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This may be a stupid question, but this has been bugging me. Why is it we are so convinced that space itself is expanding rather than everything else shrinking? Is there a test that could tell the difference between these two possibilities?
For example, take two objects, A and B. If you shrink them then the distance between the two (as measured by rulers on A or B) has just increased. If you lived on A or B, you could conclude that space was expanding while instead you are shrinking. There is probably something ridiculously obvious as to why this is a dumb question, but I cant see it. Can somebody here explain it to me?
Ok, i see what you are saying. Im not saying (although is suppose it could be true) that matter is both shrinking and losing mass. I was thinking it was just shrinking. But if you think about it mathematically, I just cant see the difference between the two. Take a picture of two spheres, A and B. Shrink the sphere by some percentage. Now, rather then shrinking, expand space. The net effect is same, since the distance is measured via rulers proportional to each sphere.
but matter is not conserved. Our sun is burning matter right now, no? Radioactive decay in the earth is also "burning" matter by releasing light and reducing the mass of the radioactive elements.
I dont follow. How do forces get shrunk? Also, why would it be irrelevant? It would make two very different predictions about the starting state of the universe, no?
To observe the red shift, it would have to be the case that matter shrinks while light does not. Since light has no mass, im left with matter shrinking.
well, its more or less all confused in my head at this point. But a thought I had awhile back was this it sort of makes conceptual sense that the universe is "burning itself up" by converting matter into another form of energy (light?). Rather than space-time bending due to mass, its "bending" due to the energy-dissipation rate of this conversion process. Just like water flowing down a mountain will erode channels that ultimately act to increase the dissipation rate, space time is being "carved" or "eroded" by this process. When I see the universe like this, it makes a lot more sense to me. The big black hole is the main trunk of the river, and the stars and planets, etc are the tributaries.
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go for it!