Back in the early 1970s, Stephen Hawking wrote down an astonishing equation. It would include
relativity. It would include quantum mechanics and it would include information.
Hawking’s rather simple equation brought us a step closer to understanding the relationship between quantum physics and black holes.
When an object crosses over the edge of a black hole, its event horizon, the object
enters basically a realm of empty space and darkness and it continues to be dragged towards
the center of the black hole toward what we call the singularity where it gets crushed
out of existence. Every object, in some sense, contains information because it contains a
very specific arrangement of particles. So where is the information that describes the
arrangement of those particles? Where does it go?
Hawking’s description of this process was that the energy remains but the information disappears. For many years - for decades - people
wondered, ‘Is Hawking right?’ Is the information obliterated - it disappears from the universe
- or is it still there, and perhaps can in some way retrieved? The destruction of information
was counter-intuitive and it didn’t match the rest of things we knew. In all parts of
physics we had a situation where information doesn’t get destroyed. So it was a bit puzzling.
This debate furiously went back and forth up through the 80s and into the 90s, when
people finally began to articulate this new principle, this holographic principle. And
what it said is that all the things that were falling inside a black hole were somehow captured
in a preserved image at the horizon itself. So if the information is not lost on the surface,
it is not lost inside because they are equivalent. All of the information about those objects
- what they were like in their three-dimensional existence - was preserved or encoded on the
surface of the black hole. And that’s a little bit like a hologram. Well that suggests
that maybe that idea may apply more broadly to the universe as a whole. Maybe the three-dimensional
objects - us, everything in the world around us - maybe all of the information in these
objects is carried, is smeared around a distant two-dimensional surface that surrounds us.
And we’re just, in some sense, a holographic projection of that distant data.
The holographic principle tells us something quite astonishing. It says that our ideas of volume, the real
world in a sense, might be a kind of illusion.