Antimatter

Prologue

Well, it is definitely not a matter, but it definitely does matter. ~~Sorry, forgive my pun.~~
Why do I say so? So, it turns out that the holy world of pop culture has always been using antimatter as some kinds of fascinating science element not the literal meaning of element in science to captivate their audience.

From the immensely popular sci-fi themed television show "Star Trek" where antimatter is used in annihilation process (to be explained later) for the propulsion of space ships, the existence of antimatter universe which gave rise to the evil-being "Anti-Monitor" in the "DC Comics" to the so-called antimatter bomb in Dan Brown's bestseller "Angels & Demons", you could literally see and learn about antimatter in various cinematographic or simply literature works in our society today.

Wait, so what is actually antimatter?

If you have heard about matter, then you will surely able to understand and comprehend the concept of an antimatter easier. Essentially, antimatter is the complete opposite of normal matter. If normal matter - or matter - is made up of atom(s) and there are subatomic particles for every atom, namely electrons, protons and neutrons, then antimatter could be conveniently defined as particle made up of antiatom(s) and there are subatomic particles for every antiatom, namely positrons or antielectrons, antiprotons and antineutrons. Yes, you are seeing it correctly, they are just being differentiated by the anti prefix in front of their name.

Therefore, hydrogen, then antihydrogen. Source.

If you could still remember your classical physics well, then matter is any particle which has mass and volume. Therefore, the same goes for antimatter as well. The only difference which makes antimatter distinct is their completely opposite signs on all charges (which includes the electric charge and spin). In theory, if charge is the sole property which set them apart, then you can deduce the same properties for a matter and an antimatter. As an example, hydrogen atom (matter atom) will have the exact same mass and volume as compared to antihydrogen atom (antimatter atom). In fact, this hypothesis was tested by the ALPHA, an international collaboration based at CERN, which they confirmed the validity of quantum mechanics for antimatter by measuring the transition between the two lowest energy states of antihydrogen. Simply, it is exactly identical to that of hydrogen, therefore affirming the theory itself.

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According to scientists, the one on the right is a "matter" apple, while the one on the left is an "antimatter" apple. Jokes aside, the physical properties of matter and antimatter are really identical!

Therefore, if an electron is of negative charge, then we could know that a positron or simply, antielectron, is of positive charge.

Interesting, so who actually first discovered antimatter?

Paul Dirac

Interestingly, the first man who has managed to predict the existence of antimatter, did not really discover it, at least physically. The great English physicist, Paul Dirac actually first conjectured the vague idea of antimatter from a theoretical opinion rather than experimental evidence. In the year 1928, with extraordinary imagination and mathematical proficiency, he combined the well known Albert Einstein's theory of special relativity with quantum mechanics. His work, the Dirac equation, which is also known as a relativistic wave equation, managed to describe the motion of electrons, while shed some light on the existence of a corresponding antimatter counterpart. Most importantly, his equation revealed that the famous E = mc², which specifically the mass "m" could be both positive or negative, hence opened up the possibility of the existence of antimatter in our universe.

Carl David Anderson

In 1932, Carl David Anderson managed to finally prove the existence of positrons, which translates to the literal discovery of antimatter. He successfully tracked the positron in his study regarding cosmic rays and hence, provided the evidence that needed to validate the result of Dirac's work.

So, antimatter does exist! But... how could they be so powerful or even, destructive, in popular culture references?

Yes, antimatter is indeed dangerous and I am not even exaggerating! When antimatter particles collide, interact or come in contact with matter particles, they both will simultaneously under a process named as annihilation. As predicted by the theory of special relativity, or in case you are not familiar with the name, you will also have seen the famous equation of E = mc², where the energy will be produced by annihilation is of equivalence to the mass that disappears multiplied by the square of the speed of light in vacuum. In other words, the most interesting part of all these findings is essentially condensed into one final deduction, where the released energy can roughly be predicted by looking at the difference in mass before and after the process. If we have 1 simplest antihydrogen atom and also 1 hydrogen atom annihilate one another, the end products are simply gamma rays (energy). Note that ΔE = Δmc², then in case of this annihilation Δm = 2m_hydrogen.

Here's some comparison of annihilation with the current proposed processes of harnessing energy from fusion and fission. In a fusion process, 4 hydrogen atoms fuses together and produce 1 helium atom. For this process, Δm = m_helium- 4m_helium. Meanwhile, for a typical fission process, uranium-235 is being bombarded by neutrons to form barium-141 and krypton-92. Therefore, Δm = m_{barium +}m_krypton- m_uranium. Therefore, in general, annihilation process releases the most energy because the mass difference of the same-scale of process would be most significance. Well, this is therefore, why the antimatter or annihilation process is being fantasized by the movie makers or sci-fi writers to be some energy of tomorrow or weapon of destruction.

Annihilation process representation. Source.

In Star Trek, antimatter is being described and utilized as a source of energy. The Federation starships uses the annihilation process as a mean to generate humongous amount of heat as well as kinetic energy in order to propel in the space. However in Angels & Demons, antimatter is being used for its annihilation process as well, just that this time, antimatter bomb is the main highlight of the story.

Both the applications of antimatter in two stories are kind of intriguing, and also they show us the potential of antimatter if it was to be utilized in our world. Mind you, theoretically, one pound of antimatter bomb could have the same power as equivalent to around 19 megatons of TNT. That's really powerful! Meanwhile for if the annihilation process is used for propulsion, it would definitely become the most efficient process, as all the mass of the matter and its counterparts antimatter would be converted into energy. The energy which could be potentially utilized is equivalent to about 10 billion times the energy produced from the combustion of hydrogen and oxygen, the kind we currently used for space shuttles in 21st century.

Therefore, the questions arise, why are we not using antimatter-matter reaction just yet? If antimatter annihilate matter, why are we still be able to live in a "matter" world? How about an antimatter world?

Join me for my next post soon!

Disclaimer: All uncited graphics are retrieved from Wikipedia or Pixabay under CC0 Creative Commons.