allright... this is another one of my crazy out-of-the-box questions that I know yall love so much lol!

 Now, I know that no one has any idea about what is or isn't true about this particular topic, but I would like to hear some ideas about what you think, or if you may have read any scientists giving their theories on this...

 
If the universe is expanding, than it must have an outside 'edge' around the circumference of it. I want to know what would happen if you were in a spaceship approaching this outside edge of the universe. Just for arguements sake, let's say the speed of your ship is faster than the expansion rate of the universe is. What would happen as you went through this edge. Would it be impossible to do? As you approached the outside edge, would your ship slow in speed as the forces of universal gravity took over and pulled you back in, no matter how fast the rate of speed you were going? Or is everything non-existent past this edge, and you would simply crash into a brick wall so-to-speak? Ever thought about this before? Has it been explored by scientists? I'm sure it has...

 
I also want to know... if the universe is expanding, what is the context and substance on the outside of the universal edge that gives it room to expand? Let's say that I blow up a balloon that represents the universe expanding, and the outside expanding lining of the balloon represents the universal edge. Now if I blow up a balloon, the balloon is allowed to expand due to the openness around it, but if I blew up a balloon that was inside of a shoebox, it would pop because there is lack of room for it to expand.

With either scenario, there has to be room outside of the edge for expansion, and this has to be the same with our universe expanding. There is area that exists outside of the universe's edge!! Do we determine that outside of the universe's exterior, there is a vast infinite amount of dark emptiness where no matter or anything exists? The only way for anything to exist in this dimension, is if it is safely stored inside this universal shell? Is this area outside of the universe just dark and empty, while at the same time infinitely massive?

 
^^^either way, all of this proves is that there is an 'edge' to the universe, and that there is something that exists outside of this universe that is probably more massive and infinite than we mortals could possibly fathom. But let's group together and see if we can figure it out anyway here on the forum!

 
I have made a chart representing the expanding universe. The gray area, represents the area outside of the universe. As the universe expands it begins to take more room from the gray area.

^^^the red arrows represent the gray area that is eventually swallowed up by the expanding universe.

WHAT IS THIS GRAY AREA!!!???  -and because it isn't in our dimension known as our universe, do we deem this area non-existent?? even though it surely exists?

thoughts on this subject?

 You're thinking of objects as they exist in space, but that's not the case with the universe. The big bang and the subsequent expansion of the universe wasn't an explosion in space, but an explosion of space.

 The Big Bang by Simon Singh is a great read and goes a long way toward explaining these ideas.

 Ah, so you're saying that the gray area is non-existent then? I have a hard time comprehending an explosion of space...It just doesn't work out for me personally. By no means am I saying you're wrong, I just have a hard time understanding that concept. I don't see how the gray area can possibly be non-existent. That book sounds like a good read. Perhaps for my quick understanding and this thread topic you could give me a cliff notes version of exactly what an explosion of space entails, and how the gray area in my chart is deemed non-existent? thanks bro

Thanks. Now my head hurts.

Killer Rob:

...That book sounds like a good read.

It is excellent. I highly recommend it.

Perhaps for my quick understanding and this thread topic you could give me a cliff notes version of exactly what an explosion of space entails, and how the gray area in my chart is deemed non-existent?

One of the current explanations (via String and Brane ideas -- which are, themselves, physically suspect) is that the Big Bang created an expansion into a new dimension. That is, other pre-existing dimensions came together in such a way as to "open" or "create" a new dimension which became our universe.

The whole idea of creating spacetime is a headache, but that is what the Big Bang model purports to have done. Our observational problems include not being able to look back far enough to determine initial conditions. And, if the BBT is correct, it would be impossible for us to get direct observational evidence of pre-existing condtions because the BB itself would have wiped them out. That is, we couldn't "get back to" those pre-existing other dimensions -- assuming they existed.

That is why the BBT cannot explain what came "before t=0" ... the initial conditions that cosmologists work with today are extrapolated by running computer models backward in time based on today's observational evidence. This allows them to test what combinations of conditions could result in the universe we observe today.

The general consensus among supporters of the current standard model is that at some point very near t=0 (on the BB timeline), everything we observe today was at some initial point of very small radius ... and if that is correct then to talk about anything "beyond" or "outside" of that point is irrational (in a mathematical sense) ...

There is no center to the universe and no edges.  Any point can be arbitrarily considered the center.  From such a point most (not all) objects appear to be moving away; the more distant ones appearing to recede more rapidly.  The term Big Bang is unfortunate in that it causes people to imagine an explosion from a central point and material streaming outward in all directions, producing a spherical shell defined by the outermost objects.  That is not the case.  As others have noted, it is space (a coordinate system) that is expanding.  It could alternatively be said that the length of a meter is shrinking.

Centaur:

... It could alternatively be said that the length of a meter is shrinking.

Curt: LOL, everytime you mention that I run for the aspirin!

jb

These sites may provide some insight on the matter:

http://www.atlasoftheuniverse.com/bigbang.html

http://www.sciam.com/article.cfm?id=misconceptions-about-the-2005-03

http://www.astro.ucla.edu/~wright/nocenter.html

http://math.ucr.edu/home/baez/physics/Relativity/GR/centre.html

Dave Mitsky

Killer Rob:

Perhaps for my quick understanding and this thread topic you could give me a cliff notes version of exactly what an explosion of space entails, and how the gray area in my chart is deemed non-existent?

 I know where you're coming from. For me, the light bulbs started going off thinking of space (as in spacetime, not just the dark part of the sky) rather than the universe. The expansion isn't about the distance between two objects, it's about stretching what they exist in.

 Like Centaur said, there's no center or edge to the universe. Once we were able to observe the directions DSOs were moving relative to us, pretty much everything was moving farther away. So we're in the middle, right? Well, no. 

 Imagine a partially blown up balloon. Make a bunch of dots on it with a marker, and watch one particular dot as the balloon gets blown up a little more. All of the other dots will move away from the one you picked to watch. But it doesn't make any sense to say that dot's in the middle, because there isn't really a middle. Even talking about the edge of the surface of the balloon is pretty hazy. Beyond that, the dots didn't really go anywhere--they're still on the same bit of balloon, and the balloon stretched to move them farther apart.

 Bear in mind I'm not claiming that the balloon analogy is representative of what space is actually doing, but it helps give an idea of the concepts you're dealing with.

I'm still not getting what you guys are trying to say, lol. I guess for a deep subject like this, I should get that book because I imagine it is hard to explain in a post on a message board.

 Are we saying that the openness of space in our dimension is pre-existing and infinite? So in my chart I made, there would be no gray area, it would all be black, with the universe part holding all the galaxies expanding instead? That would kind of make sense I guess. Never really thought about it that way before..

 ^^^but to me that represents an explosion in space?

So if that were the case, going back to my spaceship example...if you traveled out to the expansion edge of the universe and went past it, you would be in deep dark space where the openness of space is the only thing that exists in that area, but where no light or matter exists at all until the universe expands into that area? Sound plausible?

I have studied about the center of the universe, and how there is no real center to the universe...but wouldn't it be safe to say that if you had a way that you could pinpoint where the big bang explosion occurred, that it would be considered the center of the universe as it was where the birth of everything that exists started?


 

chuck81:

Thanks. Now my head hurts. Laugh

lol, maybe I can work a deal and get all my threads sponsored by extra-strength tylenol!  

What if the so called "Big Bang" didn't erupt from a central point in all directions, but instead was a directional expulsion, as in a, well crunch down from another place. The resulting exploision? could be a directional instead of a circular thing (bad wording). If it was an event parcipitated in another dimension a directional thig makes some sense to me. I think of a smoke ring (I can do those and I am ashamed to say I smoke) A blast of breath drives the ring outward. As you watch, the ring moves away and rotates around it's self. The ring eventually dissipates itself.

^^^good point Mark. As in it exploded in a direction kind of like a stream, and then started to dissipitate in all directions. So if you blew smoke out of your mouth into the atmosphere, your mouth would represent the center of the universe, but might not be directly proportional to the center of where the smoke eventually ends up. Either way, that would also be an explosion in space, correct? So we're saying that space was infinite in this dimension, and the big bang exploded into it. That would be matter exploding into space.

This thread on astronomy has been brought to you by extra-strength tylenol!

lol 

Again, there was no "explosion", despite the unfortunate moniker of the Big Bang and almost every television documentary on the subject displaying the event as such, thus implanting a false concept into the minds of the viewers.  A key concept of the theory is that the universe happened everywhere at once.   Hence, the universe has no center no matter how you look at it.

http://preposterousuniverse.com/writings/cosmologyprimer/faq.html#center

Dave Mitsky

Killer Rob:

... Are we saying that the openness of space in our dimension is pre-existing and infinite?

No, there is no evidence that it is infinite. And the Big Bang Theory makes no assumptions about what came before. So, it cannot have been an explosion "in" space. That is why we say it was an explosion "of" space.

Dave Mitsky's answer is correct. Visit the links he provided. I agree the name Big Bang is unfortunate, but we're stuck with it.

So in my chart I made, there would be no gray area, it would all be black, with the universe part holding all the galaxies expanding instead?

Yes. If you were inside an expanding balloon world, you'd have no way of knowing about anything outside the balloon. All you would know is that everything you can see seems to be moving away from everything else. You could "guess" that there was an "outside" ... but you could not know it.

So, no "gray" area as in your diagram.

 ...if you traveled out to the expansion edge of the universe and went past it, you would be in deep dark space where the openness of space is the only thing that exists in that area, but where no light or matter exists at all until the universe expands into that area? Sound plausible?

No, even if there were something "outside" we wouldn't be able to reach it. That is, if the BBT is correct, then all we can ever know about is the "inside" -- the part we can see. There would be no way to "go beyond". This makes it hard for us to talk about an "edge" ...

...but wouldn't it be safe to say that if you had a way that you could pinpoint where the big bang explosion occurred, that it would be considered the center of the universe as it was where the birth of everything that exists started?

Read Dave's answer again. If the BBT is correct, then what you see around you right now was once part of the fireball that began it all. So was the Milky Way galaxy and all its stars, gas, and dust. So were all the other galaxies. And any matter that's in between them.

Here's an exercise we use at 3RF Science Teacher's workshops to help teachers understand what we mean by expansion. You know those foam animals that come in a gelatin capsule? You put a capsule in a glass of water and it melts and then the animal shape unfolds and gets bigger and bigger. Imagine the universe is like that. Today you see the animal and all its arms and legs (galaxies, etc.). If you "rewound" the tape of time, it would shrink back into the capsule.

Now, imagine that capsule was a tiny, tiny point (no dimensions at all ... not even time). Just a zero-radius point. Suddenly (the Big Bang) it begins to expand. 

That's the idea. What's wrong with it is that we're on the outside watching it expand (into our space). For this analogy to be correct, you'd have to be inside the foam ... the expansion of the foam starts at t=0 and every instant thereafter it is creating more time and more space.


 

I'm sorry to jump in here and muddy up the waters any further, but...

It may sound like I'm contradicting myself.(and, I probably am, just too retarded to care!)  I get the aspect of an "explosion" of space and not in space.  And I understand the balloon analogies.  Likewise, I get the foam animal explanation.  But what I'm having trouble wrapping my mind around is something that ChipdataJeff stated.  He said that imagine the proverbial capsule as having no dimension...zero radius.  To me, that means that it was NOTHING.  If something has no dimension, how can it even be considered something that physically exists?  And how can there be a BB of something that doesn't exist?  Where was this NOTHING and how did it come on the scene in order to "explode" and create the universe?  It's just extremely hard for me to imagine something that created all the galaxies, nebula, clusters, etc. had a zero radius which further means to me it NEVER existed until the BB.

I know you've answered some of these questions before, but I guess I'm not getting it.  I'm not a person that takes a whole bunch of things on faith.  I need proof!  Good thing I'm from Missouri, isn't it?  And I'm sorry to say it, but Physics is by no means my strong suit.  I can understand much of the theory, but the math part...not so good.  I guess, however, I'm not understanding this little chunk of theory!

And, believe me, I will be reading some of the books and materials you all have referred to.

It helps me to think of it this way:  Not only was all of the stuff, the matter, and energy, space and time of the universe created at that initial moment, but so were all of the tools we can use to understand it.  All of the physical laws of the universe came into being then also.  And since all of our tools are tied directly to that moment of creation they can only measure, see, and help us understand the universe we know in a scientific sense.  There was no 'before' since time started at T=0, and there is no 'outside' because all of our possible understanding is 'inside'.  The only way to deal with the concepts of 'before' and 'outside' is to use philosophy and/or religon, the realms of mind and faith which are not bound by the physical laws we were constrained to at the BB.

Just one man's opinion.

I just thought my head hurt before. 

Some things are so hard to understand when you think about them literally.  Such as something with zero radius existing.  Infinity is just a hard to wrap your mind around when you actually consider it.

As a computer programmer, it's easier for me to get something with a zero radius existing.  It's just a null value.  It's there, I have to account for the possiblity.  Infinity makes my head hurt. 

chuck81:

I just thought my head hurt before. 

Some things are so hard to understand when you think about them literally.  Such as something with zero radius existing.  Infinity is just a hard to wrap your mind around when you actually consider it.

As a computer programmer, it's easier for me to get something with a zero radius existing.  It's just a null value.  It's there, I have to account for the possiblity.  Infinity makes my head hurt. 

I guess that was the point of my post.  It is a fruitless execise to try and understand, with science, those things that exist outside of our science, or that existed before it's rules were in place.  Trying to do that will make your head hurt.