All the space, matter, and energy of the Known universe was contained/compressed in an infinitesimal point (Primeval Atom: unimaginably small, dense, and hot), nearly 14 billion years earlier. Cosmologists call this ‘The Big Bang Theory’. The big bang is not about the origin of the universe, but rather about the evolution of the universe. Why? The hurdle is the “Planck era” of the early universe — the interval of time from t = 0 to t = 10^-43 seconds into the expansion of the universe. And also until the universe grew to 10^-35 meters. Cosmologists call such an infinitesimal point a Singularity, the point where space and time become meaningless. At that time, the universe was extremely small that none of the laws of classical physics turns out to be effective. The explanation of the universe on the subatomic scale: It all comes down to quantum physics, more generally, quantum cosmology. At the earliest moments of the big bang, matter and energy were inseparable. Moreover, the four fundamental forces (actually three) that jointly describe these vast cosmos were unified. At the end of the Planck era, the gravity had separated from the electronuclear force.
At about 10^-35 seconds, the universe continued to expand indescribably, inflation, the universe grew exponentially (becoming less dense and hot). Likewise, the unified forces, later on, split into strong nuclear forces, and electroweak forces. The electroweak force further split into the electromagnetic and the weak nuclear forces, which we now call the four fundamental forces of our universe: the weak nuclear force, governing the radioactive decay; the electromagnetic, binding the molecules; the strong nuclear force, binding the atomic nucleus; and gravity binding the bulk matter. Classical Physics explains gravity as a force. Modern Physics expresses gravity as the curvature of spacetime. Before the “planck era”, even the concept of particles do not go in alignment with theories. To overcome this hurdle, Physicists are dead serious about the theory of quantum Gravity. More generally, particle Physicists want to explain it as a particle (Gravitons).
Theories suggest that inflation paused at around 10^-33 to 10^-32 seconds mark — the universe’s volume having immensely increased by a factor of at least 10^78. Right after that very second, the temperature kept on increasing enormously; in fact, the temperature was stable enough for the production of elementary particles and quark-gluon plasma. During the radiation-dominated era there was not only the same enormous number of photons per nuclear particle that exists now, but the energy of the individual photons was sufficiently high so that most of the energy of the universe was in the form of radiation, not mass. Because of high temperature, the random movements of particles were at relativistic speeds, and particle-antiparticle pairs of all kinds were being continuously created and destroyed in collisions. At some point, baryogenesis took place — resulting the baryonic matter — the matter that we can see, touch, feel, and observe. This beautiful reaction endowed the cosmos with a remarkable baryonic asymmetry, where particles of matter outnumbered particles of antimatter. That is to say, a very small excess of quarks and leptons over antiquarks and antileptons.
The particle cosmology starts at around 10^-11 seconds. Scientists can artificially create this phase in lab conditions with particle accelerators. The temperature kept on lowering, around 10^-6 seconds, protons and neutrons were formed as there was the excess of baryons over antibaryons. Since the temperature kept on decreasing, the universe was unable to create new matter-antimatter pairs, and thus baryon particles outnumbered particles of antibaryon by only about one part in a billion.
The standard model of Particle physics describes/predicts the subatomic world, the smallest building block we know and love: six types of quarks, six types of leptons, three fundamental forces (and their four associated particles), plus the Higgs boson. “The Standard Model is a collection of ideas that tells us about nature and how all the particles in the universe interact with each other,” says Tulika Bose, a physics professor at the University of Wisconsin. The standard model works via 18 independent variables: the particle masses, the relation between various forces, and many more else. According to the standard model, every particle has its antiparticle with the same mass, but with an opposite electrical charge. To put it simply, a square root of 9 has two solutions: either 3 or -3, which of course will cancel each other resulting zero. Antimatters are not just mathematical constructs. The Standard Model is built from experimental measurements. The standard model has evolved throughout the decades of repetitive observations and experiments. Previously, the standard model assumed that neutrino was a massless particle. Now we know that it was not true. However, the experiments so far haven’t provided a single insight that could support the remarkable symmetry in the early episode of the universe: annihilation was a must/undeniable.
So far so good, but the clash with baryon asymmetry inexplicably horrified CERN Scientists. They are unable to figure out the cause behind symmetry break. None of the experiments showed that matter and antimatter must be radically different. The universe should have created equal parts of matter and antimatter. However, that is not the case. Surprisingly or rather annoyingly, antimatter is rare. The experiment involving the environment at the earlier stage of the universe (Particle cosmology) suggests that there’s no way asymmetry can happen. Matter and antimatter should have annihilated each other, creating a burst of unimaginable energy, leaving nothing behind, not even this vast cosmos. CERN researcher Christian Smorra was on the team who conducted the most recent experiment. He told Science Alert, “All of our observations find a complete symmetry between matter and antimatter, which is why the Universe should not actually exist.” He added, “An asymmetry must exist here somewhere but we simply do not understand where the difference is. What is the source of the symmetry break?”
Scientists point out every fundamental difference that matter and antimatter could have, which we don’t have any idea about it yet. The fundamental difference accounts for mass, or electric charge, or anything entirely different — difference that allows us to exist today. The difference that would be able to explain the matter-antimatter imbalance. CERN Scientists centered their research on magnetism in a hope that it could produce fruitful outcomes regarding the properties defining the magnetic property of matter and antimatter as well. They implied a method devised by scientists from Mainz University in Germany to assess the most detailed look at antimatter’s magnetism, in essence, 350 times more precise than ever-seen-before. That’s a huge accomplishment: readout was precise to nine places, -2.7928473441 nuclear magnetons. Despite the best efforts and wonderful precision, the study failed to explain the theoretical framework behind the baryon-antibaryon asymmetry at the earliest stage of universe formation.
The measurement was not a piece of cake. The issues were unavoidable: The measurement of antimatter was annoyingly troublesome as they don’t last long. Researchers employed a method involving two Penning traps, to retain antiprotons particles using an electrical and a magnetic field. “The measurement of antiprotons was extremely difficult, and we had been working on it for ten years. The final breakthrough came with the revolutionary idea of performing the measurement with two particles,” Stefan Ulmer, spokesperson for the multinational BASE collaboration at CERN, said in the press release. The international collaboration based at CERN, called ALPHA, fixated their research on finding out whether or not the asymmetry between hydrogen and antihydrogen atom exists or simply the experiment hopes to study fundamental symmetries between matter and antimatter. Meanwhile, the study of antiparticles magnetically will make a significant contribution to examine the matter-antimatter asymmetry.
The universe’s expansion seems to be perplexing if gravity is taken into account. Physicists explain this with antigravity force called dark energy. Some researchers believe that dark energy is not the actual hurdle, the real problem can be conceptualized and theorized only with a successful study on quantum gravity. CERN (LHC) Scientists are actively engaged in studying and measuring the properties of Higgs particles in greater detail. Unfortunately, even in 2021, the discoveries are unable to unravel the weird symmetry of our cosmos.