The Naked Scientists

The Naked Scientists Forum

Author Topic: Does the universe have an edge, and what's beyond it?  (Read 30215 times)

Chrismalta

  • Guest
Christopher Bianco  asked the Naked Scientists:

Today I came across this report about an explosion originating near the edge of the universe, seen by an orbiting NASA telescope.  The burst of gamma rays is the farthest such event ever detected.

I just can't understand the edge of universe? Does the universe has a real edge and what's beyond it??

Thanks
Chris Bianco from Malta

What do you think?


 

Offline JP

  • Neilep Level Member
  • ******
  • Posts: 3366
  • Thanked: 2 times
    • View Profile
Does the universe have an edge, and what's beyond it?
« Reply #1 on: 01/10/2008 22:02:42 »
They probably meant the edge of the visible universe.  Since light travels at a finite speed, it can only have traveled a certain distance in the 14 billion years the universe has been around.  The light which can reach us defines a giant sphere (radius = 14 billion parsecs) around the earth.  If something is further away than that, its light won't have reached us yet. 

Since light-speed is the speed limit for everything in the universe, nothing from beyond this region will have reached us yet, and so we don't know what's beyond it.  Most scientists tend to believe in the cosmological principle, which says that the universe is pretty much the same everywhere, at least on large scales.  Therefore, it should be basically the same outside our visible universe as it is inside. 

There's a lot more details here: http://en.wikipedia.org/wiki/Observable_universe
 

Offline socratus

  • Sr. Member
  • ****
  • Posts: 329
    • View Profile
Does the universe have an edge, and what's beyond it?
« Reply #2 on: 04/10/2008 05:59:43 »
They probably meant the edge of the visible universe.  Since light travels at a finite speed, it can only have traveled a certain distance in the 14 billion years the universe has been around.  The light which can reach us defines a giant sphere (radius = 14 billion parsecs) around the earth.  If something is further away than that, its light won't have reached us yet. 

Since light-speed is the speed limit for everything in the universe, nothing from beyond this region will have reached us yet, and so we don't know what's beyond it.  Most scientists tend to believe in the cosmological principle, which says that the universe is pretty much the same everywhere, at least on large scales.  Therefore, it should be basically the same outside our visible universe as it is inside. 

There's a lot more details here: http://en.wikipedia.org/wiki/Observable_universe
=====================

Does the universe have a real edge and what's beyond it??

=========================.
Let us suppose that the universe is “a giant sphere
(radius = 14 billion parsecs) around the earth. “
Is it possible to universe to be “a giant sphere
(radius = 14 billion parsecs) around the earth. “ ?
NO !!! Why?
Because the detected material mass of the
 matter in the Universe is so small  (the average density
of all substance in the Universe is approximately
 p=10^-30 g/sm^3) that this mass cannot turn the universe
 into sphere. So, the Universe as whole is flat infinite space.
Then we have question:
“  Does infinity space have any physical parameters?”
My answer is : “ Yes, the Infinite Universe has one
physical parameters. It is T=0K. Because after “ big bang”,
we must take in calculation that T=2,7K expands and therefore
 T=2,7K is temporary parameter and with time it will go to T=0K.
========================.



 

Offline DoctorBeaver

  • Naked Science Forum GOD!
  • *******
  • Posts: 12656
  • Thanked: 3 times
  • A stitch in time would have confused Einstein.
    • View Profile
Does the universe have an edge, and what's beyond it?
« Reply #3 on: 04/10/2008 11:30:24 »
Correct in principle; but aren't the maths a bit awry? 1pc = 3.26 light years. Therefore the edge of the visible universe is 14billion/3.26 parsecs, not 14 billion parsecs.

Socratus - I assume your 2.7K refers to the CMBR. Surely, that can't ever reach 0K as that would imply zero energy level and QM says that is impossible.
« Last Edit: 04/10/2008 11:41:19 by DoctorBeaver »
 

Offline JP

  • Neilep Level Member
  • ******
  • Posts: 3366
  • Thanked: 2 times
    • View Profile
Does the universe have an edge, and what's beyond it?
« Reply #4 on: 04/10/2008 16:05:19 »
Correct in principle; but aren't the maths a bit awry? 1pc = 3.26 light years. Therefore the edge of the visible universe is 14billion/3.26 parsecs, not 14 billion parsecs.

The extra distance is due to the expansion of the universe.  I didn't discuss that detail since it's a bit tricky to grasp.  The light has been traveling at c, but the space between us and those distant stars has stretched.  Your numbers are right if the universe is static.
 

Offline socratus

  • Sr. Member
  • ****
  • Posts: 329
    • View Profile
Does the universe have an edge, and what's beyond it?
« Reply #5 on: 04/10/2008 16:35:46 »

Socratus - I assume your 2.7K refers to the CMBR. Surely, that can't ever reach 0K as that would imply zero energy level and QM says that is impossible.
==============================

Classic physics says that we can't reach 0K.
We can’t reach T= 0K !!!
But not the Nature ( micro particles ) itself !!!
The Nature ( micro particles )  can reach T= 0K !!!

Therefore Quantum theory says that vacuum ( even T= 0K )
is continuum with NO Zero Energy level !!!
That is reason that “ virtual particles “ can exist in Vacuum.
And QT says that from these “ virtual particles “ the real particles
can be born.
==============.
 

Offline DoctorBeaver

  • Naked Science Forum GOD!
  • *******
  • Posts: 12656
  • Thanked: 3 times
  • A stitch in time would have confused Einstein.
    • View Profile
Does the universe have an edge, and what's beyond it?
« Reply #6 on: 05/10/2008 11:40:38 »
Correct in principle; but aren't the maths a bit awry? 1pc = 3.26 light years. Therefore the edge of the visible universe is 14billion/3.26 parsecs, not 14 billion parsecs.
The extra distance is due to the expansion of the universe.  I didn't discuss that detail since it's a bit tricky to grasp.  The light has been traveling at c, but the space between us and those distant stars has stretched.  Your numbers are right if the universe is static.

Are you sure about that? 3.26 light years is 3.26 light years. If 2 objects are 3.26 light years apart and the space between them expands, then they are now more than 3.26 light years apart. A parsec is still 3.26 light years.

Having it the way you stated would be like having an elastic ruler. You could stretch it and measure 3cm, but it wouldn't really be 3cm, it would be more.
 

Offline JP

  • Neilep Level Member
  • ******
  • Posts: 3366
  • Thanked: 2 times
    • View Profile
Does the universe have an edge, and what's beyond it?
« Reply #7 on: 05/10/2008 19:34:52 »
I'm not sure I follow you.  What I was trying to get across was that if the universe wasn't expanding, the furthest things we could see would be 14 billion light years away.  The numbers I give are answers to the question, "How far away from us (currently) is the most distant object we can see?"  In a universe that wasn't expanding, the answer would be 14 billion light years.  However, since the universe is expanding as the light is traveling, the space between us and that object has expanded since it emitted that light, and so it is actually 46 billion light years (14 parsecs) away. 
 

Offline DoctorBeaver

  • Naked Science Forum GOD!
  • *******
  • Posts: 12656
  • Thanked: 3 times
  • A stitch in time would have confused Einstein.
    • View Profile
Does the universe have an edge, and what's beyond it?
« Reply #8 on: 06/10/2008 11:50:11 »
Let's see if I understand you correctly. What you are saying is that although the light we see was emitted 14 billion years ago, the object that emitted it is now 42 billion light years away due to the expansion of the universe. Is that what you mean?
 

Offline JP

  • Neilep Level Member
  • ******
  • Posts: 3366
  • Thanked: 2 times
    • View Profile
Does the universe have an edge, and what's beyond it?
« Reply #9 on: 06/10/2008 15:46:20 »
Yes, that's basically it.
 

Offline DoctorBeaver

  • Naked Science Forum GOD!
  • *******
  • Posts: 12656
  • Thanked: 3 times
  • A stitch in time would have confused Einstein.
    • View Profile
Does the universe have an edge, and what's beyond it?
« Reply #10 on: 06/10/2008 15:56:13 »
OK. I misunderstood at first.
 

Offline LeeE

  • Neilep Level Member
  • ******
  • Posts: 3382
    • View Profile
    • Spatial
Does the universe have an edge, and what's beyond it?
« Reply #11 on: 06/10/2008 17:12:29 »
Heh - yeah - the furthest stuff we can see is now ~42 billion light years away, but the photons we see only originated ~13-14 billion light years away.  Of course, they ended up traveling a lot further than that to reach here, so it depends on how you define it - it could be the distance between us and (a) the object's current distance, (b) the object's original distance, or (c) just the total distance traveled by the photon ;D
 

Offline DoctorBeaver

  • Naked Science Forum GOD!
  • *******
  • Posts: 12656
  • Thanked: 3 times
  • A stitch in time would have confused Einstein.
    • View Profile
Does the universe have an edge, and what's beyond it?
« Reply #12 on: 06/10/2008 18:12:33 »
LeeE - Stop confusing the issue even more!  :P
 

lyner

  • Guest
Does the universe have an edge, and what's beyond it?
« Reply #13 on: 06/10/2008 19:06:22 »
jp
Quote
46 billion light years (14 parsecs) away.
??
1pc is only 3.26ly, actually. You mean 14 billion pc, I think.
 

Offline JP

  • Neilep Level Member
  • ******
  • Posts: 3366
  • Thanked: 2 times
    • View Profile
Does the universe have an edge, and what's beyond it?
« Reply #14 on: 06/10/2008 19:56:58 »
jp
Quote
46 billion light years (14 parsecs) away.
??
1pc is only 3.26ly, actually. You mean 14 billion pc, I think.

Yeah, I dropped a billion somewhere.  Good catch. :)
 

Offline DoctorBeaver

  • Naked Science Forum GOD!
  • *******
  • Posts: 12656
  • Thanked: 3 times
  • A stitch in time would have confused Einstein.
    • View Profile
Does the universe have an edge, and what's beyond it?
« Reply #15 on: 06/10/2008 20:34:52 »
PAH... what's a billion here & there between friends!
 

lyner

  • Guest
Does the universe have an edge, and what's beyond it?
« Reply #16 on: 06/10/2008 23:06:14 »
14 or 14 billion: you'd be no nearer to the edge.
 

Offline socratus

  • Sr. Member
  • ****
  • Posts: 329
    • View Profile
Does the universe have an edge, and what's beyond it?
« Reply #17 on: 07/10/2008 06:42:54 »
1.
quote author=DoctorBeaver

PAH... what's a billion here & there between friends!
2.
quote author=sophiecentaur

14 or 14 billion: you'd be no nearer to the edge.
=========.
Nice.
It only remains to understand what infinity is.
=====================
 

lyner

  • Guest
Does the universe have an edge, and what's beyond it?
« Reply #18 on: 07/10/2008 09:30:50 »
We've a long way to go yet.
 

Offline socratus

  • Sr. Member
  • ****
  • Posts: 329
    • View Profile
Does the universe have an edge, and what's beyond it?
« Reply #19 on: 07/10/2008 14:22:46 »
We've a long way to go yet.
==================

It is pity.  Is our intellect really so poor ?

==========================
 

Offline DoctorBeaver

  • Naked Science Forum GOD!
  • *******
  • Posts: 12656
  • Thanked: 3 times
  • A stitch in time would have confused Einstein.
    • View Profile
Does the universe have an edge, and what's beyond it?
« Reply #20 on: 07/10/2008 14:24:32 »
We've a long way to go yet.
==================

It is pity.  Is our intellect really so poor ?

==========================

Our knowledge is
 

Offline socratus

  • Sr. Member
  • ****
  • Posts: 329
    • View Profile
Does the universe have an edge, and what's beyond it?
« Reply #21 on: 07/10/2008 14:51:38 »
We've a long way to go yet.
==================

It is pity.  Is our intellect really so poor ?

==========================

Our knowledge is
=====================
Sorry, another paradoxical question:
How can Infinity have its Edge ?

==================


 

Offline DoctorBeaver

  • Naked Science Forum GOD!
  • *******
  • Posts: 12656
  • Thanked: 3 times
  • A stitch in time would have confused Einstein.
    • View Profile
Does the universe have an edge, and what's beyond it?
« Reply #22 on: 07/10/2008 15:29:31 »
It can't
 

Offline socratus

  • Sr. Member
  • ****
  • Posts: 329
    • View Profile
Does the universe have an edge, and what's beyond it?
« Reply #23 on: 07/10/2008 19:52:12 »
It can't
===============
 It can’t.
It can’t, because this question seems paradoxical:
“How can Infinity have its Edge ? “

It sounds like two mutually exclusive of terms;
“infinity and edge”, “infinity and  finite ”, “ infinity
and limit”…..etc. And I wanted to ask: “How does
 infinity connect with concreteness ? ”
I took this idea from German philosopher Georg. Hegel .
On his opinions it is possible to know the connection between
the infinite and the concrete, and to know about this connection
 not only with quantity, but also with quality. And he wanted
 to find rational and scientific explanation of this connection. 

And you wrote:” It can’t. “.     ( It cannot be.)
Okay.  I ask this question in other way: “ How can from
Infinite Vacuum space the local stars formations appear ?”
I don’t think that this question is paradoxical.
I think this question is unsolved process in our Universe.

Can this process be ?
============.
 

Offline DoctorBeaver

  • Naked Science Forum GOD!
  • *******
  • Posts: 12656
  • Thanked: 3 times
  • A stitch in time would have confused Einstein.
    • View Profile
Does the universe have an edge, and what's beyond it?
« Reply #24 on: 07/10/2008 21:00:56 »
You're doing it again - assuming space is infinite. It's not difficult to explain how stars and galaxies formed; but they did not form from "an infinite vacuum".

Initially, the universe was too hot for matter to form. As the universe expanded, it cooled. It reached the point where elementary particles could appear. Those particles joined to become forms of hydrogen. Gravity pulled massive clumps of this hydrogen together in areas of anisotropy - wrinkles in spacetime that hadn't been totally equalised by inflation - and galaxies formed.

Within the hydrogen clouds, stars started to form. At first, gravity-powered stars formed. As those stars condensed further, they reached the point where nuclear reactions could take place to become stars as we know them today.

There; and not a single mention of infinity  :D
« Last Edit: 07/10/2008 21:04:01 by DoctorBeaver »
 

The Naked Scientists Forum

Does the universe have an edge, and what's beyond it?
« Reply #24 on: 07/10/2008 21:00:56 »

 

SMF 2.0.10 | SMF © 2015, Simple Machines
SMFAds for Free Forums