The document discusses astronomy, the astronomical system of units, and the origin of the universe. It defines astronomy as the study of the universe and celestial bodies within it. It then describes the astronomical system of units adopted by the IAU in 1976, including the day as a unit of time, the solar mass as a unit of mass, and the astronomical unit, light year, and parsec as units of length. It closes by quoting Stephen Hawking saying the origin of the universe is like the chicken and egg problem, questioning what created the universe and what created that agency, or if the universe existed forever.
The document discusses astronomy, the astronomical system of units, and the origin of the universe. It defines astronomy as the study of the universe and celestial bodies within it. It then describes the astronomical system of units adopted by the IAU in 1976, including the day as a unit of time, the solar mass as a unit of mass, and the astronomical unit, light year, and parsec as units of length. It closes by quoting Stephen Hawking saying the origin of the universe is like the chicken and egg problem, questioning what created the universe and what created that agency, or if the universe existed forever.
The document discusses astronomy, the astronomical system of units, and the origin of the universe. It defines astronomy as the study of the universe and celestial bodies within it. It then describes the astronomical system of units adopted by the IAU in 1976, including the day as a unit of time, the solar mass as a unit of mass, and the astronomical unit, light year, and parsec as units of length. It closes by quoting Stephen Hawking saying the origin of the universe is like the chicken and egg problem, questioning what created the universe and what created that agency, or if the universe existed forever.
The document discusses astronomy, the astronomical system of units, and the origin of the universe. It defines astronomy as the study of the universe and celestial bodies within it. It then describes the astronomical system of units adopted by the IAU in 1976, including the day as a unit of time, the solar mass as a unit of mass, and the astronomical unit, light year, and parsec as units of length. It closes by quoting Stephen Hawking saying the origin of the universe is like the chicken and egg problem, questioning what created the universe and what created that agency, or if the universe existed forever.
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GENERAL SCIENCE & ABILITY
UNIVERSE: Astronomy is the study of the universe and the celestial
bodies, gas and dust within it. Astronomy includes observations and theories about the solar system, the stars, the galaxies and the general structure of space. The vast empty space around us that consists of stars, solar system, galaxies etc. is called Universe. The universe can also be defined as “ the totality of everything that existes, including all matter and energy, the planets, stars, galaxies and the contents of intergalactic space”. ASTRONOMICAL SYSTEM OF UNITS: It was adopted by the international Astronomical Union (IAU) in 1976. The astronomical system of units is a tri-dimensional system, in that it defines units of lenth, mass and time only.Astronomical Unit of time: The astronomical unit of time is the day, defined as 86400 seconds. 365.25 days make up one julian year. The symbol D is used in astronomy to refer to his unit. Astronomical Unit of Mass: The astronomical unit of mass is the solar mass. The solar mass, 1.98892×1030 kg, is a standard way to express mass in astronomy, used to describe the masses of other stars and galaxies. It is equal to the mass of the sun. Astronomical units of length: The average distance between the earth and the sun and it is approximately 150 million kilometres. Astronomical unit, light year and persec are the units for measuring huge distances. Light year is the distance that light can travel in one year in a vacuum which is about 63,240 AU. ORIGIN OF THE UNIVERSE: “The problem of the origin of the universe is a bit like the old question: which came first, the chicken, or the egg. In other words, what agency created the universe? And what created that agency? Or perhaps, the universe, or the agency that created it, existed forever, anddidn’t need to be created.” (Stephen Hawking)