input: Students' ability to describe vast distances in the universe. 4A- universe (9-12)#2: …Light from the next nearest star takes a few years to arrive. The trip to that star would take a rocket ship thousands of years. Some distant galaxies are so far away that their light takes several billion years to reach the Earth. People on earth, therefore, see them as they were that long ago in the past.
output: Unifying Concepts and Processes- Constancy, Change, and Measurement- concepts of scale including speed of light.