Eideard

The theory that our universe is contained inside a bubble, and that multiple alternative universes exist inside their own bubbles — making up the ‘multiverse’ — is, for the first time, being tested by physicists.

Two research papers published in Physical Review Letters and Physical Review D are the first to detail how to search for signatures of other universes. Physicists are now searching for disk-like patterns in the cosmic microwave background (CMB) radiation — relic heat radiation left over from the Big Bang — which could provide tell-tale evidence of collisions between other universes and our own.

Many modern theories of fundamental physics predict that our universe is contained inside a bubble. In addition to our bubble, this `multiverse’ will contain others, each of which can be thought of as containing a universe. In the other ‘pocket universes’ the fundamental constants, and even the basic laws of nature, might be different…

“It’s a very hard statistical and computational problem to search for all possible radii of the collision imprints at any possible place in the sky,” says Dr Hiranya Peiris, co-author of the research from the UCL Department of Physics and Astronomy. “But that’s what pricked my curiosity.”

The team ran simulations of what the sky would look like with and without cosmic collisions and developed a ground-breaking algorithm to determine which fit better with the wealth of CMB data from NASA’s Wilkinson Microwave Anisotropy Probe (WMAP). They put the first observational upper limit on how many bubble collision signatures there could be in the CMB sky…

The authors stress that these first results are not conclusive enough either to rule out the multiverse or to definitively detect the imprint of a bubble collision. However, WMAP is not the last word: new data currently coming in from the European Space Agency’s Planck satellite should help solve the puzzle.

Rock on UCL!

Google has announced a change to its search algorithm that reduces rankings for low-quality sites.

The changes, implemented in the last few days, impacts about 11.8 percent of Google’s queries, Google’s Amit Singhal and Matt Cutts wrote in a blog post. The duo defined low-quality sites as those that are a “low-value add for users, copy content from other websites or sites that are just not very useful.”

“At the same time, it will provide better rankings for high-quality sites—sites with original content and information such as research, in-depth reports, thoughtful analysis and so on,” they wrote.

Singhal and Cutts did not provide too many details about what this algorithmic change entailed; search engine ranking mechanisms are often closely guarded secrets. But they said this week’s change did not rely on changes it received from its “Personal Blocklist” Chrome extension. That tool, introduced last week, lets Chrome users eliminate Google search results from dubious domains. Google did, however, compare the Blocklist data it has gathered with the sites identified by the algorithm, and found that user preferences are “well represented” in the new algorithm.

“If you take the top several dozen or so most-blocked domains from the Chrome extension, then this algorithmic change addresses 84 percent of them, which is strong independent confirmation of the user benefits,” Singhal and Cutts wrote.

Google acknowledged that any change to its algorithm will affect the rankings of sites. “It has to be that some sites will go up and some will go down,” they wrote. “It is important for high-quality sites to be rewarded, and that’s exactly what this change does.”

Time will tell – to use a trite phrase – but, Google’s efforts to stem the flow of dross from the Web to our personal cpu’s is an useful step. There is little in the history of international commerce – especially media-driven commerce – to suggest that there are more than a very few individuals and companies willing to put quality above quantity.

Especially when the results of those decisions are measured in coin of the realm.