Smart Facts – Light Years
Ten fascinating Physics facts about light years to share with your KS3 science students.
- The light year is a unit of distance used by astronomers, although people often mistake it for a unit of time.
- One light year is 9,460,000,000,000 km
- The light year is a unit of distance, used when expressing distances on a massive scale related to space.
- It takes 8 minutes for light from the Sun to reach the Earth.
- The first person to use the time it takes light to travel from a distant object, was Friedrich Wilhelm Bessel, when he measured the distance to the star 61 Cygni.
- The nearest star to Earth (Proxima Centauri) is 4.3 light years away. In kilometres, this is 40,700,000,000,000 km.
- The centre of the Milky Way galaxy is 27,000 light years away.
- The distance to our nearest neighbouring galaxy, Andromeda, is 2.5 million light years.
- The speed of light is 299 792 458 m/s
- In one billionth of a second, light travels 30cm.
Exploring light years with your students this term? Why not check out the following free resources?
Scientist Biography: Bessel and light years
Free video: the size of the Universe
Homework Activity: Measure the speed of light in your own kitchen!