Twenty-five years ago this month, a conjecture shook the world of theoretical physics. It had the aura of revelation. “At first, we had a magical statement ... almost out of nowhere,” says Mark Van Raamsdonk, a theoretical physicist at the University of British Columbia, Vancouver. The idea, put forth by Juan Maldacena of the Institute for Advanced Study in Princeton, N.J., hinted at something profound: that our universe could be a hologram. Much like a 3-D hologram emerges from the information encoded on a 2-D surface, our universe’s 4-D spacetime could be a holographic projection of a lower-dimensional reality.
Specifically, Maldacena showed that a five-dimensional theory of a type of imaginary spacetime called anti–de Sitter space (AdS) that included gravity could describe the same system as a lower-dimensional quantum field theory of particles and fields in the absence of gravity, called a conformal field theory (CFT). In other words, he found two different theories that could both describe the same physical system, showing that the theories were, in a sense, equivalent—even though they each included different numbers of dimensions, and one factored in gravity where the other didn’t. Maldacena then surmised that this AdS/CFT duality would hold for other pairs of theories, with one having a single extra dimension than the other, possibly even those describing 4-D spacetime like ours.
The conjecture was both intriguing and shocking. How could a theory that included gravity be the same as a theory that had no place for gravity? How could they describe the same universe? But the duality has largely held up. In essence, it argues that the goings-on inside some volume of spacetime that has gravity can be understood by studying the quantum-mechanical behavior of particles and fields at that volume’s surface, using a theory with one less dimension, one in which gravity plays no role. “Sometimes some things are easier to understand in one description than the other, and knowing that you’re really talking about the same physics is very powerful,” says Netta Engelhardt, a theoretical physicist at the Massachusetts Institute of Technology.
In the 25 years since Maldacena mooted the idea, physicists have used this power to address questions about whether or not black holes destroy information, to better understand an early epoch in the our universe’s history called inflation, and to arrive at an astonishing conclusion that spacetime may not be fundamental, but something that emerges from quantum entanglement in a lower-dimensional system. Granted, all of these advances involve the theoretically plausible spacetime of anti–de Sitter space, which is not the de Sitter space that describes our universe, but physicists are optimistic that they’ll one day arrive at a duality that works for both. If that were to happen, the idea could help develop a theory of quantum gravity, one that would combine Einstein’s general relativity with quantum mechanics. It would also imply that our universe is a hologram in truth.
The Origins of Holography
In devising the duality, Maldacena was inspired by work done, in particular, by the late theoretical physicist Joe Polchinski of the University of California, Santa Barbara. Using string theory, in which reality arises from the vibration of impossibly tiny strings, Polchinski developed a theory of objects in string theory called D-branes, which serve as the endpoints for strings that don’t close in on themselves.
Maldacena looked at the conformal field theory describing D-branes without gravity on the one hand and an AdS theory with one more dimension of space, but with gravity, on the other. Maldacena noticed similarities between the two theories. In particular, both theories were scale invariant, meaning the physics of the systems the theories described didn’t change as the systems got larger or smaller. The lower-dimensional theory also had an additional symmetry, called conformal invariance, where the physical laws don’t change for all transformations of spacetime that preserve angles. The AdS theory describing the same objects in the presence of gravity showed similar symmetries. “That these two [theories] have the same symmetries was an important clue,” says Maldacena.
Crucially, the quantum field theory describing D-branes was strongly coupled: particles and fields in the theory interacted strongly with each other. The AdS theory was weakly coupled; here particles and fields interacted feebly. Soon, theoreticians found reverse pairings: a lower-dimensional, weakly coupled CFT and its higher-dimensional, strongly coupled AdS counterpart. In all cases, making a calculation is simpler in the weakly coupled system, but because the theories are equivalent, the results can also be used to understand the physics of the strongly coupled theory, without having to do the thornier and often-impossible calculations.
Maldacena described his discovery in a paper submitted to the International Journal of Theoretical Physics in November 1997. The idea, however, took some time to sink in. Many physicists began working on trying to make sense of the duality. “There were hundreds, thousands of papers, just checking [the duality], because at first, it [seemed] so ridiculous that some nongravitational quantum theory could actually just be the same thing as a gravitational theory,” says Van Raamsdonk. But AdS/CFT held up to scrutiny, and soon began to be used to answer some confounding questions.
AdS/CFT Proves Its Usefulness
One of the first uses of AdS/CFT had to do with understanding black holes. Theoreticians had long been grappling with a paradox thrown up by these enigmatic cosmic objects. In the 1970s Stephen Hawking showed that black holes emit thermal radiation, in the form of particles, because of quantum mechanical effects near the event horizon. In the absence of infalling matter, this “Hawking” radiation would cause a black hole to eventually evaporate. This idea posed a problem. What happens to the information contained in the matter that formed the black hole? Is the information lost forever? Such a loss would go against the laws of quantum mechanics, which say that information cannot be destroyed.
A key theoretical work that helped tackle this question came in 2006, when Shinsei Ryu and Tadashi Takayanagi used the AdS/CFT duality to establish a connection between two numbers, one in each theory. One pertains to a special type of surface in the volume of spacetime described by AdS. Say there’s a black hole in the AdS theory. It has a surface, called an extremal surface, which is the boundary around the black hole where spacetime makes the transition from weak to strong curvature (this surface may or may not lie inside the black hole’s event horizon). The other number, which pertains to the quantum system being described by the CFT, is called entanglement entropy and is a measure of how much one part of the quantum system is entangled with the rest. The Ryu-Takayanagi result showed that the area of the extremal surface of a black hole in the AdS is related to the entanglement entropy of the quantum system in the CFT.
The Ryu-Takayanagi conjecture promised something alluring. As a black hole evaporates in AdS, the area of its extremal surface changes. This changing area is mimicked by changes to the entanglement entropy calculated in the CFT. And whatever the changes to the entanglement, on the holographic surface described by the CFT, the system evolves according to the rules of quantum mechanics, so information is never lost. This equivalence would imply that black holes in AdS are also not losing information.
There was a hitch though. The Ryu-Takayanagi formula works only in the absence of quantum effects in the AdS theory. “And of course, if a black hole is evaporating, it is evaporating as a result of small quantum corrections,” Engelhardt says. “So we can’t use Ryu-Takayanagi.”
In 2014, Engelhardt and Aron Wall figured out a way to calculate the extremal surface area of a black hole that is subject to the kind of quantum corrections that cause Hawking radiation. Then in 2019, Engelhardt and colleagues, and another researcher independently, showed that the area of these quantum extremal surfaces can be used to calculate the entanglement entropy of the Hawking radiation in the CFT, and that this quantity does indeed follow the dictates of quantum mechanics, consistent with no loss of information (also, they found that the quantum extremal surface lies within the black hole’s event horizon). “This finally gave us a link between something geometric—these quantum extremal surfaces—and something that’s a litmus test of information conservation, which is the behavior of the entropy [when] the information is conserved,” says Engelhardt. “Without AdS/CFT, I doubt that we would have arrived at these conclusions.”
Emergent Spacetime and Quantum Entanglement
The connection between entanglement entropy in the CFT and the geometry of spacetime in the AdS led to another important result about the nature of our cosmos, something that Engelhardt and colleagues and Van Raamsdonk and colleagues have worked on. This additional finding is the notion that spacetime on the AdS side emerges from quantum entanglement on the CFT side—not just in black holes but throughout the universe. The idea is best understood by analogy. Think of a very dilute gas of water molecules. Physicists can’t describe the dynamics of this system using the equations of hydrodynamics because the dilute gas does not behave like a liquid. Let’s say that the water molecules condense into a pool of liquid water. Now, the behavior of those very same molecules is subject to the laws of hydrodynamics. “You could ask, originally, where was that hydrodynamics?” says Van Raamsdonk. “It just wasn’t relevant.”
Something similar happens in AdS/CFT. On the CFT side, you can start with quantum subsystems—smaller subsets of the overall system you’re describing—each with fields and particles, without any entanglement. In the equivalent AdS description, you’d have a system with no spacetime. Without spacetime, Einstein’s general relativity is not relevant at this stage, in much the same way that the equations of hydrodynamics don’t apply to a gas of water molecules. But when the entanglement on the CFT side begins increasing, the entanglement entropy of the quantum subsystems starts to correspond to patches of spacetime that emerge in the AdS description. These patches are physically disconnected from each other: going from patch A to patch B isn’t possible without leaving both A and B; however, each individual patch can be described using general relativity. Now, increase the entanglement of the quantum subsystems in the CFT even more, and something intriguing happens in the AdS: the patches of spacetime begin connecting and you eventually end up with a contiguous volume of spacetime. “When you have the right pattern of entanglement, you start to get a spacetime on the other side. It’s almost like the spacetime is a geometrical representation of the entanglement,” says Van Raamsdonk. “Take away all the entanglement and then you just eliminate the spacetime.” Engelhardt agrees. “Entanglement between quantum systems is important for the existence and emergence of spacetime,” she says. The duality suggested that the spacetime of our physical universe might simply be an emergent property of some underlying, entangled part of nature.
Van Raamsdonk credits the AdS/CFT correspondence for making physicists question the very nature of spacetime. If spacetime emerges from the degree and nature of entanglement in a lower-dimensional quantum system, it means that the quantum system is more “real” than the spacetime we live in, in much the same way that a 2-D postcard is more real than the 3-D hologram it creates. “That [space itself and the geometry of space] should have something to do with quantum mechanics is just really shocking,” he says.
Towards a Theory of Quantum Gravity
Once spacetime emerges in a theory, physicists can use it to study aspects of our universe. For example, our cosmos is thought to have expanded exponentially in the first fractions of a second of its existence, a period known as inflation. In the standard model of cosmology, theorists start with a spacetime in which particles and fields interact weakly and let inflation proceed for about 50–60 “e-folds,” where each e-fold represents more than a doubling of the volume of spacetime (as it increases by a factor of Euler’s constant e, or approximately 2.718). Such inflation can replicate the properties of the observed universe, such as its flatness and isotropy (the fact that it looks the same in all directions). But there’s no particular reason to think that inflation stops at 60 e-folds. What if goes on for longer? It turns out that if physicists design models of our universe in which inflation goes on for, say, 70 e-folds or more, then the initial state of the universe has to be strongly coupled, one in which fields and particles can interact strongly with each other. So even though a model that allows for this prolonged expansion would be more general, calculations involving strongly -coupled spacetimes are near impossible. “But it’s ideally suited to this AdS/CFT approach,” says Horatiu Nastase of the São Paulo State University–International, in Brazil.
Nastase has shown how to use the AdS/CFT duality to study a strongly coupled initial state of the universe. It’s possible because the CFT side of the duality turns out to be weakly coupled, making calculations tractable. These calculations can then be used to determine the state of the AdS after, say, 70-plus e-folds. Nastase has found that a strongly coupled spacetime that inflates for at least 72 e-folds can replicate certain observations from our own cosmos, with some fine-tuning of the model’s parameters; in particular, the model can match the kind of fluctuations seen in the cosmic microwave background, the fossil radiation from the big bang. “This is ongoing work,” says Nastase. “There are a number of issues that are not yet clear.”
Physicists hope that such insights will get them to a theory of quantum gravity for our own universe, which would combine general relativity with quantum mechanics. The lack of such a theory is one of the biggest open problems in physics. One fundamental insight from AdS/CFT that underpins all such work is that any theory of quantum gravity will most likely be holographic, in that it’ll have a dual description in the form of a theory with one less dimension, without gravity.
The AdS/CFT community is working hard to generalize the correspondence to spacetimes that are more representative of our universe. In AdS, researchers can create a spacetime with cosmic constituents such as black holes, but the spacetime has to be “asymptotically empty,” which means that as one goes farther and farther away from a black hole, space becomes empty. “In describing our own universe, we assume that there’s stuff everywhere as far as you go,” says Van Raamsdonk. “You’re never going to run out of galaxies.” Also, in AdS, empty space has negative curvature, whereas the empty de Sitter space of our universe is mostly flat.
As influential as AdS/CFT has proved, the duality still uses a spacetime that does not describe our own reality. Maldacena hopes that researchers will find a similar correspondence between de Sitter space—the spacetime we occupy—and a CFT. “I would very much like to have [a] similar statement for de Sitter,” says Maldacena. “People keep thinking about it, but no clear contender has emerged so far.”
Van Raamsdonk is optimistic that such a candidate will emerge. “If it turns out that our own universe has some underlying quantum picture, some underlying holographic description, if this is really how it works, then I think understanding AdS/CFT will be at the level of understanding quantum mechanics, at the level of understanding general relativity,” he says. “[It would be] as big of a leap in our understanding of the universe as anything else that’s happened in the history of physics.”
ABOUT THE AUTHOR(S)
Anil Ananthaswamy is author of The Edge of Physics, The Man Who Wasn't There and, most recently, Through Two Doors at Once: The Elegant Experiment That Captures the Enigma of Our Quantum Reality.Credit: Nick Higgins
Recent Articles by Anil Ananthaswamy
- Astronomers Might See Dark Matter by Staring into the Void
- Astronomers Gear Up to Grapple with the High-Tension Cosmos
- Can We Gauge Quantum Time of Flight?
The idea that the universe is a hologram has been misinterpreted, perhaps partially due to the popularity of films such as The Matrix. We shouldn't know what is inside a black hole - but can we? The laws of physics demand that we cannot see through a black hole's event horizon; it is fundamentally impenetrable.Who created the holographic universe? ›
Arguably his most famous and most significant is The Holographic Universe (1991), which examines the increasingly accepted theory that the entire universe is a hologram; the book remains in print and highly discussed today. Michael Talbot died of leukemia in 1992 at age 38.Could the universe be an illusion? ›
A new theory now suggests that the accelerating expansion of the universe is merely an illusion, akin to a mirage in the desert. In 1929, cosmologists discovered that the universe is expanding — that space-time, the fabric of the cosmos, is stretching.What does living in a hologram mean? ›
Some physicists actually believe that the universe we live in might be a hologram. The idea isn't that the universe is some sort of fake simulation out of The Matrix, but rather that even though we appear to live in a three-dimensional universe, it might only have two dimensions. It's called the holographic principle.Is everything we see a hologram? ›
According to holographic theory, everything we hear, see or feel in fact comes from a flat two-dimensional field, like the hologram on a credit card. The 3D world we experience is 'encoded' into the real 2D universe, like when you watch a 3D film on a 2D screen.Is a hologram a real image? ›
In real life, holograms are virtual three-dimensional images created by the interference of light beams that reflect real physical objects. Holograms preserve the depth, parallax, and other properties of the original item.What is the 26 dimension? ›
The 26 dimensions of Closed Unoriented Bosonic String Theory are interpreted as the 26 dimensions of the traceless Jordan algebra J3(O)o of 3x3 Octonionic matrices, with each of the 3 Octonionic dimenisons of J3(O)o having the following physical interpretation: 4-dimensional physical spacetime plus 4-dimensional ...Is reality is an illusion? ›
Whether reality is indeed an illusion perpetuated by our brains, as Dr. Hoffman proposed, remains to be seen. But the reality that we experience each and every day is what we must use to survive in our environment. To that end, the panel then turned their focus to the biological mechanisms that guide our senses.How many dimensions are proven? ›
Beyond these three visible dimensions, scientists believe that there may be many more. In fact, the theoretical framework of Superstring Theory posits that the universe exists in ten different dimensions.Is God is an illusion? ›
In Is God an Illusion?, Chopra argues that there is design in our universe and a deep intelligence behind life. Without defending organised religion, he debunks randomness as an explanation for how Nature evolves and shows how consciousness comes first and matter second.
Our universe is but one in an unimaginably massive ocean of universes called … the multiverse. If that concept isn't enough to get your head around, physics describes different kinds of multiverse. The easiest one to comprehend is called the cosmological multiverse.Is soul an illusion? ›
The Soul Illusion is the consequence of failing to appreciate the difference between the objective world and our perception of that world —that is, going beyond the adaptive convenience of acting as if our representations of reality were valid and believing that we see things as they really are.Are real life holograms possible? ›
In principle, it is possible to make a hologram for any wave. Electron holography is the application of holography techniques to electron waves rather than light waves. Electron holography was invented by Dennis Gabor to improve the resolution and avoid the aberrations of the transmission electron microscope.Is the brain a hologram? ›
Pribram does not suggest that the brain functions as a single hologram. Rather, the waves within smaller neural networks create localized holograms within the larger workings of the brain. This patch holography is called holonomy or windowed Fourier transformations.Are human holograms possible? ›
Human hologram technology is far from perfect, but its potential is unrivalled. Today it is still too early to talk about the possibility of using classic holograms for displaying humans. In most cases, they offer hologram-like 3D images or some optical illusions supported and enhanced with computer technologies.Why holograms are the future? ›
Holograms can be used for many different purposes, including security and medical uses. For example, if a doctor needed to get a close look at someone's arm, they could use the 3D image of the arm as seen by a camera to get a detailed view.Is a hologram the 4th Dimension? ›
“A hologram, as you find it on bank notes or credit cards, appears to show a three-dimensional picture, even though in fact it is just two-dimensional,” Grumiller explains. In such a case, reality has fewer dimensions than we would thinkit appears to have.Can holograms be faked? ›
INTRODUCTION. It is commonly believed that holograms cannot be counterfeited. As a matter of fact, it is rather easy to counterfeit the holograms that are commonly used today in security applications, and holograms have been counterfeited more than once.How real do holograms look? ›
Like a photograph, a hologram is a permanent record of the light reflected off an object. But a hologram also looks real and three-dimensional and moves as you look around it, just like a real object. That happens because of the unique way in which holograms are made.How is a hologram different from a picture? ›
Holography is a technique to generate 3-dimensional images. Photography is a technique to generate 2-dimensional images. Interference and diffraction of light is used in holography. Reflection of light is used in photography.
The first dimension, as already noted, is that which gives it length (aka. the x-axis). A good description of a one-dimensional object is a straight line, which exists only in terms of length and has no other discernible qualities.What is in the 10th dimension? ›
Finally, the 10th dimension is a single point that represents all the possible branches of every possible timeline of all the potential universes. But what other point can we then connect this to? According to Bryanton, it appears that there is nothing left.What is the 27th dimension? ›
The 27th Dimension features the works of digital and video-based artists exploring physical and material relationships in digital art through sculpture, video and performance.How do I know I exist? ›
How do I know I exist? IN A nutshell, you don't. Philosopher René Descartes hit the nail on the head when he wrote “cogito ergo sum”. The only evidence you have that you exist as a self-aware being is your conscious experience of thinking about your existence.Can an illusion be real? ›
Although illusions are by definition not real, scientists are increasingly finding ways to use them to make an impact on the real world.What is the 11th dimension? ›
What is 11th dimension? The 11th dimension is a characteristic of space-time that has been proposed as a possible answer to questions that arise in superstring theory. The theory of superstrings involves the existence of nine dimensions of space and one dimension of time for a total of 10 dimensions.What are all the 11 dimensions? ›
- A point (no dimension) We start with a point. ...
- The first dimension – a line. ...
- The Second Dimension – A Split. ...
- The Third Dimension – A Fold. ...
- The Fourth Dimension – A Line. ...
- The Fifth Dimension – A Split. ...
- The Sixth Dimension – A Fold. ...
- The Seventh Dimension – A Line.
While the origins of the spiritual dimensions of reality come from various channelers, some people hold the belief that there are 9 or more dimensions beyond the 3rd dimension that we currently live in.Who is the exact image of God? ›
Christ as Image
A uniquely Christian perspective on the image of God is that Jesus Christ is the fullest and most complete example of a human in God's image. Hebrews 1 refers to him as "the very image of his substance" and Colossians reveals Jesus as "the image of the invisible God".
No lasting scientific evidence of God's existence has been found. Therefore, in the case of a worldview that relies solely on scientific evidence, whether or not God exists is unknown; or even, God does not exist (depending on the strength of such a worldview).
Genesis 1:26-28 announces that human beings are made in the image of God: Then God said 'Let us make man in our image, according to our likeness, and let them rule over the fish of the sea and over the birds of the sky and over the cattle and over all the earth.How many Earths are there? ›
According to one recently-released study, some scientists now believe that there could be as many as 40 billion planets like Earth in the Milky Way galaxy.How many universes exist? ›
We currently have no evidence that multiverses exists, and everything we can see suggests there is just one universe — our own.What is our universe called? ›
There is no current name for our Universe, other than simply "the Universe", although we have names for our own home in the cosmos. Earth is part of the solar system of planets revolving around our Sun. The Sun is one of hundreds of billions of stars in the Milky Way Galaxy.What are the 3 types of soul? ›
Nutritive soul (plants) Sensitive soul (all animals) Rational soul (human beings)What the soul is made of? ›
The Platonic soul consists of three parts: the logos, or logistikon (mind, nous, or reason) the thymos, or thumetikon (emotion, spiritedness, or masculine) the eros, or epithumetikon (appetitive, desire, or feminine)What is the true nature of the soul? ›
PLATONIC-HINDU: The human soul is naturally and essentially immortal; it is uncreated and eternal. The soul passes from one body to another through a series of many incarnations. After paying off its sin (karmic debt), the soul is liberated from somatic existence and lives in a totally blissful state.What is the most advanced hologram technology? ›
Hologauze® is the latest technology in large scale 3D hologram effects, working with 3D polarized projection systems and as a 2D hologram effect.What are the benefits of holograms? ›
- Makes specialized training easier.
- Brings together learners who are in different locations.
- Makes history come alive.
- Makes multiple lectures possible.
- Signing off.
Abstract. Long-range holographic experiments have been performed over distances as large as 12 km. Holograms and images of retroreflector and Scotchlite objects were obtained.
The human brain functions thanks to its wide neuronal network that is deemed to contain approximately 69 billion neurons. On the other hand, the observable universe can count upon a cosmic web of at least 100 billion galaxies. Within both systems, only 30% of their masses are composed of galaxies and neurons.Is hologram a mixed reality? ›
Holograms, one form of mixed reality, could potentially revolutionize adult learning as we know it.Can your brain tell the difference between 2d and real life? ›
The brain can't tell the difference between the real and the imagined – is a myth. It is intriguing to wonder why perception differs from person to person, how imagination can evoke a creative frenzy or intrusive memories that debilitate those with PTSD.Who is the leader in hologram technology? ›
Musion™ is the global leader in the development, marketing, production and broadcasting of realistic, life-sized, interactive 3D holographic video shows and effects.Is hologram a technology? ›
In simple terms, hologram technology is a three-dimensional projection which can be seen without using any special equipment such as cameras or glasses. The image can be viewed from any angle, so as the user walks around the display the object will appear to move and shift realistically.Who invented a hologram? ›
Dennis Gabor, father of holography
The Hungarian Dennis Gabor, who invented the hologram, explained his discovery in simple terms in this article published in 1948: "The purpose of this work is a new method for forming optical images in two stages.
“A hologram, as you find it on bank notes or credit cards, appears to show a three-dimensional picture, even though in fact it is just two-dimensional,” Grumiller explains. In such a case, reality has fewer dimensions than we would thinkit appears to have.Is a black hole a hologram? ›
One particularly trippy outgrowth of this research is the idea that black holes are two-dimensional holographic projections of three-dimensional objects. In other words, black holes could be optical illusions analogous to holograms that produce a 3D image from a 2D surface.What reality is a hologram? ›
A holographic Universe means information that makes up what we perceive as a 3D reality is stored on a 2D surface, including time. This means, essentially, everything you see and experience is an illusion.Is a 5th dimension possible? ›
As of now, we can't see the fifth dimension, but rather, it interacts on a higher plane than we do. It's because of this that we can't really study nor fully prove it's existence.
We see the world around us in three dimensions. Einstein predicted a fourth which he called space/time. He theorized energy from colliding black holes causes gravitational waves that pass through objects without changing. That makes them nearly possible to measure or prove that they exist.Is God a 4 dimensional being? ›
God is a 5th dimensional being - an incarnation of the Holy Spirit, which is not only a 7th dimensional existence, but literally that from which all of existence itself came. Both the physical third dimension and the metaphysical fourth dimension were created by God at the beginning.How many dimensions is the holographic universe? ›
The real universe is a 4-D system: it has volume and extends in time. If the physics of our universe is holographic, there would be an alternative set of physical laws, operating on a 3-D boundary of spacetime somewhere, that would be equivalent to our known 4-D physics.Is a hologram 2D or 3D? ›
That is, the view of the image from different angles represents the subject viewed from similar angles. In this sense, holograms do not have just the illusion of depth but are truly three-dimensional images.Is there another universe inside a black hole? ›
In turn, all the black holes found so far in our universe—from the microscopic to the supermassive—may be doorways into alternate realities. According to a mind-bending new theory, a black hole is actually a tunnel between universes—a type of wormhole.How many dimension are there? ›
The world as we know it has three dimensions of space—length, width and depth—and one dimension of time. But there's the mind-bending possibility that many more dimensions exist out there. According to string theory, one of the leading physics model of the last half century, the universe operates with 10 dimensions.What does a real hologram look like? ›
Holograms are a bit like photographs that never die. They're sort of "photographic ghosts": they look like three-dimensional photos that have somehow got trapped inside glass, plastic, or metal. When you tilt a credit-card hologram, you see an image of something like a bird moving "inside" the card.