<p align="right">Last Update: <font color="#4f81bd">July, 15, 2024</font></p> ## BIG IDEAS ### **Kepler's First Law (Law of Ellipses)**: **Statement**: The orbit of a planet around the Sun is an ellipse, with the Sun at one of the two foci. **Explanation**: This means that the path a planet follows as it revolves around the Sun is not a perfect circle but an elongated circle (ellipse). ### **Kepler's Second Law (Law of Equal Areas)**: **Statement**: A line segment joining a planet and the Sun sweeps out equal areas during equal intervals of time. **Explanation**: This implies that a planet moves faster when it is closer to the Sun and slower when it is farther from the Sun. As a result, the area covered over a specific period is constant regardless of where the planet is in its orbit. ### **Kepler's Third Law (Law of Harmonies)**: **Statement**: The square of the orbital period of a planet is directly proportional to the cube of the semi-major axis of its orbit. **Formula**: $T^2∝a^3$ $\frac{T^2}{a^3} = constant $ **Explanation**: This law provides a relationship between the time a planet takes to orbit the Sun (its orbital period) and the average distance from the Sun (semi-major axis of the ellipse). It implies that planets farther from the Sun take longer to complete an orbit than those closer to the Sun. --- Return [[Home|Home]] | [[Astronomy]] | [[Newton's Third Law]] | [[Circular Motion]] | [[Gravity]]