Orbiting Bodies | Physics for GCSE/IGCSE - Year 11 PDF Download

Light Speed

• Planets and moons in the Solar System become visible from Earth by reflecting sunlight
• The outer regions of the Solar System are approximately 5 × 10¹² meters away from the Sun, leading to a delay in light travel
• It takes 8 minutes for sunlight to reach Earth, and the nearest star beyond the Sun is so distant that its light takes 4 years to reach us
• The Milky Way galaxy comprises numerous stars at vast distances, resulting in even longer light travel times to Earth
• The Milky Way galaxy harbors billions of stars, situated at significant distances, with light taking even longer to be visible from our planet.

Speed of Light

• The speed of light is a constant value of 3 x 10⁸ meters per second
  • Therefore, using the equation:
    
• The duration required to cover a specific distance can be determined by rearranging the equation.
  

Elliptical Orbits

• Planets, minor planets, and comets move in elliptical paths, which are elongated circles.
• An ellipse, a flattened circle, describes the shape of these orbits.
• While these celestial bodies follow elliptical paths, the Sun is not always at the center of these orbits. This alignment occurs primarily in nearly circular orbits.

Analysing Orbits

• Information gathered about planets, moons, and the Sun over time provides insight into:
  • Factors influencing surface conditions of planets
  • Environmental challenges for manned or robotic missions
• Factors affecting planetary conditions and encountered environmental issues include:
  • Variations in planetary surface conditions
  • Challenges faced during space missions