Rahu and Ketu are controversial figures in Hindu Mytho logy, Astronomy and Astrology. Whatever may have been the liables of mythology, the physics of eclipses tells us that the shadows are caused by the Earth, the Sun and the Moon. and they do not exist by themselves. In solar Eclipse. it is Moon that covers thd orb of the Sun and casts its shadow on the Earth and causes the eclipse, ln Lunar Eclipse, it is reasonably the Earth that casts the shadow on the Moon and cause the eclipse. But if we see the movement in both the cases, it is the Moon that causes the eclipse by playing hide and seek. What are Rahu and Ketu. The usual explanation given by some of the learned astrologers is that they are as much physical bodies (planets) as other planets are and they are invisible because their discs are dark. Others are of the opinion that they are points in the ecliptic where the plane of Moon's orbit cuts the plane of Sun's orbit. Rahu and Ketu pose difficult problems for the astrologer and have been the cause of considerable controversy in the recent past. Authorities differ about them. From what Varahmihira observes in is his Brihat Somhita. itis obvious that he was aware of the true causes of eclipses and other celestial phenomen. It must, however, be stated at the very outset that there is a fundamental difference between Rahu and Ketu and the other planets. The other planets are bodies of physical mass, actually existing in the sky and visible to the eye. They have form, shape and colour and their mass, gravity, atmosphere, motion, distance from the Sun etc., have been studied in detail and ascertained. On the other hand, Rahu and Ketu are only tqre imaginary points in the heavens, without shape or form. They are the points of intersection of the apparent path of the Sun with the path of 5 the Moon. As these paths are nearly circular, the points of intersection are two which lie I80 degrees apart. Now the basic assumption of astrology is that planets in fluence the earth and its inhabitants. Man dwells upon the earth and so is influenced by them. The planets possess mass and have force of gravity. They also emit electro-magnetic viberations. These effect the earth and its inhabitants. Rahu and Ketu do not exist in the heavens and posses no mass. They are only two imaginary points in the heavens. Then how do they effect the earth and its inhabitants ? It has already been stated that Rahu and Ketu are the two points of intersection of the path of the Sun and the Moon. The apparent motion of the Sun is due to the revolution of the earth around the Sun. And the Moon revolves around the Earth. Therefore, Rahu and Ketu are the points of intersection of the paths of the earth and the Moon in the heavens. The Earth and the Moon are two bodies possessing physical mass. They move on defined paths in the heavens. Their movements on their paths create fields of force. The naine of the force is not material. It may be called electromagnetic or any other. The inhabitants of the earth are not aware of the field of force created by the earth, because they are a part of the earth and move along with it. This fact may be explained through an example. The movements of a Railway Train on its track creates a field of force which is noticed by a passerby and not by persons who are in an equilibrium. Similarly, the inhabitants of the Earth are in an equilibrium with reference to the field of force created by the earth during its motion around the Sun. The equilibrium is, however. disturbed where the paths of the earth and the Moon intersect. It is natural that where two fields of force meet with each other, something unsual should happen. Rahu and Ketu are two 6 Nodes of the Moon, are the two points of disturbance on the paths of the Earth and the Moon. The path of the earths or the apparent path on the Sun is thb ecliptic. Thus Rahu and Ketu are the two points on the ecliptic 180 degrees apart and in whose vicinity disturbed condition prevail. They represent the cross-roads on the fields of force of the earth and the Moon. But what about the influence of Nodes, whibh are ima ginary points ? They cannot either emit rays or reflect rays emanating from the other celestial bodies. So what is their position in Astrology. Latitudes of the planets depend on their Nodes. so the mutual relationship in the position of the planets will not be the same at any two instants in Kalpa, (one Kalpa, being equal to 1090 Maha-yugas and one Maha-yuga is of 4,32000 years), as the periods of revolution of the Nodes are different for different planets. It is said that History repeats itself but not in a identical manner. This truth is established on a consideration of astrology. The events may be similar but can never be identical. Since the astrological influence of planets depends on their latitudes, (their Nodes), even though they are tmaginary points naturally exercise astrology influence on the earth and the living beings on it. The effect of Rahu and Ketu forces itself on our attention most clearly at the time of the eclipses of the Sun and the Moon. When the Sun and the Moon come near the Nodes at the time of the Full Moon or the new Moon and a certain other conditions are fulfilled an eclipse of the Moon or the Sun take place. Then the light and other electro-magnetic viberations coming from the Moon or the Sun are cut off and the normal arrangenents which obtains for the earth are disturbed. Persons, who are born at the tinte of.eclipscs are always prone to mental abnormality and to other physical suffering. They are also likely to have week 7 constitutions and short lives. It is known fact that during the period of eclipses and sometimes before and after them. the normall functioning of the human system-such as digestive apparatus etc. is disturbed and that is why it is said that no food should be taken during the period of an eclipse. But it is not only the Sun and the Moon that suffer when they come in contract with Rahu or Ketu. Other planets also develop abnormal traits when they come in contact rvith them and their natural quaiities suffer, usually for the worse. When Sun comes in conjunction with Rahu. this gives a strong advantage to the Rahu area. The ego and the new activity flow along the same path. Whenever the Sun is located is where there is strength, vitality, action and warmth. But when Sun is in conjunction with Ketu, this gives greater difficulty in establishing the new growth. In order to grow and learn, the person must build a strong ego. To cut short, whenever Rahu is in conjunction with any planet, it will en hance the basic quality of that planet. It is only in recent years that Rahu and Ketu are recogni sed in Western astrological texts-this is surely a sign of Indian influence on Western astrological thought. Lately few astrologers of the West have written few books proving with illustration that the Moon's Nodes play an impartant part in human affairs.