Kepler's Laws of Planetary Motion

Master Kepler's Laws of Planetary Motion! Understand elliptical orbits and speed changes with our engaging worksheet.

Click on the blank and select the word that best completes the statement. The orbits of all planets in the solar system are ellipses. A circle is drawn relative to one center or focal point and all the points on the circle are equidistant from the center. An ellipse drawn relative to two points (foci). There is no center an all the diameters are not the same in an ellipse. Eccentricity describes the shape of an ellipse. Eccentricity measures have far from circular the orbit is. The eccentricity of a circle is zero. Therefore the closer the eccentricity is to zero, the more circular; the larger the eccentricity, the more elliptical the orbit is. Comets have very elliptical orbits. Eccentricity is ALWAYS rounded to the thousandth place and does NOT have a unit! All planets, comets and asteroids orbit the Sun in an elliptical path with the Sun at one of the focal points. The distance from a planet to the Sun varies in a cyclic pattern. This is why the apparent diameter of the Sun as viewed from Earth changes during the year. Moons have elliptical orbits with planets at one of the focal points. As a planet orbits closer to the Sun (perihelion), its orbital velocity increases (it revolves faster). This occurs because the Sun is exerting a greater pull at the perihelion. When a planet, asteroid, or comet is at the perihelion, it has more orbital velocity and more kinetic energy. At the aphelion (further from the Sun), there is less gravitational pull so the orbital velocity is less with more potential energy. The rate of rotation is not affected by the changing distance from the Sun. Due to the changing speed of revolution, the area of space "swept out" by an orbiting object is the same for equal time areas. The further a planet is from the Sun, the longer the orbital path so more time it takes to complete one revolution or a greater period of revolution. Aphelion vs. Perihelion Aphelion Planet is furthest from the Sun Star Weakest gravitational attraction Slowest orbital velocity Greatest potential energy Summer in Northern Hemisphere ~July 4th Perihelion Planet is closest from the Sun Star Strongest gravitational attraction Fastest orbital velocity Greatest kinetic energy Winter in Northern Hemisphere ~January 5th Use the image provided and keep Kepler's Second Law in mind, answer the following question. In the diagram below the area of section y and x are equal to each other. Knowing this, according to Kepler’s second law which distance ( a or b) takes a longer time to travel. Distance A takes longer to travel Distance B takes longer to travel Distance A and B take an equal amount of time to travel According to Kepler's Second Law of planetary motion, what do we know about the speed of an orbiting body? Planets orbit at a constant speed Planets orbit faster when they are further away from the sun Planets orbit faster when they are closer to the sun Planets don't really orbit and we actually live in the eye of a blue-eyed giant In our solar system, the orbits of the planets are best described as circular, with a planet at the center circular, with the sun at the center elliptical with the planet at once of the foci elliptical, with the sun at one of the foci Using ESRT p. 15, the Solar System Data Table, which planet's orbit is most nearly circular?** Remember the closer the eccentricity is to 0 = more circular; larger the eccentricity = more elongated Earth (0.017) Venus (0.007) Neptune (0.009) Jupiter (0.048)