Kepler's Laws of Planetary Motion

Kepler's Laws of Planetary Motion

Law of Periods

• States that the square of the orbital period of a planet is proportional to the cube of its semi-major axis
• Mathematically expressed as: P² ∝ a³
• Where P is the orbital period and a is the semi-major axis of the planet's orbit
• This law shows that planets with larger orbits take longer to complete one orbit around the Sun

Planetary Motion

• Orbital Shape: Kepler's laws state that the orbits of planets are elliptical in shape, not circular
• Orbital Speed: The speed of a planet varies as it moves through its orbit, with the fastest speed at perihelion (closest point to the Sun) and the slowest speed at aphelion (farthest point from the Sun)
• Orbital Path: The path of a planet's orbit is not a perfect circle, but rather an ellipse with the Sun at one of the foci
• Astronomical Unit (AU): The average distance between the Earth and the Sun, used as a standard unit of measurement for distances in our solar system

Kepler's Laws of Planetary Motion

Law of Periods

• The square of a planet's orbital period is proportional to the cube of its semi-major axis, expressed as P² ∝ a³.
• The law illustrates that planets with larger orbits take longer to complete one orbit around the Sun.
• Orbital period and semi-major axis are directly related, with an increase in semi-major axis resulting in a longer orbital period.

Planetary Motion

Orbital Characteristics

• Planetary orbits are elliptical in shape, not circular.
• The speed of a planet varies throughout its orbit, with the fastest speed at perihelion (closest point to the Sun) and the slowest speed at aphelion (farthest point from the Sun).
• The orbital path of a planet is an ellipse with the Sun at one of the foci.

Units of Measurement

• The Astronomical Unit (AU) is the average distance between the Earth and the Sun, used as a standard unit of measurement for distances in our solar system.