Scientists use two pieces of information to determine the true brightness (or absolute magnitude) of a star. Use the slider to change the apparent magnitude, and drag the Earth to change the distance (measured in parsecs). Once you input these two factors, your absolute magnitude should appear.
Answer these questions: 1. At what distance are the apparent magnitude and absolute magnitude the same? 2. What happens to brightness (size) when apparent magnitude is decreased? 3. What happens when apparent magnitude is increased? 4. Castor, a star in Gemini, is 15.6 parsecs away and has an apparent magnitude of 1.93. What is the absolute magnitude?