Our solar system

Solar System

The solar system consists of the sun, the eight planets, and satellites (or moons), and thousands of other smaller heavenly bodies such as asteroids, comets, and meteors.
The sun is at the center of the solar system and all these other objects revolving around it. Thus, the motion of all the members of the solar system is governed mainly by the gravitational force of the sun.
Planets revolve around the sun in elliptical orbit.

Solar System

In the solar system, the planet nearest to the sun is Mercury and planet farthest to the sun is Neptune (not Pluto).
The size of the solar system has been estimated to at about 10^5 A.U.
The solar system is dominated by the sun which accounts for almost 99.9% of the matter in the whole solar system.
The sun is also the source of all the energy in the solar system.
Pluto is a dwarf planet.
Mercury, Venus, Earth, Mars are called terrestrial planets and Jupiter, Saturn, Uranus, and Neptune are called gaseous planets.

Members of the Solar System

THE SUN

The sun is at the center of the solar system.
Its size is 13,00,000 times of the earth.
It is the nearest star to the Earth.
It is an ultimate source of energy for life on earth.
Its diameter is 14,00,000 kms.
It is composed of 71% of Hydrogen,26.5% Helium and 2.5% other elements.
Hydrogen and Helium are the main gases present in the sun.
Within the sun,, hydrogen is converted into helium due to nuclear fusion releasing the tremendous amount of heat and light.
It has a surface temperature of 5778k
The temperature at the center is around 1.571*10^7k
A shinning surface of the sun is called photosphere, it appears like a disc, radiates energy and acts as a source of energy.
The outer layer of the sun's atmosphere made up of all thin hot gases is called Corona. Corona is visible only during a total eclipse of the sun (or with a special solar telescope is called coronograph)
The planet travels with the sun through millions of the star in our galaxy at the speed of about 70,000 km/hr.
The sun is about 150 million km away from earth.
Light takes about 8.6 min. to reach the earth from the sun.

The Planets

These are opaque bodies which continuously revolve around and are lighted by the sun.
There are eight planets in the solar system.
The sequence of the planets according to their distance from the sun is Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune.
The sequence of planets according to their size (in descending order i.e. from big to small ) is Jupiter, Saturn, Uranus, Neptune, Earth, Venus, Mars, Mercury.
Jupiter is the biggest and mercury is the smallest planets of our solar system.

Classification of Planets

The eight planets have been divided into two groups. All the planets of a particular group have some common features. 'Terrestrial planets' or 'Rocky planets' and 'Jovian planets' or 'Gaseous planets'(Gas giants) are divided into two groups of planets.
The four planets nearest to Sun-Mercury, Venus, Earth, and Mars are called Terrestrial planets because their structure is similar to the earth.
Other four planets - Jupiter, Saturn, Uranus, and Neptune are called Jovian planets.

Some Notable Facts About Various Planets

Mercury

Mercury is the closest planet to the sun.
It is an extremely hot planet.
The planet has no water on it.
Mercury planet has no gases CO2, N2, H2 and O2 which can act as building blocks of life.
Mercury planet has no protective blanket like Ozone around it to prevent us from harmful radiations.

Venus

Venus is the second planet in distance from the sun. This planet is nearest to earth and also the brightest planet.

venus is known as the 'Evening star' as well as 'Morning star'.

venus is surrounded by a thick cloud cover, hence known as the 'Veiled planet'.
venus is like the eath in size and mass, and hence also known as the 'Earth twin'.
It also rotates clockwise like Uranus. It is an extremely hottest planet (even hotter than the Mercury).
The planet has no water on it.

Earth

Earth is the largest of the inner planets.
The earth is 23^(0.5) degree on its axis and thus make 66^(0.5) degree angle.
It takes 23 hours 56 minutes and 4.091 seconds to rotate on its axis.
It takes 365 days, 5 hours and 48 minutes to revolve around the sun.
Earth is known as the 'water planet' or the 'blue planet' due to the presence of huge water on it.
Earth has only known planet which provides substance or life on it.
It has a large quantity of oxygen which supports life.

Mars

JUPITER

Jupiter is also known as winter planet of the as its temperature is very low (-148 degree c).
Ganymede, the satellite of Jupiter is the largest satellite in the solar system.

Saturn

Saturn is the second largest planet in the solar system.
Saturn has bright-concentric rings which are made up of ice and ice-covered dust particles which revolve around it.
Titan is the largest satellite of Saturn.

Uranus

Uranus is about four times the size of the earth. This planet appears greenish in color because of methane gas present in its atmosphere.

Uranus was discovered in 1781 by Sir William Herschel.
Uranus is the 7th planet from the sun.
Uranus is the first planet to have been discovered by the use of the telescope. Uranus is the third biggest planet in the solar system.
Uranus rotates from east to west on its axis, which is opposite to another planet except for venus.
The axis of Uranus has a large inclination so that it appears to be lying down, hence it bears the name 'A Planet on its Side'.