1. Th e average distance between the earth and the sun is about 149.6 million kilometer. Th is average distance is taken as one  30astronomical unitaverageEarthlightlight yearProxima Centauriyear.

2. Neptune is  30astronomical unitaverageEarthlightlight yearProxima Centauriyear AU away from the Sun. It means it is thirty times farther than the  30astronomical unitaverageEarthlightlight yearProxima Centauriyear.

3. One astronomical unit is defined as the  30astronomical unitaverageEarthlightlight yearProxima Centauriyear distance between the earth and the sun.

4. The nearest star to our solar system is  30astronomical unitaverageEarthlightlight yearProxima Centauriyear.

5. Astronomers use a special unit, called ‘ 30astronomical unitaverageEarthlightlight yearProxima Centauriyear’, for measuring the distance in deep space.

6. One light year is defined as the distance travelled by  30astronomical unitaverageEarthlightlight yearProxima Centauriyear in vacuum during the period of one  30astronomical unitaverageEarthlightlight yearProxima Centauriyear.