Where Does Space End? It Must End Somewhere!

[brodyoneill1]

I'm only in an 8th grade science class, so sorry if I get anything totally off, but according to the book, the universe is infinitely expanding, almost like a cell when it splits in two and so forth. But, like how cancer works, is it possible to stop the spread of the universe in some places, making empty holes of nothing? But still, the universe should continue on forever, constantly spreading.

[Strange]

I'm only in an 8th grade science class, so sorry if I get anything totally off, but according to the book, the universe is infinitely expanding, almost like a cell when it splits in two and so forth. But, like how cancer works, is it possible to stop the spread of the universe in some places, making empty holes of nothing? But still, the universe should continue on forever, constantly spreading.

 

It is important to realise that the big bang theory is not about the universe spreading into existing empty space, rather it is the space itself that is increasing and the galaxies are just flowing along with it.

[nostradamus]

The end point of the universe is its beginning point.

[TJ McCaustland]

The end point of the universe is its beginning point.

Exactly the point of the dots on a balloon demonstration.

[jeffellis]

I think space (as we know it) never ends. I think that stellar black holes are universes. Because gravity is constantly "feeding" each black hole, it corresponding universe is ever expanding equal to or faster than the speed of light. Although there would be an end or edge of space in each universe, we are unable to go fast or far enough to reach it.

I think that stellar black holes are universes. Because gravity is constantly "feeding" a black hole, its corresponding universe is constantly expanding at or greater than the speed of light. Thus, an end or an edge of space, although existing, would not be observable to us (yet).

[catman]

 

Firstly, work on grammer. It hard was follow.

 

Second, the God thing, there are plenty of threads here where you can try to prove that he made everything in the universe but for all intensive purposes, you have no proof of this. If you don't believe me ask that guy sayonara, he'll tell you all about it.

 

But if our universe is like a baloon, outside that balloon of what we know, our universe, how could there be an infinite void? There has to be something there eventually. That is an awefully conceited veiw. Our universe is the only area that is that has anything in it. Mathmatically speaking the area of our universe is a speck in the infinite expanse of space. The same way you and i are specks in the universe. You want to tell me that in pin-prick in space is where all the mass is. All the energy is. All the everything is.

 

Not possible...

 

Firstly, work on grammer. It hard was follow.

 

Second, the God thing, there are plenty of threads here where you can try to prove that he made everything in the universe but for all intensive purposes, you have no proof of this. If you don't believe me ask that guy sayonara, he'll tell you all about it.

 

But if our universe is like a baloon, outside that balloon of what we know, our universe, how could there be an infinite void? There has to be something there eventually. That is an awefully conceited veiw. Our universe is the only area that is that has anything in it. Mathmatically speaking the area of our universe is a speck in the infinite expanse of space. The same way you and i are specks in the universe. You want to tell me that in pin-prick in space is where all the mass is. All the energy is. All the everything is.

 

Not possible...

 

First of all, brainiac, if you are going to pick on someone for their poor use of grammar, make sure you use correct grammar yourself.. it's "for all INTENTS and purposes" not intensive purposes..

And second, there is no "proof" of anything in this discussion.. so tellung someone that they have no proof god created the universe is, well, just plain ridiculous.. this whole topic of discussion is nothing but people's personal beliefs.

I personally don't follow the god theory, but that is for a separate discussion other than this one.

Before you can even begin to theorize about where space ends.. you must first answer the question: "when did space begin?" For that you must have an understanding of space AND time, and be open to the idea that there is TWO sides to both... it's mind bending stuff.. but we as humans, because we are born, and we die, and everything we come in contact with basically does the same thing.. we think everything must have a beggining and an end.. we are so limited in our thought process that this is all we can believe.

How ignorant is THAT?

[Strange]

this whole topic of discussion is nothing but people's personal beliefs.

 

No. Some of it is about science. Ideally, this being a science forum, it would all be about science. But people can't help brininging their irrational beliefs into any discussion.

 

 

Before you can even begin to theorize about where space ends.. you must first answer the question: "when did space begin?"

 

And do you have any references to science regarding that question?

 

but we as humans, because we are born, and we die, and everything we come in contact with basically does the same thing.. we think everything must have a beggining and an end.. we are so limited in our thought process that this is all we can believe.

 

You probably shouldn't project your beliefs and limitations on to others.

[bluescience]

First, some people on this forum are correct since, yes, the reason why you cant reach the end of the universe(which is space since space is created as our universe has started to expand from a point of singularity since the "big bang") is because we will always be stumped by the fourth dimension. If you were the bring a 2 dimensional creature to the earth; and assuming the earth is a perfect sphere, and you told the creature to go find the edge of the earth, he wouldn't be able too since he would always be moving along that 3-dimensional sphere and sometimes reach the same exact spot he was when he started. This is the same thing that happens to us. Assuming the fourth dimension is time, the only way you could move to the edge of the universe would be moving through the fourth dimension or time. so we would need a time machine. This is because if you go back to the 'flatlander" analogy, the 2-d creature could be at any 2-d surface of the sphere, at any depth in the sphere. To reach the edge of that sphere, he would need to travel thru the 3rd dimension to reach the edge of the sphere. So we must travel through the fourth dimension if we need to reach the edge of space. Then we face the question of what happens if we were to cross that edge of space into nothingness. What would happen if we put our hand past the edge of space?

This is not what science is about. Science is the pursuit of knowledge in our universe. Remember the ultimate goal of science is to create a theory in which we can describe the whole universe in, so far we have two theories that are closest to that: The theory of relativity and Quantum Mechanics.

[Strange]

What would happen if we put our hand past the edge of space?

 

There is no edge.

[Phi for All]

 

There is no edge.

 

Homogeneous and isotropic expansion aren't intuitive concepts, that's for sure. It's hard for many to imagine expanding without expanding into something else.

[Airbrush]

"The is no edge" but what is intuitive is that the universe has variation. Once you travel far beyond the edge of our observable universe you will probably encounter regions that we never dreamed of. The image I keep visualizing is a finite-sized, finite-mass big bang beyond which there stretches vast space Trillions or Quadrillions of light years before you reach something interesting, which might be the edge of another big bang expanding in our direction, or a region of flying pink elephants.

Edited March 29, 2016 by Airbrush

[Phi for All]

Once you travel far beyond the edge of our observable universe you will probably encounter regions that we never dreamed of.

 

Why would you think that? The evidence we have is that the galaxies and their stars are pretty much made of the same basic stuff, and their distribution is fairly even and predictable as well. Why should it "probably" have "regions that we never dreamed of"? Isn't it more likely that it probably has basically the same sort of stuff we see in our observable universe?

[Airbrush]

True the universe we can see is isotropic and homogenious in every direction, but on the scale of infinity our observable universe amounts to a tiny bubble. It is about 240,000 miles to the moon, much further to the Sun, much further to the nearest star, much further to the next galaxy, and so on. Beyond our observable bubble of the universe is probably much more of the same until you go far enough away. "Much further" to the next large stucture which could be another big bang, or big whatever.

Edited March 29, 2016 by Airbrush

[Phi for All]

First, some people on this forum are correct since, yes, the reason why you cant reach the end of the universe(which is space since space is created as our universe has started to expand from a point of singularity since the "big bang") is because we will always be stumped by the fourth dimension. If you were the bring a 2 dimensional creature to the earth; and assuming the earth is a perfect sphere, and you told the creature to go find the edge of the earth, he wouldn't be able too since he would always be moving along that 3-dimensional sphere and sometimes reach the same exact spot he was when he started. This is the same thing that happens to us. Assuming the fourth dimension is time, the only way you could move to the edge of the universe would be moving through the fourth dimension or time. so we would need a time machine. This is because if you go back to the 'flatlander" analogy, the 2-d creature could be at any 2-d surface of the sphere, at any depth in the sphere. To reach the edge of that sphere, he would need to travel thru the 3rd dimension to reach the edge of the sphere. So we must travel through the fourth dimension if we need to reach the edge of space. Then we face the question of what happens if we were to cross that edge of space into nothingness. What would happen if we put our hand past the edge of space?

 

You have some misconceptions going on here. You don't need a time machine to move through the 4th dimension. You're moving through it right now, at the rate of 1 second per second. The 4th dimension doesn't "stump" us.

 

There's no edge. There's no "sphere". The universe is all there is, it isn't expanding into anything.

 

It's not easy to visualize. Expanding, in our experience, has to have "room" to expand into. But not the universe. We don't know whether it's finite or infinite.

 

I visualize a ball of matter the size of a whole galaxy. All the universe's matter in a single ball, uncompressed. Now I compress that ball until it's the size of the Earth. The matter is much, much denser. Now I compress it till it's basketball size. Extremely dense, incredibly dense. Now imagine we're going to expand that ball again, and we're going to slow down when it gets back to it's normal galaxy size. When I expand past that point, all the matter is going to start having space between it's constituent parts. This space is going to be homogeneous and isotropic, evenly distributed between the matter. As we keep expanding to the size of the observable universe, the expansion of space distributes the matter in the way we observe. No matter how large the expansion gets, it doesn't meet any "edge" or "void". Space itself is expanding, so it's not pushing against anything, just like the Big Bang isn't an explosion so much as an expansion.

 

Does that make any sense?

[John Cuthber]

"The is no edge" but what is intuitive is that the universe has variation.

The universe has no reason to conform to the intuition of an ape here on Earth.

[Airbrush]

The universe has no reason to conform to the intuition of an ape here on Earth.

 

Only when the ape guesses correctly.

 

On second thought the universe does NOT have much variation that we can see. I take back what I said. My new argument is that what we can see, which is homogenious and isotropic, is too small a sample to reach any conclusions. Beyond the observable universe is probably a lot more on the scale of infinity.

Edited March 30, 2016 by Airbrush

[Thorham]

The universe has no reason to conform to the intuition of an ape here on Earth.

Humans aren't apes. As much as I would like to have four hands...

[Strange]

 

The family Hominidae, known collectively as the great apes, include orangutans, gorillas, chimpanzees, and humans;^[1][2][3][4]

https://en.wikipedia.org/wiki/Ape

 

And now, back to the topic.

Edited March 30, 2016 by Strange

[Airbrush]

 

There's no edge. There's no "sphere". The universe is all there is, it isn't expanding into anything.

 

It's not easy to visualize. Expanding, in our experience, has to have "room" to expand into. But not the universe. We don't know whether it's finite or infinite.

 

......No matter how large the expansion gets, it doesn't meet any "edge" or "void". Space itself is expanding, so it's not pushing against anything, just like the Big Bang isn't an explosion so much as an expansion.

 

Does that make any sense?

 

It makes sense, but how can we say what (or what nothing) the universe is expanding into if we can never know what's beyond our observable horizon? Our observable universe is too small a sample to make claims about what lies beyond, it seems to me. There could have been a pre-existing universe and our big bang happened inside that universe.

Edited April 1, 2016 by Airbrush

[Delta1212]

 

It makes sense, but how can we say what (or what nothing) the universe is expanding into if we can never know what's beyond our observable horizon? Our observable universe is too small a sample to make claims about what lies beyond, it seems to me. There could have been a pre-existing universe and our big bang happened inside that universe.

 

Perhaps the better way of stating it is, rather than "there is nothing beyond our observable universe that our universe is expanding into", that "the way our universe is expanding does not require it to be expanding into anything for the expansion to take place."

 

Maybe we are inside an expanding bubble of space time inside some kind of larger universe, but the mere fact that we are expanding doesn't necessarily imply that that is the case, which seems to be a common point of confusion. And since there is no evidence that we are expanding into anything outside of our own universe, it's much more straightforward to say that we are not, rather than introducing a bunch of mostly philosophical speculation about things that we very well may never be able to find a definite answer to one way or another when trying to teach a concept that many people already find confusing and counter-intuitive to begin with.

[The Think3r]

Current estimations of this universe size make it out to be 46 Billion light-years across. So the universe, i.e. space, is extremely large and still "growing". In ten million years the universe would be bigger by about 5.25600 × 10¹² megaParsecs. so very, very large. The universe has already been around for about 14 billion years give or take about 2-3 billion years. So it could theoretical grow into what most would call infinity, meaning you ( and almost every thing else) would die before you could travel from one side to the other.

[Strange]

Current estimations of this universe size make it out to be 46 Billion light-years across.

 

That is the radius of the observable universe. (So it is about 93 billion light years across.) The size of the whole universe is almost certainly many times larger than that (if not infinite).

[David Levy]

 

That is the radius of the observable universe. (So it is about 93 billion light years across.) The size of the whole universe is almost certainly many times larger than that (if not infinite).

 

 

So, as the Universe is many times larger than 46 Bly, and especially if it is infinite:

How can we explain that size of Universe by the BBT?

[Strange]

 

 

So, as the Universe is many times larger than 46 Bly, and especially if it is infinite:

How can we explain that size of Universe by the BBT?

 

The early universe was smaller than it is now. What else needs explaining?

[Airbrush]

 

That is the radius of the observable universe. (So it is about 93 billion light years across.) The size of the whole universe is almost certainly many times larger than that (if not infinite).

 

"Almost certainly many times larger"?

 

There is no such certainty. The entire universe could be exactly as large as the observable universe, by coincidence. It could be 50% larger than the observable universe. But it is almost certainly larger, and we don't have ANY clue how much larger.

 

Explain HOW the universe can be infinite in size before saying "it could by infinite".

Current estimations of this universe size make it out to be 46 Billion light-years across. So the universe, i.e. space, is extremely large and still "growing". In ten million years the universe would be bigger by about 5.25600 × 10¹² megaParsecs. so very, very large. The universe has already been around for about 14 billion years give or take about 2-3 billion years. So it could theoretical grow into what most would call infinity, meaning you ( and almost every thing else) would die before you could travel from one side to the other.

 

A finite universe can NEVER grow to an infinite size. For the universe to be infinite in size (and/or infinite in mass) it would have to ALREADY have been infinite in size at the first moment of the big bang. That is hard to imagine.

 

If the entire universe ever had a finite size, it could never grow to an infinite size at any finite rate. Even cosmic inflation was a finite rate of expansion. The difference between finite and infinite is so great that the difference is infinite.

Edited April 7, 2016 by Airbrush