Before you start. You need a torch, a sheet of paper, and nothing else. If you have read The Night Sky Is a Time Machine you already know sunlight takes about eight minutes to reach us; that is the only number from elsewhere in the track this lesson uses, and you can skip it.
Continue reading with a plan
The first three lessons of every track are free. This lesson is included with a plan, which unlocks every lesson, board, video, lab and paper for one price.