The Edge Of The Universe

[Likekinds]

Hi, All,

I have no camera or telescope, so I wont be making contributions in that area. I have thousands of pictures from NASA, Hubble, etc. Just looking at these pictures, I get lost in time. I do fear, if I were viewing the Heavens from such as the James Webb Space Telescope, I would be in such awe, I might never return to 'reality'.

I do hope questions will be considered a form of contribution. I have lots of them, most from early childhood, on. I have limited formal education and hope to put my questions to those with a good background in astronomy. What might be considered common knowledge to those folks, might well add to my fascination of the Universe.

 

First question.

I read so much about more and more powerful telescopes. It is said they now are able to peer at the very edge of the Universe. I don't understand this. I thought it was generally accepted that there is no end to the Universe (as we know it) and therefore no 'edge'. I'm wondering. When the writers of these essays refer to the edge of the Universe, could they actually be referring to a point in time rather than  a place in space? The deeper we look into space. the farther back in time we go. Theoretically, we could approach a time where there is nothing to see as the stars would not have yet come into existence.

If I am correct, this point in time would occur in all directions. As there is no up or down, east or west in space, there is no 'place' in space, therefore no edge. So I ask you, was the word 'edge' used as a matter of convenience when time was what was actually meant? Somehow, I'm not quite ready to accept that there is an actual, literal edge to our Universe.

Thanks

 

 

[Pete Presland]

Hi welcome to SGL from Pete in Bedfordshire 🙂  The use of the word "edge" seems missleading to me as well, i dont think we will ever know for definite how what we can was formed.

[PeterCPC]

Hello and welcome.

[Mr Spock]

Hi, welcome to SGL  The 'edge' is meant to represent the farthest point we can detect.

[maw lod qan]

Welcome. I hope you find the answers you seek.👍

[Sabalias]

Hi there and welcome to the forum. For someone with no formal education you articulate yourself very well!

I have no idea if this is correct but what I think of when I hear the phrase ‘Edge of the universe’ is this:

Generally all the galaxies in the universe are moving away from each other. The further away you get from the universe’s core, the faster they are moving. If this is accepted then, if you run time backwards, everything will get closer together. You can imagine that, if you go back far enough in time, everything will be at one point which exploded. Thus we get the Big Bang. If there was a Big Bang then  you could see that there would be an edge to the explosion, so being able to peer at the edge of the universe would be to look at the edge of the expanding explosion of the Big Bang. 
 

Stu

Edited June 19, 2021 by Sabalias

[banjaxed]

Hi and welcome to SGL.

[Astro Noodles]

Welcome to SGL.

[reezeh]

Hi and welcome 👋

[Knighty2112]

Well, current thinking is that this edge (which they are really talking about the visible universe, and not the part of the universe past this visible limit) is expanding away from us faster and faster as on the galactic scale they now say gravity is a repulsive force over these vast distances. Personally, Id give it another 10 years then cosmologist will cange their minds again as to what is actually (supposedly) going on out there.  

Oh, hi and welcome too! 😁

[vlaiv]

Welcome to SGL.

Edge here is probably used in "poetic" sense rather than to represent geometrical concept, however - there is boundary that we can call an edge.

As we look into distance - we are also looking back into time. This is due to finite speed of light - it takes time for it to reach us and we see things as they were at the moment light started the journey.

At some point in distance - we no longer see galaxies, as you note yourself, but after that - comes "time" - that we can no longer see further than that. We literally can't see past that point. This "barrier" has a name at it is known as surface of last scattering.

Before that time - "stuff" in universe was in different state - it was plasma and that state is opaque for electromagnetic radiation. Photons scattered in all directions - it is a bit like Fog in sense that - everything is haze and you can't see far. We can't see past this point - we can only see up to and including that point.

Light that comes from that point is known as CMB - cosmic microwave background - and it is very much red shifted because it is old (expansion of universe) - so it is not visible light, it is in radio part of spectrum and strongest in microwave.

This can be considered as a sort of edge to volume we are able to see.

[Likekinds]

Very interesting and informative.  Now, I will ask my second question before giving you guys a break. Thank you.

[barbulo]

Hi and welcome to SGL. 

Very interesting question, in my opinion. The further objects we can observe were there billions of years ago. So, how does the universe look like right know? Where are (if there are) its limits? 🤷🏻‍♂️ 
As Gus mentioned in the previous post, the current thinking is that of an expanding universe. However, I have my doubts since the age of our planet is just a blink of an eye compared to the Universe’s magnitudes. 
Maybe that’s just a matter of faith. 

[scotty38]

I have a question that is even more baffling, why do you show as making zero posts.......

[Likekinds]

I did not get an email indicating I had replies to my question. I stopped by to check, anyway. I have a page full of replies.

Thanks to all!

[Jiggy 67]

As I understand it, there is no "edge of the universe". There can be no edge to something where nothing exists beyond it and when I say nothing, I mean absolutely nothing, no space, no time. This state of "nothingness" existed before the universe came into being. I say "before" but there was no before, because there was no time. The big bang (again, misleading, there was no big explosion) did not happen in a "place" there was no place, it occurred everywhere at the same time, creating the universe as we know it today. There is no centre of the universe, from which galaxies are speeding away from. Space (and time) themselves are stretching which gives the effect of galaxies speeding away. Because of this stretching, we can estimate distance to the furthest galaxies using the red shift end of the spectrum (created when light waves are stretched by space itself stretching). We will never observe the "edge" of the universe because there is no edge, there can't be, because nothing exists beyond it

[saac]

12 hours ago, Likekinds said:

Hi, All,

I have no camera or telescope, so I wont be making contributions in that area. I have thousands of pictures from NASA, Hubble, etc. Just looking at these pictures, I get lost in time. I do fear, if I were viewing the Heavens from such as the James Webb Space Telescope, I would be in such awe, I might never return to 'reality'.

I do hope questions will be considered a form of contribution. I have lots of them, most from early childhood, on. I have limited formal education and hope to put my questions to those with a good background in astronomy. What might be considered common knowledge to those folks, might well add to my fascination of the Universe.

 

First question.

I read so much about more and more powerful telescopes. It is said they now are able to peer at the very edge of the Universe. I don't understand this. I thought it was generally accepted that there is no end to the Universe (as we know it) and therefore no 'edge'. I'm wondering. When the writers of these essays refer to the edge of the Universe, could they actually be referring to a point in time rather than  a place in space? The deeper we look into space. the farther back in time we go. Theoretically, we could approach a time where there is nothing to see as the stars would not have yet come into existence.

If I am correct, this point in time would occur in all directions. As there is no up or down, east or west in space, there is no 'place' in space, therefore no edge. So I ask you, was the word 'edge' used as a matter of convenience when time was what was actually meant? Somehow, I'm not quite ready to accept that there is an actual, literal edge to our Universe.

Thanks

 

 

You are correct and as Vlaiv eluded the term "edge" owes more to poetic intent than perhaps a literal meaning.  If you like, we can see to the "edge" of the visible universe, light from beyond which will never be able reach us. So in that respect then the "edge" is real but it represent a visual/information edge.

Jim  

[vlaiv]

1 hour ago, barbulo said:

However, I have my doubts since the age of our planet is just a blink of an eye compared to the Universe’s magnitudes. 

Not really. Age of Earth is estimated to about 4.5 billion years while age of universe is estimated to about 13.8 billion years.

This means that universe is only about x3 older than Earth

[Ouroboros]

I thought the “edge” was set by the time light has been able to travel since the Big Bang.   

You might suppose that was 14.5 billion light years away, but for some reason I can’t now recall it’s actually much further than that …. Because it’s been expanding during that time or something. 

[vlaiv]

1 minute ago, Ouroboros said:

I thought the “edge” was set by the time light has been able to travel since the Big Bang.   

There are different "horizons" related to big bang, light travel and expansion of universe.

 

[vlaiv]

Here are two more interesting and entertaining videos on this topic:

https://www.youtube.com/watch?v=vIJTwYOZrGU

https://www.youtube.com/watch?v=AwwIFcdUFrE

 

[Astro Noodles]

6 minutes ago, Ouroboros said:

I thought the “edge” was set by the time light has been able to travel since the Big Bang.   

You might suppose that was 14.5 billion light years away, but for some reason I can’t now recall it’s actually much further than that …. Because it’s been expanding during that time or something. 

You're talking about 'expansion theory' and 'dark energy'. 

In my mind these are not clearly defined mechanisms yet for explaining why the observable universe is older/larger than it logically should be.

[vlaiv]

2 minutes ago, Astro Noodles said:

You're talking about 'expansion theory' and 'dark energy'. 

In my mind these are not clearly defined mechanisms yet for explaining why the observable universe is older/larger than it logically should be.

What do you mean?

[Cornelius Varley]

2 hours ago, scotty38 said:

I have a question that is even more baffling, why do you show as making zero posts.......

The thread was originally started in the Welcome section and then moved to a more appropriate area.. Posts made there don't count to your overall post count.

2 hours ago, Likekinds said:

Very interesting and informative.  Now, I will ask my second question before giving you guys a break. Thank you.

Please post in the relevant sections of the forum rather than the Welcome section.

[Astro Noodles]

20 minutes ago, vlaiv said:

What do you mean?

I see it is actually called 'Inflation Theory'.

What I mean is that if the universe was created by the big bang 13.8 billion years ago, which is generally accepted, an if objects in space/time can travel at  no more than the speed of light, then the furthest observable object can be no more than 13.8 billion years ago. The furthest observed objects fall into the 13+ billion year light travel distance. However, the red-shift of these objects suggests that they are more than twice that distance away.

Either there is something wrong with the observational techniques (which seems unlikely), or the universe itself is expanding .

The way understand it as a layman is that the universe itself is expanding but the physical mechanism that causes this to happen is posited to be dark energy. But as dark energy has yet to be observed or measured directly in any way, in my mind it is not clearly defined yet.