We all had this curious question from our childhood. How did our Earth come into existence? What are these Solar Systems, Galaxies and Universes? How were they formed? How life started on Earth? From where did the species called Human come from? Can life exists in other parts of the outer space too? Are we not alone in this Universe?Are we humans trying to contact species which may be available in outer space?
The Age of our Mother Earth is nearly 4.5 billion years. Scientists believe that life on Earth could have started only 3.6 billions years ago. The fossil records supports this theory. But to reach that point there were a lot of things that happened in the passage.
Let’s go 13.8 billion years back from current date. At this point of time, the universe existed in a singularity where no physics laws work, a point with zero radius, zero time, no matter or form or structure. It existed as a superforce (Super force means the combination all fundamental forces – Gravity, Electromagnetism, the Strong nuclear force and the weak nuclear force). A sudden explosion kind of phenomenon occurred in this singularity that it started expanding. This is the Big Bang theory. As the universe expands, it created space and thus the Stars, galaxies and all other things in the universe got created. It is believed that the expansion of the universe will stop at a point. And after this point the universe will start contracting till it reaches the point of singularity again.
The clouds of interstellar gas and dust started forming all around the universe once it started expanding. Those clouds were called Nebulas. Nebulas cover several light years of space. After the universe started expanding, nearly 9.3 billion years later. (i.e.) 4.6 billion years ago from the current date. One such Nebula in Milky Way Galaxy started collapsing (means contracting) due to a shockwave created by a star that exploded nearby (SuperNova). This made all the gas and dust particles to swirl around the space. It gathered speed by angular momentum as the swirling continued. The gravitational potential energy of the cloud of dust and gas got converted into kinetic energy. Thus as the speed increased, the space covered by the nebula decreased. The dust and gas particles of the nebula started colliding with each other. This induced heat energy which got collected in the center of the nebula along with the cloud of gas and dust particles. The temperature at the centre got increased to very high level as high as 10 million Kelvin. The collision was so violent that it led to nuclear reactions and thus the sun got birth as a star. The sun at the center with all other clouds of particles circling around at a high speed which is the first version of our solar system.
As the time passed by, the small particles circling around the sun bound together by the force of gravity, into larger particles. Thus forming asteroids and meteors. These asteroids and meteors got collided with each other and got bound to each other, thus forming the rocky planets.The solar winds swept away the lighter particles from closer radius of the sun. Thus forming heavy rocky planets like Mercury, Venus, Earth and Mars around it. But the solar winds were ineffective when it comes to larger radius of the nebula. Thus the gas giants like Jupiter, Saturn, Uranus, Neptune got formed on the outer radius of the Nebula. Gas giant planets completely consists only of interstellar gas and dust particles and not the rocky surfaces. Earth was a molten state in the beginning stage. When many interstellar rocks collided with Earth, it formed heat and also the binding force of the rocks had set the molten earth to spin around its axis. Slowly earth started cooling. And thus the crust formed and the molten core went deeper and deeper. Earth’s core is believed to be hotter than the surface of the sun. During such transformation of Earth, it got hit by a very large body than it (may be nearly the size of Mars) and thus some of it turned into interstellar rocks again. These rocks got bound by gravity again to form the moon. Once the moon was formed, it moved towards the Earth. But it moved in a way tangential to the Earth’s gravitational field thus it started revolving around the Earth like ball tied to string that is swung. Instead if it had moved directly perpendicular towards the Earth, it would have collided on earth like any other meteor. But since it moved in a tangential way, and may be due to its high speed instead of colliding with earth it started revolving around it due to the gravitational force of the earth. And thus the moon that we know now has formed. Like the ball tied to the string which is being swung, in a similar the moon is trying to escape the gravitational force of the earth. Approximately, the Moon is moving 1.5 inches away from Earth each year. The day on earth was very less in this point of time relatively less than 9 hours.
And thus now at 4.51 billion years from current date, we have our Solar System, Earth and the moon. But the Earth was not exactly the same blue planet as of now. It never had any life in it at this point of time. It was completely a hot rock with molten core inside it. Lot of Meteors were falling on the surface of the earth at this point of time since there was no atmosphere even. This induced a lot of volcanic eruptions. As the time passed, earth cooled and the crust got thicker and thicker. Slowly traces of water started accumulating at places around the Earth. It was believed the first trace of water may have originated from both asteroidal material and also from gases left over from the formation of sun. Researchers noted that since comets contain a lot of ice, it could have supplied some water too. Slowly water started covering the surface of the crust. The temperature on the surface of the earth decreased to 60-70°C. But still it was not habitable. There were mega thunderstorms and hurricanes at very high speeds common all around the Earth. These things occurred since the moon was a lot closer to earth. The gravitational pull between the moon and the earth caused very high waves as high as a current skyscrapers. But as time passed by and the moon moved away from Earth slowly, the waves became calm and also the rotation of the earth slowed down. The Crust was cooled but the core was still in a very hot condition. This induced volcanic eruptions often. The lava from the volcanic eruptions cooled down when it flowed out and it formed tiny islands all around the water that covered the surface of the earth. But still since earth has no atmosphere, the land regions were too hot and toxic for life to sustain or begin. But it was a lot cooler deep beneath the water level. The meteors continued falling on the surface of the earth. Now as they fell, they reacted with water. As the Meteors started dissolving, it reacted and it released all the minerals from it. It also transported the carbon and other primitive proteins like amino acids from outer Space to the bottom of the ocean. Somehow the sea water seeped into the crusts and reacted with the heat inside the surface of the earth and it formed hot water fountains or chimneys that blew out hot water inside the Ocean towards the surface. Thus hot water mixed with amino acids and other minerals and it formed something which we can call a chemical soup. This mixture of chemicals gradually lead to formation of microscopic organisms like bacteria which are single celled. Slowly as the time passed by. The bacterias gathered/accumulated over the surface of the rocks under the sea. These colonies of bacteria on the rock surfaces were called Stromatolites.
Stromatolites acquired the sunlight and also the carbon dioxide that was dissolved in the waters and started producing starch/glucose. This is the process we call photosynthesis. As a result of this process, the most essential ingredient of life was released as a byproduct – The gas called Oxygen. Slowly the oxygen started dissolving throughout the water level and it also reacted with the minerals like iron to form rust which deposited into the rocks under the sea level. These iron rich rocks are one of the basic resources, the extracts of which we use today for building bridges, constructions of houses and also many other most essential things in life. As we go up above the water level, the oxygen started accumulating even there too. As the time passed by, oxygen level continued increasing. The rotation speed of the earth also slowed down thus the length of a day increased to nearly 16 hours. Now the earth has water, land and oxygen. Slowly the Earth crust started breaking and moving. The tectonic plates of the Earth’s crust moved all the islands towards each other and it formed a single large supercontinent Rodinia. Slowly, the oxygen level increased above the surface of the earth. Thanks to the hard work of the Stromatolites. The temperature at Earth’s surface reduced to 30°C and also day became 18 hours long.
At 750 millions ago from the current date, the Rodinia supercontinent broke away into two pieces due to the heat energy under the surface of the earth. Slowly both part of it moved away from each other. These activities increased the volcanic activities on the surface of the earth. The volcanic eruptions released carbon dioxide, smoke and other gas into the atmosphere. Carbon dioxide increased the temperature level as it trapped the sun’s light. The evaporated water and carbon dioxide mixed together to produce acid rain. And these acid rains fell on the surface of the earth and got locked up there. Since the earth is covered by a lot of rocks now almost all of the carbon dioxide got locked into the rocks as acid rain deposits. Thus the temperature above the surface of the earth decreased with decrease in carbon dioxide level. Thus leading to the longest ice age. Slowly earth got covered by ice. The ice covering the crust was more than 3 KMs thick. The earth now transformed into a ball of ice which was a molten ball once upon a time.
But as the time passed by, the heat inside the core got disturbed and volcanic eruptions started again breaking open the icy covering at many places over the surface of the earth. This time the carbon dioxide from the volcanic eruptions got accumulated in the atmosphere level since there were not a lot of rocks to trap it. All rocks were now covered in ice. This carbon dioxide accumulated over the surface of the earth trapped the sunlight inside it, thus increasing the temperature level again. This melted all the ice and it made fissures and other things on the surface of the earth. The melting of ice caused a lot of chemical reactions and it rocketed the releasing of oxygen to a very high level into the atmosphere. The ultraviolet light from sun rays reacted with the icy surface of the earth to produce hydrogen peroxide which dissolved over the ice and now it indeed helped to increase oxygen levels too.
At around 540 Million years ago from current date, the day was 22 hours long. Under the Ocean now the bacteria that existed as Stromatolites evolved into plants and other primitive multicellular organisms. The life under oceans started blossoming from microscopic bacteria to a large multicellular organism. But still the land is not ready to accommodate life although oxygen level is higher. The only explanation why is the sun. The sun is still sending out the harmful ultraviolet radiations from it to the earth’s surface which is not allowing any life forms to exist. But gradually as time passed by the oxygen level in the atmosphere started reacting with the sun’s radiation and formed a new gas, which we call the Ozone. Gradually Ozone level increased and it started covering the earth’s surface like a blanket thus preventing it from exposure of harmful ultraviolet radiation from the sun.
At around 375 million years ago from current date, Ozone layer got thicker and thicker as time passed by. And this became the starting point for life on land to blossom. Small mossy algaes and primitive plants started forming on the land surface which released more and more oxygen into the atmosphere. It was at this point of time when the organisms from water tried to move towards the land. Gradually the fishes (Sea water Organisms) evolved and moved towards the land. Thus the first tetrapods, the amphibians were formed. Amphibians have gills like fish. Later the reptiles had evolved from amphibians and made the land their home. The reptiles had developed lungs to breathe in the oxygenic gas. The fins of the fish evolved into the legs of the tetrapods gradually. Fish lay eggs in water and the water had all the nutrients for it to hatch. But now the animals on land started laying eggs that contained water and nutrients within itself. This was a great evolutionary breakthrough. Thus life started evolving on land without the necessity of moving inside the water. Slowly the reptiles started flying. The legs of the reptiles evolved into wings. Dragonflies were one of the flying organisms in those times. But actually all these organisms were giants. They were of very huge sizes. Dragonfly as huge as an eagle was there. Also Mammals started evolving from reptiles which gave birth from inside it’s own body instead of the eggs. May be the eggs were not safer means for birth at that point of time, so this sort of evolution was needed. Also after birth, mammals started feeding glucose from its own mammary glands. This is how mammals got evolved. As like birth, death was also important. All plants and animals started dying after death and deposited on the surface of the earth and it got buried gradually deeper and deeper and thus gave rise to the coal which we use now. Likewise in water, they buried deeper to become a source to oil. The reptiles on land started growing bigger and bigger. They got divided into Herbivores, Carnivores and also the omnivores. Just when life started evolving, the volcanic eruptions started again and it induced acid rain again and it killed most of the life on the earth.This acid rain produced sulphuric acids and it released heat on reaction with water. Also methane got released into the atmosphere as the temperature of sea water started to increase and it started to accumulate in the atmosphere and this increased the temperature level more to nearly 40°C. Methane is a greenhouse gas which is a lot more dangerous than carbon dioxide. This lead to the Permian extinction. This lead to the extinction of a lot of organisms on the earth. Almost 95% of life was wiped out.
Around 225 million years from current date, there was only a supercontinent called pangea which stretched from Pole to Pole. Gradually as time passed by, the temperature stabilized, acid rain neutralized and the left out plants and other living organisms from extinction started blossoming. This era gave rise to the most dominant species to live on the earth – Dinosaurs. They were also of all three types – Herbivores, Carnivores and omnivores. These dinosaurs are the evolved species of lizard like reptiles. They existed on land, sea as well as air. They swam,walked as well as flew in the air. They were of many types – Raptors, Tyrannosaurus, Brachiosaurus, Pterosaurs etc. Dinosaurs were the most dominant ones ruling the earth in those times. They were the King of all the reptiles. All other mammals and other minor species used to hide from them and were of no comparison in front of the mighty dinosaurs. Mammals used to live on trees and also underground at this point of time in hiding from the dinosaurs. Dinosaurs reigned earth for 165 million years.
Around 100 million years ago, the supercontinent got separated into two and they moved away from each other thus giving rise to the Atlantic ocean. And slowly the world started taking shape same as today. It induced a lot of geological activity as it took its shape. As this gradually proceeded, the organisms adapted to the changing environments and got evolved with it. Fishes and other land organisms grew bigger in size and also developed big teeth to adapt to the quote “Survival of the fittest”. Even many bird types had evolved. But still Dinosaurs ruled the world, they dominated the earth for a long long time. But as the time passed at one point of time, a huge asteroid travelled towards the surface of the earth which was 11000m height and the size of Mexico hit earth. It released a very high energy as it impacted on the surface of the earth. The energy was higher than what even a millions of nuclear bombs cannot produce. Due to the impact, earthquakes were high, tsunamis attacked the lands, volcanic eruptions increased and smoke and ash covered the atmosphere. This had extinct all the dinosaurs once and for all. As the dinosaurs became extinct, mammals came out from underground and started taking over the world. They were safe underground under all such geological happenings. Mammals started consuming each and everything on the earth’s surface. Actually rodents (Rats) were the primitive mammals. Slowly as time passed, the tectonic plates of the earth’s crust moved apart from each other forming relatively equal to the continents as of now. The rats got evolved into a lot of other mammals as they got adapted to the environment. One such mammal is the “Darwinius masillae” of type primates which was believed to be the ancestor of humans. Darwinius masillae evolved into monkeys, apes and eventually us – Humans.
At around 50 million years ago from current date, Earth’s tectonic plates started moving again. Now the Indian plate moved towards the Asian plate. It started to buckle up and contorted upward to form the Himalayan mountain range, the height of which increased to more than 8000m. And thus the highest mountain on earth got formed, the Mount Everest. It was covered by ice on top. When this ice got melted it gave rise to rivers and rivers helped in improving vegetation and life.
At around 20 million years ago, the earth was exactly the same as it is now except for one thing, it is us – Humans. Near East coast of Africa, the tectonic plates started to become active again thus it formed ridges which pulled up the surface higher and higher and thus forming a lot of mountains. The apes and other types of monkeys were living on the trees those times. But these new mountains that were formed blocked the moisture from the Indian ocean to enter the land surface thus the vegetation got affected and the land became drier and drier, it lead to the formation of arid lands. Thus, it affected the habitat of the living creatures. This made apes to adapt to the situation and go in search of food towards places. Slowly they started walking on two legs instead of using all four legs which made to increase their speed while attacking and hunting. Initial humans were called Homo erectus who evolved from apes. Later they evolved into Homo Sapiens. Thus humans (Homo Sapiens) evolved from the apes gradually.
Around 70000 years ago, the sea level decreased and the sea became shallow and the distance between continents decreased. Thus Humans traveled from Africa and into Europe and Asia. The Earth cooled again at this point of time due to natural changes in earth orbit, co2 levels and water level on earth led earth to the second ice age with Homo Sapiens in it.
Around 20000 years ago, there arose a strip of land at the northern hemisphere emerged between Siberia and Alaska. It was the starting point for humans to move from Asia to North America and then gradually to South America through the Panama canal. Around 14000 years ago, the ice started melting again and it created the many lakes and rivers that are existing today in America and other continents. Around 6000 years ago, gradually the ice retreated to the polar regions (Arctic and Antarctic) as time passed by. Thus the world which we see today came into existence exactly as we see it. There were a lot of natural and manmade disasters that are occurring day to day. But we overcome it and adapt to it. As the Humans came into existence and the time passed by they invented many things. The first one was ways to produce fire for heating the hunted animals. Also they started regularizing the sounds they make into a speech to communicate with each other thus a language was formed. After that they wanted to find a shelter in which they can safeguard themselves. Thus they started to build houses from trees and leaves. Also for covering their body parts they used the leaves from the plants. Thus a civilization started. To travel from one place to another by walking with huge loads was getting difficult, so they invented the wheel and used it to make a two wheeled vehicle with which they carried loads from one place to another. Initially humans pulled those vehicles, gradually they used cattle, donkeys and horses for it. Slowly as population increased hunting never gave them enough food, so they started cultivating food in their own lands. They used Cattles and other things to do agriculture. Thus Agriculture came into existence. Slowly the Houses with Trees and leaves were changed to Houses made of stones and rocks when they realized that they were not safe enough in times of disasters. Then gradually they used metals along with rocks to stabilize their houses for safeguarding in times of disasters. People started living alongside the rivers for making use of the water to produce more cultivation. So many people occupied the nearby land of rivers. One of the earliest Riverside civilization was the Indus Valley Civilization. Once the vegetation got sufficient for themselves, they exchanged the cultivated vegetables or fruits with others for what others cultivated (Maybe rice). Thus the Barter system came into existence. People started exchanging whatever they cultivated. Then eventually they thought exchanging things are not working out, if the opposite party doesn’t have anything in exchange. So Money came into existence. They accounted the lending of things in terms of money. Initial money were in terms of coins made of gold, copper which was being exchanged for goods. Then people gradually moved from barter system to Money controlled system. Gradually coins turned into papers. People started to invent things to earn more money and to develop the world as it has formed now. So they invented many things from wheel to light bulb to cars to airplanes etc. Thus the money started playing a major role in the economy. To keep all people in control and to avoid chaos because of this sudden growth in economy, leaders started emerging among them and they become powerful among everyone. They named themselves King. Kings promised that they would take care of all the people generations after generations. There were laws and customs that were designed. Thus a society/kingdom was formed. People started splitting into various societies and kingdoms with various kings. Each kingdoms had different languages and separate cultures and traditions. Also in each kingdom, they segregated people based on the work they do and money started playing major role in ruining people’s life from there on. Also the intelligent people in all kingdoms gave ideas to the kings to how to make people live together and also in loyal to the king. Thus came into existence castes and religions. Some religions started spreading based on the followers of great people who lived in the world and became martyrs whom they believed as their ultimate leader even above the king. Some others were adopted from the preaches from the very intelligent people in the society/kingdom. And others were just some mythical beliefs that came into existence for preventing people from doing sins. There were a lot of back stories that were developed for these religions and castes which were made into books. These books became the Constitution of every religion. Initially Kings accumulated all the coins and other things with them and provided it to people based on the needs. But gradually money started playing a major in the status of people’s lives and it ruined everything. Thus some of them got richer and richer and earned more powers. While others got poorer and poorer. Kings were dethroned by other Kings. And so the leader got changed again and again. Then after a long time, people started moving from monarchy to Democracy, communism etc since they believed that king is a lot dominating and is not of much help. So in democracy they elected in unison (using votes) one among them to lead them and thus the current world with presidents and prime ministers came into existence. They have dwelled in both inventions and also arts. They have built huge monuments, temples and other places of arts. Along with making world useful, they also made the world beautiful. And thus the history of colonizations and inventions of the world followed which we already know. If needed it can be covered in a different post. Since this is already too biggggggg !!!.
As the colonies expanded and people started conquering the world. They also had an interest in getting to know how the world was formed. After a lot of struggle and once they got to know that sky was not actually blue and it goes on till infinity. They wanted to know if people like humans are in outer space too. So they started sending spacecrafts like the rockets into outer space. This had been a lot challenging to achieve. Then they sent a human to moon and also an unmanned space shuttle till Pluto even. They also built a space station to control things from outer space. They have sent satellites which were the most important means of today for Navigation and Communication.
Even today NASA is sending RadioWaves with encrypted messages into outer space so that if there are any other intelligent species on outer space they would respond. There is a lot of possibility that life can exist on any part of the universe like it is existing in Earth(which is actually just a very very very minute dot in the universe) You may have realized after reading this that there must be life in outer space too because the life through which the earth has traveled. There is a possibility that another planet revolving around another star in the same or different galaxy could have been through the same life.
Earth is still only half way through its life. Minimum there is around 4.5 billion years more to go for earth in this Universe. Now they even say that there are lot universes too. Means Universe is not single. Multiverse is possible. In this huge broad space, we are just a tiny dot. If you think of this from your inner heart, you will realize whatever happening in your life is nothing and you here to just enjoy the life and not care about anything. Have a Smiling Face always. Love Everyone. Make Everyone Happy. Importantly Believe in Science. Thank you readers _/\_ !!!!!