Explain how parallax is used to measure the distance to nearby stars.

Understand how alternative methods such as using the inverse square law and color/magnitude diagrams or Cepheid variables must be used to find the distances across our galaxy or to other galaxies.

Most students don't comprehend the size and scope of the universe or that the only way we can study celestial bodies and galactic objects is by the light which comes from them. Traditional methods for determing distance to objects with which students may be familiar (such as using trigonometry) do not work on the majority of intergalactic objects or any extragalactic ones.

Parallax can be demonstrated directly with labs and then the concepts applied to finding distance to nearby stars.

Understanding other methods of finding distance to celestial objects that are further away requires knowledge of the inverse square law, the relationships between color and luminosity, and the magnitude and period relationships for Cepheid variables.