Many of my more diligent readers are likely familiar with the concept of string theory, since I mention it fairly regularly on this blog. Part of my intense interest over the last year has been motivated by a project of mine - the writing of String Theory for Dummies for Wiley Publishing. I am pleased to announce that my first book, String Theory for Dummies, is now available at your local and online bookstores!

String Theory for Dummies covers all of the major topics in string theory, from branes to supersymmetry to extra dimensions, and looks at how string theory may ultimately explain things such as dark matter, dark energy, black holes, and even their link to more speculative concepts such as parallel universes and time travel.

And it does so in language that is completely accessible to the average reader, regardless of their level of scientific background, with much of jargon (and mathematics) eliminated! You can get a glimpse of it now by accessing the free online String Theory for Dummies Cheat Sheet.

String Theory for Dummies is one of the most accessible and complete guides to this advanced topic written for the general public, written with the assistance of Daniel Robbins, a string theorist at Texas A&M University. You can follow future information - such as speaking appearances - by becoming a fan on my Facebook page.

Over at the About.com Birding site, there's a report that a bird dropped a piece of bread into a cooling unit at the Large Hadron Collider (LHC). The piece of baguette caused irregularities in the cooling system, which were quickly recognized by technicians. The situation was resolved before there was major damage to the system. (A slightly more technical description of the situation is available on The Register.)

With yet another in a long series of misadventures for the prototype particle accelerator, this lends some anecdotal credence to the speculative idea that "influence" from the future is sabotaging the experiment. Of course, anecdotal evidence isn't enough, and I made an argument that these predictions are logically inconsistent.

I guess nothing will put these speculations to rest until we actually get the LHC up and running and performing the groundbreaking research that physicists are hoping for.

Many recent theoretical physics ideas allow for the possibility that our universe is part of a multiverse - a set of distinct alternate universes. Both particle physics and cosmology, for various reasons, have found this notion

String theory, for example, can (in some interpretations) view our universe as being confined onto a 3-dimensional brane, which allows for other multi-dimensional branes. (In string theory, the total universe has 9 or 10 dimensions, not counting the time dimension, so there's a lot of room for various types of branes ... and therefore various types of universes.)

In the vast majority of these theories, the different universes can't interact. The theories often predict that in the early universe, at the moment of the big bang (or shortly thereafter) minor quantum fluctuations in the fabric of the universe itself expanded rapidly during the period of inflation, resulting in large regions which ended up with different physical laws as they cooled down. (This process of eternal inflation, of which Linde is one of the primary founders, is described in great detail by his colleague Alex Vilenkin in his book Many Worlds in One: The Search for Other Universes.)

Still, it's fun for scientists to speculate on these sorts of things. Andrei Linde and Vitaly Vanchurin at California's Stanford University have done just that. By making some basic calculations, making assumptions about the quantum properties of the early universe at the moment of the big bang, they were able to consider how that universe would have expanded through the process of inflation - where small variations in the early universe expanded rapidly. Each of these regions would have eventually settled into regions which ended up with their own sets of physical laws as it cooled down.

Anyway, their result is the "humungus" number 10¹⁰¹⁰⁷. However, they did point out that the human brain can't really comprehend more than 10¹⁰⁶ pieces of information, so realistically that's the most universes that could be distinguished by a human being, even in principle. (In practice, that's still a heck of a lot of information to process.)

Their original paper, How many universes are in the multiverse?, is available on arXiv.org.

No, it's not the great pumpkin, Charlie Brown. Physicists are kept up by questions about the very nature of space, time, and reality itself ... and New Scientist has broken these concerns down into the "Seven questions that keep physicists up at night." These questions come out of a panel discussion among physicists speaking at the "Quantum to Cosmos" festival, which took place at the Perimeter Institute for Theoretical Physics in Waterloo, Canada, last week. Videos from the festival are available on the website.