Dear Readers,
Current affairs forms an important component of several competitive exams such as the UPSC Civil Services Examination, SSC CGL, Bank PO & PSU entrance tests, etc. Therefore, understanding terms/concepts/events that are in the news is critical for aspirants. We at PaGaLGuY bring you this series of articles in which we shall explain some of these important concepts/events for you. In this article, we are discussing the Universe.
The Universe (Cosmos):
It consists of everything that physically exists namely, matter, energy and momentum.
It is a three-dimensional extent in which objects and events occur.
The order in the universe is provided by the gravitational force, which is the fundamental force of the universe.
Fundamental forces in universe:
Force Range Nature Produced by
Gravitational Long Range Attractive Mass of objects
Electrical Long Range Attractive/repulsive Charged particles
Magnetic Long Range Attractive/repulsive Movement of charged particles
Nuclear Short Range Attractive/repulsive Change of pi meson in nucleus
The universal constant: During the inter-relationship between fundamental forces and objects, their value remains unchanged in space of time. Eg. Charge of electron, Mass of electron etc.
The origin of the universe: The universe originated billions of years ago. Here are some approximate calculations of the time of its origin as provided by scientists:
Universe : 13.78 Billion yrs
Sun : 5 Billion yrs
Earth : 4.5/4.6 Billion yrs.
Note : Billion yrs : 10^9 yrs
Million yrs : 10^6 yrs
Theories about Origin of the universe:
Various scientists and philosophers have put forth various theories regarding the origin of Universe.
a) German philosopher Immanuel Kant had written about the origin of universe in his book ‘Universal Natural History and Theory of Heaven’
b) Nebular Hypothesis by Pierre-Simon Laplace, a mathematician: According to this theory, the planets were formed of cloud of material associated with the Sun.
c) By Chamberlain & Moulton(1900): This theory gives a hypothesis stating that due to a clash of another star with the Sun, a cigar shaped material separated and continued to revolve around the Sun.
Theories regarding the existence of companion star of the Sun are called binary theories.
Otto Schmidt & Carl Weizascar (1950): Their idea considered that the sun was surrounded by solar nebula containing mostly hydrogen and helium. The friction and collision of particles form a disk-shaped cloud and planets were formed through the process of accretion.
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