The Solar System

The Solar System An Intro Designed By www.CBSEQuestionPaper.com

About the lesson…. Things we will learn: üComponents of our Solar System. üRelative positions of our planets. üSome Interesting facts about space!!! üMore about Sun. üWhat are Planets & Satellites?? üTerrestrial and Jovian Planets. üAbout Asteroids, Meteors and Comets. üInternal Structure of Earth

An Introduction Solar System consists of: Sun The Nine Planets (Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, Pluto) Large number of Asteroids between the orbit of Mars and Jupiter Large number of Comets revolving around sun in highly elliptical paths.

Lets See How It Looks Like..

Planets revolve around the sun and also rotate about there own axis. All planets, except Pluto, revolve in almost the same plane.

Some Interesting Facts Do you know????? Sun accounts for 99.9% of the mass of the solar system. Mercury is the smallest planet. Jupiter is the largest planet. Alpha Centauri is the nearest star to our solar system (about 4.3 Light Years) Cirus, Cirus the brightest star, star is about 8.7 light years away from us. Only Earth has life on it among all the planets in our solar system.

Sun The centre of Attraction!! Sun is the source of energy for earth. It is made up of Hydrogen (70%), Helium (28%) and other gases like Nitrogen, Oxygen and Carbon (2%). The energy is produced in the Sun due to Nuclear Fusion Reaction in which four hydrogen nuclei fuse to form a Helium nuclei (and two positrons). RIt is the nearest star from us and hence looks much bigger than other stars. RThe sun has a diameter of about 1, 392, 000 Km (about 109 times the diameter of earth!!!!) RSun is about 333000 times as heavy as Earth. RAverage distance of sun from earth is 15 crore Km RLight takes about 500s (about 8 minutes) to travel from sun to earth. RThe temperature at the core of Sun is about 14 x 106 Kelvin.

The Planets What are they? The heavenly bodies that revolve around the stars (like Sun) in an orbit are known as planets. e. g. there are Nine planets in our solar system. They have different structures due to their different temperatures. These have been temperatures divided into two types depending upon their similarity of structure. structure 5.Terrestrial Planets 6.Jovian Planets.

Terrestrial Planets The four planets near to Sun, namely Mercury, Venus, Earth and Mars are known as Terrestrial Planets because their structure is similar to Earth. Common Features of these planets are: ii. A thin rocky crust. iii. A mantle rich in Iron and Magnesium iv. A core of Molten Metals. v. Thin atmosphere vi. Very few moons

The first colour image of the Martian Surface, transmitted by Viking 1 Lander on July 26, 1976. (NASA)

Jovian Planets The five planets beyond the orbit of Mars are known as Terrestrial Planets because their structure is similar to Jupiter. Jupiter These are Jupiter, Saturn, Uranus, Neptune & Pluto. Common Features of these planets are: ii. They are Gaseous Bodies iii. They have ring system around them. iv. Except Pluto they all have a large number of moons (i.e. natural satellites). Pluto has only one moon. v. They are too distant from Sun as compared to Terrestrial Planets.

How to remember their Sequence? Just remember the phrase.. My Very Educat ed Mother Just Served

Mercur y Venus Earth Mars Jupiter Saturn

A brief intro - Mercury ØNearest to Sun ØSmallest Planet ØNo Atmosphere ØVery Hot during Day and Very Cold at night.

A brief intro - Venus ØClosest to Earth ØSize almost same as Earth ØVisible before dawn and after sunset. ØKnown as Morning (or Evening) Star ØCalled sister planet of Earth due to similarities.

A brief intro - Earth ØDiameter: 12 800 Km ØMass: 6 x 1024 Kg ØRotation time: 24 hours. ØOne Revolution: 365 ¼ days ØOnly Planet that can sustain life. ØHas Nitrogen and Oxygen rich atmosphere.

A brief intro - Mars ØKnown as RED PLANET ØNo Atmosphere ØVery Cold ØHas two Moons ØHas a lot of solid CO2.

A brief intro - Jupiter ØLargest Planet ØCan contain as many as 1300 earths!!!!!! ØCovered by clouds of gases ØHas 28 Moons !! ØStorms are always raging on its surface

A brief intro - Saturn ØHas beautiful rings around it ØHas 30 moons in addition to rings!! ØAppears bright yellow.

A brief intro - Uranus ØVery Cold ØHas 21 moons in addition to rings

A brief intro - Neptune ØVery far from Sun ØVery Small ØHas 8 moons.

A brief intro - Pluto ØFarthest planet ØVery Small ØHas just one moon

Satellites What are they? The heavenly bodies that revolve around the PLANETS (like Earth) in an orbit are known as satellites. e. g. Moon is the satellite of Earth. It revolves around earth in an elliptical orbit. orbit Other planets like Mars, Jupiter and Saturn also have their satellites

Moon’s Surface

Asteroids The small rock like bodies revolving around Sun between the orbits of Mars and Jupiter are called Asteroids. These are very small to be considered as Planets. The largest among them is Ceres with a radius of about 800 Km only while the smallest one is as small as a pebble. Where did they come from? It is believed that they were formed due to some collision between planets which resulted into its breaking into small fragments. Though their exact origin is not known till date.

Asteroid Named GASPRA

Asteroid Named IDA (Along with its tiny satellite)

Meteors (Shooting Stars) These are pieces of rocks floating in space, which sometimes enter the earth’s atmosphere. They experience a force of friction of air and start burning. They appear as a ball of fire falling towards earth emitting intense light. They are also known as Shooting Stars but they are not actually Stars or in anyway connected to them. Most of them get completely burnt in the atmosphere.

Meteorites Some meteors are so large and do not get completely burnt. So they reach earth and are known as Meteorites.

Comets These are heavenly bodies which revolve around the sun in highly elliptical paths. They appear in the sky as a ball of fire with a TAIL. The tail always pointing away from the Sun. e.g. HALLEY’S COMET Why do they have tail??? They are composed of rocks like material surrounded by large masses of easily vaporised substance like water, ammonia, methane etc. When these approach Sun, some of its material gets vaporised due to heat of the Sun. Light of the Sun exerts pressure on these vapours and forces them away from the comet in form of a tail. Are they Important? Yes, from the analysis of their material we can know about the origin of Universe and the life of Universe.

Halley’s Comet It has a time period of 76 years. Last seen in 1986 and will now be visible in 2062.

Structure of Earth The Earth can be broadly divided into Three different Layers. Crust Mantle Outer Core Inner Core

Structure of Earth Earth is composed of a number of layers. Though we have not been able to dig more than 10 Km into the earth’s crust but we have studied it in details from the study of Seismic Waves. Seismic waves are produced during Earthquakes. But in addition to natural seismic waves we can also produce artificial waves by Underground Nuclear Tests. Velocity of seismic waves depends on composition of region from which they pass. From the study of their velocities we can collect more information and a picture of earth’s interior. Three layers of earth are:

The Three Layers- A Comparison Crust: a. Top 30-40 Km layer of earth. b. Contains mainly rocks of silicates (Containing SiO2). c. Its thickness is lesser under sea floor. Mantle: a. From 40 km – 3000 Km. b. Rich in Iron and Magnesium Silicates. c. Not under direct observation. Core: a. Innermost layer beyond 3000 Km. b. It consists mainly of Pure Iron alloyed with some Nickel. c. Its material is in FLUID state.

True or False 1. Meteors that reach Earth are called Meteorites. 2. Planets revolve around their satellites. 3. There are Nine Planets in our Solar System.

4. Asteroids are there between the orbits of Mars and Satu 5. Mercury is the nearest planet to the Sun.

T rue

Fals e

know your knowledge … Q1. _________ is NOT a planet. b)Saturn c)Earth d)Moon e)Mars

know your knowledge … Q2. The debris present between the planets Mars and Jupiter are called __________. b)Meteors c)Meteorites d)Comets e)Asteroids

know your knowledge … Q3. The ratio of diameter of Sun to that of earth is _______ b)109 c)500 d)1/109 e)33000

know your knowledge … Q4. Morning and Evening Star is the name given to the planet _______ b)Mercury c)Venus d)Pluto e)Neptune

know your knowledge … Q5. Hottest Planet in our Solar System is: b)Mars c)Venus d)Mercury e)Earth

I Know !!! There are ???? planets in our solar system. They are ?????, Venus, Earth, Mars, ???????, Saturn, Neptune and ????. They ?????? around Sun and rotate about their own axis. ??? is at the centre and accounts for about 99.9% of the mass of solar system. Planets have been classified into two types namely ?????? planets and ??????? planets depending on similarity of their structures. Beside these planets our solar system has Asteroids between the orbits of ???? and ??? Then we have ?????? which revolve around sun in highly elliptical paths. We can see ?????? ????? after every 76 years.

I Know !!! There are nine planets in our solar system. They are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Neptune and Pluto. They revolve around Sun and rotate about their own axis. Sun is at the centre and accounts for about 99.9% of the mass of solar system. Planets have been classified into two types namely Terrestrial planets and Jovianplanets depending on similarity of their structures. Beside these planets our solar system has Asteroids between the orbits of Mars and Jupiter Then we have comets which revolve around sun in highly elliptical paths. We can see Halley’s comet after every 76 years.

Home Work Q 1. Name the nine planets of our Solar System. Q 2. What is a comet? Q 3. Why is life only possible on earth? Q 4. Define following terms: A. Planet B. Satellite C. Meteor D. Asteroids Q 5. Differentiate between Jovian and terrestrial planets.

From: www.cbsequestionpaper.com For: Class X Students