How and when did the universe begin? No other scientific question makes such spirited debate among researchers and science enthusiasts. After all, no one knows what really happened! The best thing that scientists can do is work out the most convincing theory by observing the universe. The best-supported theory among these is the big bang theory. This theory was originated from the observation that other galaxies are moving away from our galaxy at great speed in all directions as if they had all been propelled by an ancient explosive force.
In the beginning, there was nothing. Then, around 13.8 billion years ago, the universe formed. In 1927, an astronomer named Georges Lemaître proposed the theory that the universe started from a single point. That is, the universe began from the singularity. Then the universe stretched and expanded to get as big as it is now, and it keeps stretching.
We still don’t know the exact conditions under which this happened, and whether there was a time before time. But using telescopic observations and models of particle physics, researchers have been able to produce a rough timeline of major events in the cosmos’ life. Here we take a look at some of our universe’s most important historical moments, from its infancy to what we see now, in a simple way. That is, If we can hold the whole history of the universe to a single year, then
1. On New Year’s Eve – The Big Bang
This is the instant when nothingness exploded from a point into all matter that makes up the universe. The point is the singularity. The universe’s next step was to grow big really fast. Within the first 10-30 seconds after the Big Bang, the cosmos could have expanded exponentially in size, driving apart areas of the universe that had previously been in close contact. This era, known as inflation.
2. A few milliseconds after the beginning of time
The early universe was really hot. That was between 7 trillion and 10 trillion degrees Fahrenheit hot. At such temperatures, elementary particles called quarks that are normally bound tightly inside protons and neutrons wandered around freely. The fundamental force known as the strong force-carrying particles Gluons were mixed in with these quarks in a soupy primordial fluid that spread the cosmos.
3. After 20 minutes – first light from the cosmic explosion
For a very long time, nothing in the universe gave off light. This period, which lasted around 100 million years, is known as the Cosmic Dark Ages.
As the cosmos expanded, it cooled. And these conditions were suitable enough for quarks to come together into protons and neutrons. One second after the Big Bang, the universe’s density dropped enough that neutrinos (the lightest and least-interacting fundamental particle) could fly forward without hitting anything. This created the cosmic neutrino background and thus, the first light from the cosmic explosion produced.
4. Few months later – emergence of galaxies
The protons and neutrons combined to produce hydrogen and helium. By around 180 million years after the Big Bang, these elements began to collapse into large spheres and generated infernal temperatures in their cores, and formed the first stars. The universe entered a period known as Cosmic Dawn, or reionization because the hot photons radiated by early stars and galaxies broke neutral hydrogen atoms in interstellar space into protons and electrons, a process known as ionization.
Around 1 billion years after, small early galaxies began to merge together into larger galaxies and supermassive black holes formed in their centers. Bright quasars were also evolved. The universe continued to evolve over the next several billions of years. It gradually evolved into galactic clusters and long chains of gas and dust, eventually forming the magnificent filamentary interstellar web we see today.
5. September 1st – Birth of Solar system
About 4.5 billion years ago, in one particular galaxy, a huge star or cloud of gas collapsed and eventually exploded down set off for the birth of a yellow star with a system of rings around it. These rings coalesced into eight planets, various comets, asteroids, dwarf planets, and moons, from the clouds of dust leftover, forming a stellar system known as the Solar system. Because of the Sun’s gravitational force, hydrogen feeds into it, allowing it to expand and evolve.
Then the evolution of planets began. Collisions between the planets and asteroid-like particles gave birth to moons for the planets. During one of the collisions, a larger object hit the Earth with enough force to cause the formation of the Moon, Earth’s only natural satellite. The Earth then began its journey and evolution, as a mass of rock hostile, covered by volcanoes, and completely lifeless.
6. October – Life started to evolve
Volcanic eruptions continued to pump water vapour and gases into the atmosphere, from the earth’s interior. The earth’s oceans evolved within 500 million years of the planet’s evolution. Life started to evolve around 3.8 billion years ago in the oceans, and photosynthesis developed around 2.5-3 billion years ago in bacterias. Primarily, life remained confined to the oceans for a long time. Then these bacterial organisms also began to enrich the atmosphere with oxygen.
7. December – Emergence of multicellular organisms
For the first time, photosynthesis allowed organisms to grow their own food. This process provided a significant benefit and accelerated the evolution of life from prokaryotes to eukaryotes, which began sexual reproduction 1.2 billion years ago, to multicellular life. Multicellularity brought new capabilities.
8. December 25 – Dinosaurs would appear
Complex multicellular organisms started to evolve. During the Triassic, Jurassic, and Cretaceous periods, dinosaurs existed. The Earth was much warmer during these years, with CO2 levels about four times higher than they are today. This resulted in abundant plant life, and herbivorous dinosaurs may have evolved large bodies in part as a result of the abundance of food. Also, Various organisms such as carnivorous dinosaurs, crocodiles, etc evolved at this period of time.
9. December 30 – They wiped out
Dinosaurs developed into a wide range of shapes as the climate shifted and new organisms adapted to the new conditions. Dinosaurs who did not adapt died out. Then, 66 million years ago, dinosaurs vanished entirely in a very short period of time (except for birds). Many other species, such as pterosaurs, huge marine reptiles, and ammonites, died out as a result of something that caused unfavourable environmental changes to occur faster than dinosaurs and other creatures could adjust.
10. The last 2 days – Evolution of mammals
Just 200,000 years after the mass extinction that wiped out all dinosaurs except birds, the first ancestral mammal species to be present during the day lived about 65.8 million years ago. This is confirmed by the fossil record, which indicates that after dinosaurs died out, the number and types of mammals rapidly increased. The evolution of mammals happened during this time.
The last 6 minutes – Evolution of modern human beings
Human evolution is the process that led to the emergence of anatomically modern humans, starting with the evolution of primates (particularly the genus Homo) and culminating in the emergence of Homo sapiens as a distinct species of the hominid family, which includes the great apes.
The first human-like beings emerged on the earth’s surface 5.6 million years ago. Following this, many human species appeared and then vanished. Humans that look like us (referred to as “modern humans”) first appeared about 160,000 years ago. Those People obtained food by scavenging, hunting, and collecting plant protists during this long period of human history.
Last 30 seconds – kind of regular history with written records and agricultural settlements
The emergence of humans and the domestication of plants and animals are the subjects of this timeline. It focuses on significant technical advancements including the use of fire, metals, plough agriculture, and the wheel. The growth of civilizations and cities and the use of writing also emerged. Cities were at the center of all earlier civilizations. Agriculture, literature, and religion all became more sophisticated, and writing systems and written documentation, including alphabets, began to emerge.
Very last seconds – Modern history from Columbus to the birth of scientific revolution to all the wars
The Middle Ages were preceded by the Modern Era, which was marked by a firm belief in reason or logic, a scientific temperament, and secular credentials. The changes that were taking place at the end of the Middle Ages had led to the birth of the modern world by the 12th century. The development of cities, the growth of trade and commerce, the widespread use of money and the outbreak of peasant revolts and, the rise of a middle class are among the changes.
Renaissance, Reformation, and Counter-Reformation, Geographical Explorations, and the Rise and Growth of Nation States are the four historical events that mark the beginning of the modern era. Modernity also refers to the birth and development of a new socioeconomic order – capitalism – that has had far-reaching consequences not just in Europe but throughout the world.
Credits: NASA
Read the previous article of the same writer:
Time Travel: Are Paradoxes A Contradiction To Logical Possibilities?
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