Holiday shopping can be tough. Holiday shopping for that special someone can be tougher—especially if that someone happens to be a theoretical physicist. Luckily, for the brainiac who has everything there's this beautiful Calabi-Yau Manifold crystal.


But what is it, you ask? Why, put simply, it's a great representation of something we primitive humans will never be able to observe directly:

According to string theory, space-time is not four-dimensional as you might expect, but actually 10-dimensional. The extra six dimensions are believed to be compactified or rolled up into such a small space that they are unobservable at human scales of sight. Their size and six dimensions make Calabi-Yau spaces difficult to draw. But, this model shows a three-dimensional cross-section of this likely space to reveal its structure and shape. - Scientifics Online

And all that mind-bending fun is just $90! String theory, in the palm of your hand! Or, if you don't subscribe to string theory, it's a paperweight. [Scientifics Online via MSNBC]