if there is one thing we may never know is how the universe will end, there have been many theories on how it will end. but recently i have thought of a new theory that makes sence to me, not sure about you, but as the universe expands it cools so what if it gets so cold it will cause stars, electrons and everything to freeze and time itself will stop or something.

This is not really a new theory, it has been around for many decades. The problem was that no one knew if the universe was open (expanded for ever) or closed (would contract again).

Which of these occured depended on the amount of matter and therefore gravity in the universe. If there was enough matter then the gravity would slow down the expansion of the universe and cause it to contract again, with the universe ending in a "big crunch".

If there was insufficient matter then the universe would continue to expand forever and would have a cold dark death (as you said).

The problem was that the amount of matter in the universe is borderline between the possibilities that it was difficult to say which of the two would be the ultimate fate of the universe.

Recently the measurements have become more accurate. Something astonishing was discovered, rather than slowing down the universe is accelerating. There must be some, hitherto, unknown force in the universe acting as a kind of anti-gravity. The nature of this force is still not known but it does mean that it now looks certain that the universe will end up with a cold dark death, or as T.S. Elliot put it:

QUOTE

This is the way the world ends
This is the way the world ends
This is the way the world ends
Not with a bang but a whimper.

The universe end will just be another beginning. I believe that at some point the universe will stop expanding and will contract all matter back together until the next big bang. This is just an opinion, don't let it destroy your universe.

This was an opinion held by many (maybe most) cosmologists until very recently. The evidence is now against it.

really?
why didnt anyone tell me this before

Interesting question. Three possibilities come to mind off hand.

1. It will expand to such a point and then either pop or start to get smaller again.

2. It will never die.

and the most likely IMHO

3. It can collide with another universe at any time to create a new Big Bang!

I believe Cosmologists call this scenario 'The Big Freeze' (as opposed to The Big Bang'). You are correct with your hypothesis that the Universe will become colder the more it expands, though this won't happen for billions of years so I wouldn't go ordering any thermals just yet .



In a book by Michio Kaku, he says that it might be possible for matter to spontaniously appear in the Universe. Unfortunately it was a while ago since I read it and I can't remember the exact circumstances he mentioned. Perhaps you know something of this Waspie? If this is so, how would this affect your measurements of matter in the Universe and, therefore, the rate of expansion? Also, does this measurement take into account Dark matter?
I'm going to try and find that book and see what Kaku says. If I find it, I'll post what it was he said.

I'm not a cosmologist or theoretical physicist and so it's not my measurements. However I do that as a consequence of E=mc² matter and energy are interchangable. Also quantum theory alows particles to spontaneously appear and disappear. I asume it is as a consequence of these that Kaku makes his statement, but I haven't read it myself.



Yes. The very definition of dark matter is that it's gravitation effects can be measured but it can not be seen using ordinary means. As the acceleration of the expansion of the universe is a measured effect it must, therefore, include dark matter.

i dont think the universe will end up popping like a baloon because i believe the universe is expanding due to a massive chemical reaction. and im not sure if the universe is capable of going backwards because the expansion is accelerating and it will be going too fast and i think there will be too much matter to end up becoming a super atom again

This is not correct. Chemicals.. which are matter, did not exist in the early stages of the big bang, it was far too hot. Matter and energy are interchangeable. As the universe began to cool matter began to condense from the energy of the big bang.


This certainly seems to be the case.


The super atom concept is a very out dated one. In the early days of the big bang theory is was believed that all the matter existed as one super dense object, nicknamed the super atom, which exploded. With modern understanding of the early universe and of the nature of matter/energy we know know this super atom concept is wrong. Matter simply did not exist at or immediately after the big bang. Matter only began to be formed in a period between 3 minutes and 300,000 years after the big bang.

There is an informative articel on Wikipedia about this HERE.

what im sort of trying to say that it is like a chemical reaction between time fabric and space fabric to make space-time

I'm really not sure what you are trying to say here. I'm not sure you have grasped what a chemical reaction is or what space-time is.

Do you think that the energy of acceleration is contributing to the increase of accelaration?

Why should the universe end? Perhaps it has always been.

you cant say that because everything has a beggining, it has actualy been proven that the universe had a beggining because the hubble space telescope has taken pictures of the echos of the big bang

In science, there are almost never absolutes. Hell, there probably aren't absolutes... Which means, however unlikely, the data could be interpreted wrong. The big bang happened -- no doubt -- but there's always a what-if.

Should have left off the "almost" part.


The Big Bang Theory is only a model that helps us analyze what we perceive. It is by no means "proven" and will certainly never be proven.

It is, however, a very good and extremely useful model.

That's the best thing that can be said for any scientific theory.

Harte

I would argue that only in the limits of most human understanding and experience do things have beginnings and ends with the exception of circles and the unicursal hexagram. I'm sure there are other examples.

You can argue it all you like but based on the available evidence you would be wrong. The universe, space and even time had a beginning.

We know the universe had a begining all you need to do is exaimine the C.M.B / COSMIC MICROWAVE BACKGROUND,S dispersal pattern to see this.
Its not a metaphysical question its scientific fact

Agreed. I would add it's pretty much a given that it will also have a end too. The m theory opens up some very interesting windows!

If colliding universes (mbranes) causes a Big Bang. Then at any time even the next moment, our universe could collide with another causing another Big Bang creating a new universe.

While every thing does seem to be recyclable, I think it's reasonable to assume universes have beginnings and ends like every thing else we can measure and witness.

Imagine our universe colliding with another! Our end the cause of a new beginning!

Sure this is out there! But is all part of the M theory!

Colliding with another universe.Yes that is true.But creating another big bang is a bit hard.(Waspie correct me if I am wrong) Mainly because of the magnetic tidal fields of the to universes and the stars with in them.This can clearly be demonstrated with a vandegraaf generator,some foam balls and some string,after the foam (representing planets and stars)balls have collected a charge they will push away from the globe and the nearby foam balls.Basically it comes down to this,most if not all of the stars will just push each other away.Also in the collision scientists have also contemplated that stars at the outer reaches of the galaxies will be thrown into space and those that are near the center will just be swallowed by the supper massive black hole at the center of the two colliding galaxies.Also you all know that the Andromeda galaxy is heading towards us but that will still take millions of years so no need to panic .

BTW.I gladly except a reply on this if anyone does not agree with the info I have given,this is just the my explanation with the info I have gathered over the years on what could happen and the results that goes with it.



Yes agree on this.



All depends on what happens to the Earth.

Way out of my area of expertise I'm afraid. Remember though that string theory, M-theory and brane theory are all hypothetical. There is no evidence to support them or multiple universes,

I will correct myself.Did not read to post correctly.My earlier reply was actually nothing to do with universes colliding but actually galaxies colliding.

Sorry about the misunderstanding to future viewers.

The Hubble Ultra Deep Field is one of the most beautiful images I have ever seen.

This is just my opinnion, i think that there might be forces in space that we don't understand. Possibly beyon our understanding of physics. Maybee the universe will just continue to expand. I mean we will never know, but if i had to go down speculating i wouldn't picture the universe ending in one of these fashions. Theories are constantly changing. I mean most of the old thoeries have all been replaced with new ones. Based on our level of technology today, or whatever, i think that scientists are doing the best they can with the information they have. Forever building and changing and it will just continue to do so.... just a thought.

I believe in dark matter.

Do you mean Dark Energy?

Here's a thought. Can the expansion accelerate up to - or even beyond - the speed of light?
If it can, then is lightspeed really the limit?
If it can't, then doesn't that mean the expansion will have to eventually stop accelerating?

if the universe's expansion is accelerating then of course its going faster than the speed of light. 6 trillion miles per second probably isn't even close to it. so yes it can expand beyond the speed of light.
for all we know the speed of light could be increasing due to the acceleration as well.
and the expansion will stop if there is a big freeze or in other terms when the universe ends its lifetime based currently on this conclusion. you could actualy think of the expansion as expanding foam it will eventualy stop expanding, but if you do look at the expansion of the universe as expanding foam it could answer many questions about the universe's beggining, how it expands and how it may stop.

And if all matter is traveling at some level faster than the speed of light already, what do you think that would mean?

What? How do you work that out? There is no " of course" about it.

I was on a bus today, it accelerated. At no point did it exceed the speed of light. Sorry dr alien but you really are not making any sense here.

if the universe's expansion weren't exceeding the speed of light, how come we're millions/billions of lightyears away from far away objects in the universe. not saying that everything is that far away.

Distance in light years is a scientific function.It only explains the time it takes for light from a far object to reach us.It does not say that the galaxies are flying apart at the speed of light.

There are galaxies so far away that using Hubble's Ultra Deep Field imaging they only appear as dim specs of light.

Even without taking into account the acceleration of the expansion, within the standard Hubble formulation of a homogeneous expansion there are galaxies or objects that are receding from us faster than the speed of light (though this doesn't necessarily mean that we can't see them). Aside from that, one of the linchpins of modern theoretical cosmology relies on a faster-than-the-speed-of-light expansion of the universe to explain certain features of the universe.

So there's no real problem with that.

How is this possible when it's a widely held fact that 'nothing' can exceed the speed of light? Yes, Physicists say that Neutrinos can travel faster than light. But, if this were the case, then Neutrinos also travel backwards in time. For an entire Galaxy to do this would render that galaxy invisible to us. Therefore, if we can see it, it must be traveling slower than light. Yes, these receding Galaxies are subject to the Doppler Effect, but that doesn't mean they are traveling faster than light, just that they are receding at a high speed.

As I understand it:

While these galaxies might appear to have a velocity relative to us which exceeds c, their absolute velocity (if such a thing could exist) does not. This is due to the nature of the expansion of space and it's a bit simplistic to say these galaxies are receding from us when the 'absolute' velocities of both galaxies could be zero and the effect we see (of them getting 'further away') is simply down to the space in between expanding.

Anyway, think of the light wave as simply stretching as the space it is crossing expands. Since the 'space' isn't moving (just expanding) that is why we can still detect these galaxies. Nothing is actually 'moving' faster than c.

Thanks for that Leo, interesting.
However, as the Galaxies are moving away, whether through the expansion of space or through their own movement, wouldn't they still have a 'velocity' so to speak? I mean, the Galaxies are moving, we can see this by the red shift of their Doppler Effect. So surely they must have velocity? Or have I misunderstood you (it wouldn't be the first time lol).

The Redshift is caused by the stretching of the light wave as it crosses the expanding space - red light is a longer wave-length so the stretched light seems red to detectors - hence the 'red-shift'. Technically this is not caused by anything moving, just stretching.

The galaxies still have a velocity relative to each other, true, and due to the expansion of space this relative velocity can seem to be >c. The expansion of space doesn't actually add anything to the galaxy's velocity, however, it just seems to do so because of the stretching of the light waves.

I have questions about this theory and don't necessarily accept the standard answer, although it's the only answer we have that seems to explain the breaking of the c limit. I try not to think about it too much - especially at 5am!

Some articles:
Dark energy (here you can find more related articles)
Big Rip (that would be R.I.P. indeed)
Big Crunch
Anyway, there is no definite answer (yet) how the universe will end.

THE FATE OF THE COSMOS
That means that the 100 billion or so galaxies we can now see though our telescopes will zip out of range, one by one. Tens of billions of years from now, the Milky Way will be the only galaxy we're directly aware of (other nearby galaxies, including the Large Magellanic Cloud and the Andromeda galaxy, will have drifted into, and merged with, the Milky Way).

By then the sun will have shrunk to a white dwarf, giving little light and even less heat to whatever is left of Earth, and entered a long, lingering death that could last 100 trillion years—or a thousand times longer than the cosmos has existed to date. The same will happen to most other stars, although a few will end their lives as blazing supernovas. Finally, though, all that will be left in the cosmos will be black holes, the burnt-out cinders of stars and the dead husks of planets. The universe will be cold and black.

But that's not the end, according to University of Michigan astrophysicist Fred Adams. An expert on the fate of the cosmos and co-author with Greg Laughlin of The Five Ages of the Universe (Touchstone Books; 2000), Adams predicts that all this dead matter will eventually collapse into black holes. By the time the universe is 1 trillion trillion trillion trillion trillion trillion years old, the black holes themselves will disintegrate into stray particles, which will bind loosely to form individual "atoms" larger than the size of today's universe. Eventually, even these will decay, leaving a featureless, infinitely large void. And that will be that—unless, of course, whatever inconceivable event that launched the original Big Bang should recur, and the ultimate free lunch is served once more.

here's a good interesting link

http://www.time.com/time/covers/1101010625/story.html

The short answer is that it's because Hubble law is a simple proportionality relation between the recession velocity v of an object and its distance D from us (with a proportionality constant--the Hubble constant H--thrown in for good measure): v=HD. If we cap the recession velocity at c then we put a limit on how big the universe is--unfortunately, the universe disagrees; it's actually bigger. That's not to say there's nothing interesting about the distance associated with a recession velocity of the speed of light. That defines the radius of what's called the Hubble sphere. But the Hubble sphere is not the entirety of the universe. We figure out the distance to distant objects by measuring the redshift of the light coming from them; anything with a redshift higher than about z= 1.46 is receding from us faster than the speed of light (for reference, the furthest quasar has a redshift of about z=6.4). Any expansion of the universe obeying Hubble's law (be it cosmic inflation or the expansion of today) necessarily entails superluminal expansions.

But that probably doesn't tell you why this is ok and jibes with the rest of physics. The answer is that "nothing can exceed the speed of light" is a phrase often associated with special relativity, a theory that deals with local, flat areas of spacetime. Which is exactly what we're not talking about here. We're going global and talking about facets of cosmic geometry. There's a much broader theory--general relativity--that deals with this and it's from GR that we derive our understanding of this stuff. It's important to note that even when galaxies have superluminal recession velocities, people living in those galaxies still can't beat a local beam of light in a race. Our own galaxy is receding faster than the speed of light from somebody's galaxy, and yet everything's still working as it should. So I suppose the simplest answer to your question is that things are a little different in general relativity than they are in special relativity.




Not quite. As I said, anything a redshift of about z=1.46 is receding faster than the speed of light and yet we know of many, many objects with higher redshifts. Things outside that Hubble sphere I mentioned are receding faster than c but the catch is that the Hubble sphere itself is receding from us. This is related to the fact that the proportionality constant in Hubble's law--the Hubble constant, more accurately called the Hubble parameter--isn't a constant at all but rather is determined by the way something called the scale factor behaves in certain cosmological equations (the Friedmann equations). But what happens is this: the Hubble sphere can catch up to light that has been emitted by objects receding at faster than the speed of light (i.e. outside the Hubble sphere when the light is emitted), making them eventually visible to us, despite the fact that the object is still receding faster than the speed of light.

Startraveler,

Does the measurement of the redshift of the light from a distant, and fast receding, object not depend on the wavelength of the light as measured at the detector?

If so, and the expansion of space is not apparent (or so apparent) in proximity to large masses (like galaxies, solar systems, planets etc), then how does the expansion of space affect the measurement of this redshifting?

Or have I got my understanding of the effect of space's expansion on the apparent velocity of recession of distant galaxies wrong?

I posted this a while ago - very interesting about the speed of light -

Joao Magueijo's Big Bang



Cosmologist João Magueijo has tried to make sense of the universe for the past 20 years. For his efforts in cosmology, Magueijo has been called an anarchist, a heretic, a radical and even a moron by his peers. All because of his proposed solution to the Horizon Problem – a fatal flaw of the Big Bang Theory which states that distant areas of space cannot have similar physical properties due to the immense distance between each area relative to the speed of light. The Horizon Problem is commonly accepted as solved in by Alan Guth’s theory of Cosmic Inflation. Now, however, Joao has sent shockwaves through the scientific community by challenging Cosmic Inflation and claiming instead that one of the central tenets of Einsteinian physics is wrong.

http://roychristopher.com/joao-magueijo-frontier-cosmology

João Magueijo is a cosmologist and professor in Theoretical Physics at Imperial College London.

He is a pioneer of the varying speed of light (VSL) theory of cosmology, which proposes that the speed of light was much higher in the early universe, of 60 orders of magnitude faster than its present value. It is presented as an alternative to the more mainstream theory of cosmic inflation. The model was first proposed by John Moffat, a Canadian scientist, in 1992.

Magueijo discusses his personal struggles pursuing VSL in his 2003 book, Faster Than The Speed of Light, The Story of a Scientific Speculation.

Magueijo is the host of the Science Channel series, João Magueijo's Big Bang, which premiered on May 13, 2008.

Thats a mouth full Lt. Ripley but I like your style,I guess we need to plan and meet at Millyways then before the end a toast to Humankind ! Cheers! DONTEATUS p.s. dont forget the mice

All of the wavelengths are affected by the redshift. Suppose we had a long line of chairs, with a red one at one end and a blue one at the other. Then everybody sitting in a chair gets up and move over by one chair, toward the side with the red chair. Everybody who was associated with some specific chair is now one chair closer to the red. Each chair in the analogy, of course, represents a given wavelength of light. Each one is affected by the redshift, in that it now occupies a spot closer to the red than it did before.




The redshifting occurs long before the light enters or galaxy or solar system or nears the Earth. It occurs as the light crosses vast cosmological scales that are expanding as the light traverses it. So by the time it gets here to be measured the damage is done, so to speak.

The big bang isnt the beginning of the universe but merely a change within it. If not then science is at a loss to explain how something comes from nothing. If the potential for the big bang has always been here then the universe in some or another has always been here. Eternally in my view. And eternally will always be here in some form or another.

Also nothing cannot be defined without contradiction.

Great point except for one thing, something which is eternal also has no beginning and you are still left with the same problem to explain... except in your case you also have no evidence.

Thanks for the reply, Startraveler.

I'll admit, I don't fully understand your analogy with the chairs. Red light has a longer wavelength than green or blue, so would a more accurate analogy be not that everyone shifts a position, but that more people are added to the line as the light shifts to red (or the same number of people occupy more seats)?

This implies it is the expansion of space doing the shifting - effectively stretching light - and that it is permanent once done and so when this light enters a region of space where expansion hasn't occurred (such as around large masses) the light remains stretched. So, how can it be ascertained this stretching is done by the expansion of space and is not simply an entropic side-effect of this expansion?

What do you mean no evidence? I am saying the universe in some form or another has always been here eternally. Eternity by definition has no beginning. What evidence are you looking for? They havnt proven the big bang. And if they do then they either have to admit that the big bang came from something or nothing. If nothing then how can something arise from nothing?

If you ask 'how did eternity get here' I would imply say I dont know it has always just been here. It makes reasonable sense to be. Even if they prove the big bang science still wont be able to explain ' why do the laws of physic exist' or 'why is there anything at all'.

The best thing the big bang theorists can do in my view is modify their theory to say a process or change in a universe that already exists instead of a 'beginning' of it.

I dont believe there is a beginning to time wheras others do. Until we can build time machines we will never know for sure.

Exactly my point, you are posting about faith not science. In science belief with out evidence is worthless (that is not to say that I am calling your beliefs worthless.. they are highly important to you, just that they have no worth from a scientific point of view).

The big Bang may not be proven but there is a vast amount of supporting evidence which backs it up. We could easily get into a philosophical debate as to the nature of proof here but this is not the right forum to do so, suffice to say that the big bang is the model accepted by the vast majority of experts. Does that mean it is right? Not necessarily, but it does mean it is the best we have got.

If you believe that the universe is eternal and had no beginning then you have a problem as big as the one you are pointing out for the big bang. You still have a universe with no explainable start. You seem to be able to accept this within your own belief system but reject the same problem out of hand when it comes to the big bang.

We also have a case of semantics going on. What do you define as the Universe? If it is the things around us that we observe, the matter the energy etc, then that was created by the big bang, if you are talking about the universe in a wider, more philosophical role then you are taking it's definition beyond that of the scientific and into the (for want of a better word) religious. That goes beyond what science can currently explain (possibly beyond what it will ever explain). If that is the case then maybe this is not the right forum for that discussion either.