Why is our universe so homogeneous? Why is it not exactly homogeneous? Why is it isotropic (same in all directions)? Why all of its parts started exp… - Andrei Linde

... We live for a while in some state which is called ... there is no preferable coordinate system ... there is no preferable choice of time ...

The theory of the inflationary multiverse changes the way we think about our place in the world. According to its most popular version, our world may consist of infinitely many exponentially large parts, exhibiting different sets of low-energy laws of physics. Since these parts are extremely large, the interior of each of them behaves as if it were a separate universe, practically unaffected by the rest of the world. This picture, combined with the theory of eternal inflation and anthropic considerations, may help to solve many difficult problems of modern physics, including the cosmological constant problem.

The best available explanation of the observed uniformity of the universe is provided by inflation. However, as soon as this mechanism was proposed, it was realized that inflation, while explaining why our part of the world is so uniform, does not predict that this uniformity must extend to the whole universe ...