Scientists suggest universe is a two-dimensional hologram in a theory eerily reminiscent of The Matrix

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Is our three-dimensional world merely an illusion - a giant holographic projection?

That's the frightening claim made by some scientists, who believe that humanity, the Earth, and everything else in the universe is not what it seems.

It may sound like an outlandish plot from The Matrix, but experts say the startling theory could have profound implications - and answer some of the most challenging questions in the field of physics. 

Spooky: It might sound eerily familiar to fans of The Matrix (pictured), but some scientists believe our three-dimensional reality is an illusion because the universe is actually a hologram 

From what happens if you fall into a black hole to what the universe was like right after the Big Bang, thinking of ourselves as holographic might just provide the answer, the experts contend.

According to Professor Marika Taylor, a theoretical physicist from the University of Birmingham in the UK, the universe is actually two-dimensional.

However, just like when you watch a 3D movie on a flat screen, the images on that 2D surface appear to have depth because of how they are projected onto it.

So, while you might see the world around you as a complex three-dimensional structure, Professor Taylor claims this is only an illusion.

That doesn't mean our lives or the universe are any less real, but it does mean that the cosmos might be a lot stranger than we had previously thought.

What is the holographic universe theory?

When you think of the universe being a hologram, you might imagine the projected images from Star Wars or ABBA Voyage.

Although this is the right basic idea, it's not quite the same type of hologram that physicists are thinking of.

The idea that the universe is a hologram doesn't have anything to do with light or projectors as the name might suggest.

In scientific language, a hologram is a two-dimensional surface that appears to have a third dimension - similar to the holographic images on some credit cards.

Since holograms appear three-dimensional you can move around them and see different parts of the image as if there were a real object there.

However, if you reached out to touch one your hand would find only a flat surface.

Scientists like Professor Taylor argue that the whole universe is just like this - a two-dimensional surface that just looks like it has three dimensions.

Seeing things: A hologram, like those used in ABBA Voyage, is a two-dimensional object that looks like it has an extra third dimension. According to the holographic principle, this is the fundamental structure of the universe - the universe is two-dimensional but looks like it is 3D 

Instead of the universe being like a solid block, Professor Taylor says we should think of it as more like a hollow ball.

Our solar systems and galaxies are contained inside the '3D' space inside the ball, but the actual surface structure of the universe only has two dimensions.

According to the 'holographic principle', we can describe the gravitational movements of the planets and stars within the ball just by talking about what's happening on the two-dimensional surface.

Although that might seem utterly bonkers, scientists maintain that turning our world on its head isn't necessarily a problem.

Professor Taylor says: 'It is very hard to visualize this. 

'However, it is also quite hard to visualize what happens inside an atom.

'We learned in the early 20th century that atoms follow quantum rules, which are also quite different from our everyday reality.

'Holography takes us into an even more extreme world, where not only are the forces quantum in nature, but the number of dimensions is different from our perceived reality.'

Does this mean the universe isn't real?

Outer limits: Even if we are living in a holographic universe, this doesn't mean that our world or our lives are any less real (stock image) 

One of the biggest misconceptions about the holographic theory is that it means the universe isn't real or that we are in some sort of simulation.

Although the holograms we are familiar with are always projected by someone and can be turned on or off at will, that isn't what scientists are saying about the universe.

Professor Taylor says: 'The Matrix movies are very thought-provoking but probably don't quite capture all the ideas in holography.'

Likewise, Fermilab, a United States Department of Energy particle physics laboratory, says that the notion of the universe as a 'simulation' can be misleading.

Fermilab writes: 'The notion that our familiar three-dimensional universe is somehow encoded in two dimensions at the most fundamental level does not imply that there is anybody or anything "outside" the two-dimensional representation, "projecting" the illusion or "running" the simulation.'

That means we don't need to worry about being in any kind of Matrix-like simulation even if the universe is holographic.

Similarly, one of the consequences of the holographic principle is that features of the universe like the third dimension and gravity aren't a fundamental part of reality.

However, that doesn't mean scientists are saying these aren't real.

Who's in charge? Unlike in The Matrix, there's no one on the outside projecting our holographic universe. This is just a different way of understanding how the laws of physics work 

Scientific boundaries: While some people believe that we are living in a virtual simulation, holographic theory doesn't suggest that this is the case 

Instead, physicists say that gravity and the higher dimensions are 'emergent' properties.

Professor Kostas Skenderis, a mathematical physicist from the University of Southampton, also in the UK, says you can think about this in the same way as temperature.

If we look at any individual atom it doesn't have a temperature, just a position and a velocity.

But if there are enough atoms all moving and bumping into one another, we can say that they collectively have a temperature.

'Temperature is not an intrinsic property of elementary particles. It rather emerges as a property of a collection of them. This does not make temperature less real. It rather explains it,' says Professor Skenderis.

Likewise, gravity and the third dimension emerge when parts of the 2D universe interact in certain ways.

And, just like knowing that temperature is simply atoms moving doesn't make your tea any less hot, this doesn't make gravity or depth any less real.

Why do scientists think the universe is a hologram?

Complex: The reason scientists believe in holographic theory is to avoid a paradox that suggests black holes, like the one at the center of the Milky Way (illustrated), break the laws of physics

Although this might sound like an interesting mathematical exercise, you might wonder why scientists bother trying to explain everything in two dimensions in the first place.

The answer to that question traces back to a problem proposed by Stephen Hawking known as the 'information paradox' that suggests black holes break a fundamental law of physics.

You might have heard the law of physics which says that matter can't be created or destroyed.

In the same way, a law of quantum physics is that 'information' can't be created or destroyed.

Professor Taylor says: 'The information paradox is that black holes seem to lose memory of what has been thrown inside them.' 

Imagine writing a message out on a piece of paper and then tearing it into tiny pieces.

You might think you've destroyed that information but no matter how small you made the pieces someone could always put them back together and read it.

However, if you threw that note into a black hole there's nothing you could ever do to piece that information back together.

Universal thinking: To avoid this paradox, scientists say that black holes must be two-dimensional. This means when information falls in, it isn't destroyed but rather smeared across the two-dimensional surface of the black hole (stock image) 

What scientists began to realize in the late 1970s was that you could get around this problem, but only if you think of black holes as two-dimensional.

On this view, when you throw your note into a black hole the information is smeared across the two-dimensional boundary of the black hole rather than being destroyed.

This is the view that Stephen Hawking, who discovered the Information Paradox, came to adopt in the final years before his death.  

If that is hard to picture, don't worry; even physicists are still working to get their heads around exactly what that might mean.

The important thing to understand is that looking at the world in two dimensions makes it easier for physicists to work out what's going on in certain cases.

This is particularly useful when we want to understand what happens when gravity is extremely strong like during the first few seconds after the Big Bang or inside a black hole.

And, if this works for the densest, wildest objects in the universe it should work for everything else in existence.

As Professor Skenderis puts it: 'Black hole physics suggests that we only need information in 2D space to describe the 3D universe.'

Pioneer: Stephen Hawking (pictured), who discovered this paradox, came to adopt the holographic theory about black holes in the last years before his death 

Do we have any evidence for this?

One of the biggest challenges for the holographic theory is that it's really hard to prove.

As yet, Professor Taylor says scientists haven't found any 'smoking gun evidence' for the holographic nature of the universe.

However, this isn't stopping physicists from trying to find the subtle differences that holographic theory predicts.

One of the best places to look is in the very earliest moments of the universe, preserved in leftover energy from the Big Bang called the Cosmic Microwave Background (CMB).

Professor Craig Hogan, an astrophysicist from the University of Chicago and director of the Fermilab Center for Particle Astrophysics, says this radiation should preserve 'holographic noise'.

Professor Hogan says: 'The CMB, and all large-scale structures, are supposed to come from quantum-gravitational noise.

'If it’s holographic, the CMB pattern shows signs of that. It preserves an image of the process that made.'

Shape shifter: Scientists say the best evidence that the universe is a hologram should be preserved in the Cosmic Microwave Background (CMB), the leftover energy from the Big Bang 

Clock this: Pictured is a timeline of the holographic universe. Time runs from left to right. The far left denotes the holographic phase. At the end of this phase (shown by the black fluctuating ellipse) the Universe enters a geometric phase. Scientists believe we should still be able to see the structure from this holographic phase in the large-scale structures of the universe 

Professor Hogan says that the CMB reveals 'surprising symmetries in the sky' that you would expect to find if the universe was a hologram.

Likewise, research conducted by Professor Skenderis does indeed show that the detailed structure of the CMB can be described by holographic theory.

Professor Skenderis says: 'We tested the predictions of holographic models against the observed properties of CMB, finding excellent agreement. 

'This is the only direct observational test of holography to date.'