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 please visit my blog Earth Moon system Gravitational attraction  pulls the earth and moon towards each other .While centrifugal force acting in the opposite direction keep them apart .If the Earth and the Moon were of the same size the centre of the revolution of the system would be located midway between them .But because the moon is only about 1/82 the mass of the earth therefore the centre of revolution of the earth moon system is located nearer the earth about 4700km from  earth centre . The centrifugal force is the same for a unit mass at any point on the earth surface but the gravitational attraction  varies according to the distance of the unit mass from the Moon . There is thus a net force directed towards the moon at the point on the earth's surface closest to the moon and a net force direct away from the Moon at the point on the earth surface  farthest from the moon. Therefore the moon's  gravitational sexy screen attraction is...

Remote Sensing    Remote Sensing is defined as the sum total of the process used to acquire and measure the information about the objects and phenomena by a recording device sensor which is not in physical contact with the objects and phenomena in study. Thus Remote sensing involves an object surface the recording device and the energy waves. The term Remote Sensing was first used in early 1960s.     A sensor is a device that  gathers electromagnetic radiations convert it into a single and  present it in a form suitable for obtaining information about the object under investigation .