Big Bang

[herme3]

If the big bang is true, wouldn't there be empty space in the middle of the universe? All matter would be sent outward, and the universe would be expanding in all directions. However, the center would be an area of empty space that is constantly increasing in size. Wouldn't this be true?

[BobbyJoeCool]

I can see that, but look at it this way... the area between our galaxy and say... M13 Galaxy is empty (aside from a bunch of random atoms) and that space is getting bigger...

 

Also, the expantion of the universe isn't so great at the center (because there isn't as much to expand), and it is possible for atoms to move against this expantion and get to the point of the "center" of the universe.

 

But in answer to your question, it is possible that at the center there is a gigantic void, completely void of anything because the expantion of the universe just carries it away.

[Cap'n Refsmmat]

You've misunderstood "big bang."

 

It was not a big explosion that sent everything careening outwards. Rather, it was the expansion of space itself.[i/] Everything got farther apart from everything else, not just from one central location.

At least, that's what studies of the cosmic background radiation show.

[herme3]

I always heard that the big bang was an explosion that keeps happening forever. All the matter moves outward at an incredible speed. This would leave a bunch of empty space in the middle. Over time, the speed in which the matter is moving outward slows down. Eventually everything comes back into the center again and collides. Then it goes outward again.

[Cap'n Refsmmat]

I suggest you buy the book The Fabric of the Cosmos by Brian Greene so you can get a firm understanding of the current big bang theory.

[ydoaPs]

think of it like a balloon. you blow it up and the surface expands, but there is no center of the expansion.

[herme3]

I suggest you buy the book The Fabric of the Cosmos by Brian Greene so you can get a firm understanding of the current big bang theory.

 

I have heard many different versions of the big bang theory. The most common one involves all the matter in the universe being compacted in a very small sphere. Suddenly, there is a huge force that causes all of that matter to expand outward. I really don't understand that theory, because if the sphere of matter had been compacted for an infinite amount of time before the big bang, I don't understand what would cause the sudden expansion.

 

In my opinion, the most reasonable big bang theory involves everything expanding, then coming together again. This creates another big bang and the whole process repeats itself. If this has been happening and will continue to happen for an infinite amount of time, that would help eliminate the question of how the universe was first created. Although, there are many parts of that theory that can't be explained yet, so I can't say I believe it is true.

 

The third big band theory involves multiple universes. I read about it in a science magazine. It basically says that there are two separate universes. Every once in a while, the two universes collide and create a big bang. I must admit that I don't understand that theory.

 

If you think about the first two theories, there would still be an empty space in the center of the universe while the matter is expanding outward.

 

think of it like a balloon. you blow it up and the surface expands, but there is no center of the expansion.

 

In that case, wouldn't the matter have to come from outside the universe? When you blow up a balloon, the air doesn't expand from the center of the balloon. It comes from outside, and goes into the balloon. If the universe works the same way, where is the outside place that the matter came from?

[Cap'n Refsmmat]

I repeat:

 

The matter does not expand outward. Space expands outward. The entire surface of the universe (think spacetime) expands, meaning everything becomes farther and farther apart from everything else. Like the dots on the outside of a balloon.

Scientists have done studies involving the microwave radiation in space, and this idea appears to be correct.

[ydoaPs]

In that case, wouldn't the matter have to come from outside the universe? When you blow up a balloon, the air doesn't expand from the center of the balloon. It comes from outside, and goes into the balloon. If the universe works the same way, where is the outside place that the matter came from?

with this analogy, the surface of the ballon is the universe, not the air. think 2-sphere.

[herme3]

I repeat:

 

The matter does not expand outward. Space expands outward. The entire surface of the universe (think spacetime) expands' date=' meaning everything becomes farther and farther apart from everything else. Like the dots on the outside of a balloon.

Scientists have done studies involving the microwave radiation in space, and this idea appears to be correct.[/quote']

 

Ok, now I think I understand what you mean. So do you believe that there is an actual wall at the end of space? Would it be possible to reach this wall of space, or is it expanding at the speed of light? What could this wall be made out of? Is it a type of force that just pushes matter away or is it made of matter?

[ydoaPs]

no, there is not a physical wall.

[Cap'n Refsmmat]

No wall. Nobody really knows what happens if you get to the end, though--does space 'curve around' so that you just 'come out on the other side,' or is it impossible to get to the edge?

[herme3]

no, there is not a physical wall.

 

If the space between matter is completely empty, how can space "end" without a type of barrier made out of a force or matter? I thought that the empty space was infinite, and only the section with matter ended. I always heard that if you come to the end of the matter, you just go through empty space forever.

 

No wall. Nobody really knows what happens if you get to the end, though--does space 'curve around' so that you just 'come out on the other side,' or is it impossible to get to the edge?

 

I know this may not be the best example, but I once tried to program a video game very similar to the first Mario games. Normally there is a physical object in the program that ends the level when you finish it. Most players call this the goal. However, if you forget to add the goal, you walk into the beginning of the same level. Could the universe work the same as a computer simulation?

[Cap'n Refsmmat]

It depends.

 

Scientists believe that if the universe has less than a certain amount of energy in it, is has negative curvature and is shaped like a saddle or Pringles potato chip. If it has more than that critical amount, it has positive curvature and is shaped like a sphere, meaning you go in one side and out the other.

[herme3]

It depends.

 

Scientists believe that if the universe has less than a certain amount of energy in it' date=' is has negative curvature and is shaped like a saddle or Pringles potato chip. If it has more than that critical amount, it has positive curvature and is shaped like a sphere, meaning you go in one side and out the other.[/quote']

 

How can scientists decide how much energy is necessary to change the shape of the universe? Do scientists even know how big the universe is? We can't see the end of the universe with our current technology. We have no idea what else is out there. There could be a place where the stars end, and there is some other type of matter for billions of light years.

 

If it is a sphere, how can you go in one side and out the other? If this was true, wouldn't it seem like the universe keeps going forever in a pattern? You could fly by Earth, then keep flying until you fly by Earth again? How would they call this a sphere? It just doesn't seem possible.

 

What do the scientists believe would happen if it has negative curvature, and you reach the end of the universe?

[swansont]

How can scientists decide how much energy is necessary to change the shape of the universe? Do scientists even know how big the universe is? We can't see the end of the universe with our current technology. We have no idea what else is out there. There could be a place where the stars end, and there is some other type of matter for billions of light years.

 

Scientists do have an idea of how big the universe is

 

If it is a sphere' date=' how can you go in one side and out the other? If this was true, wouldn't it seem like the universe keeps going forever in a pattern? You could fly by Earth, then keep flying until you fly by Earth again? How would they call this a sphere? It just doesn't seem possible.

[/quote']

 

Fortunately the universe is under no obligation to behave in a way that you comprehend.

[herme3]

Scientists do have an idea of how big the universe is

 

 

 

Fortunately the universe is under no obligation to behave in a way that you comprehend.

 

Thank you for the link to that article, it was interesting. I still don't understand how the scientists got their information. They made all of their calculations based on the fact that the universe is 13.7 billion years old. However, they never explained where they got that number.

 

Scientists can look at a very distant galaxy, and tell that the light it produced has been traveling for a very long time. However, how do they know anything about this galaxy's location. It could be near the end of the universe, or near the center. We can't judge by the light we see, because we don't know where the Earth is in the universe. The Earth could be near the edge, or near the center. How did the scientists obtain most of their data?

[swansont]

Thank you for the link to that article' date=' it was interesting. I still don't understand how the scientists got their information. They made all of their calculations based on the fact that the universe is 13.7 billion years old. However, they never explained where they got that number.

[/quote']

 

 

There are links in the article. You should check them out.