Accelerating, Expanding Universe Questions from a Noviceby yonglin426 Tags: accelerating, expanding, expansion, novice, universe 

#1
Sep2913, 02:00 AM

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What I think I know:
1. universe is expanding (from red shift observation?) 2. expansion is accelerating; farther galaxies move away at faster rate than nearer galaxies. 3. expansion rate will exceed speed of light 4. observable universe will be a lonely, dark place. Question: 1. how can expansion rate exceed speed of light? 2. Is it the space that is expanding? 3. If space is indeed expanding, what is the process by which it does so? Is the space stretching? Or is "new" space being added in between existing "space"? or something other process? What experiment is used to detect/indicate/show that the expansion process is so? 4. Are there any significant consequences between "stretching" and "new" space in terms of what that understanding tells us about the workings of the universe? 5. Is gravity counteracting the expansion for nearby objects? 6. Do we expand? If the expansion of space stretches the wavelength of light, causing a redshift, then does the expansion of space stretch matter? That is to say you and I are a little larger than you and I from yesterday. If it is the case, how would be detect it, since 1 cm is today a little larger than 1 cm from yesterday. That's all for now. 



#2
Sep2913, 02:21 AM

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Another example  if you shine a spot of light on a surface, you can make the spot travel by changing the angle you shine the source. Someone next to the surface can measure the speed of the spot. If the surface is far away, you will be able to make the spot travel faster than light. Geometry again. 



#3
Sep2913, 04:19 AM

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Instead, what we have is an effect that is SIMILAR to what you can do with real objects. IE the nature of spacetime is that it can cause distances between objects to increase based solely on the way the geometry works. The reality is that there are several ways of thinking about it and visualizing it that work. Space expanding, more space being added, space flowing, etc. However to REALLY grasp what is going on you would need to know how the math works. But, however you think about it, the results are always the same. The two main possibilities I know of are that gravity completely counteracts the expansion and no expansion takes place around massive objects at all. The other is that gravity doesn't completely counteract it, and the expansion acts like a very very tiny repulsive force. Gravity and the other forces of nature are still overwhelmingly more powerful than the expansion, so everything still stays together just fine. 



#4
Sep2913, 04:40 AM

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Accelerating, Expanding Universe Questions from a Novice 


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