Galaxies on the Edge: Understanding the Expansion of the Universe

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In summary, Jim's analogy is of an expanding euclidian 3D object, not a map from a 2D one to a 3D one. The raisins are popped onto the outer surface of the dough, and the zone of raisins or spots is a 2D surface in a 3D world. The dough rises and the outer surface gets bigger, and all the raisins move farther away from each other. There is still no boundary so the raisins maintain their viewpoint.
  • #1
jimjohnson
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The analogy for the expansion of the universe is explained as raisins (mass, or galaxies) expanding inside an expanding loaf of bread (bread being space), everything is moving away from everything else. This may be a simplistic question, but when the expansion started some raisins were on the outside of others. Where are the raisins on the outer surface, how can all raisins be in the middle? These galaxies would look opposite the expansion and "see" nothing. What am I missing?
 
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The analogy is from the SURFACE of the loaf to the VOLUME of space.
 
  • #3
Sorry, do not understand response, the surface would be 2 dimensions. tks
 
  • #4
What Mathman is saying is that the analogy is an analogy. The analogy is a 2D example of what could happen in 3D.
 
  • #5
I think jim asked a very fair question, which is a long way short of an answer.

Jim's pudding analogy is of an expanding euclidian 3D object, not a map from a 2D one to a 3D one.

This issue of the edge galaxies can be addressed in two ways?

How do we know (what evidence is there) that the inhabitants don't see an asymmetric universe?

The second is the current explanation which is by no means proven.

The thinking runs as follows.

Instead of the raisins being distributed throughout your pudding, imagine they are just popped onto the outer surface, as if they were spots painted on a balloon. So the zone of raisins or spots really is a 2D surface in a 3D world. In this model or analogy no raisin sees an asymmetric view as there is no boundary in the 2D of the durface.

Now let the dough rise so the pudding expand. The outer surface gets bigger and all the raisins move farther away from each other. There is stil no boundary so the raisins maintain their viewpoint.

Translating this model to our 3D universe, The most widely accepted explanation of theory and observable facts in modern physics is that our 3D space is 'curved' in 4D, just as the 2D surface of the pudding is curved in 3D.
 
  • #6
This is hard to visualize but a logical explanation which I have not read before. Thanks for response.
 

1. How do raisins affect the expansion of bread?

Raisins can negatively impact the expansion of bread due to their high sugar content. As the bread dough rises, the sugar in the raisins can cause the yeast to work too quickly, resulting in uneven rising and a denser texture.

2. Can adding more raisins make the bread expand more?

Yes, adding more raisins can increase the expansion of bread to a certain extent. The moisture from the raisins can help the dough rise, but too many raisins can also hinder the rising process. It is important to find the right balance of raisins in the dough for optimal expansion.

3. Why does bread with raisins expand differently than plain bread?

Raisins add moisture and sugar to bread dough, which can affect the fermentation process. The sugar feeds the yeast, causing it to produce more carbon dioxide gas and make the bread rise. The moisture from the raisins also helps to keep the dough soft and pliable, allowing for a larger expansion.

4. Are there any other ingredients that can impact the expansion of bread?

Yes, there are several other ingredients that can affect the expansion of bread. Salt, for example, can slow down the fermentation process and result in less expansion. On the other hand, certain flours and additives like gluten can help increase the expansion of bread.

5. Can the temperature of the environment affect the expansion of bread with raisins?

Yes, temperature plays a crucial role in the expansion of bread, including those with raisins. Warmer temperatures can speed up the fermentation process and result in a larger expansion. However, if the temperature is too hot, it can kill the yeast and prevent the bread from rising at all.

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