Rajasthan Board RBSE Class 9 Science Notes Chapter 12 Celestial Bodies and Indian Calendar
- Celestial bodies is as expansive as the entire universe, both known and unknown. A celestial body is any natural body outside of the Earth’s atmosphere, examples are moon, planets, Sun, Stars, Meteors, comets etc. They are also known as heavenly bodies.
- At night, we seen thousands of stars in the sky. If we watch the sky through a telescope, we may see millions of stars, many of them are visible. Some stars appear twinkling and some do not twinkle, but appears to shine more brightly.
- Our Sun is also a kind of medium star. It appears bigger to us, because it is too close to earth as compared to other
- Indian Panchang is an astronomical book in which we study the nomenclature and motion of astronomical bodies.
- Panchang is one of the most popular reference manual for astrologers and people of the hindu community, who rely on a day’s planetary position to determine the auspicious timing, for festivals, vrats etc.
- It refers to the five attributes of the day.
- Tithi – lunar day
- Vara- week day
- Nakshatra – Constellation
- Yoga (luni Solar day)
- Karana (half of a lunar day)
- The most appropriate time, which ensures proper balance of five attributes is known as Muhurat.Panchang shows the padas, Moon rise and Moon set, Sunrise and Sunset timings for the different locations. It shows Griha position in both Sayana and Nirayana system. It also shows the date of Hindu festivals
Nakshatras are considered to be the lunar mansions seen higher up in the sky, which creates a huge impression on the people and impact their lives as well as behaviour. Vedic astrology divides nakshatra into 27 parts and each part has its unique name.
|Name||No. of stars in group|
|Punarvasu||05 or 06|
|Mula||09 or 11|
|Pushya||01 or 03|
|Vishakha||05 or 06|
Solar System and its Planet:
- The Sun along with the eight planets, their moons, other heavenly bodies like asteroids, comets and meteors constitute the solar system.
- The Sun is the biggest star of our solar system. The diameter of Sun is 109 times the diameter of earth. Sun is approximately 300000 times heavier than the earth. Sun is a huge bright ball comprising hydrogen and helium gases. It is the primary source of energy. Formation of day and night, change of seasons and formation of rain all these are because of Sun. The life of all living beings depends upon the solar energy.
- A solid heavenly body which revolves around the Sun in a closed circular orbit is called a planet. There are eight planets in all, including the earth. All planets rotate from the west to the east except Venus which rotates from east to west except Venus which rotates from east to west. Due to their different speeds, the position of the planets with respect to the earth changes every day. In Indian astronomy, the planets are called Graha.
Table of all planets their distance from the Sun and speed:
|Planet||Distance from the sun||Diameter in kilometres||Time taken to rotate about its axis||Time taken to revolve around the Sun||Number of moons|
|Mercury||57.9 million km||4879 km||59 days||88 days||Nil|
|Venus||108.2 million km||12104 km||243 days||225 days||Nil|
|Earth||149.6 million km||12800 km||24 hours||1 year||1|
|Mars||228 million km||6794 km||24 hours-37 minutes||2 years approximately||2|
|Jupiter||778.6 million km||142984 km||9 hours – 54 minutes||12 years (app.)||61|
|Saturn||1433.5 million km||120500 km||10 hours- 14 minutes||*||31|
|Uranus||2872.5 million km||51118 km||17 hours- 49 minutes||84 years||26|
|Neptune||4495.1 million km||49528 km||16 hours- 40 minutes||165 years (app.)||13|
|Pluto||5870 million km||3000 km||6.9 days||248 years (app.)||1|
- In 2006, International Astronomical Union (IAU), empanelled committee met to define what is the status of Pluto and the objects beyond it. This committee met at Paris observatory in June 2006 and reached unanimous agreement. The decision of the committee was discussed in Prague at IAU General Assembly of Astronomers of the world.
Following were the decisions of the General Assembly of IAU on the 23rd August 2006:
- A planet is a body orbiting in near circular orbit around a star, which is big enough for the force of gravity, to make it round and should not take more than 2 centuries to revolve around the Sun.
- Pluto takes 248 years to revolve around the Sun, so it is disqualified as a planet.
- Now the Pluto and objects beyond it are called Plutons, new members of solar family.
- The order of plutons is:
(iii) 2003 UB313.
- The bright star-like objects which appear suddenly in the sky for a few moments, and glow with a brilliant white flash of light falling towards the earth and finally disappear are called meteors. It is believed that meteors are the debris of comets floating in the sky. When a chunk of this debris enters the gravitational field of the earth, it starts falling towards the earth. When it passes through the atmosphere, it becomes white hot, on account of friction of the atmosphere. Thus, it catches fire and appears like a brilliant flash of light. Meteors are commonly known as shooting stars, though they are not stars.
- If a meteor is too big and fails to burn completely in the atmosphere, then a part of it reaches the surface of the Earth. The unburnt piece of a meteor, which reaches the surface of the earth, is called meteorite.
Special Information about Planets:
- Mercury [Budha]: It is the first planet of the solar system and is closest to the Sun. Because of its closeness to the sun, it is one of the hottest planets in the solar system. The surface features of Mercury are similar to that of the moon. It neither has water nor atmosphere. Because of its extremely high temperature, lack of water and atmosphere,life is not possible.
- Venus [Shukra]: It is the second planet from the sun. Except the sun and the moon, it outshines all the heavenly bodies and hence, regarded as the brightest and hottest planet. It appears as an evening star just above the western horizon for 292 days. After this, it appears as a morning star for another 292 days in the eastern horizon. In spite of the fact that Venus is the second planet from the sun which Mercury is the first, it is the brightest planet due to cloudy atmosphere of carbon-dioxide. This cover reflects more than of the sunlight falling on its surface. The mass of Venus is 0.8 times the mass of the earth. However, its size is almost similar to that of the earth.
- Earth [Prithvi]: Earth is the third planet from the Sun. The tilted axis of rotation of the earth is always in the same direction. Due to this tilt in the axis of rotation, the position of the northern and southern hemisphere of the Earth towards the sun, keeps on changing through out the year.
- Mars [MangalJ: It appears like a red star and hence, is sometimes called the Red Planet. There are two moon revolving around it, namely, phobos and deimos. Both these moons are very close to surface of the Mars and are less than 20 km in diameter.
- Jupiter [Guru or Brihaspati]: It is the largest planet in the solar system. One special feature of this planet is a big red spot, which is 30000 km long and 13000 km wide. It is known to have 61 moons. It has a faint ring around its equatorial plane.
- Saturn [Shani]: Saturn is surrounded by three flat rings, which consist of rocks whose size may vary from a speck to few kilometres in diameter. Among the three rings ring the third ring is the brightest. It has 31 known moons, the largest being Titan.
- In Vedic astrology, Rahu and Ketu are known as invisible planets or shadowy planets
There are 12 zodiac signs and each sign has its own strength and weakness, its own specific traits, desires and attitude towards life and people.
Makar Sankranti marks the transition of the Sun into the zodiacal sign of Makara (Capricorn) on its celestial path).
Uttarayan – After 22 December, the sunrise gradually shifts towards east. This continue till 21 June. It is the period between the makar sankranti and karka Sankranti. Uttarayan means north movement. This is the sixth month period which indicate a semantic of the northward movement of the Sun on the celestial hemisphere. In this period, the day is longer than night.
The summer solstice occurs around 21 June. So from 21 June, the sunrise gradually shifts towards south. This continues till 22 December. According to Indian Astronomy, in this period the sunrise is said to be dakshinayan, moving towards south. It is the period between karka sankranti and makar sankranti. In this period, days are shorter than night. ‘
Transit of Venus:
A transit of Venus across the Sun takes place when the planet Venus passes directly between the Sun and a superior planet, becoming visible against the solar disk. During the transit, Venus can be seen from Earth, as a small black disk moving across the face of the Sun. The duration of such transit is usually measured in hours (the transit of 2012 lasted 6 hours and 40 minutes). A transit is similar to a solar eclipse by the Moon.
Although the diameter of Venus is more than 3 times that of the Moon, Venus appears smaller, and travels more slowly across the face of the Sun, because it is much farther away from Earth. The last transit of Venus was on 5 and 6 June, 2012, and was the last Venus transit of the 21st century, the prior transit took place on 8 June 2004. The previous pair of transits were in December 1874 and December, 1882. The next transits of Venus will be on 10, 11 December, 2117; and 9 December, 2125.
Transit of Mercury:
A transit of Mercury across the Sun takes place when the planet Mercury passes directly between the Sun and a superior planet, becoming visible against (and hence, obscuring a small portion of) the solar disk. During the transit, Mercury can be seen as a very small black disk, moving across the face of the Sun.
Transits of Mercury are much more frequent than transits of Venus, with about 13 or 14 per century, because Mercury is closer to the Sun and orbits more rapidly. Transits of Mercury usually occur in May or November. The last four transits occurred on November 15, 1999; May 7, 2003; November 8. 2006 and May 9, 2016. The next will occur on November 11, 2019, and then on November 13, 2032. A typical transit lasts several hours.
In Vedic timekeeping, a tithi (also spelled thithi) is a lunar day, or the time it takes for the longitudinal angle between the Moon and the Sun to increase by 12°. Tithis begin at varying times of day and vary in duration from approximately 19 to approximately 26 hours. Tithi plays an important role along with nakshatra in Hindu’s daily as well as special activities, in selecting the muhurta. There are good tithis as well as bad tithis.
There are 30 tithis in each lunar month, named as:
|S.No.||Krishnapaksha (dark fortnight)||Shukla paksha (bright fortnight)||Interval between Sun and Moon|
|1.||Prathama||Prathama||0 – 12|
|2.||Dwitiya||Dwitiya||12 – 24|
|3.||Tritiya||Tritiya||24 – 36|
|5.||Panchami||Panchami||48 – 60|
|6.||Shashthi||Shashthi||60 – 72|
|7.||Saptami||Saptami||72 – 84|
|8.||Ashtami||Ashtami||84 – 96|
|9.||Navami||Navami||96 – 108|
|10.||Dasami||Dashami||108 – 120|
|11.||Ekadasi||Ekadashi||120 – 132|
|12.||Dvadasi||Dwadashi||132 – 144|
|13.||Trayodasi||Thrayodashi||144 – 156|
|14.||Chaturdashi||Chaturdashi||156 – 168|
|15.||Amavasya (new moon)||Purnima or Paurnami (full moon)||168 – 180|
Celestial Relations of Name of Indian Months:
The set of months name named after nakshatras, is used by both solar and lunisolar calendars, adding to the complexity of the Indian calendar system. Indeed, as we shall see, in this type months initially named after nakshatras; there has been an infusion of solar rules into an essentially lunar convention. Motion of the moon is related to lunar months.
Let us then, first consider the original rule. Saha and Lahiri mention that Pakshas or fortnights were differentiated based on the nakshatra where there is fullmoon. That is to say, if a particular fullmoon occurs near, say, the lunar asterism, Visakha, the fullmoon would be called as Vaisakha Purnimasi, and the month would be Vaisakha.
The earliest lunisolar months, then, were purnimanta, that is , the name of the full Moon corresponded to the name of the month. Of course, the fullmoon occurs at all nakshatras. Fifteen were taken into account for naming of the month, spaced more or less equally.
We thus have the following set of names along with their respective nakshatras.
|Rashi||Approximate nakshatra or purnima||Lunar month name||Solar month name|
|Karkata||(Purva & Uttara) Aashaadha||Aashaadha||Sraavana|
|Kanya||(Purva & Uttara) Bhaadrapada||Bhaadrapada||Asvayuja (Aasvina)|
|Tula||Asvini (Aasvina)||Asvayuja Kaarthika|
|Mina||(Uttara & Purva) Phalguni||Phalguna||Chaitra|
Knowledge of Indian Scientist:
There are many Indian scientists which gave their great contribution in the progress of Science.
Some Indian astrologers are:
- Aryabhatta: Aryabhatta was an acclaimed mathematician- astronomer. He was born in Kusumapura (Patna) in Bihar, India. His contribution to mathematics, Science and astronomy is immense and yet he has not been accorded the recognition in the world history of science. At the age of 24, he wrote his famed “Aryabhattiya”. He was aware of the concept of zero, as well as the use of large numbers up to 1018. He was the first to calculate the value for ‘pi’ accurately to the fourth decimal point. He devised the formula for calculating areas of triangles and circles. He calculated the circumference of the earth as 62832 miles, which is an excellent approximation, and suggested that the apparent rotation of the heavens wasdue to the axial rotation of the earth on its axis. He was the first known astronomer to devise a continuous counting of solar days, designating each day with a number. He asserted that the planets shine due to the reflection of sunlight, and that the eclipses occur due to the shadows of moon and earth. His observations accounts for the ‘flat earth’ concept and lay the foundation for the belief that earth and other planets orbiting the Sun.
- Direct details of his work are known only from the Aryabhatiya, His discile Bhaskara I calls it Ashmakatantra (or the treatise from the Ashmaka).
- The Aryabhattiya is also occasionally referred to as Arya-shatas-ashta (literally, Aryabhata’s 108), because there are 108 verses in the text. It also has 13 introductory verses, and is divided into four or chapters.
- Aryabhattiya’s first chapter, Gitikapada, with its large units of time-Kalpa, manvantra, and Yuga-introduces a different
- cosmology. The duration of the planetary revolutions, during a mahayuga is given as 4.32 million years.
- Ganitapada, the second chapter of Aryabhattiya has 33 verses covering mensuration (), arithmetic and geometric progressions, gnomon or shadows, simple, quadratic, simultaneous, and indeterminate equations.
- Aryabhatiya’s third chapter Kalakriyapada, explains different units of time, a method for determining the positions of planets for a given day, and a seven day week with names for the days of week.
- The last chapter of the Aryabhatiya, Golapada describes geometric/ trigonometric aspects of the celestial sphere, features of the ecliptic, celestial equator, shape of the earth, cause of day and night and zodiac signs on horizon.
- It is speculated that Aryabhata used the word (approaching), to mean that not only is this an approximation, but that the value is incommensurable or irrational.
- In Ganitapada, he gives the area of a triangle as: “For a triangle, the result of a perpendicular, with the half side is the area. He discussed, sine by the name of ardha-jya or half -chord.
- Like other ancient Indian mathematicians, he too was interested in finding integer solutions to Diophantine equations, with the form: ax + by = c; he called it the (meaning breaking into pieces) method.
- His contribution to the study of Algebra is immense. In Aryabhattiya, Aryabhatta provided elegant results for the summation of series of squares and cubes, through well tried formulae.
- He correctly believed that earth rotates about its axis daily
- In Aryabhatiya, he writes that ‘setting and rising of planets’ is a perception, similar to that of someone in a boat going forward, sees an object going backward.
- He correctly, asserted that the pianets shine due to the reflection of sunlight, and that eclipses occur due to the shadows of moon and earth, and not by a demon called ‘Rahu’!
- He correctly deduced that orbits of the planets are ellipses.
Personal Life and Legacy:
- Aryabhatta’s work was of great influence in the Indian astronomical tradition and influenced several neighboring cultures, through translations. Some of his works are cited by Al-Khwarizmi, and in the 10th century by Al-Biruni.
- Aryabhatta knowledge University (AKU), Patna, has been established by the Government of Bihar in his honor, for the development and management of educational infrastructure related to technical, medical, management and allied professional education.
- India’s first satellite Aryabhatta, is named in his honor.At the Aryabhatta Research Institute of Observational Sciences (ARIOS), near Nanital, India, research in astronomy, astrophysics and atmospheric sciences is conducted.
- Varahamihira: Varahamihira was born in 499 A.D., in a family of Brahmins settled at Kapittha, a village near Ujjain. His father, Adityadasa was a worshipper of Sun and it was he, who taught Varahamihira, astrology. On a visit to Kusumapura (Patna), young Varahamihira met the great astronomer and mathematician, Aryabhatta. The meeting inspired him so much, that he decided to take up astrology and astronomy as a lifetime pursuit. At that time, Ujjain was the centre of learning, where many schools of arts, science and culture were flourishing in the prosperity of the Gupta reign. Varahamihira, therefore, shifted to this city, where scholars from distant lands were gathering. In due course, his astrological skills came to the notice of Vikramaditya Chandragupta II, who made him one of the nine gems of his court.
- Varahamihira’s mathematical work includes the discovery of the trigonometric formulas. He improved the accuracy of sine tables of Aryabhatta-I. He defined the algebraic properties of zero as well as of negative numbers. Furthermore, he was among the first mathematicians to discover a version of what is now known as the Pascal’s triangle. He used it to calculate the binomial coefficients.
- His treatise such as Pancha Siddhantika (Five Principles), Brihatsamhita (Master collection), Brahjataka (Astrological work) have put him on as high a pedestal in Astrology, as Kautilya’s in Political philosophy, Manu’s in Law or Panini’s in Grammar.
- Varahamihira’s main work is the book Pancha Siddhantika (“Treatise on the five Astronomical Canons gives us information about older Indian texts which are now lost). The work seems to be a trea’stise on mathematical astronomy and it summarises five earlier astronomical treatises, namely, the Surya Siddhanta, Romaka Siddhanta, Paulisa Siddhanta, Vasishtha Siddhanta and Paitama Siddhanta. Panch Siddhanta holds a prominent place in the realms of astronomy.
- Varahamihira had learned the Vedas, but he was not a blind believer in the supernatural. He was a scientist. Like Aryabhatta before him, he declared that the earth was spherical. In the history of science, he was the first to claim that some “force” might keep bodies stuck to the round earth. The force is now called, gravity.
- Bhaskara II: Bhaskara was born in 1114, near Vijjadavida (believed to be Bijjaragi of Vijayapur in modern Karnataka).
- Bhaskara II. also kown as Bhaskara or as Bhaskaracharya, was a 12th century Indian mathematician. He was a renowned astronomer, who accurately defined many astronomical quantities, including the length of the sidereal year. A brilliant mathematician, he made the significant discovery of the principles of diffferentia! calculus and its application to astronomical problems and computations centuries, before European mathematicians like Newton and Leibniz made similar discoveries. It is believed that Bhaskara-ll was the first to conceive the differential coefficient and differential calculus. Bhaskara-ll wrote the first work with full and systematic use of the decimal number system and also wrote extensively on other mathematical techniques and on his astronomical observations of planetary positions, conjunctions, eclipses, cosmography, and geography. In addition, he also filled many gaps in his predecessor, Biahmagupta’s work. In recognition of his invaluable contributions to mathematics and astronomy, he has been called the greatest mathematician of medieval India.
- He made many significant contributions to mathematics, throughout his career. He is credited to have given a proof of the Pythagorean theorem by calculating the same area in two different ways and then cancelling out terms to get
a2 + b2 = c2
- His work on calculus was ground breaking and much ahead of his times. He not only discovered the principles of differential calculus and its application to astronomical problems and computations, but also determined solutions of linear and quadratic indeterminate equations (Kuttaka). The works in calculus, performed by the European mathematicians of the 17th century is comparable to the rules he had discovered, way back in the 12th century.
- His major work ‘Siddhanta Siromani’(“Crown of treatises”) was completed in 1150, when he ws 36 years old. Composed in Sanskrit Language, the treatise consists of 1450 verses. The work is divided into four parts called “Lilavati, “Bijaganita’, and ‘Goladhyaya’. which are also sometimes considered four independent works. The different sections deal with different mathematical and astronomical fields.
- The first part, ‘Lilavati’ consists of 13 chapters,mainly definitions, arithmetical terms, interest computation, arithmetical and geometrical progressions, plane geometry, and solid geometry among others. It also has a number of methods of computing numbers, such as multiplications, squares, and progressions.
- His work ‘Bijaganita’(“Algebra”) was a work in 12 chapters.This book covered topics like positive and negative numbers, zero, surds, determining unknown quantities, and elaborated the method of ‘Kuttaka’, for solving indeterminate equations and Diophantine equations. He also filled many of the gaps in his predecessor Brahmagupta’s work.
- The sections ‘Ganitadhyaya’and ‘Goladhyaya’of ‘Siddhanta Shiromani’ are devoted to astronomy. He used an astronomical model developed by Brahmagupta to accurately define many astronomical quantities, including the length of the sidereal year. These sections covered topics, such as mean longitudes of the planets, true longitudes of the planets, solar and lunar eclipses, cosmography and geography etc.
- Bhaskara II was especially known for his in-depth knowledge of trigonometry. Discoveries first found in his works, include computation of sine’s of angles of 18 and 36 degrees. He is credited to have discovered spherical trigonometry, a branch of spherical geometry which is of great importance, for calculations in astronomy, geodesy and navigation.
- The other Indian mathematician are Brahmagupta (628 A.D), Jain mathematician Mahaviracharya (850 A.D), Shridharacharya (991 A.D), Ramanujan (1887), S. Chandrashekhar (1938), Sawi Jai Singh II (1686-1748), who gave their great contribution in the development of Astrology.