A universe without end

[glenc]

"...The cosmos was assumed to be expanding at a decreasing rate. This was based on the premise that the initial outward force of the big bang, and subsequent period of inflation, was counteracted by gravity, which acted as a kind of cosmic brake on galaxies in their headlong rush away from one another.
Then along came two teams of scientists, one led by Brian Schmidt of the Australian National University's Mount Stromlo Observatory near Canberra and the other by Saul Perlmutter of the Lawrence Berkeley National Laboratory in the US.
After scrutinising supernovas, or exploding stars, in relatively nearby and distant deep space, the teams reached an astounding conclusion: the universe's expansion was accelerating. The discovery rocked the cosmology world and earned its pioneers the 2011 Nobel prize for physics..."

Read more at: http://www.brisbanetimes.com.au/technology/sci-tech/a-universe-without-end-20120327-1vvsc.html#ixzz1qO7bF4jG

[Barrykgerdes]

All these theories suggest a finite universe. If you don't believe in an infinite universe you need to explain what is outside the universe. We only know of the visible universe.

Barry

[xelasnave]

What is outside the Universe???

A vacant lot maybe.

There is only the Universe so there can be no outside probably even no edges.:D

Does this mean it is infinite:shrug:.

Can the big bang theory turn finite into infinite? How does a finite double up to become infinite? These questions are difficult to answer and there are more:eyepop:.

And how many Universes are there?

Well there is the one we can observe, the observable Universe (and I am not too sure if we can give it a specific number in terms of a diameter (I grab 14 billion light years but it is more complex than that for many reasons) but I think it is suggested there is much more and that we may be dealing with something in the order of 100,000,000,000 light years diameter ..does that mean the edge is found about there:P..well no as we can never find an edge (I think).

What I am trying to say describing the Universe is not easy and even if you are one of the lucky folk to be at the cutting edge of human understanding in this area making a one sentence statement will never describe the Universe. It is exciting that we do however:)

It is very interesting the observations suggesting expansion is accelerating and one wonders again how we have an infinite but finite Universe that is huge but is expanding at an accelerating rate...so one wonders into what does it expand:shrug:. But it does not expand into anything:question:...But how can that be:confused2:...if it is "nothing" how far does the nothing go before we get to something else:D....

Grasping any reality for us is difficult we see only the visual part of the specrum so we think in the visual spectrum creating a perception that reality is all in the visual spectrum...all the time knowing and being capable of converting other parts of the spectrum into code we can comprehend ...

And so althought we know of the range of the spectrum we tend to disregard what we dont experience personally. I like a description (follows)to aid comprehension of the spectrum...if we have a lenght of movie film 2500 miles long of that only one frame could be representing the visual part of the spectrum...we are near blind.

The trick is not to let this blindness interfere with our understanding of what we cant see but "see" it nevertheless:rolleyes:.

So we are at a disadvantage when describing reality even though we are doing rather well.

My point is ..things are much more complex than even our best brains can fathom so be careful when you think you can visualize a Universe ..how can a human visualise in all parts of the spectrum (and time as well) and perhaps other things HBs for example;)...so complex ones brain should bust.

But I think be the Universe finite or infinite there is no "outside" even that though leaves me far from content.
alex:):):)

[Barrykgerdes]

Only one thing to say
These are questions I always ask and come up with the same answers.
You can also try a bit of Sherlock Holmes, "Eliminate the impossible and what is left must be the answer no matter how improbable"

Always keep an open mind!

Barry

[Barrykgerdes]

Here is one scenario regarding the "big Bang"

The "brains" talk about singularity and creation out of nothing. This may be so but what if all the matter we know of in the visible universe collapsed into a single mass, a monster black hole.

According to our physical laws that may or may not apply the pressure could creat a temperature at the core of unbelievable magnitude. What if the "matter" could not exist at this temperature and caused a massive "explosion", "big bang". The temperature would instantly drop as the mass "exploded" reducing the pressure, cooling and condensing the atoms, elements, compounds etc as we know them. Just one idea to think about.

Every theory creates more questions than answers

Barry

[xelasnave]

How big is a monster black hole:shrug:, After the event horizon can we measure the size of the pysical black hole? Can we describe it in lenght and width? I dont think we can as is seems irrespective of its mass it is so small we can not measure it .. my impression here only and I wonder if that is the reality.

As to your hypothetical black hole senerio what can I say... the big bang sortta worked that way I think..but I really dont know I was not there and dont understand those who claim they know exactly what happened.

I dont like the inflation aspect of the big bang theory as it offends my human experience.. not that counts for anything.. but it is hard to accept all could grow from the size of a basket ball to all there is in less than a second ..from zip to 30 billion light year diameter in less than a second:eyepop: ..rather from zip to approx 200 billion light years dia:eyepop:....or from zip to infinite in less than a second:eyepop:.:question:

I cant manage that I am only human and must proceed on the basis that it may however be possible..scientists seem to be confident and one frequently hears of more new news which supports the current view.
AND I think the big bang is the only acceptable view with no alternative theory in contention:shrug:.

If only one could know it all.

My fantasy goal in life was to travel from one end of the Universe to the other and stand at the edge and peer at what may lay beyond.
Even to imagine such (with out the burden of real science;)) would be difficult.

More to the observation reported in Glen's post I would love to hear why such may be so... why should things be speeding up... are we in a giant cake ready to be taken out of the oven ...will matter finally reach near C as it races away from other matter? Will the relationship of space and matter change... I must keep these questions by the phone and ask the various telemarketers who call :D



alex:):)

[avandonk]

Alex space and time are the same thing. Inflation does not break any laws of physics. Inside a promordial universe undergoing inflation light still travels at the speed of light. It is the space time construct that is expanding 'faster' than light. It has no meaning as there is no reference.

It is a bit like a barrel roll in an aircraft. You experience 1g yet the aircraft has just done a 360 degree roll.

http://www.youtube.com/watch?v=tOZEgKXJMCE


Bert

[xelasnave]

Thanks Bert.
I was aware that Inflation does not break any laws of physics and that light still travels at the speed of light and that it is the space time construct that is expanding 'faster' than light although my comment "will matter finally reach near C as it races away from other matter?" would appear not to reflect my understanding that it is space that is expanding as oppossed to matter travelling away from each other. I think the matter can be stationary in effect but the expansion continues to seperate them at increasing distance.

Thanks for the link.

alex:):):)

[KenGee]

I'd like to pick up on another point as well. There was no time before the big bang. Time started at the the big bang. The universe didn't spring from nothing it has always existed. The universe has existed for all of time ever since the begining.

[mill]

Does the universe even know time?
Humans started to use time because they need it to be on time somewhere.
humans think in time, the universe? who knows???:question:

[ballaratdragons]

Bit of a contradiction there :P

'Always existed' and 'since the beginning'.
A beginning means there was a start, so it couldn't always have existed or there would be no beginning.

Now I'm getting myself confused :lol:

I hope you know what I mean ;)

[mill]

Stop it Ken, now you are confusing me :P

[rcheshire]

Is the expanding and accelerating universe subject to time? Acceleration is a rate of movement of a body defined by a vector and time. The processes within the universe are observed as in time. If there was no observer, can it be said that time exists. An observers intervention at any time would note the same universal properties. And even if the observer was not able to make this observation, would the physical properties of the universe change or cease to exist because it is not observed? It just means that it is not observed and time is a property of our physical universe. The whole thing becomes existentialist otherwise.

If time is a period that can be measured between events, that is we are conscious of a passing of time - maybe observing the movement of a clocks second hand - does it mean that the universe had a beginning and will have an end. Is time unique and an essential property of the universe, without which it would cease to exist and if so what remains? Endlessness? Which is a different matter altogether because most of us have no reference point.

You might ask, what point to the universe without observation? We are here and observing with interest.

[xelasnave]

I recall in a forum where time was the subject for discussion and someone posted that nature has/uses time so everything does not happen all at once:).

I thought that to be a joke but when you think of it that is probably a reasonable explaination.

The photon travells at C and that is the upper limit of how things will have to take turn as it were and through out nature we find there is a "time" limit , chemical reactions atomic reactions ...anyways nature recognises time one could think.

I have always seen even the emptiest part of space as full of something:screwy: photons for example but one could make a long list and each of the units that make up the something that is nothing is rushing in all directions at c or near it (with an infinite empasis on all directions) and so one can imagine this could not happen all at once all the photons just would not fit if they arrived all at once.

Maybe photons cant go faster because we are getting to close to the propostion of everything happening at once:shrug:.

Just imagine what we would find in nothing if we simply limit finding to the spectrum...I try and see a multitude of 2500 mile strips of movie film (in a wave;))on every tradgetory all trying to fit and marvel at how they must fit... like a box full of eels.

Oh if one could know the before the big bang. Some say the universe in effect may cycle between singularity and ...mm a burnt out universe. I think some think there may be other bubble universes...but the word universe means they would really be part of our universe:D.

It was not long back when we thought the milky way was the entire universe... so one needs to be prepared for maybe further news of how little we are.

alex:):):)

[xelasnave]

Thats it:eyepop:.

The universe expands because space has to make room for all the new radiation of stars if it does not it approaches the possibility of everything happening at once;) which is impossible one would think even for the universe:D ..so it has to accomodate all this movie film waving thru space:). Is it dark energy or is it really light energy causing expansion:P. If you have 2 ton of movie film it wont fit in a 1 ton box so you get a bigger box:D...and the new box needs to be able to grow to fit the load:D... dam it thats too close to the ballon idea... but yes I like it:rolleyes:

Could there be any other explaination of the accelerating expansion..or rather does any one have a view of the current thinking from the folk at the cutting edge.

alex:):):)

[mithrandir]

My understanding:

Space is expanding away from us, and every other point in the universe, at around 73.5 (+-3.2) Km/sec/megaparsec. (Hubble Constant from WMAP.)

Using that figure and the speed of light of 300000 Km/sec, a rough calculation puts anything more than 4100 (+-100) megaparsecs = 13.3 (+-0.5) billion Light Years away having expansion taking it away from us faster than the speed of light, so the light emitted will never reach us.

As objects we can see reach that distance they get red shifted to invisibilty.

Gravity holds the Local Group together more strongly than expansion is trying to tear it apart, so given long enough the visible universe will be cut down the Local Group, and maybe the Virgo Super Cluster.

How can you talk about what is outside the universe? There is no outside. The universe is everything.

Time starts at the Big Bang. There is no meaning to time before that.

[xelasnave]

Your understanding seems rather sound Andrew:thumbsup:.
Do you know what lies beyond our observable Universe? Can there be a diameter we expect currently emcompasses all that there is?

I think Karl suggested 100 billion light years but I wonder if we can work out such a thing. if it is infinite there is no way it can be measured one would think.

I think Prof Hawking suggested Bubble Universes but I have no idea of what was suggested but one would think the word Universe can have no plural as there can be only the one.

alex:):):)

[mithrandir]

Alex, the "observable universe" and the "universe" are not the same thing. The 100 billion LY value looks like the guestimate of the size of the universe allowing for the expansion since the Big Bang.

My 13ish billion LY is a measure of the distance back in time to where the light was emitted. Those objects are now more like 45 billion LY away, which is consistent with an estimated diameter of around 93 billion LY.

[xelasnave]

Yes that was my original point that there is more universe than the observable universe.

Many folk assume because it is approx 13.5 billion years old it can only be 26 billion light years diameter on the rational that nothing travels faster than light so starting at a point radiation travelling at c we arrive at 26 bly dia...But inflation was not limited to c .well matter was but inflation dealt with the "growth" of space . I think that was one of the points Bert thought I was unaware of..

I must read up on why expansion is accelerating and if anyone has any views etc.

alex:):):)....

[rcheshire]

Reading Einsteins theory of relativity recently, I am led to believe that time causes space to curve. Is the expanding universe a function of time since its inception? Just a wild thought. There are a lot of complex ideas wrapped up in that question, and I wont begin to elaborate. If everything is rushing away from everything else, will there come a time when nothing will be visible from any other point in the universe. That is, everything will red shift out of view of everything else:question:

[mithrandir]

Rowland,
The current theories have expanding space carrying the contents of the universe with it. At some distance space is moving away from us (and every other place since there is no preferred frame of reference) faster than the speed of light, and everything red shifts out of sight as it gets dragged along. That distance seems to be something of the order of 14-15 billion Light Years.

All that will be left are those objects where the gravitational attraction is strong enough to beat expansion and to keep them together. For us that probably means the Local Group (http://en.wikipedia.org/wiki/Local_Group). There won't be many DSOs left to image, but that it won't happen in our lifetimes, unless you expect to live a few billion years.

[rcheshire]

Thanks Andrew. That is how I visualized it. 14 odd billion light years is a 'visual' limitation in that case and does not necessarily define a boundary, as we know it:question: