module 3

• astronomical unit - distance between the earth and sun
• eccentricity - distance between the foci to the major axis
• ellipse - distance from any point on the ellipse to two points is always the same
• focus - one of the two fixed points inside an ellipse which the sum of the distances to any point on the ellipse is the same
• keplers 1 law - each planet move around the sun with the sun at one focus of the ellipse
• keplers 2 law - straight line joining planet and the sun sweeps out equal intervals in time
• keplers 3 law - the square of a planets orbital period is directly proportional to the cube of the semimajor axis of its axis
• major axis - the maximum diameter of an ellipse
• orbit - the path of an object that is revolution about another object or point
• orbital period - the time it takes for one complete orbit of the earth around the sun
• orbital speed - the speed at which an object ( usually a planet) orbit around the mass of an object
• semimajor axis - half of the major axis
• tycho brahe - a danish astronomer who was able to determine the position of 777 fixed stars accurately
• johannes kepler - he was recommended by emperor rudolf II to be his assistant and imperial mathematician
• kepler was brahes assistant
• brahe assigned to kepler the interpretation of his observations of mars
• kepler - postulated that there must be a force from the sun that moves the planets
• rudolphine tables - useful in determining the positions of the planets for the past 1000 years and the future 1000 yeras
• rudolphine tables - the most accurate table that is known to the astronomical world
• the first law of keplers planetary movements - the planets orbit the sun in ellipses
• the law of ellipses - 1rst law of keplers planetary movements
• second law of keplers planetary movements - when an imaginary line is drawn from the center of the sun to the center of a planet, the line will sweep out an equal area of space in equal interval
• a planets moves fastest when it is nearest the sun and slowest when it is farthest
• 2nd law describe how fast a planet moves in its orbit
• second law - the law of equal areas
• 3rd law - describes that the square of a planets orbit period is proportional to the cube of a planets average distance from the sun
• 3rd law - states that the ratio pf the square of the periods of two planets is equal to the ratio of the cubes of the average distance of these two planets from the sun
• johannes kepler - best known for the laws of planetary movements
• johannes kepler - demostrated that the planets move in elliptical orbits around the sun
• johannes kepler - brahes most famous student
• the greatest contribution of brahe - observe planetary movements positions with sufficient accuracy so that kepler cpulf later use the data
• planets move along an elliptical path with the sun at one of the foci
• galileo galilei - considered to be the first truly modern scientist
• johannes kepler - was recommended by the emperor to be brahe's assistant
• nicholaus copernicus - the first modern astronomer to propose a sun centered solar system
• kepler finds about the shape of the orbit is that the orbit is elliptical
• tycho brahe and johannes kepler had an unsteady relationship
• brahe dies on 1601
• johannes kepler was a scholar of at the university of tubingen in 1589