According to Kepler's second law, what does a line connecting a planet to the Sun do over equal time intervals?

• A. It remains stationary
• B. It sweeps out equal areas
• C. It contracts in size
• D. It rotates in a circular path

Answer: (B)

Kepler's second law, also known as the law of equal areas, states that a line segment joining a planet to the Sun sweeps out equal areas during equal time intervals. This principle is fundamental to understanding the motion of planets in elliptical orbits.

As a planet travels along its orbital path, its speed varies; it moves faster when it is closer to the Sun and slower when it is farther away. Despite this variation in speed, the area swept out by the line connecting the planet and the Sun over fixed time intervals remains constant. This conservation of area is a consequence of the gravitational interaction between the Sun and the planet, and it highlights the elliptical nature of planetary orbits.

Understanding this law is crucial because it illustrates that the motion of planets is not uniform but is governed by gravitational forces, which result in variations in speed depending on the distance from the Sun. The other options do not accurately represent the implications of Kepler's second law and do not align with the principles of orbital mechanics.