Astronomy

The universe is essentially fascinating and its mysterious phenomenon has always given rise of to human curiosity to explore and unmask it. A number of theories and hypotheses have been put forth to explain the nature ,origin and fate of the universe and its components like galaxies ,constellations ,etc .Inventions like telescope,manned and unmanned spacecraft etc . are being  great helful for space exploration but still we know very little about the universe  as it is very fast .According to Albert Einstein ,no object can travel faster than light.The velocity of light in vacuum is 3*10^8 m/s.Even at this speed ,light takes some thousands years to travel the distance between the stars .Now we can easily imagine how the distance between the stars.
All the aggregate of all existing or the whole creation embracing all the celestial bodies(heavenly bodies) and all of the space is called the universe .
The universe  consists of everythings  including earth ,solar system,constellations ,galaxies,etc.Solar system in the universe is like a very fine particle.Nobody knows the size and the limit of the  universe .The sun is the nearest star near to the earth ,which is the main source of energy.It is medium sized star out of the billions of stars that make up the universe .The sun is too large that if it is a hollow ball , we could  place more  than one billion earth into it .it is 1.5*10^8 km away from the earth . All the planets  of the solar system  revolve around the solar system in their elliptical orbits.