How big is the universe ... compared with a grain of sand?

How big is the universe ... compared with a grain of sand?

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'You'll never get your head around how big the universe is,' warns astronomer Pete Edwards of the University of Durham in this film about measuring astronomical distances. 'There are as many stars in the universe as there are grains of sand on the Earth.' So how far is a light year? And supposing our galaxy were the size of a grain of sand, how big would the universe be?

Видео How big is the universe ... compared with a grain of sand? канала The Guardian