solar system (linawati 9ig3, 09)

8/18/2019 Solar System (Linawati 9ig3, 09)

1/9

PHYSICS - SOLAR SYSTEM

SOLAR SYSTEM

The meaning of solar system is the sun and all other celestial objects ( planets and comets )

which move around the sun. The sun is a stationary object at the centre of the solar system. Themass of the sun is greater than that of the other celestial objects, thus the celestial objects move

around the sun. Nicolas Copernicus declared the heliocentric theory which stated that the planets

move around the sun. This theory broke the geocentric theory which stated that the planets and the

sun moved around the earth.

The principal component of the olar ystem is the un, a !" main#se$uence star that

contains %%.&' percent of the systems known mass and dominates it gravitationally. The uns four

largest orbiting bodies, the gas giants, account for %% percent of the remaining mass, with upiter

and aturn together comprising more than %* percent.

+ost large objects in orbit around the un lie near the plane of arths orbit, known as the

ecliptic. The planets are very close to the ecliptic while comets and -uiper belt objects arefre$uently at significantly greater angles to it. ll the planets and most other objects orbit the un in

the same direction that the un is rotating (counter#clockwise, as viewed from above the uns north

pole). There are e/ceptions, such as 0alleys Comet.

The overall structure of the charted regions of the olar ystem consists of the un, four

relatively small inner planets surrounded by a belt of rocky asteroids, and four gas giants

surrounded by the -uiper belt of icy objects. stronomers sometimes informally divide this

structure into separate regions. The inner olar ystem includes the four terrestrial planets and the

asteroid belt. The outer olar ystem is beyond the asteroids, including the four gas giants. ince

the discovery of the -uiper belt, the outermost parts of the olar ystem are considered a distinct

region consisting of the objects beyond Neptune.

+ost of the planets in the olar ystem possess secondary systems of their own, beingorbited by planetary objects called natural satellites, or moons (two of which are larger than the

planet +ercury), or, in the case of the four gas giants, by planetary rings1 thin bands of tiny particles

that orbit them in unison. +ost of the largest natural satellites are in synchronous rotation, with one

face permanently turned toward their parent.

-eplers laws of planetary motion describe the orbits of objects about the un. 2ollowing

-eplers laws, each object travels along an ellipse with the un at one focus. 3bjects closer to the

un travel more $uickly, as they are more affected by the uns gravity. 3n an elliptical orbit, a

bodys distance from the un varies over the course of its year. bodys closest approach to the un

is called its perihelion, while its most distant point from the un is called its aphelion. The orbits of

the planets are nearly circular, but many comets, asteroids and -uiper belt objects follow highly

elliptical orbits. The positions of the bodies in the olar ystem can be predicted using numerical

models.

4ue to the vast distances involved, many representations of the olar ystem show orbits the

same distance apart. 5n reality, with a few e/ceptions, the farther a planet or belt is from the un, the

larger the distance between it and the previous orbit. 2or e/ample, 6enus is appro/imately *.77

astronomical units (8) farther out from the un than +ercury, while aturn is 9.7 8 out from

upiter, and Neptune lies :*.; 8 out from 8ranus. ttempts have been made to determine a

relationship between these orbital distances, but no such theory has been accepted.

number of olar ystem models on arth attempt to convey the relative scales involved in

the olar ystem on human terms. ome models are mechanical < called orreries < while others

e/tend across cities or regional areas. The largest such scale model, the weden olar ystem, usesthe ::*#metre ricsson !lobe in tockholm as its substitute un, and, following the scale, upiter is

a =.; metre sphere at rlanda 5nternational irport, 9* km away, while the farthest current object,


2/9

edna, is a :*#cm sphere in >ule?, %:" km away.

@ange of selected bodies of the olar ystem from the middle of the un. The left and right

edges of each bar correspond to the perihelion and aphelion of the body, respectively. >ong bars

denote hih orbital eccentricity.

Composition

The un, which comprises nearly all the matter in the olar ystem, is composed of roughly%&A hydrogen and helium. upiter and aturn, which comprise nearly all the remaining matter,

possess atmospheres composed of roughly %%A of those same elements. composition gradient

e/ists in the olar ystem, created by heat and light pressure from the un1 those objects closer to

the un, which are more affected by heat and light pressure, are composed of elements with high

melting points. 3bjects farther from the un are composed largely of materials with lower melting

points. The boundary in the olar ystem beyond which those volatile substances could condense is

known as the frost line, and it lies at roughly 9 8 from the un.

The objects of the inner olar ystem are composed mostly of rock, the collective name for

compounds with high melting points, such as silicates, iron or nickel, that remained solid under

almost all conditions in the protoplanetary nebula. upiter and aturn are composed mainly of gases,

the astronomical term for materials with e/tremely low melting points and high vapor pressure suchas molecular hydrogen, helium, and neon, which were always in the gaseous phase in the nebula.

5ces, like water, methane, ammonia, hydrogen sulfide and carbon dio/ide, have melting points up to

a few hundred kelvins, while their phase depends on the ambient pressure and temperature. They

can be found as ices, li$uids, or gases in various places in the olar ystem, while in the nebula they

were either in the solid or gaseous phase. 5cy substances comprise the majority of the satellites of

the giant planets, as well as most of 8ranus and Neptune (the so#called Bice giantsB) and the

numerous small objects that lie beyond Neptunes orbit. Together, gases and ices are referred to as

volatiles.

There are " type of solar system,

a. The 5nner olar ystems the traditional name for the region comprising the terrestrial planets

and asteroids. Composed mainly of silicates and metals, the objects of the inner olar

ystem are relatively close to the un, the radius of this entire region is shorter than the

distance between upiter and aturn. The four inner or terrestrial planets have dense, rocky

compositions, few or no moons, and no ring systems. They are composed largely of

refractory minerals, such as the silicates, which form their crusts and mantles, and metals

such as iron and nickel, which form their cores. Three of the four inner planets (6enus, arth

and +ars) have atmospheres substantial enough to generate weather1 all have impact craters

and tectonic surface features such as rift valleys and volcanoes. The term inner planet should

not be confused with inferior planet, which designates those planets that are closer to the

un than arth is +ercury and 6enus

b. The outer region of the olar ystem is home to the gas giants and their large moons. +any

short#period comets, including the centaurs, also orbit in this region. 4ue to their greater

distance from the un, the solid objects in the outer olar ystem contain a higher

proportion of volatiles such as water, ammonia and methane, than the rocky deniens of the

inner olar ystem, as the colder temperatures allow these compounds to remain solid. The

four outer planets, or gas giants (sometimes called ovian planets), collectively make up %%

percent of the mass known to orbit the un. upiter and aturn are each many tens of times

the mass of the arth and consist overwhelmingly of hydrogen and helium1 8ranus and

Neptune are far less massive (D"* arth masses) and possess more ices in their makeup. 2or

these reasons, some astronomers suggest they belong in their own category, Bice giantsB. ll

four gas giants have rings, although only aturns ring system is easily observed from arth.The term outer planet should not be confused with superior planet, which designates planets

outside arths orbit and thus includes both the outer planets and +ars


3/9

THE SUN AND ITS PART

The sun is a flaming ball of gas which emits energy. The sun consists of the layers, i.e. atmosphere,

photosphere, and the sunEs core.

. olar tmosphere

The solar atmosphere is the outer part of the sun. 5t consists of two layers, the outer layer, which is

called the crown ( corona ), and the inner layer, which is called the color layer (chromospheres ).:. Corona

Fe can see the corona during a total solar eclipse in the form of a circle. Corona can also be seen by

using a specially designed telescope which is called the coronagraph. The layer of corona contains a

very thin gas, but its temperature can reach :,***,*** -. the corona layer has a thickness about ".;

G :*H' km.

". Chromosphere

Fe can also see the chromospheres layer during the total solar eclipse. 5t emits a weak red light

which is originated from the hydrogen gas with a temperature of 9,*** -. the chromospheres layer

has a thickness of :',*** km.

I. Jhotosphere

The photosphere is a solar disk which covers the core of the sun. Its color isyellow because it has a temperature range from 5,000C – ,000C. Thethickness of the photosphere layer is !"0 km. The sunspots, granules andfaculae are located on the photosphere.

C. olar Core

The core of the sun is located at the inner part of the sun. 5ts temperature can reach :;,***,*** -.

The reaction of nuclear fusion occurs in the core. The core has a spherical form with a radius of

:=;,*** km.

The space between the core and the photosphere are divided into ones ( not layer ), i.e. theconvection one and the radiation one. The convection one is located beneath the photosphere.

Thermal convection of gas occurs at this one. 5f its temperature decreases, the gas will flow to the

upper side, otherwise if its temperature decreases, the gas will flow to the lower side. 0eat is

transferred together with the flow of the gas. The thickness of the convection one can reach :;*

km.

The radiation one is located below the convection one. t this one, the energy is

transferred from the core to the outer layer through radiation mechanism.

T0 +33N N4 5T J@T

The moon is the satellite of the earth. The moon looks very bright because it reflect the

incident sunlight upon it. The orbital period of the moon is "=.7 days. The moon gravitational forceis :K' of the earthEs gravitational force. The surface of the moon that faces the earth is always the

same. The natural phenomena that occur on the moon are sea, mountain, valley and crater. The

moon has no atmosphere because the gravitational force of the moon is too weak to tie up the

atmosphere. s the result, the temperature at the moon surface changes very $uickly. Fe canEt hear

any sound at the moon because there is no medium for the propagation of the sound wave. Fe canEt

find any water at the moon either, so it is impossible to find any life there.

The +oon is the only natural satellite of the arth, and the fifth largest satellite in the olar

ystem. 5t is the largest natural satellite of a planet in the olar ystem relative to the sie of its

primary, having a $uarter the diameter of arth but only :L&: its mass. The +oon is the second

densest satellite after 5o, a satellite of upiter. 5t is in synchronous rotation with arth, always

showing the same face with its near side marked by dark volcanic maria that fill between the brightancient crustal highlands and the prominent impact craters. The +oon is the brightest object in the

sky after the un, although its surface is actually very dark, with a reflectance similar to that of coal.


4/9

5ts prominence in the sky and its regular cycle of phases have, since ancient times, made the +oon

an important cultural influence on language, calendars, art and mythology. The +oons gravitational

influence produces the ocean tides and the minute lengthening of the day. The +oons current

orbital distance, about thirty times the diameter of the arth, causes it to appear almost the same

sie in the sky as the un, allowing it to cover the un nearly precisely in total solar eclipses. +oon

CompositionM r, 0e, Na, -, 0, @n

The +oon is a differentiated bodyM it has a geochemically distinct crust, mantle, and core.The +oon has a solid iron#rich inner core with a radius of "9* kilometers and a fluid outer core

primarily made of li$uid iron with a radius of roughly 7** kilometers. round the core is a partially

molten boundary layer with a radius of about ;** kilometers. This structure is thought to have

developed through the fractional crystalliation of a global magma ocean shortly after the +oons

formation 9.; billion years ago. Crystalliation of this magma ocean would have created a mafic

mantle from the precipitation and sinking of the minerals olivine, clinopyro/ene, and

orthopyro/ene1 after about three#$uarters of the magma ocean had crystallised, lower#density

plagioclase minerals could form and float into a crust on top. The final li$uids to crystallise would

have been initially sandwiched between the crust and mantle, with a high abundance of

incompatible and heat#producing elements. Consistent with this, geochemical mapping from orbit

shows the crust is mostly anorthosite, and moon rock samples of the flood lavas erupted on thesurface from partial melting in the mantle confirm the mafic mantle composition, which is more

iron rich than that of arth. !eophysical techni$ues suggest that the crust is on average ;* km

thick.

The +oon is the second densest satellite in the olar ystem after 5o. 0owever, the inner core of the

+oon is small, with a radius of about 7;* km or less1 this is only "*A the sie of the +oon, in

contrast to the ;*A of most other terrestrial bodies. 5ts composition is not well constrained, but it

is probably metallic iron alloyed with a small amount of sulphur and nickel1 analyses of the +oons

time#variable rotation indicate that it is at least partly molten.

a. urface geology

The topography of the +oon has been measured with laser altimetry and stereo image analysis. The

most visible topographic feature is the giant far side outh Jole O itken basin, some ","9* km in

diameter, the largest crater on the +oon and the largest known crater in the olar ystem. t :7 km

deep, its floor is the lowest elevation on the +oon. The highest elevations are found just to its

north#east, and it has been suggested that this area might have been thickened by the obli$ue

formation impact of outh Jole O itken. 3ther large impact basins, such as 5mbrium, erenitatis,

Crisium, mythii, and 3rientale, also possess regionally low elevations and elevated rims. The

lunar far side is on average about :.% km higher than the near side.

b. 6olcanic features

The dark and relatively featureless lunar plains which can clearly be seen with the naked eye are

called maria (>atin for BseasB1 singular mare), since they were believed by ancient astronomers to

be filled with water. They are now known to be vast solidified pools of ancient basaltic lava. Fhilesimilar to terrestrial basalts, the mare basalts have much higher abundances of iron and are

completely lacking in minerals altered by water. The majority of these lavas erupted or flowed into

the depressions associated with impact basins. everal geologic provinces containing shield

volcanoes and volcanic domes are found within the near side maria.

+aria are found almost e/clusively on the near side of the +oon, covering 7:A of the surface on

the near side, compared with a few scattered patches on the far side covering only "A. This is

thought to be due to a concentration of heat#producing elements under the crust on the near side,

seen on geochemical maps obtained by >unar Jrospectors gamma#ray spectrometer, which would

have caused the underlying mantle to heat up, partially melt, rise to the surface and erupt. +ost of

the +oons mare basalts erupted during the 5mbrian period, 7.*O7.; billion years ago, although

some radiometrically dated samples are as old as 9." billion years, and the youngest eruptions, dated by crater counting, appear to have been only :." billion years ago.

The lighter#coloured regions of the +oon are called terrae, or more commonly highlands, since they


5/9

are higher than most maria. They have been radiometrically dated as forming 9.9 billion years ago,

and may represent plagioclase cumulates of the lunar magma ocean. 5n contrast to the arth, no

major lunar mountains are believed to have formed as a result of tectonic events.

SOLAR & LUNAR ECLIPSE

n eclipse is one of the most spectacular natural phenomena. clipse is caused by the

shadow of the earth or the moon when they are in a straight line. The shadow is divided into two

regionsM

a. The main shadow or the umbra. The umbra forms a cone#shape region of shadow from the

earth or the moon.

b. The outer shadow or the penumbra.

lunar eclipse occur when the moon enters the shadow of the earth. The earth is positioned

between the sun and the moon. s the conse$uence, the sunlight is blocked by the earth, but the

moon is not completely dark, so we still can see it in a faint illumination. total lunar eclipse occur

when the moon passes through the earthEs umbra, a partial lunar eclipse occur when the moon

partially crosses the earthEs umbra and penumbra lunar eclipse occur when the moon enters theearthEs penumbra.

lunar eclipse takes about ' hours to complete, meanwhile a total lunar eclipse takes only about :

hour and 9* minutes.

solar eclipse occur when the moonEs shadow crosses the earthEs surface. The moon is located

between the earth and the sun. The solar eclipse takes place at a day time. partial solar eclipse

occur when the moonEs penumbra crosses an area on the earthEs surface which is partially blocked

the sunlight on that area.

The other type of solar eclipse is the annular eclipse. 5t occur when the length of the umbra cone

does not reach the earthEs surface, but only the e/tension of the cone. The area on the surface which

is crossed by the shadow e/periences an annular eclipse.

ROTATION AND EARTH REVOLUSION

Iesides revolving the sun, earth also turns around on its a/is. The rotary motion of earth around its

a/is called the earth rotation. 5t takes "9 hours to complete one rotation or 7'* of longitude. The

effects of the earthEs rotation areM

a. The sun and the other celestial objects appear to move from the east to the west.

b. There will be a time difference between the places with different longitude.

c. The earth surface is divided by latitude and longitude.

The earth revolution is the movement of the earth around the sun. when the earth revolves, the earth

a/is is not perpendicular to the plane of the ecliptic. The orbital period of the earth is 7'; day or one

solar year. The earth has four different position on its orbitM#. $n %arch "#th 3n +arch ": the sun is located e/actly at the e$uator. ll places in the earth have the same length

of day time and nightfall. The northern hemisphere will be in spring, and the southern hemisphere

will be in autumn.

". $n &une "#th

$n &une "#th, the northern hemisphere and the southern hemisphere are farfrom the sun, which is apparently located at "!.5 ' latitude. (rom &une "#th to)eptember "!rd, the southern hemisphere is in winter because it is far from thesun, meanwhile the northern hemisphere is in summer because it is close the

sun.!. $n )eptember "!rd

$n )eptember "!rd, both the northern hemisphere and the southern


6/9

hemisphere are far from the sun, which is apparently located at the e*uator.(rom )eptember "!rd to +ecember "#st,the northern hemisphere is far from thesun, so it eperiences autumn, meanwhile the southern hemisphere is springbecause it is close to the sun.-. $n +ecember "#st

$n +ecember "#st, the sun is apparently located at "!.5o) latitude from

+ecember "#st to %arch "#st, the southern hemisphere is getting closer to thesun, thus this region is in summer. $n the cuntrary, the northern hemisphere isin winter because its position is getting farther from the sun

(rom the eplanation above, we can see that the sun seems to move from thee*uator march "#st / to the "!.5o' latitude &une "#st /, go back to the e*uator)eptember "!rd/ , move again to the "!.5o) latitude +ecember ""nd/, and goback again to the e*uator %arch "#st/. The displacement is called the apparentmotion of the sun.

The effects of the earthEs revolution are M

a. Changes in season

b. Changes in the length of daytimec. The apparent motion of the sun

d. The appeareance of different constellations every month

SPECIAL CHARACTERISTIC OF SEVERAL PLANETS

5n our solar system there are several planets. The list of eight planets in order of their distance from

the sun started from the closest one isM

a. +ercury

This planets is the smallest sie and it has almost no atmosphere. 5ts surface is filled with craters

similar to the moonEs surface. 3n day time, the temperature at the mercuryEs surface is so hot that itcan reach 9**C but the temperature becomes so cold at night that it can reach #"**C

b. 6enus

This planets looks very bright because its surface is covered by a thick atmosphere. 5ts temperature

at day time can reach ;**C. 6enus is usually called as the morning star or the evening star because

it shines so brightly in the eastern sky during the sunrise or in the western sky during the sunset.

c. arth

arth is our home planet, the place where we stand on and live. arth has an atmosphere which

makes the temperature on its possible for presence of life.

d. +ars

+ars has a rocky surface. 5t also has ice poles and active volcanoes. The greatest volcano is

3lympus +ountain, which is height of "7,***m high. 5t is predicted that there used to be a presenceof life at mars.

e. upiter

upiter is the biggest planet in our solar system. The diameter of upiter is :: times longer than that

of the earth and its volume is :,7** times bigger than of that the earth. 5ts atmosphere consist of

hydrogen and helium. 5t also has clouds made from ammonia and crystal of ice.

f. aturnus

aturnus is the second biggest planet in our solar system after upiter. 5ts sky is covered by cloud

belts mainly composed of hydrogen. The cloud belts are able to reflect the sunlight very well. The

temperature at aturnEs surface is about #:=*C. aturn has multiple rings comprise of crystal of ice

with a width of 9*",*** km and it thickness of :; km.

g. 8ranus

8ranus was found by Filliam 0erschel in :=&:. This planet is covered by thick fog which mainly

composed of methane gas. 5ts diameter is about four times longer than the earthEs diameter.


7/9

h. Neptune

The condition at Neptune is almost the same as the condition at 8ranus. That is why these planets

are considered as twin planets. The temperature at Neptune surface can reach #:"* C

THE EARTH

arth (or the arth) is the third planet from the un, and the densest and fifth#largest of the

eight planets in the olar ystem. 5t is also the largest of the olar ystems four terrestrial planets.

5t is sometimes referred to as the world, the Ilue Jlanet, or by its >atin name, Terra. Composition of

the arth =&.*&A nitrogen , dry air, "*.%;A o/ygen, *.%7A argon, *.*7&A carbon dio/ide, and :A

water vapor (varies with climate).

arth formed 9.;9 billion years ago, and life appeared on its surface within one billion years.

The planet is home to millions of species, including humans. arths biosphere has significantly

altered the atmosphere and other abiotic conditions on the planet, enabling the proliferation of

aerobic organisms as well as the formation of the oone layer which, together with arths magneticfield, blocks harmful solar radiation, permitting life on land. The physical properties of the arth, as

well as its geological history and orbit, have allowed life to persist during this period. stimates on

how much longer the planet will to be able to continue to support life range from a mere ;**

million years, to as long as ".7 billion years.

arths outer surface is divided into several rigid segments, or tectonic plates, that migrate

across the surface over periods of many millions of years. bout =:A of the surface is covered by

salt water oceans, with the remainder consisting of continents and islands which together have

many lakes and other sources of water that contribute to the hydrosphere. arths poles are mostly

covered with solid ice (ntarctic ice sheet) or sea ice (rctic ice cap). The planets interior remains

active, with a thick layer of relatively solid mantle, a li$uid outer core that generates a magnetic

field, and a solid iron inner core.arth interacts with other objects in space, especially the un and the +oon. t present,

arth orbits the un once every 7''."' times it rotates about its own a/is, which is e$ual to 7';."'

solar days, or one sidereal year. The arths a/is of rotation is tilted "7.9P away from the

perpendicular of its orbital plane, producing seasonal variations on the planets surface with a period

of one tropical year (7';."9 solar days). arths only known natural satellite, the +oon, which

began orbiting it about 9.;7 billion years ago, provides ocean tides, stabilies the a/ial tilt, and

gradually slows the planets rotation. Ietween appro/imately 7.& billion and 9.: billion years ago,

numerous asteroid impacts during the >ate 0eavy Iombardment caused significant changes to the

greater surface environment.

Ioth the mineral resources of the planet and the products of the biosphere contribute

resources that are used to support a global human population. These inhabitants are grouped intoabout "** independent sovereign states, which interact through diplomacy, travel, trade, and

military action. 0uman cultures have developed many views of the planet, including personification

as a deity, a belief in a flat arth or in the arth as the center of the universe, and a modern

perspective of the world as an integrated environment that re$uires stewardship.

COMET, METEOR, SATTELITTE, etc

Ieyond the Neptune orbits, far from the sun, there are billions celestial objects in the form of icy

rocks which revolve the sun in an elongated elliptical orbit. Those celestial objects are called

comets. comets consist of a nucleus, a hydrogen layer, and tail. The nucleus is composed ofcarbon compound with very high density. Fhen the icy materials in the comet evaporate, it turns

into gases and forms a certain kind of atmosphere called the coma.


8/9

The cometEs tail (in form of gas) always points away from the sun due to the sunEs radiation

pressure. comet is often called as a star with hair.

The orbital period of each comet is different. 3ne of the famous comets is the Comet 0alley which

has an orbital period of =' years. The comets which are originated from the -uiper belt and 3rbit

cloud can have an orbital period from : to 7* million years.

meteoroid is formed from debris or fragment of comets which keep moving in the space.

5f a meteoroid reaches the earthEs surface, then it is keep moving in the space. 5f a meteoroidreaches the earth surface then it is called a meteorite. huge crater named Iarringer Crater is

predicted to be the place where a meteor down.

)mall celestial obects smaller than meteoroid/ which revolve around thesun are called asteroid belt is located between %ars and &upiter. The biggestasteroid is called Ceres with diameter #,000km. &earus asteroid was onceapproaching the earth1s orbit.

)un2 The brightest star of our solar system is sun. The approimatediameter and mass of sun is approimately #.!3" 4 #03m and #.3 4 #0!0kgrespectively. The sun is #03 times bigger than that of earth.

arth and sun have an average distance of near about :.9%' Q :* ::m. This distance can becalled as: stronomical unit. Iasically two types of rotations are there one is rotation around some

other body and other is rotation around own a/is. 2or a complete rotation around its a/is sun needs

"; days. s we all know it is a ball of heat and gases. o there is no need to e/plain that the

temperature and pressure inside the sun are e/tremely high. Iy conducting e/periments the

appro/imately calculated temperature on the surface of sun is near about '***k. The light from the

sun reach at the earth surface in near about &.7 minutes.

JlanetsM The heavenly body which doesnEt have light of its own. These bodies revolve

around the sun. They have the capability to reflect the light of sun that falls on them. Nine planets

are present in our solar system. ll of these are rotating in different orbital around the sun and also

on their own a/is.

+ercuryM The planet nearest to sun is mercury. 5ts radius and mass are "9:*km and 7.7; Q

:*"7 respectively. Time taken by it to complete one revolution around sun is && days. 4ue to high

temperature on the planet no water is present there. 0ence occurrence of life on mercury is

impossible.

6enusM The planet present after mercury in se$uence is 6enus. This planet is similar to that

of earth. 5ts density, radius, mass etc are appro/imately similar. 4ue to its similarities it is also

known as RarthEs sisterE. The percent of carbon dio/ide on 6enus is e/tremely large as compared to

that of other gases. %;A composition is of Carbon 4io/ide and ;A composition is of the other

gases. 2orce e/erting per unit area on 6enus is appro/imately :** times more than that of earth.

Temperature present on the surface of 6enus is also very high as compared to earth. 5t is near about

9;*oC. 4ue to such high temperature the life on 6enus is also not possible. 5t takes about ""; daysto complete its one revolution around the sun. 5t is also known as morning star. 5t is called so

because it is the brightest planet in the solar system. 5t does not have any satellite of its own.

arthM tarting from the sun and moving towards Jluto it is the third planet. 5t takes near about

7';."; days to complete one revolution around the sun. fter the passage of four years we get a

leap year because the rotation time ."; after four years (.";S.";S.";S.";:day) becomes : .o, one

day is increased after 9 years. 5n a leap year rather than having 7'; days we have 7'' days.

tmospheric conditions are suitable for life thatEs why we are living on earth. Fater is also present

in plenty.

+arsM Jlanet ne/t to earth is mars. 5ts radius is about 79**km. 5t takes near about :.% years

to complete its one revolution around the sun. >ike 6enus carbon dio/ide gas is present here in

plenty. Iut atmosphere is not so thick like other planets. ome patches are present on its surface.They contract and e/pand according to the environmental conditions. +ostly e/pansion can be seen

in winters and contraction can be seen in summers. 5tEs like chameleon which changes color as the


9/9

season changes. Uet no life has been founded on mars. +ars is also called as the red planet of the

solar system. 2obos and 4imos are the names of its two moons.

@emaining planetsM s we go farther from the sun the atmospheric temperature goes on

decreasing. o, on the other planets the temperature on their surfaces is low. 3n the remaining

planets most of the poisonous gases like methane, ammonia etc can be found. 4ue to these

poisonous gases no occurrence of life can be seen there.

+oonM arth has only one natural satellite i.e. +oon. +oon is present at a distance of nearabout 7.&9 Q :* ;. @adius of moon is about :=9*km. Total mass of moon is =.7; Q :* "". The

gravitational pull of moon is :K' then the gravitational pull of earth. +oon completes its one

revolution around the earth in "=.7days. 5t is also called R@adio moonE because it has the capability

of emitting of electromagnetic waves in radio wave region. +oon face that is towards earth remains

always the same. Temperature ranges of moon in day time and at night are ::*oc and #:;*oc. Ioth

water and atmospheric conditions are absent on moons surface. arlier it was said that there was no

water and atmosphere present on the moons surface. Iut cientists have found some evidences of

water molecules on the moons surface. o, we can say that at some later stage their may be the

possibility of life on moons surface. ccording to the estimations, it is said that age of moon is near

about four billion years.

steroidsM This is an area also we can say it as a belt between mars and upiter in whichlarge no of bodies having irregular shapes are present. These bodies are called asteroids. These are

large no of rock pieces moving at higher speed between both mars and upiter and around the sun.

The largest asteroid is Ceres. 5t is about 7;*km.The smallest asteroid of all is having a radius of

near about ;*m. 5t is supposed that these rock pieces are the broken pieces of any large planet,

which were broken due to the string gravitational pull of the planet upiter. The asteroids which is

larger in sie, completes its one revolution around sun in appro/imately 9.' years.

CometsM Comets are heavenly bodies made up of hard and soft rocks mostly covered with

substances that can be changed into vapors easily like water, ice methane etc. Their revolution

around sun is in fi/ed orbits. Fhen the comets are passing near to the sun they show a long tail

behind them with a bright head. 3n the other hand when the comets are far from the sun then their

tail disappears.

Fhen the comets came near to sun then due to the e/treme hot temperature of sun some of

the material present in the comet gets evaporated. The vapors of comet feel great pressure due to

sun light. The light of the sun also compel them to leave the comet. This process helps in formation

of tail of the comet.

0alley comet completes its one revolution around the sun in =' years. >ast it was seen in the

year :%&'. Now it is e/pected that we will able to see it again in the year "*'".

+eteorsM 4ue to the damage of the comets some small pieces of metals and rocks are

formed. These are called +eteors. Iut these cases are very rare. s we know that friction is present

in our atmosphere. 5t is due to the presence of air and the gravitational pull of earth. s the meteors

enter the region of earthEs gravitational pull these are burnt out due to the friction. Fhen themeteors catch fire then the bright light is produced. The light produced can be seen easily from the

earthEs surface. These luminous meteors are called as fire balls or shooting stars. +eteors can be of

any sie. ome large meteors, after entering the earthEs atmosphere did not burn completely. Then

those meteors reach the earthEs surface in state of stones, iron balls, etc and cause destruction in the

form of large craters.

solar system (linawati 9ig3, 09)

Documents