摘自李淼老师博客 http://limiao.net/2402 的转载，取了原理介绍部分和成果介绍部分，去掉具体的实验探测介绍部分。
博客原文在：http://blogs.discovermagazine.com/cosmicvariance/2010/12/22/observing-the-multiverse-guest-post/
宇宙学常见假说的简介见：http://limiao.net/2376
大意为：
在一个暴涨的宇宙中，如果一块区域在介稳的真空中，拥有不同物理定律和常数的bubble universe会形成并展开，却由于宇宙暴涨过快而来不及合并消失，渐行渐远。该文描述的实验迈出对此假说进行实验观测验证的一步，从宇宙微波背景辐射中找寻bubble碰撞的迹象。
The laws of physics, and the various “fundamental” constants appearing in them, could have been otherwise.
There is no unique vacuum in theories of high energy physics that involve spontaneous symmetry breaking, extra dimensions, or supersymmetry.
When a spacetime region undergoing inflation is metastable, there are cases when all of the vacua in a theory can be realized in different places and at different times.
In an inflating universe, if a region is in a metastable vacuum, bubbles containing different vacua will form.These bubbles then expand, and eat into the original vacuum. However, if the space between bubbles is expanding fast enough, they never merge completely. There is always more volume to convert into different vacua through bubble formation, and the original vacuum never disappears: inflation becomes eternal. In the theory of eternal inflation, our entire observable universe resides inside one of these bubbles.
In the past four years, a few groups have tried to understand if it is possible to confront this radical picture of a “multiverse” with observation. The idea is to look for signatures of a collision between another bubble universe and our own. Even though the outside eternally inflating spacetime prevents all bubbles from merging, there will be many collisions between bubbles.
While we didn’t make any clear detections of bubble collisions, we did find four features in the WMAP data that are better explained by the bubble collision hypothesis than by the standard hypothesis of fluctuations in a nearly Gaussian field.
While identifying the four features consistent with being bubble collisions was an exciting result,These features are on the edge of our sensitivity thresholds, and so should be considered only as a hint that there might be bubble collisions to find in future data.