Problem
Background: Distances to stars are usually measured in light years, but it's hard to grasp just how far a light year is. However, if we calculate how long it would take to travel to a few stars it will help us appreciate what distances in light years imply.
I. Predict and Explain: In Your Personal Constellation the distance to three of the stars is listed in light years. Predict which of these stars it would take the longest to travel to, and explain why. (Note: Part a is strictly qualitative: you do not need to calculate a time here.)
II. Calculate: Calculate the time it would take for a very fast rocket (traveling at 45 km/s) to reach the three stars whose distances are listed in your table. Give your answers in both seconds and in years.
Hint: Use the distance, time, velocity formula d = vt, which means t = d/v.
III. Compare: Does your answer to b make sense and agree with your answer to a? If not, explain what went wrong. Was there a mistake in the calculation or in your prediction? How can you tell?