dimension, or is that carrying the balloon analogy further than is meaningful?

It only implies that our universe may behave in a manner similar to as it would act if it were embedded in a higher dimensional space. Whether it is embedded or not is unknown and probably can't be known since we have no way of interacting in a hypothetical 4th spatial dimension.
 
  • #45
Keep in mind if you traveled to the most distant known galaxy the universe would be many billions of years older than it is at this moment - simply because nothing can travel faster than c and the universe would continue to age and expand during the journey. Were you at one of these distant places this very moment, the universe would be billions of years younger than it currently is because you had to already have been there when the light we currently observe here was emitted from there - for the same reason. No matter where or when you are in the universe you are always at the center of your observable universe. The long and short of it is - the 'edge' of the observable universe is like a rainbow: an illusion that never actually exists anywhere at any time irrespective of whether it is finite or not.
 
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  • #46
@Chronos Thanks for the reminder. Its very easy for me to fall into thought experiments that ignore c or other constraints and then spend lots of time trying to make sense of things.
 
  • #47
@Jason R Carrico, Grinkle, et al:

Have a look at the following article by Charles Lineweaver and Tamara Davis. "Misconceptions about the Big Bang." This was published in the March 2005 edition of Scientific American. It deals fairly directly with most of what is being kicked about here.

Here is a link to a copy of the article:
http://www.mso.anu.edu.au/~charley/papers/LineweaverDavisSciAm.pdf

Highly recommended.

diogenesNY
 
  • #48
Thanks, but I got a 404 error code.
 
  • #49
No 404 for me, it may have been a temporary server outage.
 
  • #50
Oh well, it just won't open for my phone then I guess. I will try to hunt it down some other way
 
  • #51
  • #52
Thank you so much. I've got it now
 
  • #53
I am not convinced that I have not got it yet, but it is fun trying,.
 
Last edited:
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  • #54
diogenesNY said:
@Jason R Carrico, Grinkle, et al:

Have a look at the following article by Charles Lineweaver and Tamara Davis. "Misconceptions about the Big Bang." This was published in the March 2005 edition of Scientific American. It deals fairly directly with most of what is being kicked about here.

Here is a link to a copy of the article:
http://www.mso.anu.edu.au/~charley/papers/LineweaverDavisSciAm.pdf

Highly recommended.

diogenesNY

That article makes it very easy to understand 'universal expansion'
thanks
 
  • #55
in my not-so-humble opinion, if we could see a person looking thru a telescope in our direction, that person could not see us, but how our galaxy looked 13-14 billion years ago. since that person was alive at the 'beginning of the universe' the visible universe may have been that one galaxy. it wouldn't actually be the only galaxy, just the only one to shed enough light to see. light from other galaxies hasn't reached the viewer yet, so darkness in all directions would be seen.
 
  • #56
fencewalker said:
in my not-so-humble opinion, if we could see a person looking thru a telescope in our direction, that person could not see us, but how our galaxy looked 13-14 billion years ago.

Let's replace "person" with "observer", since we commonly use the latter term when discussing how things look in the universe. This observer would be constrained by the time it takes light to travel to their location, yes, but so would we. So this observer would have had to exist 13 billion years ago and would be long, loooong dead. They wouldn't have been able to see us, or rather our area of the universe, because at this time the light from our area of space had not yet had time to reach them.

fencewalker said:
since that person was alive at the 'beginning of the universe' the visible universe may have been that one galaxy. it wouldn't actually be the only galaxy, just the only one to shed enough light to see. light from other galaxies hasn't reached the viewer yet, so darkness in all directions would be seen.

Pretty much. At this time, the visible universe for this observer would have been a very small area of space that contained matter in the early stages of galaxy formation.
 

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