How was our Universe created? How did it come to be the seemingly infinite place we know of today? And what will become of it, ages from now? These are the questions that have been puzzling philosophers and scholars since the beginning the time and led to some pretty wild and interesting theories. one of them being the BIG BANG THEORY.
WHAT IS THE BIG BANG THEORY?
The Universe as we know it was created in a massive explosion that not only created the majority of matter but the physical laws that govern our ever-expanding cosmos. This is known as The Big Bang Theory. It has become the most accepted theory of our origins.
In short, the Big Bang theory states that all of the current and past matter in the Universe came into existence at the same time, roughly 13.8 billion years ago. At this time, all matter was compacted into a very small ball with infinite density and intense heat called Singularity. Suddenly, the Singularity began expanding and then burst out with energy, and the universe as we know it began.
After the initial expansion, the theory maintains that Universe cooled sufficiently to allow the formation of subatomic particles and later simple atoms. Giant clouds of these ancient elements later combined through gravity to form stars and galaxies.
Through the testing of theoretical principles, experiments involving particle accelerators and high-energy states, scientists have constructed a timeline of events of and after the Big Bang.
10^ -43 seconds: this is the Planck era, the earliest known meaningful time. At this time, all matter was condensed on a single point of infinite density and extreme heat. During this period, it is believed that the quantum effects of gravity dominated physical interactions and that no other physical forces were of equal strength to gravitation.
From approximately 10^ -43 seconds and 10 ^-36, the universe began to cross transition temperatures. It is here that the fundamental forces that govern the Universe are believed to have begun separating from each other. The first step in this was the force of gravitation separating from gauge forces, which account for strong and weak nuclear forces and electromagnetism.
10 ^-35 seconds: cosmic inflation creates what is known as quark-gluon plasma. Protons and neutrons cannot exist yet. It appears that it is this early quark soup that gave rise to dark matter. Additionally, The quark soup is likely the phase in which matter gained superiority over antimatter. Ultimately, cosmologists speculate that the universe had equal amounts of each but, at some point, it developed one extra quark for every billion antiquarks. This imbalance ensured that enough matter survived annihilation as the universe expanded and cooled.
At 10 ^-5 seconds: protons and neutrons are formed from quarks. Within the first 300 seconds of the existence of the universe, the elements helium, lithium, and heavy hydrogen form from the protons and neutrons by a process called nucleosynthesis.
380, 000 years: when the nearly uniform soup cooled to about 3000 Kelvin, atoms formed nuclei and electrons. Photons ceased to scatter and streamed through space unhindered, turning the prior opaque universe into one with visible light.
380,000 years to about 1 million years: we enter a period called the Dark ages; existing between it is known as the final frontier of cosmology. We know little about this period except that the first stars and galaxies should have formed at about
100 million years: the limit of current observations, that is, the highest red-shifted objects detectable (the oldest objects that we can see) are at a time of when the universe was 600 million years old. Two future projects that have already begun construction, the James Webb Space Telescope and the Square Kilometer Array, are specifically designed to shed some light on this era and (hopefully) bring the dark ages to an end.
9 billion years: our solar system forms
10 billion years: when dark energy, a mysterious force that cosmologists have yet to wholly pin down, starts to accelerate. At 20 billion years the Milky Way will collide with the Andromeda galaxy.
WHY IS IT SO POPULAR?
Evidence from Redshift: Astronomers have discovered that, in general, the further away a galaxy is, the more red-shifted its light is. This means that the further away the galaxies are, the faster they are moving. This is similar to an explosion, where the bits moving fastest travel furthest from the explosion. Redshift data provides evidence that the Universe, including space itself, is expanding.
Evidence from CMBR: Astronomers have also discovered cosmic microwave background radiation (CMBR). This comes from all directions in space and has a temperature of about -270°C. The CMBR is the remains of the thermal energy from the Big Bang, spread thinly across the whole Universe. The discovery of the CMBR, after it had been predicted by the theory, provided very strong support for the Big Bang theory, and led to the Big Bang becoming the currently accepted model of the development of the Universe.