1 GENERAL KNOWLEDGE LATEST STUDY MATERIALS WITH KEY POINTS THE UNIVERSE SOLAR SYSTEM - STATISTICS (4) MARS The solar system consists of the Sun and 9 planets Diameter : 6,755.2 Kms. revolving around it in different orbits. The statistics of Distance from the Sun : 225.6 Million Kms. the sun and the planets are given below : Period of revolution : 687 days SUN Period of rotation : 24 hrs 37 mts. 22.663 sec. Age : About 5 Billion years Distance : 149.8 Million Kms (5) JUPITER : This is the largest planet in the solar system. Diameter : 1,38,400 Kms. Diameter : 141,968 Kms. Photosphere temperature : 5,770 K Distance from the Sun : 772.8 Million Kms. Core temperature : 150,000,000 K Period of revolution : 11.9 years Absolute visual magnitude : 4.75 Period of rotation : 9 hrs 50 mts. 30 sec. Rotation (as seen from the earth at the equator) : 25.38 days (6) SATURN : It was discovered by Rotation (near the poles) : 33 days Galileo. The sun consists of 71% of Hydrogen, 26.5% Helium and Diameter : 119,296 Kms. 2.5% of other elements. Distance from the Sun : 1,417.6 Million Kms. The rays of the Sun take about 8 minutes to reach the Period of revolution : 29.5 years earth. Period of rotation : 10 hrs 14 mts. PLANETS (7) URANUS (1) MERCURY : It is the planet nearest to Diameter : 52,096 Kms. the earth. Distance from the Sun : 2,852.8 Million Kms. Average distance Period of revolution : 84 years to the Sun : 57.6 Million Kms. Period of rotation : 16 hrs 10 mts. Diameter : 4,849.6 Kms. Period of revolution : 88 days (8) NEPTUNE Period of rotation : 58 days 15 hrs 30 mts. 34 Diameter : 49,000 Kms. sec. Distance from the Sun : 4,497 Million Kms. (2) VENUS : It is also known as the Period of revolution : 165 years Morning Star or the Period of rotation : 18 hrs 26 mts. Evening Star. It is the (9) PLUTO : This is the coldest and brightest of all the smallest of all planets. It planets. is also the most distant Diameter : 12,032 Kms. one. Period of revolution : 225 days Diameter : 3,040 Kms. Period of rotation : 243 days 14mts. Distance from the Sun : 5,865.6 Million Kms. (3) EARTH Period of revolution : 248 years Equatorial diameter : 12,756 Kms. Period of rotation : 6 days 9 hrs and 18 mts. Polar diameter : 12,714 Kms. MOON : Moon is earth's satellite. Distance from the Sun : 149,597,900 Kms. Its period of rotation and Period of revolution : 365 days 5 hrs, 48 mts, Period of Revolution are 45.51 sec. 1 the same. i.e.29 days. Period of rotation : 23 hrs 56 mts. 4.09 sec. 2 © THE RAMAN’S BOOKS 2 THE EARTH DATA Surface Area : 510,100,500 Sq.Kms. Polar radius : 6,357 Kms. Land Surface : 148,950,800 Sq.Kms. Polar Diameter : 12,714 Kms. (29.08%) Mean distance from the Water Surface : 361,149,700 Sq.Kms. Sun : 14,95,97,900 Kms. (70.92%) Period of revolution : 365 days 5 hours 48 mts. Equatorial circumference : 40,075 Kms. 45.51 Sec. Polar circumference : 40,008 Kms Period of rotation : 23 hrs. 56 mts. 4.091 Sec. Equatorial radius : 6,377 Kms. Escape Velocity from Equatorial Diameter : 1,22,756 Kms. the earth : 11 Km per Sec. (minimum) THE WORLD The Earth and the Solar System : The seasons are due to the change of the Earth’s The Earth is a member of the Solar System. It is one position in the course of its revolution about the Sun, of nine major planets revolving round the Sun. Of these, and to the inclination of its axis. The Equator is an Mercury and Venus are nearer, and Mars, Jupiter, Saturn, imaginary line drawn round the Earth midway between the Poles. There are two other lines, namely, Tropic of Uranus, Neptune and Pluto are farther away from the O O Sun than the Earth. Cancer (23½ N) and the Tropic of Capricon (23½ S). The word tropic means, ‘turning place’. The inclination The planets radiate no light of their own, but shine of the Earth’s axis together with its revolution round the with that reflected from the Sun. The Sun has a diameter Sun is the cause of the varying length of day and night in of 864,000 miles (1,390,000 Kms) and it is 93,000,000 miles different parts of the world. On March 21 (Vernal Equinox) (150,000,000 Kms) from the Earth. The Sun is a star. The and September 23 (Autumnal Equinox) the Sun is over- stars, unlike the planets, are self-luminous bodies. The head at the Equator. On these dates, except at the Poles, other stars appear small because they are so far away; (a) days and nights are equal all over the world; and (b) the nearest star, Proxima Centauri, is 200,000 times more the Sun rises exactly due east and set exactly due west at distant from us than the Sun. all places on the Earth’s surface. At the Equator itself The Moon is a dead planet. It is about 240,000 miles days and nights are equal throughout the year. Between (386,000 Kms) from the Earth. The Moon revolves round March 21 and September 23, when the North Pole is tilted the Earth taking approximately 29 days to complete one towards the Sun, the days are longer than the nights round. The phases of the Moon are the result of its throughout the Northern Hemisphere and there is position in relation to the Earth and the Sun. continuous daylight at the North Pole. Similar conditions are experienced in the Southern Hemisphere and the The Moon’s orbit is ecliptical and inclined at an South Pole between September 25 and March 21. angle of 5o to the plane of the Earth’s orbit. This explains why we do not have a total eclipse of the Sun every time Latitude and Longitude: there is a new moon. Latitude is distance, measured in degrees, north or south of the Equator. Longitude is distance, measured in The Earth: degrees, east or west of any fixed meridian. The meridian The Earth is a sphere but it is not a perfect sphere. passing through Greenwich is numbered 0O. On a globe It is slightly flattened at the poles and bulges at the the meridians are numbered from 0O to 180O E (East) or W equator. The circumference of the earth is approximately (West). At the equator the degrees are 69 to 70 miles 25,000 miles (40,000 Kms). apart (25000÷360). Since earth completes one rotation on its axis in 24 hours, 360 meridians pass under the Sun in It rotates on its axis once in every 24 hours, spinning that time. Therefore, 1 degree passes under the Sun every from west to east. Besides spinning on its axis, it also 4 minutes. moves round the Sun, called the revolution. Its orbit round the Sun is oval or ecliptical. The International Date Line: time taken to complete one revolution is approximately If we travelled westward to a place X on longitude 365¼ days or one year. For convenience, one year is 180o W, the time there would be 12 hours behind taken as 365 days and the shortfall of ¼ day each Greenwich time (180 x 4 minutes = 720 minutes = 12 hours). year is made good in the Leap Year which consists of If we journeyed eastward to a place Y on longitude 180o 366 days. The Earth’s axis inclined to the plane of its E, the time there would be 12 hours ahead of Greenwich orbit at an angle of 66½O. time. Thus X and Y both on 180o have the same time but © THE RAMAN’S BOOKS 3 differ in date by a day (12 hours + 12 hours = 24 hours). by prolonged denudation are known as Residual To overcome the confusion that would otherwise arise, Mountains, e.g. Highlands of Scotland and Scandinavia. the International Date Line has been established. It runs along 180o E or W. Westward-bound vessels crossing Denudation: the Date Line drop a day from the calendar, while those The process known as denudation or the wearing going eastward add a day by giving the same date to two away of the land is continually going on. The chief causes consecutive days. Instead of changing the time exactly of such erosion are (a) changes in temperature; (b) frost; according to change in degrees at the rate of 4 minutes (c) winds; (d) water, including rivers; (e) ice; and (f) the per degree, certain time zones have been established. All action of the sea. Steps to combat soil erosion include (i) places in the same area or time zone or time belt, use terracing; (ii) contour ploughing; (iii) strip cropping (iv) what is called Standard Time. Thus we have the planting shelter belts of trees; and (v) plugging the gullies Greenwich Mean Time (G.M.T) and the Indian Standard by building small dams etc. Time (I.S.T). There are five time-belts in Canada and four in United States. The Atmosphere: The air is composed mainly of nitrogen (78%) and The Lithosphere: oxygen (21%) with small proportions of carbon dioxide, The mass of the Earth is generally divided into three water vapour and rarer gases like argon and neon. layers, namely, Crust, Mantle and Core. The Lithosphere Atmosphere is 200 miles thick, but nine-tenths of the air is the name given to the outer Crust which is not more composing it is found within 12 miles, and half within 3½ than 10 miles thick.