"Mom, why is it dark at night?" My daughter asked, looking into the evening sky.
Why is it dark at night?
I explain to her that the sun shines on the other side of the globe at night, so it's dark with us.
But this is only half the truth. On the internet, I learn that it should actually be bright at night, considering that there are infinitely many stars in the sky. These are also suns.
However, their light does not reach us like that of the sun. Why it's dark at night is because the stars that could turn night into day are very far away.
Why it is dark at night, but also because of the great distance of the other galaxies from each other. Because even if the stars seem close to us, they usually belong to very different galaxies.
And they are ten to twenty-three light-years apart. A number that is older than the universe itself. Therefore, the stars can never be so close together that it is daylight at night.
Why it is dark at night, so has something to do with the age of the universe. It's 14 billion years old - appreciated, of course. The distance between the galaxies is about one hundred billion billion light-years. Sounds paradoxical, but is possible as the universe expands.
If this all seems too complex and is asked by his children why it is dark at night, but may like to first give the standard answer. Where the nocturnal suns in the sky and the long distances for children have their charm!