[CharlesCably (OP)]

i am starting this threat for preparation of general science notes topic wise. please check them and point out deficiencies .
. Physical Sciences
Constituents and Structure:-

all existing matter and space considered as a whole; the cosmos.
comonly universe is
,,The vast empty space around us that consists of stars, solar system, galaxies etc is called Universe.,,
the universe can also be define as " the totality of every thing that exist, including all meter and energy,the planets , stars, galaxies and content of intergalactic space"  The space between stars is known as interstellar space, and so the space between galaxies is called intergalactic space.
The part of the Universe that we can see, referred to as the observable universe, is about 28 billion parsecs 91 billion light-years in diameter at the present time. The size of the whole Universe is not known and may be infinite. Scientific observation of the Universe has led to inferences about its composition and evolution.
Definition
The Universe is customarily defined as everything that exists, everything that has existed, and everything that will exist. According to our current understanding, the Universe consists of three principles: spacetime, forms of energy, including electromagnetic radiation and matter, and the physical laws that relate them. The Universe also encompasses all of life, all of history, and some philosophers and scientists even suggest that it encompasses ideas such as mathematics.
before detail discussion about universe difference between three terms must be knownastronomycosmologyastrologyAstronomy
 Copernicus is a father of modern astronomy
 .it is a natural science which is the study of celestial objects such as stars, galaxies, planets, moons, asteroids, comets and nebulae, the physics, chemistry, and evolution of such objects, and phenomena that originate outside the atmosphere of Earth, including supernovae explosions, gamma ray bursts, and cosmic microwave background radiation. A related but distinct subject, physical cosmology, is concerned with studying the universe as a whole.
Astronomy is one of the oldest sciences. However, the invention of the telescope was required before astronomy was able to develop into a modern science.
Astronomy is one of the few sciences where amateurs can still play an active role, especially in the discovery and observation of transient phenomena and Amateur astronomers have made and contributed to many important astronomical discoveries.Amateur astronomy is a hobby whose participants enjoy watching the sky, and the abundance of objects found in it with the unaided eye, binoculars, or telescopes. Even though scientific research is not their goal
cosmology

this is branch of science that deal with scientific study of origin and evolution of universe and nature of universe and nature of universe its largest scale.
To religious studies, cosmology is about a theistically created world ruled by supernatural forces. To scientists, modern cosmology is about developing the most complete and economical as possible understanding of the Universe that is consistent with observations elucidated by natural forces.Cosmology has exploded in the last 20 years with radically new information about the structure, origin and evolution of the Universe obtained through recent technological advances in telescopes and space observatories and basically has become a search for the understanding of not only what makes up the Universe the objects within it but also its overall architecture.
Modern cosmology is on the borderland between science and philosophy, close to philosophy because it asks fundamental questions about the Universe, close to science since it looks for answers in the form of empirical understanding by observation and rational explanation. Thus, theories about cosmology operate with a tension between a philosophical urge for simplicity and a wish to include all the Universes features versus the total complexity of it all.

astrology
Astrology is the study of the influence that distant cosmic objects, usually stars and planets, have on human lives.  It is not a science and not based on scientific development neither it changes with scientific progress.
cosmological theories
the human have been examining and wondering about sky and universe for many millennial. there are many concepts and theories about the shape and center of the universe.
The center of the Universe is a concept that lacks a coherent definition in modern astronomy; according to standard cosmological theories on the shape of the Universe, it has no center.
Historically, the center of the Universe had been believed to be a number of locations. two are commonEarth as the center of the UniverseGeocentric modelsun as center of universe  Heliocentric theory or modelEarth as the center of the UniverseGeocentric model
In astronomy, the geocentric model also known as geocentric, or the Ptolemaic system is a description of the cosmos where Earth is at the orbital center of all celestial bodies.
Ptolemy, and Alexandrian proposed this theory. Ptolemaic theory held that earth is stationary. Closest to earth is moon . according to them sun also resolve around the earth.
evidences

Two commonly made observations supported the idea that Earth was the center of the Universe. The stars, the sun, and planets appear to revolve around Earth each day, making Earth the center of that system. The stars were thought to be on a celestial sphere, with the earth at its center, that rotated each day, using a line through the north and south pole as an axis. The stars closest to the equator appeared to rise and fall the greatest distance, but each star circled back to its rising point each day. The second observation supporting the geocentric model was that the Earth does not seem to move from the perspective of an Earth-bound observer, and that it is solid, stable, and unmoving.



please dear fellows check these then i will paste further more notes

[Colin2B]

Charles
This isn’t an A to Z topic so I’ve moved it here so you are free to post any ideas and others to comment. In this section we also relax the restriction on the topic being a question.

Note that you won’t necessarily find that anyone will want to proof check your text, so don’t take nil replies as aggreement.