Why Is Space Black?

A simple bedtime question. A 200-year-old physics paradox. Daddy is not responding. Force quit?

It started as a bedtime question. It ended with Daddy on the floor.
Aura, just trying to draw on her tablet, accidentally asked the universe's oldest trick question: if space is full of stars, why is it dark at night?
This is real. It has a name: Olbers' Paradox. If the universe is infinite and full of stars, every direction your eye points should eventually hit one. The whole sky should glow.
But it doesn't. Why?
Two reasons. First, the universe has an age, about 13.8 billion years. Light from stars beyond a certain distance hasn't had time to reach us yet. Second, the universe is expanding, and light from very distant stars stretches into infrared, which our eyes can't see.
So the real answer to Aura's question is this: space is black because the universe is finite in time, even if it's infinite in space.
Now you know why Daddy short-circuited.