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| how is the universe expanding?
Posted: 5/2/2009 12:36:39 AM | i seriously doubt the universe itself is expanding and there isnt any factual definitive proof that it is expanding. its just a theory to explain why things "move" the way they do in space.
that doesnt mean that there wasnt a big bang somewhere WITHIN the universe. i believe the universe itself is infinite. the universe is not a growing mass like a balloon growing bigger and bigger as more air is blown into it.
the way i see it, the only way to prove beyond a reasonable doubt that the universe is expanding is to measure from where we are, all the way to the edge of the universe. comeback a few billion years or so later and measure it again to see if it "expanded" any. that is definately not going to happen in our lifetime if at all.
if you believe the big bang, it could be that we are in a populated zone and when i say populated i mean stars, planets, galaxies, etc... if you go far enough out, there might be a dead zone in space. a zone where there are no planets, stars, galaxies. just dead, black space because all the objects that exploded from the big bang havent traveled far enough to reach that point yet. | |
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| how is the universe expanding?
Posted: 5/2/2009 3:57:36 AM |
there can only be existence! the only other option is non-existence, and non-existence doesn't exist. So what is the universe expanding into? The only thing existence can be broken by is non-existence, and again, non-existence doesn't exist! So the universe cant expand, cause theres only ONE existence and its infinite. So how is the universe expanding? You are right, in that the universe cannot "expand". It's a term, to reference a theory that the "known universe", the galaxies, stars and planets, are all moving further and further away from each other, as if they exploded from a big bang, expanding ever outwards. Part of that, is based on Einstein's idea, that if you travelled all the way to one end of the known universe, and kept going, that you'd just find yourself on the other end of the known universe. Of course, if you did that, then you'd be expanding the known universe, and so you could never get past the end of the known universe, so that could never actually happen. But it's just an idea, to show how gravity works to Einstein, that space "shapes" itself around masses, and makes it harder and harder to get away from them. | |
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| how is the universe expanding?
Posted: 5/2/2009 7:12:21 AM |
Part of that, is based on Einstein's idea, that if you travelled all the way to one end of the known universe, and kept going, that you'd just find yourself on the other end of the known universe.
Huh? That would mean the universe curves back in on itself...However measuring the background cosmic radiation shows the universe is flat and thus infinate in size...Which is another mind puzzle to think about.
At the end of Kubrick's 2001: a space odyssey, during the closeing moments of the "trip the light fantastic" sequence we are shown a number of shots that seem to depict star and even galaxys expanding. These shots were done through filming dropplets of oil basied paint in a tank of water basied paint. As the oil dropplet is introduced it sits atop the water and slowly spreads out, never mixing with the water. It was a neat surreal effect.
And I think of the universe in those terms. The instant before the big bang all matter was compressed into an infinetly small space. Then boom! And the universe started expanding. But thinking of it in terms of perspective of the compressed matter, nothing really happened other than the introduction of "empty space"...The amount of matter isn't expanding, just the "empty space" is. So the closest analogy I can think of is that 2001 paint filming tank and the interaction of the different types of paint. Its one of those subjects that is really hard to wrap your head around without simple analogies to explain it. | |
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| how is the universe expanding?
Posted: 5/2/2009 8:40:37 AM | RE Msg: 28 by bikemandarren:
Huh? That would mean the universe curves back in on itself...However measuring the background cosmic radiation shows the universe is flat and thus infinate in size...Which is another mind puzzle to think about. The universe does curve back in on itself. Gravity gets stronger around any large planet, or star, in space. But everything appears as if you are not moving. If you started moving away from the Earth, you'd keep getting pulled back into a circular orbit, so, you'd see the Earth moving away, and then, for no apparent reason, it would appear from over the horizon. The reason is that you would think you're going in a straight line, but in reality, you'd be pulled into an orbit.
CMR (Cosmic Microwave Radiation) is different, because it has an extremely high velocity, and an extremely low mass level, compared to us. So, although we would be pulled back, the amount of force on CMR would be negligible, except in the event horizon of a black hole, which has enough gravity to affect even CMR, and this is exactly what scientists have found. | |
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| how is the universe expanding?
Posted: 5/2/2009 9:25:41 AM |
The universe does curve back in on itself
Then wouldn't the universe be finite in size? By the "universe is expanding" it means the empty space between objects(galaxy clusters, galaxies, mass) is getting larger, not that there are more objects (more mass), no? So if the universe curves back in on itself it stands to reason that the universe isn't overall expanding...rather its "churning" like you mix cookie doe...some stuff is moveing away from us while other stuff it moveing twords us, caught in our gravity and us in thiers. But I don't think this "churning" is what is ment by the universe is overall expanding and thus flat and infinate in size. Besides its not like Voyager 1 is ever going to return to earth orbit.  | |
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| how is the universe expanding?
Posted: 5/2/2009 10:40:50 AM | Yes, the Universe is finite in size (well ok, current theory says it must be), but if you're talking about the "meta universe", it must be infinite, because otherwise you have nowhere to regress to, unless of course you say, "it just is". Also a reasonable response.
Space itself is expanding, according to the theory. What I don't understand is the concept of "inflation". This is the theory that at some point in the past space was expanding at an incredible speed (much faster than the speed of light - which of course it can do - it's only things inside space that can't travel faster than light, space itself is free to do so). In order for the theory to work, this must have been the case. There hasn't been enough time to generate the large scale structures you see in the universe if the universe is only 14bn or so years old.
Bit of a dodgy theory that requires "inflation" if you ask me. My gutt feeling is that it's very wrong. I think requring `dark matter' and `dark energy' to make cosmology work is also a bit of a red flag that our theories are wrong or incomplete. | |
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| how is the universe expanding?
Posted: 5/2/2009 10:44:47 AM | Universe is expanding; Cosmic microwave background radiation doesn't leave much doubt.
It's proven because the spectral lines are shifted all the way to the microwave length. CMBR is pretty much the remains of the Big Bang, so the universe has been expanding from the beginning.
If universe wouldn't be expanding we should see pretty much same amount of objects getting closer and farther. However, most of the objects are showing redshift.
About the center of the universe... According to the Big Bang theory all the universe has been in an infinitely dense spot. It means that everything has been the center of the universe.
If there isn't an existence beyond the universe, it isn't expanding into anything. However, it doesn't mean it isn't expanding. It just means there aren't any edges or boundaries in the universe. | |
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| how is the universe expanding?
Posted: 5/2/2009 1:33:30 PM | sighs
How does one define nothingness as creation from an alleged singularity ( to zilcho),
tooter of to blow up a balloon
I believe something from nothing is provable, incidentally.
we dont really know but that the best guess to date pedantic un ;)
and erm what that other dude said
he knows who he is :P
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| how is the universe expanding?
Posted: 5/2/2009 3:45:47 PM | | emman, it's not conclusive, the microwave background. It supports the theory, yes, but then you have to add hypotheticals that are unprovable, such as "dark energy", "dark matter" and "inflation". I like to think that any theory that requires invisible things to make it work is almost certainly wrong. | |
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| how is the universe expanding?
Posted: 5/2/2009 9:20:57 PM | Why do you think it has to be exapnading into anything? Nothing requires one manifold to be embedded into another.
You are right, in that the universe cannot "expand". It's a term, to reference a theory that the "known universe", the galaxies, stars and planets, are all moving further and further away from each other, as if they exploded from a big bang, expanding ever outwards.
WRONG. The general theory of relativity doesn't permit a stable, static universe. The cosmological constant can be used to obtain a static solution, but not a stable static solution. If there is insufficient matter to close the universe so that it contracts, it will expand. The evidence all agrees with a universe that is expanding. Not only is it expanding, but the expansion is accelerating.
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| how is the universe expanding?
Posted: 5/2/2009 9:30:31 PM | | Our entire universe/multiverse could simply be a singularity and spacetime only a conventionalization that allows us to say things about it. Not that it helps much to think that "all that is" might only be a singularity. Large or small are concepts that are equally meaningless without a comparative reference. Without a yardstick to go by, any discussion of "expansion" is meaningless. All we have to compare what we see of the universe with is what is inside our corner of it so the idea of cosmic expansion is all a matter of how it looks from our perspective, which is limited and skewed at best. | |
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| how is the universe expanding?
Posted: 5/2/2009 11:58:44 PM | | There is a hypothesis called MOND that allows for the use of a modified Newtonian Dynamic to explain what we pbserve in the universe without adding Dark Matter. There is also a belief that sections of the universe are slowing their expansion at different rates which would allow for the observations that galaxies that are farther away are travelling faster than those closer and not need any sort of Dark Energy to explain why they are increasing in speed (Because if this is true they actually aren't increasing in speed) | |
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| how is the universe expanding?
Posted: 5/3/2009 1:42:19 AM |
emman, it's not conclusive, the microwave background. It supports the theory, yes, but then you have to add hypotheticals that are unprovable, such as "dark energy", "dark matter" and "inflation". I like to think that any theory that requires invisible things to make it work is almost certainly wrong.
Dark energy and dark matter are only names for the unknown variables in equations. These invisible or unproven things do not disprove the fact that according to all observations the universe is expanding, and seems to be accelerating. | |
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| how is the universe expanding?
Posted: 5/3/2009 3:03:34 AM | There are a few things we can infer from what we can observe by looking up at the night sky.
The universe is either young (in cosmological terms), or it is not infinite. The proof being that light travels, stars live for long periods of time, if the universe was old or infinite in it's existence, there would not be any darkness between the stars. Through measuring the weights of elements and understanding the process in which they form, we can safely assume it is relatively young, infinite or finite however can't be assumed so easily.
The universe has no concept of existence as we do. From measurements taken both near Earth and far from it through telescopy and radioscopy, we find that matter is sparsely distributed into pockets. These pockets get lots of names, planets, solar systems, galaxies, clusters, so on and so forth.
Gravity is the thing keeping it all together both microscopic and macroscopic. While this has and is contested on a regular basis, it's held up for quite a long time now (in human terms of time). Since gravity is just a function of mass affecting other mass I think, but am not sure, it's the matter that makes what we know as existence, that there is no edge of existence unless you measure existence as the area where matter is present, in which case there's more non-existence than there is existence in the known universe, but moving into such non-existence areas would be taking existence with you into those areas.
There is however the end-condition. Using just the force of gravity itself it's entirely possible to accelerate a body of mass into escape velocities (velocity that is required to escape a field of gravity). That suggest that eventually through sheer random chance alone, mass will reach those escape velocities to spread itself so thin that the heat required for the universe to exist as it is today will not be possible. This is what is known as the expanding universe in the easiest terms I can think to explain it, it results in a deep cold.
There's also the opposing end-condition. Gravity will force all matter into a single point in space, what happens then is purely speculation as we have no basis for comparison outside of theoretical terms. This is what is known as the collapsing universe, it results in heating (from friction) on magnitudes of the likes we can't even begin to imagine. | |
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| how is the universe expanding?
Posted: 5/3/2009 4:23:26 AM |
ark energy and dark matter are only names for the unknown variables in equations.
Indeed, if you want to abstract like that, that's fine. But then in this context my point is that we keep having to add new variables! Something is clearly wrong, don't you agree? | |
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| how is the universe expanding?
Posted: 5/3/2009 10:01:43 AM |
Indeed, if you want to abstract like that, that's fine. But then in this context my point is that we keep having to add new variables! Something is clearly wrong, don't you agree?
I don't see anything wrong, because that's how mathematical and physical problems are solved. Most of us have probably learned this from school.
We place all known variables into an equation. If it doesn't still work after other posibilities for an error have been excluded; there must be an unknown variable x involved. In fact it's possible to calculate the effect of that variable. | |
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| how is the universe expanding?
Posted: 5/3/2009 10:17:12 AM |
We place all known variables into an equation. If it doesn't still work after other posibilities for an error have been excluded; there must be an unknown variable x involved. In fact it's possible to calculate the effect of that variable.
Err no, that's not how it works. Consider the theory of epicycles. I won't bore you with an explanation, but in general (although not always), the newer theory explains more with less. Occam's Razor. | |
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| how is the universe expanding?
Posted: 5/3/2009 2:02:02 PM |
The proof being that light travels, stars live for long periods of time, if the universe was old or infinite in it's existence, there would not be any darkness between the stars.
Um...no. Think of shotgun pellets. The closer you are, the more pellets(light photons) hit the target. The further the target, the wider the spread and fewer pellets(light photons) hit the target. So we only get a handfull of light photons from stars millions of light years away, which is why they are so dim, practicaly black. | |
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| how is the universe expanding?
Posted: 5/3/2009 2:16:42 PM | bike, the theory was that if the universe was infinite, then there must be an infinite number of stars in it. If that were the case, the entire sky would be lit up with star light (just 1 photon from each star in an infinite universe would be more than enough, wouldn't it?).
I think I recently read a rebuttal of this argument however but I can't remember where it is or what it was! | |
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| how is the universe expanding?
Posted: 5/3/2009 2:43:14 PM | I'm sure everyone has seen the picture of the Hubble deep field study. The Hubble telescope was aimed towards a small, apparently completely black piece of space and was held there for, I believe, a couple months to take in all the light it could. The outcome was what we see in this image:
http://www.sciencemusings.com/blog/uploaded_images/HUDF-777866.jpg
Every single one of those points are galaxies that the human eye can not see because they are far to dim. However the light from them is still hitting Earth. | |
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| how is the universe expanding?
Posted: 5/3/2009 2:49:38 PM | | I remember that image. It's just unbelivable. I mean the sheer size of the Universe compared to the relatively microscopic little garden we have here. | |
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| how is the universe expanding?
Posted: 5/3/2009 3:24:48 PM |
If that were the case, the entire sky would be lit up with star light (just 1 photon from each star in an infinite universe would be more than enough, wouldn't it?).
Not sure I follow. That assumes stars doen't have a lifespan, that they can't go nova and spread thier mass through the universe to become planets and even us. And that at some far off distant point in time we too, may well be reborn as a new star. An infinite number of stars means there is an infinite amount of mass, no? | |
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| how is the universe expanding?
Posted: 5/3/2009 3:42:17 PM | Infinity wouldn't necessarily require infinite space.
The storage room need only be big enough to accommodate an infinite amount of states, including what it takes to have space, time, blue, red, happy, sad, egg salad and toast, if it has to. It might require far less space in systems which get better at creating new states of existence.
I have no idea what I mean.  | |
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| how is the universe expanding?
Posted: 5/3/2009 6:40:23 PM | vancer
you must litterally be the smartest man in the world right now or an alien from a distant galaxy because you seem to speak in a language that only you can understand.
maybe you know something we dont. your post are very mind boggling and after reading them 3 or 4 times in a row, i still find myself thinking WTF?
who am i kidding, i dont understand a single message in this entire topic....
UHHHH..... THE UNIVERSE IS NOT, I REPEAT, NOT EXPANDING DAMNIT!
carry on...
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| how is the universe expanding?
Posted: 5/3/2009 7:05:55 PM | Mike, I think I'm just more confused from a growing obsession.
Existence is so deep and rich. Yet, I don't know why, but everyday it seems to make so much more sense that an origin of complete absence, is compelled to generate behaviours seeking further absences within.
Like the origin of our existence has always surrounded us, and it is total absence.
I can't even talk about it properly.  | |
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