Three laws that describe the motion of planets around the sun.
Newton's laws of motion: The foundational principles on which Kepler's laws of planetary motion are based.
Law of Gravitation: The force of attraction between two objects is directly proportional to the product of their masses and inversely proportional to the square of the distance between them.
Central force and radial motion: The motion of an object under a central force, such as gravity, follows a path that is always directed towards the center of force.
Circular motion: The motion of an object along a circular path, including concepts such as centripetal force and angular velocity.
Elliptical orbits: An object in orbit follows an elliptical path with the center of force at one of the foci of the ellipse.
Kepler's first law: Also known as the law of orbits, states that planets move in elliptical orbits with the sun at one of the foci.
Kepler's second law: Also known as the law of areas, states that planets move faster when closer to the sun and slower when farther away, such that a line drawn from the planet to the sun sweeps out equal areas in equal time intervals.
Kepler's third law: Also known as the law of periods, states that the square of an object's orbital period is proportional to the cube of the semimajor axis of its orbit.
Orbital motion and energy: The relationship between an object's orbital motion and its kinetic and potential energy.
Newton's version of Kepler's laws: The mathematical equations that describe the three laws of planetary motion in terms of force and acceleration.
Applications of Kepler's laws: How scientists and engineers use Kepler's laws to study and predict the motion of planets, comets, asteroids, and other celestial objects.
The first law, also known as the law of orbits, states that all planets move in elliptical orbits with the Sun at one of the foci: This means that the distance between the planet and the Sun changes throughout its orbit, with the furthest distance being the aphelion and the closest distance being the perihelion.
The second law, also known as the law of areas, states that the line connecting a planet to the Sun, sweeps out equal areas in equal times: This means that a planet moves faster when it is closer to the Sun and slower when it is further away, to maintain the equal area rule.
The third law, also known as the law of periods, states that the square of the period of any planet's orbit is proportional to the cube of the semi-major axis of its orbit: This means that the further a planet is from the Sun, the longer its period (time for one orbit) will be, and this relationship between period and distance applies to all planets in the solar system.