Matter and antimatter are only produced or annihilated in equal amounts. Likewise equal amounts of matter and antimatter should have been created in the early universe at the time of its origin also. But still matter dominates the universe compared to antimatter, the smallest life on earth to the largest cosmic objects are made almost entirely of matter. So how come the matter dominate antimatter and thus making our existence possible in the universe?
For a while let us do a time travel to the very moments of origin of universe… the time of Big bang.
It all started from a small singularity which then inflated over the next 13.8 billion years to the cosmos that we see today, filled with energy, particles and antiparticles. This the mostly accepted theory of origin of universe, the Big bang theory. And as already mentioned above, our universe was thought to be born matter-antimatter symmetric.
But if this symmetry or balance in matter and antimatter prevailed, we would not have been existing at all- neither would I be here to write this, nor you to read this- as when a matter and antimatter meet, the result is just light and nothing else, the process known as annihilation. (Antimatter and matter are actually the same, only reversed in a way, with opposite charges, so when they meet, they collide and gets annihilated releasing immense energy.)
Obviously that didnt happen. We are existing, and we could see mostly ordinary matter all around us and not much of antimatter particles (though little bit is still there) . So what had happened to their most of the counter particles or the anti matter? Where did they disappear immediately after the first fraction of second?
Pic Big Bang
Dominance of matter in the universe
So why is our universe made of matter and not antimatter?
The possibilities are
- Matter and antimatter were not created in equal amounts at the time of big bang— But evidences reveals that they were created in equal amounts (https://home.cern/science/physics/matter-antimatter-asymmetry-problem)
- Matter and antimatter particles were created in equal amount, but after a fraction of second due to some reasons which could evoke an asymmetry, most of the antiparticles got annihilated leaving behind just a few quark particles and light. And universe got evolved from those few quarks and light. The recent scientific thought is that matter and antimatter behaves differently. That is for elementary particles containing charmed quarks, matter and antimatter decay differently. This could leave behind an imbalance in matter and antimatter. (Read http://thecollege.syr.edu/news/2019/matter-antimatter-syracuse.html)
- Immediately after the formation of matter and antimatter, antimatter matter particle had a repulsive force making them far apart from the origin. So what was left behind was matter alone. Maybe those escaped antimatter particles have formed another universe or even a time reversed world which is beyond our knowledge. (This is just my pure imagination)
We are here as there is more matter than antimatter in the universe
This asymmetry of matter and anti matter in the observable universe is one of the biggest mysteries of universe. In physics this problem is known as baryon asymmetry problem or matter asymmetry problem. Maybe something is missing in the laws of physics to incorporate this antimatter.