Robin Klein, Age 10 Of Provo, Utah, for his question: 

How Big is the universe?

We need to stretch our imaginations to think about this question. So let's begin with the solar system and expand from side to side, our solar system is about billion miles wide. Beyond it is the ocean of space, dotted with rich distant stars.  All our stars are in the milky way, which is like a giant pinwheel more than 20 light years from side to side. Each light year equals about six million million miles. There is more space out beyond the milky way. It is dotted with millions of Starry pinwheels like our milky way. The universe extends farther and farther in all directions, and where it ends nobody knows.