Have you ever considered the possibility that we may all live in a holographic universe constructed by vastly superior beings? I know -- it sounds like the basis for good science fiction (The Matrix, anyone?), but Nick Bostrom famously hypothesized (pdf) that our very existence may be nothing more than the algorithmic results of a computer simulation. This may sound totally absurd to most, but that modern existential notion is really no less credible than the equally mind-bending (and sometimes physics-bending) theories proposed by both science and religion.
The news here though, is that researchers now believe they have a way to test this thought experiment. A team of scientists from Germany -- University of Bonn, to be exact -- suggest that even the most powerful Universe simulation would be subject to certain limitations of its host Universe. The team believes those limitations would be observable by its inhabitants too, appearing in the form of physical constraints which may not jibe with otherwise universal laws.
What makes their discovery particularly exciting is scientists believe we actually have sufficient technology to test whether or not we are all just electric sheep. How, you ask? Simple -- by creating our own simulation of the Universe, of course.
The problem with all simulations is that the laws of physics, which appear continuous, have to be superimposed onto a discrete three dimensional lattice which advances in steps of time.
The question that Beane and co ask is whether the lattice spacing [example: our three dimensions + time] imposes any kind of limitation on the physical processes we see in the Universe. They examine, in particular, high energy processes, which probe smaller regions of space as they get more energetic.
What they find is interesting. They say that the lattice spacing imposes a fundamental limit on the energy that particles can have. That's because nothing can exist that is smaller than the lattice itself.
So if our cosmos is merely a simulation, there ought to be a cut off in the spectrum of high energy particles.
Bonn scientists believe limits inherited by a simulation would affect high-energy particles like cosmic rays. Most interestingly, one such example could be the Greisen-Zatsepin-Kuzmin limit, a phenomenon produced by the interaction of cosmic rays and cosmic microwave background radiation, creating an unexpected limit on their energy -- a fact which doesn't fit neatly into physics.
In a totally meta way, this may essentially be us observing the orientation of the dimensional lattice from the reality in which our creators exist. Whoa...
This may be surprising, but we've gotten quite good at representing the tiniest nooks of the quantum universe digitally. Granted, we're only recreating areas spanning femtometers -- that's far less than a nanometer -- but hey, that's a start. Simulations of these incomprehensibly miniscule portions of our reality yield particles, energies and interactions which are indistinguishable from the real thing. Well, except for having the results displayed on a computer screen, anyway.