🔭 Light-years and cosmic distances

Unit 2 · Earth, Moon & stars · 9 min

Light travels about 300,000 km per second. A light-year is the distance light covers in a year (about 9.46 trillion km) — a unit of distance, not time. Sunlight takes about 8 minutes to reach Earth, so we see the Sun as it was 8 minutes ago.

Words in this lesson

• 光年 (guāng nián) — light-year
• 距离 (jù lí) — distance

Project: Make a scale model: if the Sun were in Cairo, how far away would Earth and Jupiter be?