What is Exotic Matter?

Exotic matter: Breaking barriers of Physics

 But what makes it “exotic”? 

To save us a lot more time, the right question to ask would be, “what’s not exotic with this type of matter?”

The answer to the first question would be everything. And that’s exactly why you can see the name exotic matter, in almost every context that deals with advanced futuristic concepts like wormholes or time travel or even gravitational repulsion!

In this post, we’re going to discuss some of its odd properties, the theoretical origin of this concept and most importantly, its potential to literally tamper with our natural world.

What is Exotic matter?

Exotic matter is a type of hypothetical matter that is believed to lie outside our physical laws of nature. It was first brought up by Einstein and Satyendranath Bose in the early 1920s, to introduce the fifth state of matter. This kind of matter, although various forms of it exist like complex mass and degenerate matter, one of them called negative matter, is thought to possess negative mass, and other contradicting properties that form the basis of our understanding of physical nature.

I know what you’re thinking. Negative mass? Is that even a thing? Because mass can never be negative, and everything we know around us has a positive mass. Be it a tree or a star or an atom, the mass is a positive value. 

We can also approach this notion of mass in another way, by introducing a term called energy density. Any substance with a positive mass is said to have a positive energy density, which means that every object (matter) in the observable universe has a positive energy density associated with them. 

Now, the mass of an object or a particle can explain a lot of its properties, like gravitational force and density. From their relations, we can see that all these phenomena are directly affected by an object’s mass. The more massive and denser an object is, the more will be its gravitational pull on other objects. 

But what about matter whose mass is a negative value? What will be the effects on those whose energy density is negative? For starters, they will show repulsive gravitational properties, and that’s because whatever change occurs in an object’s mass, the change will affect its gravitational properties too. The matter with negative mass tends to act opposite to that exhibited by normal matter with positive mass. If we give a certain force in a certain direction to a particle with negative mass, its resultant motion won’t be in the direction where the force was applied, instead, it’ll move in the opposite direction of the force applied.  

Another weird behaviour of exotic matter is that they don’t create positive curvatures in spacetime. We know from Einstein’s Theory of Relativity,  that massive objects in space create spacetime curvatures, that enables smaller objects to follow that curved path around them, called orbits (what we call gravity, Einstein’s interpretation). This phenomenon occurs because the massive object has a positive energy density, which causes the region of spacetime around it to curve or bend. But for an object with negative mass, will bend the spacetime to form a negative curve, such that it repels objects from it. This is because it has a negative energy density associated with it.

The Blue object causes a positive curve and the Red object causes a negative curve

The effects of ‘negative matter’ can be seen in the Casimir Effect, where virtual particles, also known as particle-antiparticle pairs, constantly pop in and out of existence in a vacuum, by annihilating each other. Their random appearance and disappearance by cancelling out each other causes a fluctuation (disturbance) in the energy density of the vacuum, which is called quantum fluctuations. But this isn't a feasible and reliable way to observe exotic matter (in this context, it’s the antiparticle) since they exist for less than a split second, which makes them too quirky to observe.  

Implications

Because of their anti-gravitational properties, the production of exotic matter can open a whole new world of possibilities. For one, the long-sought idea of wormholes would be back on the table. Engineering of traversable wormholes only stands a chance if we’re somehow able to stabilize the wormhole, with the help of exotic matter. Such matter with negative energy density and repulsive properties can enable the wormhole to prevent it from collapsing inward, under its own gravity. 

With exotic matter, concepts like time reversing and time-travel would possibly become a reality, including sophisticated technologies like faster-than-light travel, by harnessing energy from antimatter fuel. The famous theory of black hole radiation or Hawking radiation was described based on quantum effects displayed by particle-antiparticle pairs in space. 

Although all these seem exciting and overwhelming, isolation of exotic matter is harder than ever. This is because they seem to annihilate on contact with normal matter, which practically comprises the whole observable universe. They could be stored in a vacuum placed in a strong magnetic field, just like they do at CERN, Switzerland, for conducting experiments. 

But this goal of accessing exotic matter still seems like a long way from our current technological aspects, and from reality as well.

To check my post on Casimir Effect, CLICK HERE

To check my page on wormholes, CLICK HERE