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revolution around the galactic centre. This period isknown as a cosmic year. The solar system consistsof the Sun and all other objects that move around it.Inner planets are Mercury, Venus, Earth and Mars.The orbits of inner planets are very close to the sun.

The movement of the entire solar system around thegalactic centre of the MilkyWay is known as galacticmovement.

The following is the order of the size of planets fromsmall to big: Mercury, Mars, Venus, Earth,Neptune, Uranus, Saturn, Jupiter.

Planets in the Solar System Planets in the solar system are classified into two1. Inner Planets : Mercury, Venus, Earth and Mars.2. Outer planets : Jupiter, Saturn, Uranus and Nep-

tune. kqcy-t\mSv ASp¯v ØnXn- sN-¿p-¶h InnerPlanets Dw AIse ØnXn-sN-¿p-¶h Outer planetsF¶pw Adn-b-s -̧Sp-¶p.

3. Dwarf Planets : Pluto, Eris and Ceres are the threedwarf planets in solar system. {Kl-§-fpsS kz`m-h-

apÅ F¶m hep¸w hf-sc-Ip-d-ª-h-bmWv Ipų

{Kl-§Ä.

There are 8 known Planets in the solar system. Theyare Mercury, Venus, Earth, Mars, Jupiter, Saturn,Uranus and Neptune.

Mercury (_p[³)

Mercury is the planet nearest to the Sun. It is thesmallest planet.

ASTRONOMYOur Universe Our universe is infinite in space and time. Another

name for universe is cosmos. The most distant detected galaxies and quasars lie 10

billion light years or more from Earth and are movingfarther apart as the universe expands.

A galaxy is the congregation (group) of millions orbillions of stars held together by gravity. kqcy\pw`qanbpw DÄs¸-Sp¶ kuc-bqYw ØnXn-sN-¿p-¶XvMilky Way (£oc-]-Yw) F¶ Kme-Ivkn-bn-em-Wv.

The are 12 constellations in the Milky way There are two broad classes of galaxies, elliptical

and spiral. Millions of galaxies constitute the uni-verse.

Milky Way (B-Imi KwK)MilkyWay is our home galaxy. It appears as a river ofbright light flowing through the sky. It belongs to acluster of 24 galaxies called local group. Milky Wayis made up of over a hundred billion stars. LargeMagellanic Cloud (1,60,000 light years away fromEarth) and Small Magellanic Cloud, (1,80,000 lightyears away from Earth) are the two irregular galax-ies closest to Earth

The Milky Way is a spiral galaxy to which our solarsystem belongs.

The solar system is in the outskirts (edge) of thegalaxy.

Andromeda is the closest (about 2.25 million lightyears from Earth) spiral galaxy to our solar system.

The solar system moves with an average speed of250 km/sec. It takes 250 million years to complete one

Lunar Eclipse 4-3-2007

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Mercury is the fastest planet, it takes only 88 days torevolve around the sun.

Mercury is surrounded by an extremely small amountof helium, hydrogen, oxygen and sodium.

The United States’, Mariner 10, is the first space-craft to reach Mercury.

On August 3, 2004 NASA launched its messengerspace craft to mercury. It will reach mercury in 2011.

Mercury has no satellites. Mercury is covered by a thin layer of minerals called

silicates.Diameter : ................... 4878 kmPeriod of rotation : ...... 58 daysPeriod of revolution : .. 88 days

Venus (ip-{I³)

The Venus is named after the Roman Goddess ofLove.

The planet nearest to Earth is Venus, the secondbrightest object in the night sky (next to the sun andthe moon).

Venus is called the twin planet of earth because thetwo planets are almost similar in size.`qan-tb-¡mÄ hen¸w Ipd-hmWv ip{I-\v.

It is called the Morning Star and the Evening Star. Venus is the hottest planet (4620C). Ing-¡p-\n¶pw ]Sn-ªm-tdm«v {`aWw sN¿p¶ Htc-

sbmcp {Kl-amWv ip{I³ (Venus). Magellan space probe aims to study Venus. About 95 per cent of the planet is marked by meteor-

ites, craters and extensive volcanic activity. European Space Agency (ESA) launched Venus Ex-

press on November 9, 2005 to study about venus.Diameter : ............... 12, 102 kmPeriod of rotation : .... 243 daysPeriod of revolution : 227 days

Earth (`q-an)

April 22 : Earth Day. Earth is the largest of the inner planets. It is the

densest planet. Earth is the fifth largest planet in terms of size. Earth’s

axis is tilted at 23.5o from a line perpendicular to itspath around sun.

Earth is also called “blue planet”, because it appearsblue when seen from space. This is because of thepresence of water (oceans) on earth.

Poh-Pm-e-§sf Is­-¯n-bn-«pÅ Htc Hcp {Kl-amWv`qan.

Moon is earth’s natural satellite. The moon is aboutone- fourth the size of earth.

The star nearest to earth is the Sun. Swift Tuttle is the name of a comet which is on a

collision course with earth on August 17, 2116. The shape of the earth is oblate spheroid. {[ph-§Ä

]c¶pw `qa-[y-tcJ {]tZiw hoÀ¯pw ØnXnsN¿p¶p. It is also called Geoid.

Earth is a bit pear shaped rather than true sphere withan 18 metre rise at the North Pole and 26 metredepression at the South Pole.

Earth is at least 4½ billion years old. Total surface area of earth is 510,100,500 Sq km of

which 29% is land and 71% is water. The average density is 5.53 gm/cc. The average surface temperature of earth is 14oC. The highest temperature 58oC at A1 Aziziyah (Libya) Lowest temperature –89.60 at Vostok Station at

Antartica. The mean speed of the earth on its orbit is 29.72 km/

sec.Equatorial Diameter : ............................. 12, 756 kmPolar Diameter : ..................................... 12, 714 kmPeriod of rotation : .......23 hours 6 minutes and 4.091seconds.Period of revolution : 365 days, 5 hours, 48 minutes.

Mars (sNm-Æ)

Mars is named after Roman Godess of War. Mars has two satellites– Phobos and Deimos. Since

Mars is very similar to earth in different ways, scien-tists are hopeful of finding life on it.

Pathfinder, the US spacecraft, landed on Mars, andthe robot in the spacecraft, Sojourner, travelled onthe Martian surface.

The NASA’s mission to Mars Odyssey was launchedon April 7, 2001 from Cape Canaveral. It is NASA’sfirst mission to Mars since the loss of Mars PolarLander and Mars Climate Orbiter in 1999.Diameter ................ 6794 kmPeriod of rotation : 24 hours 37 minutes 22.663 sec-onds

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Period of revolution : 687 days. Ignª Adp-]-Xn-\m-bncw hÀj§Ä¡nsS BZy-am-

bn, 2003 BKÌv 27-þ\v sNmÆbpw `qanbpw X½nÂGähpw Ipdª AI-e-amb 557.60 e£w In.-ao. ASp-s¯-¯n.

NASA’s mars Exploration Rovers Spirit andOppertunity landed on the red planet on January 4,and January 25, 2004 to search for water and life.

Europe’s Mars Express orbiter and its Lander Beagle2 land on Mars and ditected evidence of water butBeagle 2 suddenly lost in Mars.

NASA launched Mars Reconnaissance orbiter onAugust 12, 2005. It will probe mars, weather, climateand geology.

NASA is launching Phoenix Mars Scout and MarsScience Laboratory in 2007 and 2009 respectively.

Jupiter (hym-gw)

Jupiter is the largest planet in the solar system. It is11 times bigger than earth.

Jupiter rotates faster than any other planet. It takes only9 hours 55 minutes to spin around once on its axis.

kz´w A¨p-X-­n Gähpw thKw Npän-¯n-cn-bp-¶Xv(rotation) Gähpw henb {Kl-amb hymg-amWv (Jupiter).

Jupiter has now 63 satellites. Ganymede, the largest

satellite in our solar system, is a satellite of Jupiter. In March 1993 astronomers Eugene Shoemaker,

Carolyn Shoemaker and David H. Levy discovered acomet near Jupiter. The Comet was later namedShoe maker - Levy 9.

Jupiter is also known as Jovian Planet. Jupiter is named after the King of Roman Gods.

Asteroids Gähpw IqSp-X-embn ImW-s¸-Sp-¶XvsNmÆbv¡pw hymg-¯n\pw CS-bn-em-Wv.

One special feature of this planet is the ‘‘Great RedSpot’’.

Galileo space craft launched by NASA completed its14 years of successful mission on September 21, 2003.It discovered nine moons on Jupiter.Diameter : ............................................ 142, 880 kmPeriod of rotation : .. 9 hours 50minutes 30 secondsPeriod of revolution : ............................... 12 years

Saturn (i-\n)

Saturn is the second largest planet in the solar sys-tem.

Saturn is the outermost planet visible to the nakedeye.

Saturn has 45 satellites. Titan is its biggest satellite. Christian Huygens, the Dutch astronomer, discov-

ered Titan in 1656. Titan is called Earth’s Little sister. Saturn has rings around it. Saturn’s rings were dis-

covered by Galileo. These rings are dense gas and solid rock particles

revolving around the planet. When light falls on them,they show themselves as a ring. sNdnb sSe-kvtIm¸vsIm­v Cu he-b-§Ä ImWm³ km[y-am-Wv.

Cassini : Huygens mission, a joint project of NASAand ESA was launched in 1997 to study about Sat-urn. In July 2004, the mission In December 2004, theSaturn explores Cassini, the biggest and costliest In-terplanetary exploration ever, dropped off Huygensfor its three week Titan Odyssey. Huygens landedon Titan and valuable photograph of the Satellite.Diameter : ........................................... 120, 500 KmPeriod of rotation : .................. 10 hours 14 minutesPeriod of revolution : ............................... 30 years.

Uranus (Acp-W³-)

Uranus, the third largest planet in the solar systemwas discovered in 1781 by William Herschel.

Uranus has 27 known satellites. Cu D]-{K-l-

Mars is known as the red planet.Ccp-¼nsâ km¶n-[y-amWv Nph¸v

\nd-¯n-\m-[m-cw.

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§Äs¡Ãmw sjIvkv-]n-b-dpsS IYm-]m-{X-§-fpsSt]cp-I-fmWv \ÂIn-bn-cn-¡p-¶-Xv.

Its two largest moons, are Titania and Oberon. In 1977, it was found that the planet has nine rings

similar to those of Saturn but are much fainter. Twomore were found in 1986.

1977 bpdm-\-Ên\v Npäpw A©v he-b-§Ä (i\n{Kl-¯n-\p-ÅXv t]mse) Is­-¯pIbp­m-bn.]s£ i\n-bp-tS-Xp-t]mse Chbv¡v A{X Xo{h-X-bn-Ã.

Diameter : 51, 400 kmPeriod of rotation : 17 hours 12 minutesPeriod of revolution : 84 years.

Neptune (hcp-W³)

Johann Galle discovered Neptune in 1846. Neptune has 13 satellites. Triton is a satellite of Neptune. It was discovered by J.G. Galle in 1846. The Farthest planet, coldest planet and slowest planet

are all Neptune. Its Great Dark Spot is as large as Earth. Neptune’s winds

are the fastest in the solar, system at 2,000 km/hr.Diameter of Neptune : 48, 600 kmPeriod of rotation : 16 hours 6 minutesPeriod of revolution : 165 years.

Dwarf Planets International Astronomical Unions (IAU) the world

authority on astronomical decision, in a meeting heldon August 24, 2006 at Prague decided to stripped.Pluto of its planetary status and made it a dwarfplanet pluto has been disqualified because of itsoblong orbit which sends it soaring above and be-yond the main plane of the solar system where Earthand other seven planets circles the Sun. The othertwo dwarf planets are Eris and Ceres.

Pluto (ba³) Pluto is the Roman God of Underworld. Pluto is the second largest dwarf planet. Earlier it was the 9th planet in the Solar System. The average diameter of pluto is 2306 km. Pluto was discovered by Clyde Tombough in 1930. Pluto need 248 years to revolve around sun. Charon is the satellite of pluto. It was discovered by

James Christy in 1978 New Horizon launched in 2006 will study about Pluto.

Eris Eris is the largest dwarf planet. It is 70 miles wider

than Pluto in Solar system. It revolves around sunbeyond Pluto.

Eris is the farthest object in solar system. Eris is the Greek Goddess of discord. American team led by Michael Brown discovered

Eris and it was initially named 2003 UB 313. It wasalso called Xena.

Dysnomia is the moon of Eris.

Ceres Ceres revolve around sun in between Mars and Ju-

piter. Ceres was the largest astroid in solar system. IAU

promoted it to a dwarf planet in 2006. It is the smallest dwarf planet. Its average diameter

to revolve around is 585 miles. It takes 46 years torevolveid around sun once.

Sedna Sedna is the coldest and the most distant object ever

discovered in solar system. It is smaller than the dwarfplanet pluto and three times farther away.

Moon (N{µ³)

The moon is earth’s natural satellite and it is our near-est neighbour in space.

The moon is about one-fourth the size of earth. The moon takes 27 days 7 hours 43 minutes and 11.47

seconds to complete one revolution around earth. Moon light reaches earth in about 1.3 seconds. Lunar Eclipse happens when the Earth comes be-

tween the moon and the sun. A lunar eclipse occursonly on a new moon day.

America took the lead by landing a man on the moonin July 1969.

Neil Armstrong was the first astronaut to land on themoon in Apollo 11.

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Ocean of Storms is the name of a waterless spot onthe moon.

The element found on the surface of the moon istitanium.

The first spacecraft to land on the moon was Luna 9(1966) of the erstwhile USSR.

Sea of Tranquility is the place on moon where Apollo11 landed.

The mean distance between earth and moon is384, 400 km.

The average orbital speed of moon is 3680km perhour.

Over 59% of the moon’s surface is directly visiblefrom Earth.Diameter : 3, 476 km.

Six American spacecrafts from 1969 to 1972 brought12 astronauts to walk on the surface of moon.BZy-ambn N{µ-\n Cd-§nb a\p-jy³ \oÂBwkvt{SmMv BWv (1969). EugeneCernen BWv Ah-km-\-ambn Cd-§n-b-Xv (1972).

The period of rotation of moon isequal to its period of revolutionaround the Earth. That is why onlyone face of the moon is visible fromthe earth.

NASA sent Lunar prospector in1998 to study about water in moon.

C´y-bpsS N{µ-]-cy-th-jW ZuXy-amWv N{µbm³ - -þ I 2008 emWv CXv

hnt£-]n-¡p-I.

Sun (kqcy³)

The star nearest to earth is the sun,and it is the brightest object in the sky.

Heat and light is produced in the sun by means ofnuclear fusion. Heat and light from the sun come toearth by means of radiation.

The sun is made up of hydrogen (71%) helium (26.5%)and Carbon (2.5%). Hydrogen is being converted tohelium in the sun. This process is called nuclear fu-sion.

Sunlight takes about 8.2 minutes (500 seconds) toreach Earth.

A solar eclipse occurs when the moon comes be-tween the sun and the earth. A solar eclipse occursonly on a new moon day.

Sun spots are dark patches which appear on the sur-face of the sun.

The orbits around the sun are elliptical in nature. Corona is the outer atmosphere of the sun which is

visible during a total solar eclipse. The glowing surface of the sun is called Photosphere.

Above it is the chromosphere and beyond this layeris the corona which is visible during eclipse.

Sun takes 224 million years to complete one revolu-tion around the galactic centre. This period is calleda cosmic year.

Comets and Asteroids Comet is a small body that moves usually in a very

elongated orbit around the Sun. The biggest comet is Centauri 2060 Chiron. It was

discovered in 1977. Its diameter is 113 miles. There are nearly 10,000 comets in

our solar system.Shoemaker Levy – 9 is the name

given to the comet which collidedwith Jupiter in 1996.

Swift Tuttle is the name of anothercomet which is on a collision coursewith Earth on August 17, 2116.

Halley’s comet is seen every 76years. It was last seen in 1986. It willreappear in AD 2062.

Comet Hale Bopp is called “Cometof the Century”. It visited the solarsystem in 1996.

The only exception to this isHalley’s comet. It is named after the man who calcu-lated its orbit. (not the person who discovered it)

I­p-]n-Sn-¡p¶ BÄ¡v CjvS-apÅ t]cv \nÀt±-in-¡m³ Ign-bp-¶Xv £p{Z {Kl-§Ä¡v (asteroids) am{X-amWv. ]t£ CXn\v International AstronomicalUnion sâ AwKo-Imcw thW-sa¶v am{Xw.

Asteroids are also called Minor Planets or Planetoids.They are relatively small planetary bodies which arefound in between the orbits of Mars and Jupiter.

The first spacecraft to land on an asteroid is NearEarth Asteroid Rendezvous (NEAR).

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2000 Bf 19 is an asteroid that will hit Earth in 2022. A new asteroid discovered has been named J99TO 4G. Ctäm-¡mh F¶ On¶ {Kl-̄ n-en-d-§nb P¸m-\okv

_ln-cm-Imi ZuXy þ lbm-_pk

The largest asteroid is Ceres. 2014 Â hmÂ\-£-{X-¯nsâ inc-Ên-en-d-§m³ hnt£-

]n-¡-s¸« _ln-cm-Im-i-ZuXyw þ tdmkä

Stars and other Heavenly BodiesA galaxy is a group of millions of stars. Constellationmeans a group of stars. A large number of constella-tions make a galaxy. A ‘cluster of stars’ is anothername for a group of stars.

The biggest constellation is Hydra (sea serpent). Itcontains at least 68 stars visible to the naked eye.

Sirus or the Dog star is the brightest star in the MilkyWay.

Supernovae are violent explosions of massive starswhere all but the inner core of the stars are blown offinto interstellar space.

Quasars are quasi-stellar radio sources. They are thepowerful source of radio energy.

Stars twinkle because starlight comes to us throughdifferent media of universe and the moving layers ofair that surround the earth.

There are four kinds of stars (1) Fixed stars (2) Binarystars (3) Temporary stars (4) Variable stars.

Fixed stars do not appear to alter their positions. Theyare also called Dog stars.

Binary stars are group of two stars revolving roundeach other under mutual gravitational attraction.

Temporary stars are those which suddenly flare up

to increase brightness and fade away after a shorttime. They are also called nova.

Variable stars are stars the brightness of which var-ies from time to time.

Dwarfs are small stars. Red giants are stars which have consumed about 10

percent of their hydrogen on account of which theyappear reddish. They consume hydrogen in a rapidmanner and they finally become white dwarfs.

We do not see the stars during the daytime becauseof the scattering of sunlight by the dust particles ofthe atmosphere which makes the sky too bright forstars to be seen. The biggest star in our galaxy, MilkyWay is Proxima Centauri.

The nearest star to earth (excluding the sun)in our galaxy is Proxima Centauri. It i s 4.2light years away. I t is one of the stars that makeup the Alpha Centauri System.

Pole star is a fixed star; the north pole of earth pointstowards it.

Meteors are small bodies often seen in the sky pro-ducing a trial of light. They are also called shootingstars. It may burn up or fall on earth in the form ofdust or fragments called Meteroites. The largestknown meteorite was found at Hoba in Namibia whereit landed in prehistorictimes.

Nebulae are clouds of rarified gas which exist be-tween stars. They glow due to the radiation of thelight of the stars. Their visibility is hazy and faint.

Pulsar is a rapidly rotating neutron star which sendsout a flash or radiation to the observers after everyrotation.

Themis projectNasa will launch five identical spacecraft from Cape Canaveral inFlorida, in an attempt to answer the question. By measuring howthe magnetic field around the Earth fluctuates in real time, theThemis project will allow scientists to better predict the weatherin space that lies behind the northern lights - crucial for keepingcommunications satellites and, eventually, humans safe in orbit.The northern lights - aurora borealis - are a visual representation ofthe turmoils of the Earth’s magnetic field. The sun continuallystreams energy towards our planet, some of which is stored by theEarth’s magnetic field at heights of 10,000km above the surface.The field creates a protective sheath for the Earth in space, calledthe magnetosphere, which shields our planet from much of thedeadly radiation coming from the sun. But every so often, the fieldwill release the energy it has stored and shower energetic electronstowards the upper atmosphere. When these hit air molecules, theenergy released causes a characteristic glow.

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Branches of Astronomy Cosmology is the study of the structure of the uni-

verse. Astronomy (tPymXn-im-kv{Xw) is the study of uni-

verse as a whole and objects like heavenly bodiessuch as stars, planets, comets etc.

Astrology (tPymXn-jw) is the art of foretelling thefuture on the basis of the study of the position of theheavenly bodies. Astrophysics is the study of thephysical component of the stars by means of thespectroscope.

Exobiology is the study of life in outerspace. Extrater-restrial region is another expression for outer space.

Cosmogony ({]]-t©mÂ]¯n imkv{Xw) is thetheory of the creation of the universe.

Astronomer is a person who studies about the uni-verse : tPymXnÀim-kv{X-Ú³.

Astronaut is a person who has been trained for trav-elling in a spacecraft.

Cosmonaut is the Russian name for astronaut. Taikonaut is the Chinese space traveller. Cosmopolitan þ temI ]uc³, temIs¯ Xsâ

Xd-hm-Smbn ImWp-¶-h³, hkp-ss[-h-Ip-Spw-_Iw F¶hnizm-k-¡m-c³.

Space tourist is a person who travel to space as atourist: _ln-cm-Imi hnt\mZ k©m-cn.

Space Explorations Galileo (U.S.)

Galileo spacecraft was launched on October 18, 1989to study the chemical composition, physical stateand atmosphere of Jupiter and four of its moons. Itsfirst mission was achieved in 1997. But its missionwas extended beyond 2000 A.D.

Ulysses(U.S. and European Space Agency)Ulysses was launched on October 6, 1990 to studythe sun and interstellar space above and below itspoles. The spacecraft was put into orbit at rightangles to the solar system's elliptic plane. This spe-cial orbit enabled Ulysses to examine for the first timethe Sun's north and south polar regions. The space-

craft completed its first full orbit around the Sun onApril 17, 1998. It continues to orbit the sun, passingover the north and south poles in 2000 and 2001.

Cassini(U.S., European Space Agency and the Italian SpaceAgency)Cassini was launched on October 15, 1997 to orbitSaturn and study about its moons. It will orbit Saturnfor four years after arriving there on July1, 2004.Before reaching Saturn, Cassini encountered Jupiteron December 30, 2000. The Cassini Mission is namedafter the Italian-French astronomer, Gian DomenicoCassini, who discovered four of Saturn's majormoons.

Deep Space 1 (U.S)Deep Space I was launched on October 24, 1998. Itflew past near-earth asteroid Braille on July 28, 1999and its mission was extended to fly past cometBorrelly by September 2001.

The Mars Odyssey : The NASA’s new mission toMars, Mars Odyssey, was launched on April 7, 2001from Cape Canaveral. It is NASA’s first mission toMars since the loss of Mars Polar Lander and MarsClimate Orbiter in 1999.

The following are the names of the Space Shuttles ofUSA : Columbia, Challenger, Discovery, Atlantis andEndeavour. Space shuttle is a reversable spacecraft.

The first Russian space shuttle was Buran, launchedin 1988.

The first spacecraft to go beyond the solar systemwas Pioneer 10 in 1986. It was followed by Pioneer11.

Escape velocity is the minimum velocity which a pro-jectile must have in order to escape from a particulargravitational field. The escape velocity from Earth'ssurface is 11,200 m/s (7 miles / sec).

UFO - Unidentified Flying Objects. Their popularname is flying saucers (]-d¡pwXfn-I-IÄ).

sNmÆm-{K-l-̄ n ]T-\-§Ä \S-̄ m³, 2004 Cd-

¡nb tdmt_m-«nIv hml-\-§-fmWv kv]ncn-ä v ,

Hm¸ÀNyqWnän F¶n-h.

_p[³ {Kl-s -̄¡p- -dn v̈ ]T-\-§Ä \S-¯m-\mbn 2004þ

BK-kvXn hnt£-]n¨ ZuXy-amWv sak-©À.

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2006 P\p-hcn 19\v hnt£-]n-¡-s¸« \yqslm-ssd³kv

¹qt«m-sb-¡p- -dn¨v ]Tn-¡m-\p-Å-Xm-Wv.

NASA-The National Aeronautics and Space Admin-istration was set up in 1958 by the U.S. Government.

Cosmic rays are atomic particles from space whichtravel close to the speed of light.

Skylab : America’s first earth orbiting space sta-tion.

Salyut 7 : The Russian counterpart for skylab wassalyut 7.

Indian Space Programme was launched in 1962. In-dian Space Research Organisation (ISRO) was setup in 1969.

The International Space Station, Mir, was launchedby the former USSR on February 20, 1986.

Gähpw IqSp-XÂ Imew _lncm-Im-i¯v Nne-hn«

_ln-cm-Imi k©mcn 427 Znhkw andn Ignª

djy¡mc-\mb hsecn t]mfn-tbm-t¡mhv (ValeriyPolyakov) BWv.

andn-te¡v bm{X \S-̄ nb BZys¯ Ata-cn-¡³

space shuttle, Discovery bmWv (Pq¬ 29, 1995).

andn\v kw`-hn¨ tISp-]m-Sp-Ifpw AXns\ kwc-£n-

¡m-\pÅ ̀ mcn¨ sNehpw ]cn-K-Wn¨v 15 hÀjs¯

tkh-\-̄ n\v tijw amÀ¨v 23, 2001 djy AXns\

`qan-bpsS A´-co-£-¯n-te¡v Xmgv¯n \in-̧ n-̈ p.

Voyager 1 and Voyager 2 which were launched byUSA in 1977 followed the suit of Pioneer I and II andslipped into the boundaries of solar system to probethe deep space. 2015 apX 2020 hsc Cu _ln-cm-Imi hml-\-§-fn \n¶pw messageIÄ e`y-am-Ip-sa-¶mWv imkv{X\nK-a\w.

Phobos I and II were launched to study Mars. Viking landed on the Mars in 1976. Galileo was launched by USA in October 1989 to

probe Jupiter. In 1929 Edwin Hubble discovered that the Universe

was expanding. Georges Lemaitre propowed in 1931 that the Uni-

verse began in an exploding prineval atom (Big Bang). Pathfinder, the US spacecraft, landed on Mars on

July 4, 1997. India’s first satellite : Aryabhatta.

It was launched on April 19, 1975.India’s second satellite : Bhaskara (1979)India’s first geostationary satellite : APPLE. It waslaunched on June 19, 1981.India’s first Satellite Launch Vehicle : SLV - 3

Satellite is a manmade object intended to movearound the earth for some purpose.

Communication satellites relay telex, telephone andT.V. transmission to ground stations on earth. Theyare geosynchronous ie., they revolve around theearth in 24 hours.

The Soviet, ‘Sputnik 1’, launched on October 4, 1957,was the first artificial satellite sent by man.

Explorer, launched on February 1, 1958, was the firstUS satellite.

TIROS, launched by USA in 1960, was the firstweather satellite.

Edward White is the first US space walker. The firstwomen to walk in space is Svetlana Savitskaya ofUSSR in 1984.

Vikram Immarsat is India’s first satellite mobile com-munication land - earth station at Arvi.

C´y-bpsS BZy Imem-hØm D]-{K-l-amb METSAT{iol-cn-t¡m-«-bnse kXo-iv [-hm³ kvs]bvkv skâ-dn \n¶pw 2002 þ sk]väw-_À 12\v hnt£-]n-̈ p.

Iev]\ Nuf-tbm-SpÅ BZ-c-kq-N-I-ambn saävkmäns\Kalpana-I F¶v \ma-I-cWw sNbvXp.

The exclusive astronomy related satellite of ISRO isAstrosat.

World’s first one-metre resolution satellite is Ikonos. Terrestrial : `qansb kw_-Ôn-¡p-¶-Xv.

Extra-terrestrial : Related to outer space. The famous US rocket launching station in Florida

- Cape Canaveral The number of signs in the Zodiac is 12. But recently

a new 13th sign was discovered in the Zodiac. It isnamed Ophucus. ]s£ Cu signs s\ AwKo-I-cn-

¡m³ ̀ qcn-`mKw t]cpw X¿m-dm-bn-«n-Ã.

The science of space travel is known as Aeronau-tics.

Name the Indian Satellite Launch Vehicle whichlaunched three satellites on May 26, 1999 fromSriharikota

PSLV – C2 SMART I is going to be the European Space

Agency's first probe to moon.

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Explorers Yuri Gagarin of the erstwhile USSR was the first man

in space. He flew to space on 12th April 1961 inVostok Spaceship.“I looked and looked and looked, but couldn’t findGod”. _ln-cm-Im-i-̄ n BZy-ambn t]mbn Xncn¨p

h¶ bqdn KKm-dn-t\mSv kzÀ¤-¯nse ssZhs¯

It­m F¶p tNmZn¨Xn\v At±lw \ÂInb adp-]-

Sn-bm-Wn-Xv.

The first woman to go into space was ValentinaTereshkova (Russia) in 1963.

The first American to go into space was AllenShepperd.

Sally K.Ride (1983) is the first American woman inspace.

The first American to orbit earth is John Glenn inFebruary 20, 1962. He is also the oldest person to goto space (1998).

US astronauts, Mark Lee and Judy Davis, are thefirst couple in space aboard the shuttle, Endeavour.

Rakesh Sharma is India’s first astronaut. Kalpana Chawla was the 2nd Indian and first Asian

woman to go to space. She was sent to space twicein 1997 and 2003. She died in space, in her secondmission, when the space shuttle Columbia, disinte-grated while reentering Earth.

Sunitha Williams is 3rd Indian and Second IndianWoman in Space. iq\ym-Im-i¯v Gähpw IqSp-XÂ

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Neil Armstrong is the first person to step on themoon.

Eileen Collins was the first woman commander of aspace shuttle (Columbia)

Dennis Tito of USA is the first person to go for apleasure trip to space on April 30, 2001.

The first man to walk in space was Alexi Leonav ofUSSR (1965).

The first taikonaut or China's first 'Yuhang Yuan'(astronaut or space traveller) is Lieutenant ColonelYang Liwei.

China landed its second manned space mission on

October 12, 2005. It carried two taikonauts - FeiJunlong and Nie Haisheng - into Orbit.

China placed its first orbit in April 1970. Anousheh Ansari of US the first Female Space tour-

ist. She set to blast off from Russia’s Baikanourcosmodrome in Kazaksthan - Ansari is a US nationalof Iranian Origin.

Telescope Telescope þs\ Is­-¯n-bXv s\XÀemâ vkp-Im-c-

\mb Hans Lippershey (1608) BsW-¦nepw BZy-ambnsSe-kvtIm¸v D]-tbm-Kn v̈ {]]-©-\n-co-£Ww \S-̄ n-bXv (1609) Keo-entbm BWv.

Hubble telescope, launched in 1990 by NASA, is thefirst space telescope.

First reflecting telescope was designed by Issac New-

Abbreviations related to SpaceASLV ........ Augmented Satellite Launch Vehicle.GSLV Geosynchronous Satellite Launch Vehicle.APPLE ... Ariane Passenger Payload Experiment.INSAT ......................... Indian National Satellite.NASA ...............................................................National Aeronautics and Space Administration.ESA ............................ European Space AgencyUFO ...................... Unidentified Flying Objects.SETI .......Search for Extra-Terrestrial Intelligence

Sunitha Williams

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ton in 1668. The first large X-ray telescope was ‘Einstein obser-

vatory’ launched in 1978 (USA). Chandra X-ray observatory was launched by NASA

in 1991. The observatory was named afterS. Chandrasekhar, the Indian Physicist, who won theNobel Prize in 1983.

Chandrasekhar Limit : A limiting mass, below which astar can become a white dwarf.

The world’s largest low frequency Giant MeterwaveRadio Telescope (GMRT) has been set up atNarayanagao, near Pune.

Karl Jansky discovered Radio Telescope.

Units for space calculation Light year is the common unit of distance in space. It

is the distance light travels in one year at a speed of3,00,000 km/sec.

Vast distances in space (stellar distances) are ex-pressed in astronomical units, light years or parsecs.

An astronomical unit (A.U) is half the diameter ofthe earth’s orbit around the sun. Or, in other words,an astronomical unit is the mean distance of the earthfrom the sun.1 A.U = 1.49598 x 108 km or 1.58129 x 10----5 Lightyear.

A parsec is the distance to an object (such as a star)that subtends an angle of 1 second of arc at a baseline1 astronomic unit long.

One parsec is equal to 3.26 light years. A light year has 63,290 A.U.

Recently Asked Questions What are Sun Spots?

They are dark regions in sun’s photosphere and arevisible on Earth as irregular dark patches scatteredon either sides of sun’s equator.

What is the name of India’s first indigeneously builtsecond generation satellite ?

INSAT - 2A The Largest inner plannet: Earth What happens if Earth were to stop its rotation on its

axis ?Neither day nor night occurs.

Visible surface of the sun is ––––––

Photosphere ————— have bright head and long tail.

Comets The comets orbit around —— .

the sun ———— is a cloud of galactic dust .

Nebula ———— is an exploding star.

Supernova ————— is a fast rotating star that emits radio

signals.Pulsar

The first space vehicle to softland on moonLuna 9

The dwarf planet that crosses the orbit of anotherplanet

Pluto The first space rocket to hit the moon

Lunik 11 New stars are born from

galactic dust Halley’s comet returns after

76 years. It last appeared in 1986. The constellation also known as Hunter is

Orion Aryabhata satellite made India, the ––––– nation to

orbit a satellite round the Earth.11th

Bits of meteors falling on the ground are calledMeteorites

The heavenly bodies known as followers of planetsare

Satellites The planet known as ‘Earth’s Twin’ is

Venus The planet in the solar system which has the largest

number of satellites.Saturn

The first Indian communication satellite.APPLE

First living being to go to space.Laika, a dog

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Name the space shuttle which exploded seconds af-ter its launch and killed 7 astronauts

Challenger What are blackholes?

They are stars whose gravitational pull is so power-ful that even light cannot escape from it.

Who is known as the Law Maker of Heaven?Johannes Kepler

Which plannet is known as Sun’s pet?Venus

What is a sidereal month?Time taken for one lunar orbit (27 days, 7hrs, 43 min-utes)

The first man-made object to orbit another planet.Mariner 9

The comet that came close to earth in March 1997.Hale Bopp

Objective Questions-Rare Facts What will be the weight of a man on a black hole who

weighs 70 kg on earth?Infinite

The space station where Rakesh Sharma stayed forseven days and returned to earth on April 11, 1984

Salyut 7 Who set the record of the longest stay in human

flight in space?Russian Cosmonaut, Valeriy Polyakov, spent 427days in Mir

Of all the known periodic comets which has the short-est period?

Eucke Comet The star like objects at the edge of universe are known

asQuasars

Which star determines the latitude of a southern hemi-sphere?

Hadley’s Actant Name the comet which is going to appear in 2062?

Halley’s comet The first spacecraft to land on Jupiter.

Venus -3 of USSR The first space probe to touch a planet

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§p-¶Xv 1966Â hnt£-]n¨ Luna 9 BWv.

Which planet has the Great Red Spot?Jupiter

The Great Red Spot is an oval shaped storm cloudwhich has the size of earth.

Where is Carl Sagan memorial station?Mars. It is the name given to the Pathfinder which

landed on Mars on July 4, 1997. Which is the largest volcano in the solar system.?

Olympus Mons in Mars What is blue moon ?

When two full moons occur in any calendar year thesecond moon is called a

blue moon. hfsc _p²n-bpÅ a\p-jy-hÀ¤w Pohn-¨n-cp¶p F¶v

hniz-kn-¡p-¶Xv FXv {Kl-¯n-emWv?

sNmÆ (Mars) Who discovered the asteroid Ceres?

Piazzi Planet known as rusty planet.

Mars Which is the most mysterious planet?

Venus Which satellite of Saturn is nicknamed the ‘Death

Star’?Mimas

Which is the most hostile planet?Mercury

Which celestial object is sometimes referredto as ghost?

Comets Which planet has the highest escape velocity?

Jupiter. Its escape velocity is 37 miles/ second.

The Moon’s escape velocity is only 1½ miles/sec.Escape velocityIpd-hm-b-Xn-\m space station \nÀan-

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The first disabled satellite repaired in space.Solar max, April 1984

5 8 4

The first returnable space shuttle.Columbia

The satellite known as the “artificial baby moon”Sputnik

The first mission of a link up in space by mannedspace ships of the USA and the Soviet Union.

Apollo – Soyuz Test projectMission on July 15, 1975

The first unmanned moon buggy to explore surfaceof moon.

Lunokhod -1 (USSR) The moon walking mission of the USA which failed

to reach moon. Apollo 13 The highest mountain range on moon?

Mount Huyghens The colour of young stars is blue What does the word Albedo mean in astronomy?

Whiteness Which planet is considered as the father of Jupiter?

Saturn Which planet is called as an ‘old and harsh world’?

Mars Which planet is known as rolling planet?

Uranus What are called the lighthouse in sky?

Neutron stars At what rate does earth increase its weight each day?

By 25 tonnes Where is the Sea of Shower?

Moon Father of modern astronomy.

Nicholas Copernicus What is Ursa Minor?

A group of stars of Northern hemisphere. Ursa Mi-nor means the Little Bear.

The living beings in outer space are calledAliens

Planet on which prehistoric water channel exist isMars

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Ares Vallis is the plane where pathfinder landed onMars in 1997

The heavenly bodies which are also known as

wanderers. Planets The observable limit of the Universe is

20 billion light years The Hubble constant is the measure of

the rate of expansion of Universe The stars of extremely high densities are called

Neutron stars Relative to the stars the sun moves towards the

east A mass of less than 1.4 solar mass is known as

Chandresekhar Limit “The farther the galaxy is from us, the greater is its

speed of recession”. This law is known asHubble’s Law

What is the source of electric energy in an artificialsatellite?(a) A thermopile (b) Solar cells(c) A dynamo (d) A mini nuclear reaction

Ans: (b) Solar cells On re-entry of the space shuttle into Earth’s atmosphere, a

situation of radio black out arises, which meansa situation of no communication

Oort Cloud Theory is connected withComets

Time taken by the sun to move through one degreelongitude is 8 minutes

The maximum time that astronomers can spend onmoon is 24 hours

Most of the known galaxies are:(a) elliptical (b) irregular(c) spiral (d) None of these

Ans: (c) spiral Who propounded the signs of the Zodiac?

Babylonians International Geophysical year

July 1957 to December 1958 Which of the following is the most famous of all

comets?(a) Hale Bopp (b) Halley’s Comet(c) Shoemaker Levy - 9 (d) Swift Tuttle

Ans: (b) Halley’s Comet The planet known as “will-o’-the wisp”. Neptune Which planet has the most circular orbit? Venus Father of Mathematical Astrophysics.

S. Chandrasekhar The founder of Scientific Astronomy.

Hoffman

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1. What is the colour of the hottest star?(a) Red (b) White(c) Violet (d) Blue

2. Who was the founder of Scientific Astronomy?(a) Hippalus (b) Hippocrates(c) Hoffmann (d) None of these

3. Who discovered the planet Uranus?(a) Ptolemy (b) William Herschel(c) Copernicus (d) Newton

4. Which planet is known as the Will-o-the Wisp inthe sky?(a) Mercury (b) Pluto(c) Neptune (d) Mars

5. Which is the coldest Planet?(a) Neptune (b) Mercury(c) Jupiter (d) Neptune

6. Which is the hottest Planet?(a) Pluto (b) Mercury(c) Venus (d) Neptune

7. Which planet has the most circular orbit?(a) Venus (b) Mercury(c) Mars (d) Neptune

8. Which planet is known as the Red planet?(a) Mars (b) Venus(c) Jupiter (d) None of these

9. Who first observed the Saturn through a tele-scope?(a) Galileo (b) Newton(c) Charles T. Kowed (d) None of these

10. Which is the predominent gas present in the at-mosphere of Uranus?(a) Hydrogen (b) Ozone(c) Methane (d) Ethane

11. Who discovered Neptune?(a) Clyde Tombaugh(b) Ubrain V.J. Levierrier, John C. Adams andJohanne Galle(c) Carolyn Shoemaker(d) Christiaan Huygens

12. What is the shape of the Earth?(a) Oval (b) Oblate(c) Circular (d) Conical

13. Which of the following is the most famous of allcomets?(a) Hale-Bopp (b) Halley’s Comet(c) Shoemaker-Levy 9 (d) Smith-Tuttle

ASTRONOMY : OBJECTIVE - SET 114. Who discovered the Radio telescope?

(a) Galileo (b) Newton(c) Einstein (d) Karl Jansky

15. Which one of the following conditions is mostrelevant for the presence of life on Mars?(a) Occurrence of ice caps and frozen water(b) Occurrence of ozone(c) Thermal conditions(d) Atmospheric composition

16. Which was the International Geophysical Year?(a) July 1957 to December 1958(b) September 1951 to November 1952(c) No such period at all(d) None of these

17. The time taken by Pluto to revolve round the Sunis...(a) 4 years (b) 200 years(c) 248 years (d) 350 years

18. What is one light second?(a) 1,86,000 km. (b) 2,99,300 km.(c) 1,86,282 km. (d) None of these

19. Who propounded the signs of the Zodiac?(a) Indians (b) Egyptians(c) Babylonians (d) None of these

20. Who is the Father of Space Science?(a) Andrin Nikaleyev(b) Konstantin Tsiolkovsky(c) Valentina Tereshkova(d) None of these

21. Who was the oldest man to go to space(a) Andrin Nikaleyev (b) John Glen(c) Allen Bien (d) Jack Lusmen

22. Who was the first American to enter space?(a) Alan Bartlett Sheperd(b) Owen Garriat(c) No American entered space so far(d) None of these

23. From where was Aryabhatta launched?(a) Russia (b) India(c) China (d) None of these

24. Halley’s Comet revolves round the Sun once in(a) 10 years (b) 60 years(c) 76 years (d) 100 years

25. ‘Sea of Tranquility’ and ‘Ocean of Storms’ are in(a) Jupiter (b) Moon(c) Mars (d) None of these

Answers: 1. (d) 2. (c) 3. (b) 4. (c) 5. (a) 6. (c) 7. (a) 8. (a) 9. (a) 10. (a)11. (b) 12. (b) 13. (b) 14. (d) 15 (a) 16. (a) 17. (c) 18. (c) 19. (c) 20. (b)21. (b) 22. (a) 23. (a) 24. (c) 25. (b)

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26. Supernovae is(a) a black hole (b) a comet(c) a dying star (d) an asteroid

27. When will be the Earth very near to Sun?(a) 1st March (b) 3rd January(c) 2nd January (d) 6th December

28. When will be the Earth very far away from theSun?(a) 12th December (b) 6th August(c) 7th March (d) 10th November

29. Why does the Moon always keep roughly thesame face turned towards us?(a) Because it has no atmosphere of its own(b) Because it rotates on its axis in about thesame time as it takes to go round the Earth(c) Because it does not rotate on its axis(d) Because its surface is covered with enor-mous plains which look identical

30. Which of the following motions of the Earth isthe slowest?(a) Its rotation on its axis(b) Its revolution around the Sun(c) Precession (or motion) on its axis(d) None of these

31. Counting outwards from the sun, ..... is the eighthplanet of the Solar System(a) Neptune (b) Pluto(c) Saturn (d) Uranus

32. Which of the following planets turns on its axisin 24 hours and 37 minutes?(a) Earth (b) Jupiter(c) Mars (d) Saturn

33. In which part of the Solar System is the Sun lo-cated?(a) At the top of the system(b) At the bottom of the system(c) At the left hand corner of the system(d) Approximately at the centre of the system

34. The Sun is(a) made of rock and metal(b) a solid body(c) a mass of hot gases(d) party rock and metal and partly a mass of hotgases

35. How much of the surface of the Moon is visiblefrom the Earth?(a) More than 75% (b) Only about 40%(c) About 59% (d) None of these

36. The Earth rotates on its axis from(a) west to east (b) east to west(c) south to north (d) north to south

37. The planet with the shortest day is(a) Pluto (b) Saturn(c) Venus (d) Mercury

38. Which of the following gases is most predomi-nant in the Sun?(a) Hydrogen (b) Nitrogen(c) Ozone (d) Helium

39. The biggest star in our galaxy is(a) Epsilon Aurigae(b) Proxima Centauri(c) Sirius(d) Sun

40. The nearest star to Earth (except the Sun) in ourgalaxy is(a) Epsilon Indi (b) Proxima Centauri(c) Sirius A (d) GQ Andromedae

41. Who was the first to observe Sun spots?(a) Galileo (b) Halley(c) Newton (d) None of these

42. What are Sunspots?(a) These are great flames of gases which shootout of the Sun(b) These are areas of the Sun where nuclearfission takes place(c) These are areas of the Sun where the heat ismost intense which shows up as dark spots(d) These are cooler areas which move about theSun’s surface and show up as dark spots

43. Which of the following planets takes very nearlythe same time for a rotation on its own axis asdoes the Earth?(a) Jupiter (b) Mars(c) Neptune (d) Uranus

44. The visible part of the Sun is called(a) Ionosphere (b) Hydrosphere(c) Photosphere (d) Troposphere

45. The Sun shines vertically on the Equator(a) Throughout the year (b) Four times a year(c) Twice a year (d) Once a year

46. The distance between the Earth and the Sun isgreatest during(a) Aphelion (b) Perihelion(c) Winter Solstice (d) Summer Solstice

47. The time taken by the Uranus to revolve roundthe Sun is approximately(a) 76 years (b) 80 years(c) 84 years (d) 90 years

48. How much time is required for the sunlight toreach the Earth?(a) 8 min. (b) 8 min. 15 seconds(c) 1 hour (d) 24 hours

Answers: 26. (c) 27. (a) 28. (a) 29. (b) 30. (c) 31. (a) 32. (c) 33. (d) 34. (c) 35. (c)36. (a) 37. (d) 38. (a) 39. (c) 40. (b) 41. (a) 42. (d) 43. (b) 44. (c) 45. (c)46. (a) 47. (c) 48. (a)

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Answers: 49. (d) 50. (a) 51. (b) 52. (a) 53. (b) 54. (b) 55. (c) 56. (b) 57. (a) 58. (b)59. (a) 60. (b) 61. (b) 62. (c) 63. (c) 64. (a) 65. (b) 66. (d) 67. (a) 68. (b)69. (a) 70. (b) 71. (d) 72. (c)

49. Which planet was first found in space?(a) Sun (b) Pluto(c) Neptune (d) Jupiter

50. Which of the following is responsible for life onthe Earth?(a) Sun (b) Moon(c) Jupiter (d) None of these

51. When does Solar Eclipse take place?(a) When the Moon is between the Jupiter andthe Earth(b) When the Moon comes between the Sun andthe Earth(c) When the temperature of the Sun reaches toa superlative degree(d) None of these

52. Who discovered the earth’s revolution?(a) Copernicus (b) Einstein(c) Galileo (d) Bhaskara

53. Space Application Centre is in(a) Bangalore (b) Ahmedabad(c) Thumba (d) Thiruvananthapuram

54. The rotation of the Earth causes(a) Tides (b) Days and Nights(c) Solar eclipse (d) Lunar eclipse

55. The theory of Expanding universe was first pro-pounded by(a) Einstein (b) Galileo(c) Newton (d) Hubble

56. Which one of the following planets has noMoon?(a) Earth (b) Mercury(c) Neptune (d) Venus

57. During Equinoxes, all places have equal(a) Days and nights (b) Temperature(c) Sunshine (d) Atmospheric Pressure

58. The Sun releases its energy due to(a) Nuclear fission (b) Nuclear fusion(c) Conduction (d) None of these

59. The time taken by the Earth to rotate once aboutits axis is called(a) Sidereal day (b) Solar day(c) Mean solar day (d) Mean sidereal day

60. In the southern hemisphere, the hottest period is(a) 1st week of January (b) 1st week of February(c) 1st week of July (d) 1st week of August

61. A century year is a leap year(a) if it is divisible by 4(b) if it is divisible by 400(c) if it is divisible by 10 (d) always

62. Scientists believe that the Universe is created by(a) accident (b) a holy plan by god(c) a big bang (d) nobody knows how

63. Name the two planets lying between the Sun andthe Earth.(a) Mercury and Mars (b) Venus and Mars(c) Mercury and Venus (d) Jupiter and Saturn

64. Name the planet which appear as ‘morning star’in the eastern sky and ‘evening star’ in the west-ern sky.(a) Venus (b) Jupiter (c) Saturn (d) Mercury

65. Which dwarf planet was for the first time ob-served in 1930?(a) Uranus (b) Pluto(c) Neptune (d) Jupiter

66. All the planets, except one, in the Solar Systemrotate on their axis from west to east. Which isthe exception?(a) Earth (b) Mars (c) Saturn (d) Venus

67. “Galileo Satellites”, named after their discoverer,are four large moons of the planet(a) Jupiter (b) Neptune(c) Saturn (d) Uranus

68. Who wrote the book “The Harmonies of theWorld”?(a) Issac Newton (b) Johannes Kepler(c) Einstein (d) Giordano Bruno

69. A Comet(a) has a tail always pointing away from the Sun(b) has a tail always pointing towards the sun(c) has a tail sometimes pointing towards theSun and sometimes away from it(d) has no tail at all

70. Which of the following makes the planet Saturnunique in the Solar family?(a) It is the biggest among the planets(b) There is a well-developed system of ringsaround it(c) It sends out very strong radio signals whichsound like the noise of sea waves(d) It shows phases like those of the Earth’s Moon

71. The speed per minute at which Earth revolvesaround the sun is(a) 800 km (b) 900 km(c) 1,500 km (d) more than 1,600 km

72. If earth had no satellite of its own (i.e.themoon), which of the following phenomena wouldnot occur ?(a) Climate (b) Ocean currents(c) Spring tide (d) All will not occur

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Answers: 73. (a) 74. (d) 75. (a) 76. (d) 77. (a) 78. (d) 79. (d) 80. (d)81. (c) 82. (a) 83. (b) 84. (a) 85. (c) 86. (a) 87. (c) 88. (d) 89. (d) 90. (d)91. (d) 92. (c) 93. (c) 94. (c) 95. (c) 96. (c)

73. Which one of the following categories of starshas relatively small volume but very high den-sity ?(a) Dwarf stars (b) Lightweight stars(c) Middleweight stars(d) Heavyweight stars

74. Which planet is nearest to earth ?(a) Jupiter (b) Mecury (c) Mars (d) Venus

75. The first ever robot spacecraft to probe theplanet Venus was named(a) Magellan (b) Galileo(c) Newton (d) Challenger

76. The planet which is the farthest from the sun is(a) Uranus (b) Saturn (c) Pluto (d) Neptune

77. Comets are(a) Celestial bodies (b) Hand grenades(c) Pistols (d) None of these

78. How many satellites did Jupiter have?(a) 10 (b) 12 (c) 15 (d) 63

79. Where is the Sea of Tranquility ?(a) Mars (b) Venus (c) Pluto (d) Moon

80. Which one of the following planets can be seenwith the naked eye of a normal human being ?(a) Pluto (b) Neptune(c) Uranus (d) Mars

81. The sun’s heat and light energy reaches Earth bywhich of the following modes of transmission ?(a) Conduction (b) Convection(c) Radiation (d) Reflection

82. How many days does the moon take to returnto the same position among the constellations ?(a) 28 days (b) 29 days(c) 26 days (d) None of these

83. Which of the following planets takes the least timeto complete one revolution around the sun ?(a) Earth (b) Mercury (c) Mars (d) Venus

84. Which of the following planets takes the longesttime to complete one revolution around the sun ?(a) Neptune (b) Saturn(c) Uranus (d) Venus

85. Titan is the largest satellite of(a) Jupiter (b) Mars (c) Saturn (d) Uranus

86. When and by whom were the rings of Saturndiscovered ?(a) Galileo; 1610 (b) Edmund Halley ; 1682(c) Newton ; 1682 (d) Tycho Brache; 1590

87. What would happen if Earth were to stop itsrotatory motion on its axis ?(a) There would be no season on Earth

(b) The half sphere on the right side of its northpole would have daylight all the time(c) There would be no day and night as at present(d) Earth would become a ver hot planet likeMecury

88. ‘Atlantis’ is the name of the space shuttlelaunched by(a) Australia (b) Britain(c) India (d) USA

89. Skylab was a space laboratory launched by(a) Russia (b) Australia(c) India (d) USA

90. The day on which the sun is nearest to Earth,Earth is said to be in(a) apogee (b) perigee(c) aphelion (d) perhelion

91. The same face of the moon is always visible tous because(a) it rotates at the same speed as Earth aroundthe Sun(b) it revolves on its axis in a direction oppo-site to that of the Earth(c) it is smaller than the Earth(d) it takes equal time for both revolutionaround the Earth and rotation on its own axis.

92. The top atmosphere of the Earth directly re-flects back into space nearly what part of thetotal amount of the sun’s energy coming to it?(a) One-tenth (b) One-fifth(c) One-third (d) One-half

93. During a solar eclipse, which of the followingrepresents the relative position of the sun, moonand Earth correctly ?(a) The sun in between the Earth and the moon(b) Earth in between the sun and the moon(c) The moon in between the sun and the Earth(d) The sun, moon and Earth are not in a straightline

94. Which of the following was the first Indiangeostationary satellite ?(a) Aryabhatta (b) Rohini(c) Apple (d) INSAT-IB

95. India become the ––––– nation in the world tohave sent a man into space(a) 7th (b) 12th (c) 14th (d) 20th

96. The element found on the surface of the moon is(a) tantalum (b) tungsten(c) titanium (d) tin