The Naked Scientists

The Naked Scientists Forum

Author Topic: Will the Universe continue to expand forever?  (Read 12235 times)

Offline Mad Mark

  • Full Member
  • ***
  • Posts: 60
    • View Profile
Will the Universe continue to expand forever?
« on: 18/10/2009 01:27:36 »
Would space time keep on expanding even when all the matter in the universe deconstructs?

Or would the universe made up of short lived virtual particle's keep it going to infinity?

Is our understanding of what's driving the acceleration flawed. If all the galaxies are just going along for the ride where is all the new energy coming from to drive an acceleration. Have scientist been able to determine if the expansion is equal everywhere (taking the effects of local gravity out of the equation) or has our universe grown more complex in time creating ever increasing probabilities and in doing so created extra space-time in the process.
« Last Edit: 18/10/2009 12:39:32 by chris »


 

Offline Mr. Scientist

  • Neilep Level Member
  • ******
  • Posts: 1451
  • Thanked: 2 times
  • http://www.facebook.com/#/profile.php?ref=profile&
    • View Profile
    • Time Theory
Re: Will the Universe continue to expand forever?
« Reply #1 on: 18/10/2009 01:50:32 »
Would space time keep on expanding even when all the matter in the universe deconstructs?
Or would the universe made up of short lived virtual particle's keep it going to infinity?
Is our understanding of what's driving the acceleration flawed. If all the galaxies are just going along for the ride where is all the new energy coming from to drive an acceleration. Have scientist been able to determin if the expansion is equal everywhere(taking the effects of local gravity out of the equation) or has our universe grown more complex in time creating ever increasing probabilities and in doing so created extra spacetime in the process.

Chances are is that it will come to an end. Space and time simply could not extend forever because as galaxies receed, the physical signalling of the forces become strained. Eventually, this wil result in a big rip, where the fabric of spacetime cannot uphold the presence of galaxies at such long ranges, and so spacetime becomes so highly stretched, it will result in all matter being ripped apart - including spacetime... we would end catasprophically with a complete depletion of reality.
 

Offline Vern

  • Neilep Level Member
  • ******
  • Posts: 2072
    • View Profile
    • Photonics
Re: Will the Universe continue to expand forever?
« Reply #2 on: 18/10/2009 07:40:12 »
All is well in the real universe. Consider that the forever expanding universe is a mental creation. It is a creation to help satisfy observations of really old light that has survived for billions of years. We can only observe the light. We must keep in mind that anyone explaining observations of that old light will try and show how it fits their own view of the construct of the universe.

Sometimes we form opinions about reality that is not real. I suspect that most of our opinions about reality are not real. The only thing we can know for certain is that reality is real, no matter what is our opinion of it.
 

Offline LeeE

  • Neilep Level Member
  • ******
  • Posts: 3382
    • View Profile
    • Spatial
Re: Will the Universe continue to expand forever?
« Reply #3 on: 18/10/2009 12:36:51 »
The acceleration of the expansion of the universe is a very curious thing.

If you were to plot the rate of expansion over time, from the Big Bang to the present, you end up with a complex curve that can't be described by a simple formula.

Basically, in the first models of expansion, the universe started expanding very quickly but from that point on, that rate of expansion was thought to decrease as it was slowed by gravity.  This gives a nice simple curve.

Then it was found that there seemed to have been a discontinuity in the curve, just after the initial period of expansion, where the rate of expansion increased exponentially for a relatively short period of time, now called the inflationary epoch.  However, a plausible reason for this was found, so the curve still made sense.  That is to say, the factor that caused the discontinuity, and why it occurred when it did made sense.

Following the inflationary epoch, things seem to have settled down again.  The universe was still expanding, but due to gravity, the rate of expansion was slowing, as you might expect.  This put us back on an understandable and simple curve.

However, at another later point along the curve, the rate of expansion of the universe appears to have started accelerating again, introducing another change to the curve and meaning that another factor must have come into play at that point.

The current explanation for the accelerating rate of expansion is dark energy, but the problem with this is that not only do we not know what dark energy actually is, but we also don't know why it should have started acting when it did, and not before or after then.  Of course, it's difficult to say why it started acting when it did when we don't really know what it is we're talking about.

To me, there seem to be two options here: either the accelerating expansion of the universe is real and there's a lot more to the nature of energy and matter than we're aware of, or that the accelerating expansion of the universe is actually incorrect and due to misinterpretation of the observations.  Personally, and atm, I think there's still scope for either option.

Regarding the ultimate deconstruction of all matter: I just can't see this.  As the universe expands, the matter within it does not expand, otherwise the relative distances between separating galaxies would remain the same i.e. the galaxies would expand along with the universe.  They don't seem to do this though, and instead the galaxies seem to stay the same size but just move further apart.  This being so, I see no reason to suggest that matter will tear itself apart as the universe expands.  If the universe is expanding now, but matter is not already tearing itself apart, why should it start doing so at some point in the future?  Once again, it would need an additional and as yet unidentified factor, and one that is not currently operating, to bring this about.
 

Offline Vern

  • Neilep Level Member
  • ******
  • Posts: 2072
    • View Profile
    • Photonics
Will the Universe continue to expand forever?
« Reply #4 on: 18/10/2009 13:31:44 »
Quote from: LeeE
To me, there seem to be two options here: either the accelerating expansion of the universe is real and there's a lot more to the nature of energy and matter than we're aware of, or that the accelerating expansion of the universe is actually incorrect and due to misinterpretation of the observations.  Personally, and atm, I think there's still scope for either option.
It is comforting to see that wisdom still exists in the main stream of physics. :)
 

Offline Nizzle

  • Hero Member
  • *****
  • Posts: 964
  • Thanked: 1 times
  • Extropian by choice!
    • View Profile
    • Carnivorous Plants
Will the Universe continue to expand forever?
« Reply #5 on: 19/10/2009 12:14:10 »
Could I, as a layman astrophysicist, propose an idea?
Please explain me why my idea would be wrong, as I'm almost certain it will be ;)

Isn't it possible that the universe might still be expanding because there was an initial acceleration and a lack of 'spacetime friction' (?) because the universe is expanding in a 'spacetime void'

Or bizarre idea nr. 2: Maybe there's something we don't know yet outside our own spacetime, that pulls on the edges of our spacetime, instead of the general idea that expansion comes from a 'pushing' force within.
 

Offline LeeE

  • Neilep Level Member
  • ******
  • Posts: 3382
    • View Profile
    • Spatial
Will the Universe continue to expand forever?
« Reply #6 on: 19/10/2009 12:40:37 »
Or bizarre idea No. 3: The amount of expansion of the universe is constant per unit (unoccupied) spatial volume, so as the volume increases due to expansion the total amount of expansion must also increase.

For example, if we say that expansion over a set period of time will increase the side of a one metre cube by one % then after that period of expansion the side of the cube will be 1.01 metre, an increase of 0.01 metre.  However, the next period of expansion expansion will increase the side of our original cube by 0.0101 metre, so the rate of expansion has appeared to increase.
 

Offline Vern

  • Neilep Level Member
  • ******
  • Posts: 2072
    • View Profile
    • Photonics
Will the Universe continue to expand forever?
« Reply #7 on: 19/10/2009 14:12:05 »
Or bizarre idea No. 4; maybe it is the signals we use to detect the expansion that is expanding. :)
 

Offline litespeed

  • Sr. Member
  • ****
  • Posts: 419
  • Thanked: 1 times
    • View Profile
Will the Universe continue to expand forever?
« Reply #8 on: 01/11/2009 21:09:56 »
No one knows what the hell will happen to the Universe. For almost my entire adult life the only arguement was whether expansion was fast enough to keep going, or would start colapsing back towards a big crunch.  So, after 5 or 6 decades of this squabble, all of a sudden all the SOBs simply say "Never Mind"

Something similar to this took place before "inflation" of the early universe was found to be immune to the spead of light.  They call it a Scalar Field.  Who in the hell knows whether the current increasing speed of expansion is also subject to a Scalar Field that will suddenly come to an end.

You need to remind yourselves these people have very short timeframes in their lives, and do not generally think as big as they think they do.  To this very day they can not account for something like 90 percent of matter in the universe.  Black matter, black energy.  Keep sending me your newsletters, but perhaps with a bit more humility.
 

Offline litespeed

  • Sr. Member
  • ****
  • Posts: 419
  • Thanked: 1 times
    • View Profile
Will the Universe continue to expand forever?
« Reply #9 on: 01/11/2009 21:52:19 »
The early Michaelson Morley experiments on the speed of light unaccountable showed it to be the same in all directions. Once confirmed, that would make the equation E=mc2 inevitable. They were testing whether the 'either' that propogated light was similar to the 'either' that propogated the speed of sound.

It turns out you can travel fast enough to leave sound signal behind you. However, light did not seem subject to such contraints.  Later, however, the big bang theory introduced the 'either' of expanding space. Specifically, the expansion of space over long distances can actually exceed the speed of light.  In other words, at far enough distances, light will NEVER get to you because it has been propogated in an either that is expanding faster then that.

This is all very interesting and worthwhile work. However, it has convinced me there are so many dimensions in and about the universe that contemplation approaches theology. For instance, human self cognizance. We could build robots that acted like humans, and would tell us they are individuals. Could we believe them? In a deterministic universe all creatures great or small would act on the sum total of their accumulated experiences like insects.

Yet humans have a very odd idea they are separate from their fellows, and even if we act on the sum total of our accumulated experience, mine would be entirely destinct from yours.

After thinking about all this for a very long time I have become convinced each of us, perhaps supported by guantam mechanics and probability theory, has created an alternate universe from which we interact with all the other dimensions and universes that are NOT us. It might look like a seemless whole, but we inhabit our own space, created out of our own life experiences.

Just meandering thoughts...
 

Offline Vern

  • Neilep Level Member
  • ******
  • Posts: 2072
    • View Profile
    • Photonics
Will the Universe continue to expand forever?
« Reply #10 on: 02/11/2009 23:12:46 »
Quote from: litespeed
This is all very interesting and worthwhile work. However, it has convinced me there are so many dimensions in and about the universe that contemplation approaches theology. For instance, human self cognizance. We could build robots that acted like humans, and would tell us they are individuals. Could we believe them? In a deterministic universe all creatures great or small would act on the sum total of their accumulated experiences like insects.
Yes; it is very interesting. You have contemplated a scenario of human self cognizance. What about when the computers we develop progress to the point of self cognizance? Is this even possible? Will we ever see truly sentient non-life entities? Will they be friendly?

Mind boggling things, that.
 

Ethos

  • Guest
Will the Universe continue to expand forever?
« Reply #11 on: 02/11/2009 23:35:46 »
Or bizarre idea No. 4; maybe it is the signals we use to detect the expansion that is expanding. :)
Or bizarre idea #5:

Since I believe the universe to be infinite and not bounded like the Standard Model suggests, there is ample room for it to expand without limit. And I agree with Vern that the expansion we are observing is do to the expanding signal of tired light.
 

Offline Mr. Scientist

  • Neilep Level Member
  • ******
  • Posts: 1451
  • Thanked: 2 times
  • http://www.facebook.com/#/profile.php?ref=profile&
    • View Profile
    • Time Theory
Will the Universe continue to expand forever?
« Reply #12 on: 03/11/2009 16:17:17 »
Or bizarre idea No. 4; maybe it is the signals we use to detect the expansion that is expanding. :)
Or bizarre idea #5:

Since I believe the universe to be infinite and not bounded like the Standard Model suggests, there is ample room for it to expand without limit. And I agree with Vern that the expansion we are observing is do to the expanding signal of tired light.
Since everyone is wildly speculating:

Bizzare idea 6: Tired light is caused by quanta moving through a smear of virtual particles; the ether. As it ploughs through the ether, it will gradually loose energy and momentum, over large periods of time due to its sufficiently high velocity due to the vacuum energy density.

p.s. I don't support tired light :)
 

Offline Vern

  • Neilep Level Member
  • ******
  • Posts: 2072
    • View Profile
    • Photonics
Will the Universe continue to expand forever?
« Reply #13 on: 03/11/2009 17:09:20 »
I wonder if anyone has thought to look for spectral lines in lower frequencies; that might give a clue as to how long the universe has been expanding. There's already a Quasar with a spectral shift that places it about 28 billion light years away.

Some of the radio telescopes might be capable of doing it.
 

Offline litespeed

  • Sr. Member
  • ****
  • Posts: 419
  • Thanked: 1 times
    • View Profile
Will the Universe continue to expand forever?
« Reply #14 on: 03/11/2009 17:26:46 »
ethos:

You raise an interesting paradox.  If the universe is already infinite, how can it expand? By deffinition infinity can neither be added to or subtracted from! Personally, I do not believe actual infinities of any sort exist in our four dimensional universe.

For instance, if there are an infinite number of suns, we would need Sunscreen with an infinite SPF. On the other hand, if the universe is expanding space at an increasing rate, it is entirely feasible that it could exceed the speed of light, as was apparently the case during 'inflation'.

 

Offline litespeed

  • Sr. Member
  • ****
  • Posts: 419
  • Thanked: 1 times
    • View Profile
Will the Universe continue to expand forever?
« Reply #15 on: 03/11/2009 17:31:05 »
Vern,

Yeah. I think some new Eintein should begin work on human consciousness. Here is a human analog to the smart robot.  Thank Gene Rodenbery.  I enter the transporter, get disasembled and reasembled elswhere.  I feer to do so would kill me, but create my clone at the other end. No one, not even the clone would know that, however.

I quess the metaphysical part of this is whether human consciousness is created independently of the matterial brain, and can be transmitted along with the dissasembled me.

I reall love this kind of stuff!
 

Offline litespeed

  • Sr. Member
  • ****
  • Posts: 419
  • Thanked: 1 times
    • View Profile
Will the Universe continue to expand forever?
« Reply #16 on: 03/11/2009 17:36:59 »
Mr S.

Interesting. A photon that does not encounter anything in its travels, will none the less lose energy as space expands and reduces its energy through red shift. [From the perspective of someone looking at it from a long distance.] So, where would that energy go? Perhaps the very expansion of the 'space ether' draws its expansion from the photon. If that is the case, then energy is moved from electromagnetic, to physical creation and maintenance of space itself.
 

Ethos

  • Guest
Will the Universe continue to expand forever?
« Reply #17 on: 03/11/2009 17:43:55 »
ethos:

You raise an interesting paradox.  If the universe is already infinite, how can it expand?

Exactly why I don't ascribe to an expanding universe. BTW, infinities can be of different sizes. Google the term infinity and it will explain...............
 

Offline litespeed

  • Sr. Member
  • ****
  • Posts: 419
  • Thanked: 1 times
    • View Profile
Will the Universe continue to expand forever?
« Reply #18 on: 03/11/2009 18:06:34 »
Ethos

I googled Infinity and was subsequently invited to test drive the latest FX. The idea infinities can be of different sizes intriques me. Could you take the time to provide a link?

Thanks
 

Ethos

  • Guest
Will the Universe continue to expand forever?
« Reply #19 on: 03/11/2009 18:50:06 »
Ethos

I googled Infinity and was subsequently invited to test drive the latest FX. The idea infinities can be of different sizes intriques me. Could you take the time to provide a link?

Thanks
There is a book; 'One, two, three, infinity.'

One example I can think of would be the simple exercise:

Let's say we have a set of infinite numbers. Now let's divide the odd from the even into two different sets. Both are infinite but are only half as large as the original set.
« Last Edit: 14/11/2009 02:41:42 by Ethos »
 

Offline Vern

  • Neilep Level Member
  • ******
  • Posts: 2072
    • View Profile
    • Photonics
Will the Universe continue to expand forever?
« Reply #20 on: 03/11/2009 19:06:19 »
Quote from: litespeed
For instance, if there are an infinite number of suns, we would need Sunscreen with an infinite SPF. On the other hand, if the universe is expanding space at an increasing rate, it is entirely feasible that it could exceed the speed of light, as was apparently the case during 'inflation'.

This assumes that light forever remains intact; in its travels light encounters space debris. Given enough time all of the light may be absorbed.

I have thought of the same scenario about "beam me up". My first thought was whether the same mental essence, I hesitate to say soul, materializes at the destination. Yep; the beamed up person could never know. :)
 

Offline litespeed

  • Sr. Member
  • ****
  • Posts: 419
  • Thanked: 1 times
    • View Profile
Will the Universe continue to expand forever?
« Reply #21 on: 03/11/2009 20:34:16 »
Ethos! One Two Three Infinity!

Man, does that bring back memories. I read it in probably 1964, and have been hooked on the stuff ever since. Right now I am not up to the technical issues of infinity variations, however, after all these years I finally figured out the special theory of relativity!

Specifically, if we send an travelor toward point A and back at near the speed of light, he will have aged less then us.  Howevever, how old was he when he GOT there.  After all, for the entire duration we have been communicating with each other. It suddenly became christal clear, HE observes his SPEED as much greater then do we.

His time is running more slowly, and so when he does solar navigation he reports his progress much faster then we do. Theoretically, he could travel faster then the speed of light, according to his clock.


My problem was always this.  As we await his round trip return, I am perplexed at WHEN he got to Point A, from his point of view.

The obvious answer is he observes,
 

Offline litespeed

  • Sr. Member
  • ****
  • Posts: 419
  • Thanked: 1 times
    • View Profile
Will the Universe continue to expand forever?
« Reply #22 on: 03/11/2009 21:05:47 »
Vern,

You are spot on. Space is not empty of matter and photons will hit stuff. When this happens they will inevitably lose energy, but only in the form of wave lenght. They will not, however, be reduced in velocity in the vacuum of space.

One of the quandries I have thought about is the speed of light in the vacuum of space that is itself expanding.  The best I can come up with is the speed of light I see passing me will be 186,000 miles per second.  However, as space expands, that light has further to go and will loose energy by method of red shift that I will observe when it passes by.

I see no other way to accomodate this crap then to infer other spacial dimensions the likes of which could include something that could reasonably be construed as a diety. I will even go further. The arguement against a diety is that it never seems to interfere with the universe, and thus the universe is of its own thing.

I am convinced this is not the case. On the one hand, I do not believe a diety will interveine on behalf of individuals simply because they or others pray for it. I don'd discount the possibility of possitive 'karmic' energy, but the 'diety' of the old testament is described as an insecure power hungry maniac.

However, the more I study history, the  more I begin to believe in some sort of provinance. The number of close call incidents in both cosmic and human development seem statistically insurmountable. I do not want go elaborate on the Drake equation very much. It established some basic parameters by which we could estimate the number of other technological civilation in the universe.  He had almost no data, and came up with a SWAG of 19 in the Milkyway.

In recent years we have begun to fill in the equation with actual data.  In ALL cases the actual data reduces the probablitilty. Often by very large orders of magnitude.  The formation of our own moon is a near miraculous and necessary event. 

But in earth history itself, mathematically capable life forms have had 4 BILLION years to evolve, but during that time, none did. Further, our very own species, genetically speaking, seems to have been reduced at one point or another to no more the a few thousand individuals. [There is more genetic diversity in a single Chimpanzee troop then the entirety of homo sapiense.}

The modern history of climate, empire, and scientific advance coincidences beggars belief. But thats for another day.



 

Offline Vern

  • Neilep Level Member
  • ******
  • Posts: 2072
    • View Profile
    • Photonics
Will the Universe continue to expand forever?
« Reply #23 on: 03/11/2009 21:37:02 »
I suspect the probability that life exists in other systems is more probable than we suspect. We always assume our own circumstance for life. Maybe all that is needed is something that can self replicate and evolve. Maybe something like that could exist in the gasses of gas giant planets.

But I doubt that we'll ever meet up with any extra terrestrial sentient beings. Distances are too great, unless there is some as yet unknown means of communication.
 

Ethos

  • Guest
Will the Universe continue to expand forever?
« Reply #24 on: 03/11/2009 23:22:58 »

 Maybe all that is needed is something that can self replicate and evolve. Maybe something like that could exist in the gasses of gas giant planets.

Absolutely, consider the deep ocean life we have already encountered. Unbelievable diversity of life surrounding hydrothermo vents along moving techtonic plates. I believe in Murphy's Law;

"If it can happen, it will"

And because it happened here on earth, it will also happen where ever the slightest chance exists! And that would encompass areas well beyond our obsurdest imaginations....................
« Last Edit: 04/11/2009 15:51:27 by Ethos »
 

The Naked Scientists Forum

Will the Universe continue to expand forever?
« Reply #24 on: 03/11/2009 23:22:58 »

 

SMF 2.0.10 | SMF © 2015, Simple Machines
SMFAds for Free Forums
 
Login
Login with username, password and session length