If the Universe is about 13.7 billion years old, and the diameter of the observable universe is 93 billion light years, how can it be that wide if the universe isn’t even old enough to let light travel that far that quickly?

Question

If the Universe is about 13.7 billion years old, and the diameter of the observable universe is 93 billion light years, how can it be that wide if the universe isn’t even old enough to let light travel that far that quickly?

In: 5624

Answer 1

Imagine a blanket with stars printed on it. Now let’s say you can roll a ball from one star to another. The ball can only go up to a certain speed and no faster.

Now imagine you pull on the corners of the blanket, stretching it out. The stars are now further apart.

Now imagine rolling the ball while simultaneously stretching the blanket out. While the ball is rolling, the distance between the stars is getting longer.

The stars are the source and destination. The ball is the light. The blanket is space itself.