So it's Sunday morning and you sleep in a little later than usual, then shower and head out to a coffee shop for some breakfast. The check comes and you reach into your wallet and pull out a credit card with a hologram, one of those etched two-dimensional plastic film thingies that when exposed to light creates the appearance of a 3D image.
Holograms have become so commonplace as to be as mundane as potato chips, but how's this for a mind blower: Some scientists are coming around to the view that the universe may be one giant credit card . . . er, hologram.
The story of this amazing discovery, told in a gripping New Scientist article, by Marcus Brown, begins at at laboratory in the countryside near Hanover, Germany where the GEO600 project is in full swing. This joint Germany-British experiment is a boffing big gravitational wave detector, gravitational waves being extremely small ripples in the structure of spacetime caused by astrophysical events like supernovae, neutron stars and black holes. Albert Einstein predicted their existence in 1916, but they have not yet been directly observed.
GEO600 team members had been scratching their heads over an inexplicable noise that is plaguing their giant detector. That noise (try to keep up with me here) is now thought to be the fundamental limit of spacetime -- the point where spacetime stops behaving like the smooth continuum Einstein described and instead dissolves into "grains," evidence that we are living in a giant cosmic hologram.
"The idea that we live in a hologram probably sounds absurd, but it is a natural extension of our best understanding of black holes," writes Chown, "and something with a pretty firm theoretical footing. It has also been surprisingly helpful for physicists wrestling with theories of how the universe works at its most fundamental level."
Now back to those credit cards and the revelation that the same two-dimensional image becoming 3D when we pull them from our wallets may apply to the universe as a whole. That is, our everyday experience might itself be a holographic projection of physical processes that take place on a distant, 2D surface.
As Chown notes, the holographic principle is indeed a mind blower:
"It seems hard to believe that you . . . are reading this article because of something happening on the boundary of the universe. No one knows what it would mean for us if we really do live in a hologram, yet theorists have good reasons to believe that many aspects of the holographic principle are true."
But one example of this is the discovery that a black hole's entropy -- which is to say its information content -- is proportional to the surface area of its event horizon. This, as Chown explains, is the theoretical surface that cloaks the black hole and marks the point of no return for infalling matter or light.
Theorists have shown that microscopic quantum ripples at the event horizon can encode the information inside the black hole, so there is no information loss as the black hole evaporates. This, in turn, reveals that the 3D information about a precursor star can be completely encoded in the 2D horizon of the subsequent black hole -- not unlike the 3D image of an object being encoded in a 2D hologram.
Now scientists have extended that insight to the universe as a whole on the basis that the cosmos has a horizon too. That is the boundary from beyond which light has not had time to reach us in the 13.7-billion-year lifespan of the universe. What's more, string theorists have confirmed that the physics inside a hypothetical universe with five dimensions and shaped like a . . . uh, Pringle potato chip is the same as the physics taking place on the four-dimensional boundary.
While GEO600 scientists do not rule out a more mundane explanation for that noise, it appears to be increasingly likely that we dwell amidst a vast hologram, and as serendipitous discoveries go, it's hard to get more mind blowing than that.
IMAGES (From top): GEO600 laser, Albert Einstein, Illustration of a supernova, Illustration of a neutron star, Illustration of a black hole.