|MadSci Network: Astronomy|
This is quite a few questions in one, you've obviously put a lot of thought into this. We are indeed looking to pinpoint the locations of massive dark objects by making use of the fact that their gravitation bends light. It's called gravitational lensing, and can generally be observed as a temporary brightening of a distant star. As a massive body passes between us and the star, its light is focused in a lens-like manner by the gravitation. More information on gravitational lensing can be found here: http://www.iam.ubc.ca/~newbury/lenses/lenses.html According to modern cosmology, as the universe expanded and cooled it reached a point where matter was diffuse enough to allow light to travel freely through space. The light from this point in the universe remains with us, we observe it as the cosmic microwave background radiation. For some further information on measuring the size and age of the universe, and the extent of the physical universe, see here: http://imagine.gsfc.nasa.gov/docs/ask_astro/answers/971124x.html
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