Universe and Origin of Solar System: How and when did the universe begin? Even after centuries of research, this fundamental question remains as intriguing as other scientific theories. The term universe makes us think about unimaginable things that we haven’t seen with naked eyes or space and time.  It is curious to think and understand the theories of the origin of the universe and, by extension, our solar system, the earth and life as we know it. Read further to learn much more about the enigma of the Universe and the Origin of the Solar System.

Origin of Universe

The universe is a composition of matter, energy and gasses in all of space and time. Space is completely silent, as there is no medium for sound to travel in space. There are various cosmological theories about the origin of the universe, but The Big bang Theory proposed by Georges Lemaître is the most accepted one. Discussion of the universe starts with the big bang hypothesis, which is another controversial topic among astrologers. It all began as a red hot, dense, revolving gaseous cloud of cosmic dust called Ylem or primaeval matter about 10 to 13 billion years ago. The Ylem was made up of matter particles (such as neutrons, protons, and electrons) and antimatter antiparticles.

Fig: The Bigbang Theory

The chronological order of the evolution of the universe can be categorised in the following stages:

1. Early Universe: After the huge explosion, the universe was completely hot and dense and constituted fundamental particles like quarks, electrons, photons, and neutrinos. As the universe started to cool down, four fundamental forces like gravity and electromagnetic force emerged. It is believed that the early phase of the universe led to the origin of life and evolution.
2. The Dark Ages: About 400,000 years after the big bang, the universe entered an era known as the cosmic dark ages. During this age, the cosmos was devoid of light. There was no light source of any kind.
3. The appearance of the first Star and Galaxies: a few hundred million years later, as the cosmos became larger, gas pockets scattered everywhere became denser, and stars began to form. Early galaxies formed from groups of these stars. Many of these stars were far bigger than today’s most common stars.
4. Formation of the Solar System: The Sun and the planets were born from a cloud of gas and dust called the solar nebula 4.6 billion years ago. The collapse of the solar nebula was most likely triggered by a shock wave from a nearby supernova explosion. The Sun formed in the centre, with the planets surrounding it in a narrow disc. Moons evolved, similarly circling the gas giant planets. Many comets were pushed out to considerable distances by near gravitational collisions with the massive planets when they consolidated in the outer solar system. A powerful solar wind cleansed the system of gas and dust after the Sun began. The asteroids represent the remaining stony debris.
   The sun provides a constant supply of energy for all of life’s basic activities. Because Mercury is so close to the sun, it is subjected to the brunt of its scorching heat. Even on Venus, which lies between Mercury and Earth, the heat is so strong that any water that may have been present is fully evaporated. Furthermore, high carbon dioxide levels cause the globe to heat up even faster due to the greenhouse effect. Because it had a temperate temperature and abundant surface water before, Mars has also revealed evidence of the potential of life.

Origin of Earth

Earth formed around 4.5 billion years ago, as gravity drew spinning gas and dust into the third planet after stabilising the solar system into its current shape.  The formation of the earth occurred in three stages.

1. The first stage of accretion: It involves the development of a planet from existing particles inside the solar system colliding with one other to produce larger and larger bodies.
2. The second stage: It involved the collision of a protoplanet with a very young planet, Earth. It may have led to the birth of Earth’s moon.
3. Final stage: It involves the bombardment of the planet with asteroids which led to the formation of the primitive earth.

The primitive earth existed only as an enormous cloud of dust and gas. The earth began to cool over a few hundred million years, and oceans of liquid water emerged. Heavier elements like iron started plunging through the seas and magma to the planet’s core. Earth became divided into layers as a result of this, with the topmost layer consisting of a solid crust coating of a comparatively lighter material and the denser, molten stuff sinking to the centre. Water molecules on earth were broken into hydrogen and oxygen, oxygen combined with other compounds. The ozone layer was created naturally by the sun’s interaction of ultraviolet (UV) light with molecular oxygen.

Earth has a central core, a rocky mantle, and a solid crust, just like its other terrestrial planets. The incredible gaseous atmosphere composition of 21% oxygen (which we need to breathe), 78% nitrogen, and.9% argon.  Water vapour exists in our atmosphere and serves to keep our daily temperatures temperate.

Fig: Evolution of Present Day Earth

Evolution of Life on Earth

According to scientists, bacteria may have been the first life on land 3.22 billion years ago. Evidence of microbial life on land was discovered in 3.48-billion-year-old geyserite in Western Australia’s Pilbara Craton in May 2017.

The emergence of the simplest primordial life from non-living elements is referred to as the origin of life. The gradual creation of sophisticated species from simpler organisms is referred to as the evolution of life. These early species have to be simpler than those that exist now. On Earth, all living things were single-celled organisms.

The earliest living forms were prokaryotes, which were primitive animals that ate carbon compounds that accumulated in Earth’s early oceans. Other species gradually emerged that used the Sun’s light, as well as chemicals like sulfides, to make their own energy. The first multicellular species appeared much later, and Earth’s biodiversity increased dramatically as a result leading to the evolution of man and earth of the present.

Summary

The universe is a composition of matter, energy and gasses in all of space and time. Space is completely silent, as there is no medium for sound to travel in space. According to the most accepted big bang theory, it all began as a red hot, dense, revolving gaseous cloud of cosmic dust called Ylem or primaeval matter about 10 to 13 billion years ago. The chronological order of evolution of the universe can be categorised into four: (i) Early Universe, which constituted fundamental particles like quarks, electrons, photons, and neutrinos. (ii) The Dark Ages, during which the cosmos was devoid of light. (iii) Appearance of the first star and galaxies and (iv) Formation of the solar system. The Sun and the planets were born from a cloud of gas and dust called the solar nebula 4.6 billion years ago. A powerful solar wind cleansed the system of gas and dust after the Sun began. The asteroids represent the remaining stony debris. Earth formed around 4.5 billion years ago, as gravity drew spinning gas and dust into becoming the third planet after the solar system stabilized into its current shape. According to scientists, the first life on earth appeared around 3.22 billion years ago which finally led to present-day earth.

FAQs regarding the Universe and Origin of Solar System

Q.1. What is the most accepted theory of the origin of the Earth?
Ans: The nebular hypothesis is the most commonly accepted theory of planetary creation.

Q.2. How old is our universe?
Ans: About 13.8 billion years old.

Q.3. How long will our universe last?
Ans: The earliest conceivable end of the Universe is 22 billion years in the future.

Q.4. What does the Solar System Comprise?
Ans: Our solar system is composed of the planets Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune, as well as dozens of moons and millions of asteroids, comets, and meteoroids that are all gravitationally linked to the Sun.

Q.5. What is another theory for the origin of the universe?
Ans: Although the most accepted theory is the big bang, alternate theories like the Steady State universe also exist.

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