Bumping Bubbles

Via Sarah, news of the first observational evidence of the existence of other universes.  And they didn't find just one footprint, they found four.Nothing in physics prevents the possibilities of outside universes, but neither has it helped to constrain them, leaving scientists free to talk of branes and bubbles. Many of these ideas have been considered untestable, but a paper uploaded to arXiv last month considers the effects of two universes colliding and searches for fingerprints of...