Birth of the Universe
The birth of the universe, often referred to as the "Big Bang," marked the beginning of our cosmos approximately 13.8 billion years ago. This monumental event triggered the expansion of space and the formation of galaxies, stars, and planets.
The Big Bang Theory
The Big Bang theory is the prevailing explanation for the origin of the universe as we know it. It proposes that the universe began as an extremely hot and dense point, often called a singularity, around 13.8 billion years ago. This tiny, infinitely dense point suddenly expanded, giving rise to the universe we observe today.
The evidence supporting the Big Bang theory is substantial. One key piece of evidence is the cosmic microwave background radiation, a faint glow of radiation that permeates the entire universe. This radiation is a remnant of the intense heat that prevailed shortly after the Big Bang. Additionally, the observed distribution of galaxies and their movement away from each other, as evidenced by the redshift of their light, aligns with the predictions of the expanding universe concept inherent in the Big Bang theory.
The theory's implications are far-reaching. It provides a framework for understanding the universe's evolution, including the formation of galaxies, stars, and planets. Moreover, the Big Bang theory supports our understanding of the universe's age and the origin of elements. It has revolutionized cosmology and our perception of the cosmos, laying the foundation for studying the universe's past, present, and future.
Image: The Big Bang Theary
Attribution: https://creativecommons.org/licenses/by/2.0/
Formation of Galaxies
In the early universe, matter was evenly distributed as a hot, dense state. The first matter to be created was a hydrogen atom. As space expanded and cooled, tiny fluctuations in density emerged. Gravity acted on these fluctuations, causing regions of higher density to attract matter, eventually forming stars and galaxies. These cosmic structures are vast collections of stars, gas, dust, and dark matter held together by gravity. Galaxies are a group of stars. They come in various shapes and sizes, such as spiral, elliptical, and irregular galaxies, each containing billions to trillions of stars.
Birth of Stars
Within galaxies, regions of higher gas and dust density, known as nebulae, serve as the birthplaces of stars. Gravity causes these nebulae to collapse, compressing the material and raising its temperature. At a critical point, the pressure and temperature become high enough for nuclear fusion reactions. Nuclear fusion is a process of combining two atoms to create a giant atom. The abundant hydrogen collapsed together to create a heavier Helium atom. This process releases an immense amount of energy in the form of light and heat, giving rise to a new star. Our sun is made of hydrogen; its life depends on nuclear fusion, which combines hydrogen atoms.
Image: Birth of a Star
Attribution: https://commons.wikimedia.org/
Formation of Planets
Stars often form clusters, and their surrounding discs of gas and dust contain the raw materials for planet formation. As the material in these protoplanetary discs coalesces and collides, small solid particles clump together, eventually growing into planetesimals and protoplanets. Over time, the gravitational attraction of these protoplanets continues to gather gas and dust from their surroundings, forming planets. Planets are created from the leftovers of star formation.