Comments on: Podcast: Questions about the Size, Shape and Centre of the Universe http://www.universetoday.com/2008/03/27/podcast-questions-about-the-size-shape-and-centre-of-the-universe/ Space and astronomy news Sun, 8 Nov 2009 12:39:08 -0600 http://wordpress.org/?v=2.8.5 hourly 1 By: David Madison, Sr. http://www.universetoday.com/2008/03/27/podcast-questions-about-the-size-shape-and-centre-of-the-universe/comment-page-1/#comment-16610 David Madison, Sr. Fri, 28 Mar 2008 15:05:48 +0000 http://www.universetoday.com/2008/03/27/podcast-questions-about-the-size-shape-and-centre-of-the-universe/#comment-16610 Once you have a good handle on how it works in two dimensions, mentally change the balloon to a lump of dough with raisins inside. Put the dough in the oven. As the dough rises, gets larger, the rasin that was in the center stayed there. However, the second raisin that was an inch above the first is now two inches higher. The third raisin started out an inch above the second raisin and therefore two inches above the first. Now the third raisin is two inches above the second. However, it is four inches above the first. The thinking process is the same as the expanding balloon, but now the expansion also happens in the third dimension. Once you have a good handle on how it works in two dimensions, mentally change the balloon to a lump of dough with raisins inside. Put the dough in the oven. As the dough rises, gets larger, the rasin that was in the center stayed there. However, the second raisin that was an inch above the first is now two inches higher. The third raisin started out an inch above the second raisin and therefore two inches above the first.

Now the third raisin is two inches above the second. However, it is four inches above the first. The thinking process is the same as the expanding balloon, but now the expansion also happens in the third dimension.

]]> By: Neil http://www.universetoday.com/2008/03/27/podcast-questions-about-the-size-shape-and-centre-of-the-universe/comment-page-1/#comment-16560 Neil Thu, 27 Mar 2008 22:33:06 +0000 http://www.universetoday.com/2008/03/27/podcast-questions-about-the-size-shape-and-centre-of-the-universe/#comment-16560 One question i have about all this is the balloon analogy I can imagine that if you are sat on the surface of the balloon and travel along the x axis (west or east) and y axis (north or south) you will come back to where you started. Great, But thats only two dimensions, right? what about if i travel the zaxis (up or down)? i would come to the edge.. So i can understand this if we were talking about a 2d universe wrapped around a 3d balloon universe But i stuggle to see how this applys to the 3rd dimension One question i have about all this is the balloon analogy

I can imagine that if you are sat on the surface of the balloon and travel along the x axis (west or east) and y axis (north or south) you will come back to where you started.

Great,

But thats only two dimensions, right? what about if i travel the zaxis (up or down)? i would come to the edge..

So i can understand this if we were talking about a 2d universe wrapped around a 3d balloon universe

But i stuggle to see how this applys to the 3rd dimension

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