The unit, season that with the symbol UA or ua (astronomical unit) with the symbol AU, or the au to be displayed is one of The length. The greatest distance of the earth to the sun. which is about 150 million km or 93 million miles is equal to a single season is considered.

however, that the circulation of the earth around the sun in an elliptical orbit takes place but annually in a full round peak and perigee solar average distance of the planet to the sun figure is almost flat to the hands. that at the beginning of the basis for the size of some the unit season ranked, but now internationally agreed that the greatest distance that the same peak is based be placed. This distance is exactly equal to 149, the 597, the 870, the 700 km (92 of 955, the 807, the 27 miles) accepted. (very close to 150 million kilometers or 93 million miles).