Does the UNIVERSE have a boundary or OUTER LIMIT?

Actually, I didn't quite mean that the way you are thinking.



Yes, I discovered this a while back on another thread, but I can't remember where it came up.



Agreed. I do not think that it is a sphere with a radius defined by c.

In the for all we know bucket,

Spacetime and existence could be alot bigger than our conception of the universe and the Big bang could be a very small, trivial event it its existence. Imagine the Universe pre-dating the Big Bang, and our BB just being a small event - like a single small expanding bubble in an ocean. All we perceive is our bubble - not the ocean. We wonder where our bubble came from and why, not knowing its a minor happening in a jostling sea.

the Universe is both finite and infinite. Spacetime has been expanding from the moment of creation, therefore it has a boundary, but the concept of what is beyond it has no meaning as spacetime itself is part of our Universe.

Alternatively you can think of 2 dimentional creatures on an expanding balloon. The balloon is finite, but to the flat creatures on it seems infinite.

Jimmy Hoffa

"Bibliophile the BibleGuru wrote:
Let's put a twist to this question:

If the "space" within our Universe is mostly vacuous, up to the point of the "boundary," then what is on the "other side" of the boundary?

Is it vacuous also? or is it full of anti-matter?"

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As I tried to explain you cant think about it in these simple terms. However if you wish you can think of spacetime outside of spacetime being full of cream cheese, Jimmy Hoffa impersonators or anything you want.

Does the Universe have a boundary makes as much sense as asking what happens when you fall off the earth at the horizon.

Answer to this problem and All: Twin Universes Theory


The Law Of "ENERGY can neither be created nor be destroyed. It can be converted from One Form to the Other. Total amount of Energy remains Constant in the universe" holds true everywhere... even in Black Holes or beyond universe

As Stephen Fleming has said recently:

1. BLACK HOLES must GENERATE energy as it is not possible for any SYSTEM to just EAT energy and not produce it.

2. UNIVERSE has a physical cloudy LIMIT. Lights from these CLOUDS has reached our telescopes recently. On analysis, these clouds were found to be large systems that convert energy into Mass and vice versa.

Now you may ask that if Universe is expanding (which surely is) and if the mass is constant then density of universe should go 0 when Space reaches the infinite volume.

These CLOUDS precisely answer that. We do not know what's beyond these clouds.

But few scientists estimate that there may be another complimentary universe (space) outside these clouds that is Contracting and helping making our universe Expand!

Its like a balloon filled with water and twisted to make a dumbbell. press one lobe of the dumbbell water (contract) and water rushes into other lobe (expand) and vice versa

If this is the case ... One day our universe will reach a maximum physical content or volume and start contracting then onwards. This will trigger a BIG BANG in that complimentary universe (which must have contracted to Null) and it will start expanding thereon.

Here :

1. Total Mass is constant.
2. Co-ordination between them can be explained with the simultaneous oscillatory contraction & expansion of the two universes.

Now people say events like oscillation take place under application of external Force (energy) like gravitation in case of pendulum or pressing force of the hand in case of the balloon example.

So what is it that triggers this event of simultaneous oscillatory contraction & expansion of the twin universes ……

If you ask me I DON'T KNOW.

May be its a small baby with a BIG twisted balloon of twin universes in his hands and he is thoroughly enjoying playing with it. ;-)

WHAT SAY?

While thinking of this, we must remember that it wasn't just space which expanded from the BB, but also Time (as we know it). So the very concept of "before" the BB is undefined. The ideas of "before" and "after" only have meaning to us within the event which we call our Universe. Outside of that event (outside of time), we don't even have a framework for thinking about how things work.

....which is what I was trying to say but better put.

but if simple people want to think of a finite universe with a brick wall at the end let them.

I cant be bothered explaining anymore.

Neither would I be mate.But I would prefer a friendly female face to a brick wall.

The outer limits are limited by the inner limits .... feed your head.
The more you understand, the more you know

Vinsan

The laws you quoted apply to relativity not quantum mechanics. So they apply in domains where relativity applies, not those where QM holds sway.

You can't say the total energy of the universe holds constant - we don't know that yet. At a quantum level virtual particles and virtual anti-particles can be created and destroyed or escape to become real trillions of times a second. So the sum of energy and mass of the universe might depend on how spacetime itself is reacting with an underlying membrane of QM reality. We simply don't know.

Black holes aren't eating energy - they are curving spacetime to a point where it is closed. Within the event horizon may well be a reality dominated by QM where it may interact with the membrane our realistivistic reality floats in a way we don't understand.

Before the Big Bang call time virtual time, membrane time or QM time - basically you are in a different frame of reference where our perception of time based on relativity isn't grounded. You can't say it didn't exist or is meaningless - you can only say we don't have solid theoretical models for it yet.

A Big Bang / Big Crunch scenario is unlikely. But 99.999% of folk talk about our Universe when they really at most should be referencing our observable Hubble Sphere within a possibly incredibly large or even infinite universe which is itself a small component of a much larger and more complex reality, or underpinned at a minute level by SuSy or a QM variant.

We don't have anywhere near good enough models to predict much yet!

Classical Physics Vs Modern Physics
Why can't we belive on more on more trusted facts of classical physics of Energy Conservation than prefering the fragile facts of Modern day Physics.

I mean modern day physics always proposes everything on abstract manner. Look at the foundation..... Duality of Matter ... There you go ..... confused and making excuses for why things don't work as per this rule... and then propose the another rule and say "Hey, it works becoz matter is also a wave"

I would always like to be a critic of Modern Day Physics.

just because you dont understand it visnan does not qualify you to criticise it

Hay Steve,

I am very well aquainted with the facts of Modern Day Physics. I may not understand very deep and complicated theories in that as I am not that qualified in those areas. But I still doubt the way modern day physics answers theories in the "may be" fashion. Classical physics never works that way.

WHY now we say that just becoz we haven't seen Black Holes and propose that they curv spacetime to a point, classcial physics is not applicable in those scenarios & ONLY Modern Day physics can save us there.

The basic idea is that existance of Gravitation is a proven fact of Classical Physics and the ONLY reason why BLACK HOLES exist. Classical physics can go beyond these limitations and answer the "MAY BE" facts (un)cleared by Quantum physics. Then why do we think that Classical physics cannot answer beyond that.

If a fact is the reason for existence of something, the same fact can also explain out that thing completely. So what we need to study is complecations of gravitation a bit ahead.

What we have done is given CLASSICAL PHYSICS a complete setback and used Modern Physics (Quantum Physics) to explain everything. The two shouldn't be complemented like this but Used together instead.

Mr. Stephen Hawking (Sorry for mistyping his name as New Zealand's Cricket Player Stephen Fleming in my previous post. I am absolutely sorry) said "If you jump into a black hole, your mass energy will be returned to our Universe, but in a mangled form, which contains information about what you were like, but in an unrecognisable state."

Doesn't that prove The law of Conservation of the Energy. Also I never talked about whats Inside Black Hole but I talked about the limit of Universe as CLOUDS that had been revealed by recent images of proposed Big Bang ocassion that occured an eternity back. So why can't we BELIEVE that yes it can happen. A twin universe can exist.

I mean what Quantum Physics does. It also BELIEVES.

Whereas Classical physics STATES.

Finally let me make one thing clear, I completely respect g_day's justification to erase my proposition of twin universe. He is a believer in Modern Day Physics.

But you know I have this small affinity towards Classical Physics. So was my previous reply.

Visan

Classical Physics works very well to a point, but outside that sandbox it's use is limited. Even relativity has limits - the very small or galactic big (e.g. MOND), the very heavy or very high energy densities that start to really warp the very fabric of our spacetime continium. The theoretical physics models really are very new and incomplete - they can barely spell out even topology (shapes of spacetime at the edges, let alone its properties). All I am saying is wait abit and feel free to ride and point of view until the analysis is all done, knowing your spectulating on a preferred outcome.

what about virtual photons then...dont they somehow break this rule....

Ok ... less cryptic. Remember when the earth's gravity was an 'insurmountable' boundry. It was erased, so to speak, by our minds.
Place a boundry on the human mind? I don't think so ...

Is there any point talking bout boundries.. If the fastest we can go is the speed of light, we will never get there!!!

We will if spacetime is an illusory and we pierce thru to a deeper underlying reality and fine ways to powerfully and precisely manipulate it.

....thats the only way you will win the ashes back