Parallax

• Apparent shift of foreground objects with respect to the background due to a change in perspective
• Used to determine the distance of stars from the Earth
  • Using trigonometry
  • Observing shifts in the stars position in the sky from day to day
  • Limited range of 150 parsecs due to current technology
    • ~400 light years
• Provides proof that the Earth orbits the Sun

Formula

• $D = \frac{1}{p}$
  • $D$ is distance in parsecs
  • $p$ is the parallax angle in arcseconds

Space Astronomy