guenter

That seems not compelling. This catastrophic factor was calculated from QFT as the sum of zero-point energies. They could gravitate as well. On the other side this factor isn't a real problem, because you can get rid of it by renormalization. What remains to be argued are differences of energy, a good example for which is the Casimir-effect. Some hope comes from LQG to at least model the inflationary period of expansion.

No, vice versa. Some researchers discuss the possibility that we are in the center of a low matter density region. Imagine the galaxies beyond the visible universe to be spherically symmetric much more dense, then the galaxies within the visible universe would recede accelerated as observed. However having the copernican principle in mind this sounds not too trustful. Assuming vacuum outside one would rather expect deacceleration or even contraction.

Hi everybody, hopefully I can improve my knowledge about the universe, the physics behind it. There are many popular books and articles dealing with that. However even good books stay on the surface, naturally, and some even suggest wrong notions to the reader. I have got a degree in physical chemistry long time ago. Please note, that english is not my mother language. Hope for good discussions! Regards, guenter