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The universe has unlimited size and unknown shape. All the existing things include galaxies, planets, satellites, comets, and meteors. The solar system is located in Milky Way galaxy. The Milky Way galaxy is a medium sized galaxy, which consists of about 150 billion of stars. Astronomers believe that there are 1012 such galaxies in the universe. Astronomical unit (AU), Lightyear (LY) and parsec are used to measure the distance in the universe.
1 AU = 1.5 × 1011 m
1 LY = 9.46 × 1015 m
1 parsec = 3.26 LY
Only the sun is known star, which has a group, like solar family and only one planet the earth of it has suitable conditions for organisms to survive on it. The eight planets of the solar system are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. Countless meteors, meteorites, and comets also revolve around the sun beside planet. Drifting particles called interplanetary dust and an electrically charged gas known as plasma exist in the space of the solar system.
According to international convention of astronomers held on 2005 AD following criteria should be fulfilled by revolving planets:
Pluto was removed from the planet as it crosses the orbit of Neptune.
The distance travelled by a light in a year is called light year.
1 light year = 1 x 3.0 x 108 x 60 x 24 x 365 m
= 9.46 x 1015m
Therefore, 1 light year = 9.46 x 1015 m
Astronomical unit is defined as the average distance between the sun and the earth. It is used to measure the distance between two heavenly bodies in the solar system. The distance between the sun and the earth is about 1.5 x 108 km.
The spiral shaped galaxy including solar system along with other planets, comets, meteorites, constellations, etc. is called milky way galaxy. In constellation, milky way is at the center. The sun lies in the 2/3rd. length of milky way galaxy.
The universe is a huge space which contains of planets, stars, satellites, asteroids, comets and meteorites.
The system containing the sun and its family members including the earth is called solar system.
Light year is the unit to measure the distance between any two heavenly bodies.
There are eight planets in solar system. They are as follows:
Mercury and Venus don't have their own satellites.
In Greek word the meaning of planet is 'Wanderer'.
The rotation of the earth on its own axis from west to east is called diurnal motion.
The revolution of the earth around the sun is called annual motion of the earth.
In constellation, milky way is at the center. The sun lies in the rd length of the milky way.
Universe is a huge space which consists of planets, stars, satellites, asteroids, comets and meteorites.
Light year is the unit used to measure the distance between any two heavenly bodies.
There are 8 planets in the solar system. They are:
Mercury and Venus do not have their own satellite.
Jupiter (63 satellites) has largest number of satellites.
The heavenly bodies which have their own source of light are called stars. Stars have their own light because of the thermonuclear fission reaction in which the hydrogen gas is converted into helium at very high temperature and pressure.
The space contains billions of stars. They have different clusters or groups. These clusters of stars is called galaxy. Thus a galaxy is a vast system of stars, dust particles and gases isolated from similar system in the space.
The nearest star from our solar system is α - century. It is 2.42 light years far from the solar system.
There are 88 constellations known till yet. Example: Ursa major, Ursa Minor, Drecoficious, etc.
After supernova explosion, if the mass of the remaining core is three times the mass of the sun, it will contract rapidly so that gravity becomes infinite and even the light cannot escape from it. This resulting object is called black hole.
These are streak of light in the sky at night which disappears within a second. It is called shooting star or falling star. They actually are small rock fragments coming from outer space.
It is because sun has its own light.
The solar system is formed by the combination of sun, earth, other planets, satellites, asteroids, meteors, comets and dust particles, plasma, etc.
The major purposes of launching artificial satellites in the space are as follows:
Pluto has been removed from the category of planets because of the following reasons:
The differences between stars and planets are as follows:
|The heavenly bodies which have their own source of light are called stars.||The heavenly bodies which revolve round the sun and do not have their own source of light are called planets.|
|Stars are luminous objects||Planets are non-luminous objects|
|They are bigger in size.||They are smaller|
The differences between galaxy and constellation are as follows:
|It is the collection of billions of stars.||It is the collection of limited number of stars.|
|It has no regular pattern.||It has regular pattern|
|There are about 1010 galaxies in the universe.||There are about 88 constellations known.|
The differences between Meteors and Stars are as follows:
|They are made up of stone, iron or both||They are made up of gases like helium, hydrogen, etc.|
|They are not luminous.||They are luminous|
The differences between comets and meteors are as follows:
|The broom shaped shining objects with bright head which is made up of ice mass is called comet.||The pieces of stone or metal entering the earth's atmosphere are called meteors.|
|It has long glowing tail like structure||It has streaks of light falling down towards earth surface|
The differences between planets and asteroids are as follows:
|The heavenly bodies which revolve around the sun are planets.||The heavenly bodies which revolve round the sun mainly between mars and jupiter are called asteroids.|
|They are bigger.||They are smaller.|
The planets which are present inside the asteroid belt are known as inner planets. These planets have similar structure as that of the earth. So, they are also known as terrestrial planets.
The planets which are present outside the asteroid belt are known as outer planets. These planets have similar structure as that of the Jupiter. So, they are also known as jovian planets.
1 AU is equals to ______.
9.46 x 1015 m
1.49 x 1011 m
7.5 x 100 m
0.06 x 1015 m
Pluto crosses the orbit of ______.
A complete round around the sun is called ______.
tropic of cancer
22 March is called ______.