Thursday, 19 July 2012

What is antimatter?

Ever since watching the film Angels and Demons (Unless you read the book), we have discovered the term, anti-Matter. This term has now entered the public domain with great force and people are perplexed about what it is, what it does and why it is exists. Anti-Matter is a form of negative mass.

They are a bunch of negative particles, there are many anti-particles which have been determined by scientists, such as the anti-proton, anti-neutron and positron. Surprisingly these anti-particles actually have nearly identical properties, except for one fundamental property. The electric charge. These particles almost identical are actually a negative charge (-), oppose to the particles we are familiar with, the positive particles(+). Recently scientists at CERN were able to isolate anti-particles from their positive counterparts. They are usually present with a positive charge (+) particle when produced by using Gamma Rays, this is due to their light weight, allowing low intensity gamma rays to produce these pairs of anti and positive particles.

Fig. 1 Illustration of Antimatter/Matter Annihilation
Credit: NASA/CXC/M. Weiss
Some of the most famous scientists have dabbled in the science of anti-Matter, from Paul Dirac to Richard Feynman. Where Dirac had first vision a world with the existence of Anti-Matter allowing him to look deeper in the world of the negative. This was first realised when he was trying to create a relativistic wave equations for the electron. Feynman visualised the anti-Matter being able to annihilate other positive particles. This annihilation would occur when two particles would collide with each other resulting in a massive and violent cancellation, almost neutralising out both masses. A example of this is the Electron-Positron reactions causing large quantities of photons (Particles of light) to emit from the annihilation.

Energy Source?

One theory would look into energy harnessing, allowing anti-Matter engines so to speak be created as a fuel source for space travel. One ideal candidate is the proton – anti-proton collision, which would emit mesons (Hadronic Subatomic Particles: we'll come back to those later). This reaction is theorised to be a positive form of energy generation. Being the most energy efficient, including nuclear fission and also surprisingly nuclear fusion. Which fusion still has to be proven to be sustainable as of yet.

Stance in the Universe.

Scientist believe when the big bang occurred, the universe was just energy to begin with, no matter had been synthesised, this was by pair-production. For there is a light there must be a dark, and for up, there must be a down. This is thought to be the same with positive mass and negative mass. But since the big-bang, down the time line there had come a point where the universe tilted in favour of the positive mass, being dominant in the universe. Many do not know why positive mass won the battle, but Feynman theorised that it was down to the asymmetries of particles. An example of which is the reverse time behaviour.

Anti-Matter at this stage is one of the cutting edges of Physics, not knowing how to harness it, but knowing it actually exists give us hope into a clean and sustainable energy source and perhaps even more, something we didn't expect.



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