Naomi riassie, aged 11, of Ohio for her question:

What is a light year?

Suppose you wanted to measure the distance from Chillicothe to Columbus. Would you use a twelve inch ruler or a 30 inch tape measure? Unless you had all the time in the world, you would use neither. You would mark off the distance in miles. Chances are you would take the easy way and check off the miles on an automobile speedometer.

Now the astronomers have to measure distance in the sky. And a mile is a very short distance in the sky. Even a million miles would get us no place at all in the vast reaches of space. Earth’s nearest neighbor is  27 trillion miles away.

Measured in miles, these distances run up into pages of figures. So the astronomers needed a  new measuring rod. They chose a, sort of miles per hour measuring rod. When you say a place is half an hour away, you mean that it tapes half an hour to get from where you are to where it is.

The astronomers geared their measuring rod to the fastest traveler known ‑ light. On an average light travels at about 156,000 miles a second. It travels at the same speed whether it comes from our sun or from the distant stars. In one year ‑ one light year .. it travels about 6 trillion miles It is far simpler to call this figure one light year.