I've been receiving a lot of email in the last week or two from people interested in the idea that our universe is really a hologram. In my book and this blog I've talked before about the connection between the way of visualizing reality I'm proposing here and the idea of the Holographic Universe, a connection that has also been noted in a few of the reviews of my book. Now, here's a link to a recent story in New Scientist magazine that shows why people's excitement about this idea has been re-ignited: the article, written by Marcus Chown and published January 15 2009, is about new discoveries just announced by the GEO600 experiment. GEO600 is a German project that has been looking for gravitational waves for the past seven years. Here's some excerpts from the article:
 

 

GEO600 has not detected any gravitational waves so far, but it might inadvertently have made the most important discovery in physics for half a century.

For many months, the GEO600 team-members had been scratching their heads over inexplicable noise that is plaguing their giant detector. Then, out of the blue, a researcher approached them with an explanation. In fact, he had even predicted the noise before he knew they were detecting it. According to Craig Hogan, a physicist at the Fermilab particle physics lab in Batavia, Illinois, GEO600 has stumbled upon the fundamental limit of space-time - the point where space-time stops behaving like the smooth continuum Einstein described and instead dissolves into "grains", just as a newspaper photograph dissolves into dots as you zoom in. "It looks like GEO600 is being buffeted by the microscopic quantum convulsions of space-time," says Hogan.

If this doesn't blow your socks off, then Hogan, who has just been appointed director of Fermilab's Center for Particle Astrophysics, has an even bigger shock in store: "If the GEO600 result is what I suspect it is, then we are all living in a giant cosmic hologram."

The idea that our reality is not continuous, but granular, broken down into planck-unit-sized "grains" of spacetime is something I've been saying since I launched my project. The idea, though, that proving the existence of this granularity would be direct evidence that our universe is a hologram is a not a connection I've talked about before. This New Scientist article goes on to describe the groundbreaking work in the 90's of such physicists as Jacob Bekenstein, Leonard Susskind, Gerard 't Hooft, and Juan Maldacena, some of which I've talked about in my book, and in previous blogs like Why Stop at Ten Dimensions, Hypercubes and Plato's Cave, and Why Do We Need More Than 3 Dimensions?. Here's a few more excerpts from the article:
 

What's more, work by several string theorists, most notably Juan Maldacena at the Institute for Advanced Study in Princeton, has confirmed that the idea is on the right track. He showed that the physics inside a hypothetical universe with five dimensions and shaped like a Pringle is the same as the physics taking place on the four-dimensional boundary.

According to Hogan, the holographic principle radically changes our picture of space-time. If GEO600 really has discovered holographic noise from quantum convulsions of space-time, then it presents a double-edged sword for gravitational wave researchers. One on hand, the noise will handicap their attempts to detect gravitational waves. On the other, it could represent an even more fundamental discovery.

More importantly, confirming the holographic principle would be a big help to researchers trying to unite quantum mechanics and Einstein's theory of gravity. Today the most popular approach to quantum gravity is string theory, which researchers hope could describe happenings in the universe at the most fundamental level. But it is not the only show in town. "Holographic space-time is used in certain approaches to quantising gravity that have a strong connection to string theory," says Cramer. "Consequently, some quantum gravity theories might be falsified and others reinforced."

Hogan agrees that if the holographic principle is confirmed, it rules out all approaches to quantum gravity that do not incorporate the holographic principle. Conversely, it would be a boost for those that do - including some derived from string theory and something called matrix theory. "Ultimately, we may have our first indication of how space-time emerges out of quantum theory." As serendipitous discoveries go, it's hard to get more ground-breaking than that.

Regular readers of this blog will note the important idea that our universe actually comes from the fifth dimension, another drum that I've been beating from the outset, and which I've talked about in a number of blogs, such as Time is a Direction, The Fifth Dimension Isn't Magic, and Flatlanders on a Line. Speaking in terms of spatial dimensions, this article's comment that we live in a universe with five dimensions and shaped like a Pringle is extremely important.

Is Our Universe Flat or Curved?
In our four-dimensional universe, it appears that space-time is essentially flat. If it were truly flat, then parallel lines would never meet and our universe would have no boundaries in any direction. NASA's WMAP project has returned results showing that the universe is flat within a 2% margin of error. What does this mean? It means that for most intents and purposes our universe is truly flat. But in the largest picture of all, I believe that the above two ideas are going to be shown to be equivalent - our universe is very close to flat, but there is still a very slight curvature, and the 13.7 billion year "boundary" that cosmology shows us as being our line of time back to the big bang will still show that we are only witnessing a tiny region of a much larger whole, an idea that is central to this project and which we've talked about in recent entries like Dreaming of Electric Sheep and Imagining the Omniverse. So, in the same way that Euclidean geometry makes sense in our local frame of reference--a square building really is constructed from lines at 90 degree angles and parallel lines don't ever meet--if we look at the entire planet we can see that a square that encompasses a hemisphere must have angles that are slightly larger than 90 degrees and parallel lines really can meet each other as they traverse the globe. That "pringles potato chip" shape they are referring to, then, is like the horizon we see all around us as we are in the middle of the ocean: all we need to do is widen our frame of reference beyond the boundaries of 4D space-time to see how that horizon is created by a very subtle curvature that for any local observations is so small as to be inconsequential, but in the biggest picture of all it gives us a way to visualize how the holographic information that defines our universe from the fifth dimension is "just over the horizon" of our 4D spacetime.

You are a Hologram
The cover of this New Scientist issue we're quoting from here sums it up this way - "YOU ARE A HOLOGRAM - projected from the edge of the universe". While this phrase gives us one way to think about the fifth dimension as coming from the boundary of our 4D spacetime, I've talked many times about other ways of visualizing how each additional dimension is "around" or "outside" the previous one - so rather than thinking about the hologram that creates our universe as being something that is far far away, I think it's more useful to think about the hologram as being "just around the corner in time" - which is the phrase I use in my song "The Unseen Eye".

As we discussed in "What Would a Linelander Really See", the term "extra dimensions" is often used by physicists rather than "higher dimensions" when talking about the dimensions beyond spacetime: I think this is a useful distinction, because saying "higher" somehow sets the idea up in our minds that we should be gazing skyward as we think about these additional dimensions. In blog entries like Unlikely Events and Timelessness and Time in 3 Dimensions, we've talked about how "events that are so unlikely they will talk longer than the life of the universe to occur" is another useful way of visualizing how we can derive the information that represents dimensions beyond 4D space-time, another useful branch to this discussion.

Information Becomes Reality
Are we embedded in a fifth-dimensional hologram which is at right angles to the fourth dimension? Imagining what the phrase "at right angles to the fourth dimension" means has been one of the main ideas behind this project. If you've been following along, I hope that by now you have grown more used to thinking about the fifth dimensional probability space as it relates to Everett's Many Worlds Interpretation, the universe as a hologram, and the digital physics concept that information equals reality - I believe these ideas will eventually be shown to all fit together in the big picture of timelessness.