There are eight planets in our solar system: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, and Neptune. They revolve around the sun in elliptical orbits. The planets shine by reflecting sunlight and can be distinguished from stars by their lack of twinkling. They vary in size, composition, distance from the sun, and conditions. Earth stands out as the only known planet capable of supporting life.
3. About PlanetsAbout Planets
Planets are the large celestial bodies which revolvePlanets are the large celestial bodies which revolve
around the sun in closed elliptical paths calledaround the sun in closed elliptical paths called
orbits. The planets shine because they reflect theorbits. The planets shine because they reflect the
light of the sun which falls on them.The easiestlight of the sun which falls on them.The easiest
way to distinguish planets from the stars in theway to distinguish planets from the stars in the
night sky is that the stars twinkle at night but thenight sky is that the stars twinkle at night but the
planets do not twinkle at night.The planets moveplanets do not twinkle at night.The planets move
around the sun from west to east, so the relativearound the sun from west to east, so the relative
positions of the planets in the night sky keeppositions of the planets in the night sky keep
changing day by day. The planets are very small aschanging day by day. The planets are very small as
compared to the sun or other stars.compared to the sun or other stars.
4. There are eight planets in the solar system -There are eight planets in the solar system -
1. Mercury1. Mercury
2. Venus2. Venus
3. Earth3. Earth
4. Mars4. Mars
5. Jupiter5. Jupiter
6. Saturn6. Saturn
7. Uranus7. Uranus
8. Neptune8. Neptune
5.
6. MercuryMercury
Mercury is the first planet from the earth.DuringMercury is the first planet from the earth.During
day time the surface of the mercury heats up today time the surface of the mercury heats up to
430430° but during night the temperature falls up to° but during night the temperature falls up to
-180° c due to lack of atmosphere. Mercury has a-180° c due to lack of atmosphere. Mercury has a
rocky surface which is covered withrocky surface which is covered with
craters.Mercury is sometimes visible from earth,justcraters.Mercury is sometimes visible from earth,just
after sunrise or sunset. When mercury is visible justafter sunrise or sunset. When mercury is visible just
before sunrise in the morning ,it is called “Morningbefore sunrise in the morning ,it is called “Morning
star” and when it is visible just after sunset, then itstar” and when it is visible just after sunset, then it
is called “Evening star”.It can be seen as morningis called “Evening star”.It can be seen as morning
star in the eastern sky in the month September andstar in the eastern sky in the month September and
October or as evening star in the western sky in theOctober or as evening star in the western sky in the
month March and April .month March and April .
7. Planet mercury show phases like moon. This is due to thePlanet mercury show phases like moon. This is due to the
fact that the mercury lies in the orbit of the earth. So, asfact that the mercury lies in the orbit of the earth. So, as
mercury revolves around the sun, its sunlit surface is visiblemercury revolves around the sun, its sunlit surface is visible
in varying amounts from the earth this produces phases ofin varying amounts from the earth this produces phases of
mercury. Many features of the mercury and Earth’s moonmercury. Many features of the mercury and Earth’s moon
are as follows:are as follows:
1] Mercury and moon both are nearly of the same size and1] Mercury and moon both are nearly of the same size and
mass.mass.
2] Mercury and moon both have no atmosphere.2] Mercury and moon both have no atmosphere.
3] Mercury and moon both have rocky surface covered with3] Mercury and moon both have rocky surface covered with
craters.craters.
Mercury and moon both show phases when viewed fromMercury and moon both show phases when viewed from
the earth.the earth.
9. VenusVenus
Venus is the second planet from the earth Venus is slightlyVenus is the second planet from the earth Venus is slightly
smaller than the earth.Venus is a rocky planet. The planetsmaller than the earth.Venus is a rocky planet. The planet
Venus has a dense atmosphere which consists almostVenus has a dense atmosphere which consists almost
entirely of carbon dioxide gas.The cloudy atmosphere ofentirely of carbon dioxide gas.The cloudy atmosphere of
Venus is an excellent reflector of sun light. The planetVenus is an excellent reflector of sun light. The planet
Venus is the brightest object in the night sky(except theVenus is the brightest object in the night sky(except the
moon).Being quite near to the sun , the planet Venus ismoon).Being quite near to the sun , the planet Venus is
very hot .The planet Venus also gets heated excessively byvery hot .The planet Venus also gets heated excessively by
the trapping of the sun’s heat rays by carbon dioxide gasthe trapping of the sun’s heat rays by carbon dioxide gas
present in its atmosphere which is also called green housepresent in its atmosphere which is also called green house
effect The maximum temperature on the planet is 480effect The maximum temperature on the planet is 480°c.°c.
10. The planet Venus can be seen as a morning starThe planet Venus can be seen as a morning star
in the eastern sky or as a evening star in thein the eastern sky or as a evening star in the
western sky The venues shows phases likewestern sky The venues shows phases like
moon. This is due to the fact that the Venus liesmoon. This is due to the fact that the Venus lies
inside the earth’s orbit. So, as Venus revolvesinside the earth’s orbit. So, as Venus revolves
around the sun,its sun-lit surface is presented toaround the sun,its sun-lit surface is presented to
the Earth in varying amounts. This produces thethe Earth in varying amounts. This produces the
phases of the Venus.Life cannot exist on thephases of the Venus.Life cannot exist on the
planet Venus because it is extremely hot,it hasplanet Venus because it is extremely hot,it has
no water and there is no sufficient oxygen in itsno water and there is no sufficient oxygen in its
atmosphere. Mercury and Venus are only twoatmosphere. Mercury and Venus are only two
planets which have no satellites or moonsplanets which have no satellites or moons
revolving around the sun.revolving around the sun.
12. EarthEarth
Earth is the third planet from the earth.WhenEarth is the third planet from the earth.When
viewed from the outer space,the earth appearsviewed from the outer space,the earth appears
to be a blue and green ball due to the reflectionto be a blue and green ball due to the reflection
of sunlight from water and land on itsof sunlight from water and land on its
surface .The earth has an atmosphere containssurface .The earth has an atmosphere contains
gases like nitrogen,oxygen,carbon dioxide, noblegases like nitrogen,oxygen,carbon dioxide, noble
gases ,water vapor and some ozone .gases ,water vapor and some ozone .
14. The earth rotates on its axis.It rotates onThe earth rotates on its axis.It rotates on
an imaginary axis which phases whichan imaginary axis which phases which
through its north and south pole. Thethrough its north and south pole. The
average temperature of the surface of theaverage temperature of the surface of the
earth is 15earth is 15°c The earth has one natural°c The earth has one natural
satellite called moon. The two majorsatellite called moon. The two major
factors which factors which are responsiblefactors which factors which are responsible
for the existence of life on the planet earthfor the existence of life on the planet earth
are :size of the earth and distance of theare :size of the earth and distance of the
earth from the sun.earth from the sun.
15. The rotation of the earthThe rotation of the earth
causes Day and Night.causes Day and Night.
An important consequence of the rotation of the earth onAn important consequence of the rotation of the earth on
its axis is that it causes day and night on the earth. As theits axis is that it causes day and night on the earth. As the
earth rotates on its axis, first one half of the Earth isearth rotates on its axis, first one half of the Earth is
turned around towards the sun. This part of earth receivesturned around towards the sun. This part of earth receives
sunlight and has day on it. The part of earth which issunlight and has day on it. The part of earth which is
turned away from the sun does not receive any sunlight, itturned away from the sun does not receive any sunlight, it
remains dark and has night.Almost every 12 hours, a dayremains dark and has night.Almost every 12 hours, a day
changes into night, and a night changes into day.Thechanges into night, and a night changes into day.The
change in the length of a day and night is, however,change in the length of a day and night is, however,
caused by the tilt of Earth’s axis.caused by the tilt of Earth’s axis.
16. MarsMars
Mars is the fourth planet from the sun.Mars is alsoMars is the fourth planet from the sun.Mars is also
called the Red planet because its surface appearscalled the Red planet because its surface appears
red.The red color of Mars is caused by the presencered.The red color of Mars is caused by the presence
of hydrated iron oxide compound on its soil.of hydrated iron oxide compound on its soil.
Of all of the planets, Mars is most like theOf all of the planets, Mars is most like the
Earth.Mars is a rocky planet. Mars has a thinEarth.Mars is a rocky planet. Mars has a thin
atmosphere as compared to the Earth. The thinatmosphere as compared to the Earth. The thin
atmosphere of mars contains mainly carbon dioxideatmosphere of mars contains mainly carbon dioxide
with small amounts of nitrogen, oxygen, noblewith small amounts of nitrogen, oxygen, noble
gases and water vapour.gases and water vapour.
18. JupiterJupiter
Jupiter is the fifth planet from the earth.Jupiter is theJupiter is the fifth planet from the earth.Jupiter is the
biggest planet of the solar system.The diameter ofbiggest planet of the solar system.The diameter of
Jupiter is 11 times the diameter of the Earth and massJupiter is 11 times the diameter of the Earth and mass
is about 318 times that of the Earth.Because of its veryis about 318 times that of the Earth.Because of its very
big size, Jupiter can be seen easily in the nightbig size, Jupiter can be seen easily in the night
sky.Jupiter is made mainly of hydrogen and heliumsky.Jupiter is made mainly of hydrogen and helium
gases. Jupiter has a very deep atmosphere . Thegases. Jupiter has a very deep atmosphere . The
atmosphere of the Jupiter consists of helium, hydrogen,atmosphere of the Jupiter consists of helium, hydrogen,
methane and ammonia.The surface of the Jupiter ismethane and ammonia.The surface of the Jupiter is
mainly made of liquid hydrogen.mainly made of liquid hydrogen.
19. Jupiter is the first of the gas type planets.Jupiter is the first of the gas type planets.
Below the surface, increasing pressure changesBelow the surface, increasing pressure changes
this liquid this liquid hydrogen to solidthis liquid this liquid hydrogen to solid
state.Jupiter appears to be the brightest objectstate.Jupiter appears to be the brightest object
in the night sky. Jupiter’s bright appearance isin the night sky. Jupiter’s bright appearance is
due to the fact that is it has a thick, cloudydue to the fact that is it has a thick, cloudy
atmosphere which reflects most of the sunlightatmosphere which reflects most of the sunlight
falling on it.Jupiter is a very cold planet, itsfalling on it.Jupiter is a very cold planet, its
surface temperature being,-180surface temperature being,-180°c. Jupiter has°c. Jupiter has
28 satellites .It has also some faint rings28 satellites .It has also some faint rings
around it.around it.
21. SaturnSaturn
Saturn is the sixth planet from the sun.Saturn is somewhat
smaller in size and mass than Jupiter.Saturn is the second
biggest planet in the solar system.The distance of Saturn is
almost double that of Jupiter The chemical composition of
Saturn is very similar to that of Jupiter.Thus, Saturn is
made up mainly of hydrogen and helium gases.The
atmosphere of Saturn consists of hydrogen, helium,
methane and ammonia gases.Saturn has no solid
surface.The surface of Saturn is liquid hydrogen.Below the
surface is frozen hydrogen.The most distinguish feature of
Saturn is the system of colorful rings which surround it.
22. Three distinct sets of rings of Saturn are visible fromThree distinct sets of rings of Saturn are visible from
earth. Saturn is the only planet with a system ofearth. Saturn is the only planet with a system of
well-developed rings encircling it.The rings ofwell-developed rings encircling it.The rings of
Saturn are made up of tiny particles, all orbiting theSaturn are made up of tiny particles, all orbiting the
Saturn like miniature satellites The rings of SaturnSaturn like miniature satellites The rings of Saturn
cannot be seen with naked eyes, they can becannot be seen with naked eyes, they can be
observed only with the help of telescope.Theobserved only with the help of telescope.The
presence of a well-developed system of rings aroundpresence of a well-developed system of rings around
Saturn makes it unique in the solar system.RingsSaturn makes it unique in the solar system.Rings
have now been discovered around other planets –have now been discovered around other planets –
Jupiter, Uranus and NeptuneJupiter, Uranus and Neptune
24. Saturn is the most beautiful of all the planets.Saturn is the most beautiful of all the planets.
Being far off from the sun, Saturn is anBeing far off from the sun, Saturn is an
extremely cold planet.The surface temperature onextremely cold planet.The surface temperature on
Saturn is, -180Saturn is, -180°° C. So, no life can exist on Saturn.C. So, no life can exist on Saturn.
Saturn has the maximum number of satellites orSaturn has the maximum number of satellites or
moons of all the planets in the solar system.Saturnmoons of all the planets in the solar system.Saturn
has 30 satellites.has 30 satellites.
the biggest and brightest satellite of Saturn isthe biggest and brightest satellite of Saturn is
called Titan. Titan is bigger than the planetcalled Titan. Titan is bigger than the planet
mercury.mercury.
25. UranusUranus
Uranus is the seventh planet from the sun.Uranus wasUranus is the seventh planet from the sun.Uranus was
the first planet to have been discovered with the help ofthe first planet to have been discovered with the help of
a telescope.Uranus was discovered with the Williama telescope.Uranus was discovered with the William
Herschel in the year 1781.Though the diameter ofHerschel in the year 1781.Though the diameter of
Uranus is almost four times that of the Earth, itUranus is almost four times that of the Earth, it
appears as a small disc through a telescope. This isappears as a small disc through a telescope. This is
because Uranus is very, very far off from the Earth.Thebecause Uranus is very, very far off from the Earth.The
distance of Uranus from the sun is almost double thatdistance of Uranus from the sun is almost double that
of the Saturn.After Jupiter and Saturn, Uranus is theof the Saturn.After Jupiter and Saturn, Uranus is the
third biggest planet in the solar system.third biggest planet in the solar system.
26. After Jupiter and Saturn, Uranus is the thirdAfter Jupiter and Saturn, Uranus is the third
biggest planet in the solar system.biggest planet in the solar system.
Uranus is made up of mainly of hydrogen andUranus is made up of mainly of hydrogen and
helium.It is surrounded by a thick atmosphere ofhelium.It is surrounded by a thick atmosphere of
hydrogen, helium and methane. Uranus is anhydrogen, helium and methane. Uranus is an
extremely cold planet, its surface temperatureextremely cold planet, its surface temperature
being,-190being,-190°°C. It is also surrounded by anC. It is also surrounded by an
atmosphere of poisonous gases.Due to theseatmosphere of poisonous gases.Due to these
reasons, no life can exist on the planetreasons, no life can exist on the planet
Uranus.The planet Uranus has 21 satellites orUranus.The planet Uranus has 21 satellites or
moons. It has also some rings around it.moons. It has also some rings around it.
29. NeptuneNeptune
Neptune is the eighth planet from the sun.It lies beyondNeptune is the eighth planet from the sun.It lies beyond
the Uranus. Neptune is the second planet which isthe Uranus. Neptune is the second planet which is
discovered with the help of telescope.Neptune was thediscovered with the help of telescope.Neptune was the
first planet to be discovered as a result of predictions.first planet to be discovered as a result of predictions.
Neptune was discovered in 1846 as a result of the effectNeptune was discovered in 1846 as a result of the effect
of its gravitational pull on Uranus. The astronomersof its gravitational pull on Uranus. The astronomers
noticed that the planet Uranus was not moving in itsnoticed that the planet Uranus was not moving in its
orbit around the sun exactly as expected. The Uranusorbit around the sun exactly as expected. The Uranus
had a slightly,irregular orbit as if ,something, washad a slightly,irregular orbit as if ,something, was
pulling it out of its orbit due to its gravitational force.pulling it out of its orbit due to its gravitational force.
