The study of universe is known as Cosmology.
The universe is commonly defined as the totality of everything that exists including all physical matter and energy, the planes, starts galaxies and the contents of intergalactic space.
Galaxy – A galaxy is a vast system of billions of starts, dust and light gases bound by their own gravity. There are 100 billion galaxies in the universe and each galaxy has, on average, 100 billion stars.
Our galaxy is Milky Way Galaxy (or the Akash Ganga) formed after the Bib Bang.
Andromeda is the nearest galaxy to the Milky Way.
The Big Bang Theory – Big Bang was an explosion of concentrated matter in the universe that occurred 15 billion years ago, leading to the formation of galaxies of stars and other heavenly bodies.
It is believed that universe should be filled with radiation called the “cosmic microwave background.” NASA has launched two missions these radiation, i.e. the Cosmic Background Explorer (COBA) and the Wilkinson Microwave Anisotropy Probe (WMAP).
Stars are heavenly bodies made up of hot burning gases and they shine by emitting their own light.
Black Hole Stars having mass greater than three times that of the Sun, have very high gravitational power, so that even light cannot escape from its gravity and hence called black hole.
Comets Made up of frozen gases. They move around the Sun in elongated elliptical orbit with the tail always pointing away from the Sun.
Constellations The sky is divided into united to enable the astronomers to identify the position of the stars. These unites are called constellations. There are 88 known constellations.
Satellites are the heavenly bodies that revolve around the planets. Moo is the natural satellite of the Earth.
Important Fats about Universe
Biggest Planet- – Jupiter
Biggest Satellite – Ganymede (Jupiter)
Blue Planet – Earth
Green Planet – Uranus
Brightest Planet – Venus
Brightest Planet outside Solar System – Sirius (Dog Star)
Closet Star of Solar System – Proxima Centauri
Coldest Planer – Netune
Evening Star – Venus
Farthest Planet from Sun – Neptune
Planet with maximum in number of satellites – Jupiter
Fastest revolution in Solar System – Mercury
Hottest Planet – Venus
Densest Planet – Earth
Fastest rotation in Solar System – Jupiter
Morning Star – Venus
Nearest Planet to the Earth – Venus
Nearest Planet to Sun – Mercury
Red Planet – Mars
Slowest Revolution in Solar System – Neptune
Slowest Rotation in Solar System – Venus
Smallest Planet – Mercury
Smallest Satellite – Deimos (Mars)
Earth’s Twin – Venus
Only Satellite with an atmosphere like Earth – Titan
Asteroids (or Planetoids)
Small planetary bodies that revolve around the Sun and found in between the orbits of Mars and Jupiter. Also known as minor planets.