## Broadening your horizons

Stories from Physics for 11-14 14-16

A straightforward geometrical calculation can determine an approximation for the distance to the horizon given an observer’s height above the surface of the Earth: d= √ *13H* km, where d is the distance to the horizon in km and H is the vertical height in metres of the observer above the ground. A person with their eyes 2 m above the ground will see the horizon at a distance of approximately 5 km. A further correction can be made to account for the deviation of the path of light due to refraction.

### References

M. Sewell, Mathematics Masterclasses for Young People, Oxford, Oxford University Press, 2017. p. 61

A. Young, Distance to the...

...Horizon