Editing Cosmic variance (section)

== Background ==
The standard [[Big Bang]] model is usually supplemented with [[cosmic inflation]]. In inflationary models, the observer only sees a tiny fraction of the whole universe, much less than a billionth (1/10<sup>9</sup>) of the volume of the [[universe]] postulated in inflation.  So the observable universe (the so-called [[particle horizon]] of the universe) is the result of processes that follow some general [[physical laws]], including [[quantum mechanics]] and [[general relativity]]. Some of these processes are [[random]]: for example, the distribution of [[galaxies]] throughout the universe can only be described [[statistics|statistically]] and cannot be derived from first principles.