The Solar System

• Solar system is a system of Sun which includes all objects which revolve around it. Hence Solar system includes the Sun, 8 planets, asteroids, Comets, meteors etc which are revolving around sun.
• As we are saying like it because Sun is the main component of solar system and also occupies central position. It occupies 99.6 % of total mass of Solar System.

Solar System

• Solar system is the family of sun. It includes Sun and heavenly bodies which are orbiting it.

Some features of Solar system

• Sun occupies centre position in the solar system.
• Eight planets revolve around the sun in a elliptical orbits.
• Asteroids, comets and meteors are also the part of solar system.
• These heavenly bodies revolve around the sun due to gravitational pull of the sun.

• Solar system is formed from interstellar cloud, when these clouds collapse under gravitation. Sun occupies majority of mass of the solar system.
• Solar system is part of our galaxy “Milky Way” and is located in the Orion Arm of the Milky Way. Not in the centre, but two third away from the centre

• Nearest galaxy from Akash Ganga is Andromeda Galaxy
• If we calculate then Proxima Centauri nearest star next to the Sun.

The Sun

 

• Sun occupies centre position of the solar system. It contains about 99.86 % of the total mass of the solar system.
• It is 109 times bigger in size than Earth and contains mass which is 330,000 times greater than Earth.
• Sun is made up of gas and contains 70 % hydrogen, 28 % Helium and rest other gases.
• Structure of the Sun: We will study structure of the sun by dividing it into different layers. Layers of Sun are as follows:
1. Photosphere: It is the visible part of sun when we see through naked eyes during normal time (means when there is no solar eclipse). It is 6000 degree Celsius hot.
2. Sun’s Atmosphere: It is visible only during Solar eclipse and are millions of miles thick. It is divided into two part:
1. Chromospheres: It is orange red layer of the sun’s atmosphere. It is notably hotter than Photosphere. It lies between photosphere and corona.
2. Corona: It is the uppermost part of the Sun’s atmosphere. It is also visible only during solar eclipse.
3. Core: It is the centre of the Sun where fusion reactions takes place
4. Radiation Zone: Next layer after Core is the radiation zone.
5. Convection Zone: It is the third layer after core.
• Solar Flares: A storm of hot atoms overcomes sun’s gravity and goes into outer space. It dissipates from the photosphere.
• Suns Spot: The regions from where solar flares originate, some dark spots are seen, these are called Sun Spots. The spots are relatively colder regions of the Sun, having temperatures of about 1500 degree Celsius.
• Solar Cycle: Magnetic flux that rises up to the Sun’s surface varies in a cycle called the Solar Cycle or Sun Spot Cycle. It is a cycle of 11 year covering the maxima and minima.  

• Sunspot maxima correspond generally to the periods of higher solar activity.
• These activities include increased solar wind and phenomenon like Aurora and Magnetic Storms.
• Sunspot minima have no activities and Sun can be referred as ‘Quiet Sun’.

 

 Regions of the Solar System

• For study we can divide The Solar System into two different regions:
1. The inner planets
2. The outer planets.
3. Kuiper Belt
4. Oort cloud
5. Asteroid belt
• The inner planet consist of the four rocky, or terrestrial planets, Mercury, Venus, Earth and Mars, while the outer planets consists of the four gas giant planets, Jupiter, Saturn,  Uranus, and Neptune.
• The asteroid belt lies between these two regions.
• The inner planets have rocky composition. Contains silicates in their outer crusts and mantles. And their inner cores contain metals such as iron and nickel.
• The outer planets have gaseous composition with hydrogen and helium occupying major portion.
• Next to the planet belt Kuiper belt and the Oort cloud lies.
• The Kuiper belt contains dwarf planets and other small, planet­ like bodies.
• After Kuiper belt Oort cloud comes which contains icy comets.

Terrestrial planets

• Terrestrial planets mean earth like planet because terra in latin means earth. Due to rocky composition they are also called as rocky planets.
• These planets mostly have metallic core because heavy metals settles down to core.
• Terrestrial planets have mountains, volcanoes, valleys, craters, etc. on their surface. They also have atmosphere. Their atmospheres formed due to volcano eruption in which gases spewed out and forms atmosphere. And these atmospheric gases do not escape due to gravitational pull of the respective planets. However mercury is having no atmosphere as it is very close to sun and due to which mercury’s atmosphere escapes to space.
• Few of the terrestrial planets also have their own natural satellites like Earth has one satellite; Mars has two, whereas Mercury and Venus have none.

The Giant planets

• Second belt of the solar system contains gas giants planet i.e., Jupiter, Saturn, Uranus and Neptune. Jupiter is largest planet in the solar system and is 109 times larger then Earth
• Their cores are solid however their large parts are formed by gases like hydrogen, helium and methane.
• On Jupiter, Saturn, and Uranus the gases form wide bands over the surface e.g., the Great Red Spot of the Jupiter.
• Due to their bigger size and mass there gravitational attraction are very strong due to which they have attracted large number of moons or satellite.
• Jupiter has 64 satellite . And biggest four among them are called Galilean moon (Io, Europa, Ganymede and Callisto).
• Neptune’s satellite titan is the largest satellite among all the satellite of the planets.
• These giants planets have rings around them These rings are formed by broken rock and ice around them.
• Saturn’s rings are most famous and is having more than hundreds rings.
• Uranus is tilted at 90^o so it almost rolls around the sun. Hence it is also called as lying or sleeping planet.
• Due to presence of methane in the atmosphere of Uranus it looks green in colour.

 

Asteroid Belt

• Asteroid Belt contains groups of hundreds of tiny rocks between Mars and Jupiter and is also revolving round the sun.
• It is believed that this belt is formed due to breaking of a much larger planet due to gravitational pull of Jupiter.
• These asteroids are similar to the moon in density and chemical composition
• Jupiter's gravity prevented the asteroids from crashing together hence they never accumulate as a planet.
• This belt also works as a separation between terrestrial planet and giant planet.
• Sometimes under influence of earth’s gravity these asteroids moves towards earth and enters earth’s atmosphere. When they enter in the earth’s atmosphere they gets heated up after friction from atmospheric atoms and burns. After burning it splashes light called meteors.
• Meteors due to burning turned into ashes while those who are large in size do not burn completely and hits earth’s surface. These are called meteorites.

The Kuiper Belt

• It is the third region of the solar system and contains the dwarf planet Pluto.
•  The Kuiper belt holds asteroids and the “short period” comets that pass by Earth in 20 to 200 years.

The Oort Cloud

• It is a theoretical spherical cloud surrounding sun and is formed during early stage in the development of the solar system.
• The outer part of Oort cloud is the point beyond which sun’s gravitational pull doesn’t binds any objects.

Comets

• Comets are made up of rocks with easily vaporizing materials surrounding it. Ice water, ammonia and methane are some of the easily vaporizing material which surrounds the rocky comets.
• Like other heavenly body they also revolve around the sun. However orbit of their revolution round the sun are highly elliptical.
• When a comet approaches sun their easily vaporizing material vaporizes due to heat of the sun and light of the sun exerts pressure on these vaporizing material and forces them to move away from the comet. As a result comets appear to be shinning in the sky with bright head and a long tail. Some examples of periodic comet are Halley, Encke, Temple-Tuttle and Swift-Tuttle.

Meteors

• These are also heavenly body composed of rocks. Earlier we have already discussed in details.