Ever just look up at the night sky...

[Hayabusa Rider]

Originally posted by: JohnCU

Originally posted by: KK

Originally posted by: JohnCU

Originally posted by: KK

Originally posted by: JohnCU

Originally posted by: KK

Originally posted by: JohnCU
Ever wonder what it'd be like to be at the edge of space, where it is expanding, and try to touch the boundary?

there is no boundary

so, what do you see if you are at the edge? what happens if you try to move through it? the universe is expanding.

how do we actually know that the universe is expanding?

redshift data, and such?

whats that?

the expansion was discovered by Hubble

I think your leg is getting pulled.

 

[JohnCU]

Originally posted by: Hayabusa Rider

Originally posted by: JohnCU

Originally posted by: Hayabusa Rider
An analogy.

Suppose you are an ant on a ball. How far do you have to go before you reach an edge where you cannot walk further?

Space is the same thing, but with one added dimension.

Wouldn't that depend on the shape of the universe? If I had a spaceship, and I was flying toward the boundary, would I not reach it?

Where is the boundry on a ball? It could be a cylinder, or any shape you can imagine. There is no boundry. You can walk around forever.

agreed, but you could walk around the earth forever. you have to go in a direction perpendicular to the surface to leave, correct? if i'm on a ball i can jump off.

 

[Hayabusa Rider]

Originally posted by: JohnCU

Originally posted by: Hayabusa Rider

Originally posted by: JohnCU

Originally posted by: Hayabusa Rider
An analogy.

Suppose you are an ant on a ball. How far do you have to go before you reach an edge where you cannot walk further?

Space is the same thing, but with one added dimension.

Wouldn't that depend on the shape of the universe? If I had a spaceship, and I was flying toward the boundary, would I not reach it?

Where is the boundry on a ball? It could be a cylinder, or any shape you can imagine. There is no boundry. You can walk around forever.

agreed, but you could walk around the earth forever. you have to go in a direction perpendicular to the surface to leave, correct? if i'm on a ball i can jump off.

If the analogy were perfect then you could jump off the universe. You cannot. In order to escape the surface of the ball you would have to leave the two dimensional surface and jump into a third dimension. Likewise to "jump" off the universe you would have to head in a direction perpendicular to the three in our space. Which way is that? Being 3D people, we are stuck in the universe.

 

[JohnCU]

Originally posted by: Hayabusa Rider
If the analogy were perfect then you could jump off the universe. You cannot. In order to escape the surface of the ball you would have to leave the two dimensional surface and jump into a third dimension. Likewise to "jump" off the universe you would have to head in a direction perpendicular to the three in our space. Which way is that? Being 3D people, we are stuck in the universe.

oh i get it now. thanks.

 

[gabemcg]

I did tonite...wow...

 

[imported_Reck]

The universe is expanding and will eventually grow too big for it's own good and will collapse in on itself.