Orbital Energy

Definition

Orbital energy is the total energy associated with an object orbiting another body, such as a planet orbiting the Sun or a satellite orbiting a planet. It is the sum of the kinetic energy and potential energy of the orbiting object, which determines the shape and size of its orbit.

5 Must Know Facts For Your Next Test

1. Orbital energy is a conserved quantity, meaning it remains constant unless an external force acts on the orbiting object.
2. The orbital energy of a planet or satellite is negative, as the object is bound to the body it is orbiting and cannot escape its gravitational pull.
3. As an object's orbital distance increases, its potential energy increases, but its kinetic energy decreases, resulting in a lower overall orbital energy.
4. The orbital energy of a planet or satellite determines the shape of its orbit, which can be circular, elliptical, or parabolic.
5. Kepler's laws of planetary motion describe how the orbital energy of a planet is related to its distance from the Sun and its orbital period.

Review Questions

• Explain how the conservation of orbital energy affects the motion of a planet or satellite.
  • The conservation of orbital energy means that the total energy of a planet or satellite remains constant unless an external force acts on it. This results in a delicate balance between the object's kinetic energy and potential energy, which determines the shape and size of its orbit. As the object's distance from the body it is orbiting increases, its potential energy increases, but its kinetic energy decreases, causing the orbit to become more elliptical. Conversely, as the object's distance decreases, its kinetic energy increases, and the orbit becomes more circular.
• Describe the relationship between a planet's orbital energy and Kepler's laws of planetary motion.
  • Kepler's laws of planetary motion provide a framework for understanding the relationship between a planet's orbital energy and its motion. Kepler's first law states that planets orbit the Sun in elliptical paths, with the Sun at one of the foci. This elliptical shape is directly related to the planet's orbital energy, which is a combination of its kinetic and potential energy. Kepler's second law, which describes how a planet's orbital speed varies with its distance from the Sun, is also a consequence of the conservation of orbital energy. Finally, Kepler's third law, which relates a planet's orbital period to its distance from the Sun, can be derived from the relationship between a planet's orbital energy and its orbital period.
• Analyze how changes in a planet's or satellite's orbital energy would affect its motion and the shape of its orbit.
  • If the orbital energy of a planet or satellite were to change, it would have a significant impact on the object's motion and the shape of its orbit. For example, if the object's orbital energy were to increase, its kinetic energy would increase, causing it to move faster and its orbit to become more circular. Conversely, if the object's orbital energy were to decrease, its kinetic energy would decrease, causing it to move slower and its orbit to become more elliptical. These changes in orbital energy could be caused by external forces, such as the gravitational pull of another body or the application of thrust. By understanding the relationship between orbital energy and the motion of planets and satellites, we can predict and explain the complex dynamics of celestial bodies in the universe.

Related terms

Kinetic Energy:

The energy of motion possessed by an object, which is directly proportional to its mass and the square of its velocity.

Potential Energy:

The energy an object possesses due to its position or state, which is determined by the object's mass and its distance from the body it is orbiting.

Kepler's Laws of Planetary Motion: A set of three laws that describe the motion of planets around the Sun, including the relationship between a planet's orbital energy and its distance from the Sun.