
Originally Posted by
jimjam
The way I see the expansion conundrum is exactly the same as the Pacific Ocean example. If you throw a brick into the Ocean, sea level will rise, but only a very very very tiny bit. Lets say, for the sake of easy math, that it would rise 1 angstrom, far too small for us to detect on average.
But, if you threw a brick in every second, (assuming you spread them around to avoid making an island), after only ten years, you would find a measurable difference (about 3cm, by my very rough figures).
If you expand that to the level of the Solar System, the expansion effects would be very minute indeed, but should be within the threshold of what we are able to detect. We can detect the Moon moving away from Earth at roughly (I believe) 1.5 inches per year, yet if we reduce that down to the level of a brick in the ocean, it would be beneath our threshold.
If expansion were affecting the Solar System, we should be able to detect it in the orbits of some of the outer bodies. It would be highly implausible that every planet should be perfectly balanced between the sun's gravity and the expansion forces. Besides, gravity would have to be stronger than it actually is, just to simulate a negation of forces.
I hear a lot of 'expansion doesn't work inside a galaxy', but why? Galaxies are pretty big, after all. If expansion didn't affect them, and you watch time in reverse, you'll see space shrink and galaxies stay the same... you run out of space fairly fast that way. More importantly, we can see that expansion isn't changing galaxies - to the best of our ability to determine, there is no sign of galaxies in the past being more compressed than ours.
Then there's distribution, brightness, IGM temperatures... it goes on and on. Expansion just does not work, with or without 'special exceptions' like not working on gravitational bodies.