Chances are the lake closest to you is a freshwater lake. But some lakes are extremely salty. These are called saline lakes. Although freshwater lakes often have minor amounts of dissolved salts in them (less than 1-3 g/L), saline lakes have more than this (between 3 and 300g/L).
Astronomical Unit (A.U.). An astronomical unit (A.U.) is the average distance between the Earth and the Sun, which is about 93 million miles or 150 million kilometers.Astronomical units are usually used to measure distances within our solar system.ne kiloparsec (kpc), is one thousand parsecs. One megaparsec (Mpc) is one million parsecs. SUMMARY 1 Astronomical Unit (A.U.) is the average distance between the Sun and the Earth. 1 A.U. = 93 million miles = 150 million kilometers 1 light-year (ly) is the distance that light travels in one year in a vacuum.
1 AU = 149,597,870.700 kilometers (or 149,597,870,700 meters). Definition: An Astronomical Unit is the mean distance between the Earth and the Sun. In 2012, the International Astronomical Union defined the distance to be 149,597,870,700 meters. Historical Background: Tycho Brahe estimated the distance between the Sun and the Earth at 8 million kilometers (5 million miles). Later, Johannes Kepler estimated the AU was at 24 million kilometers (15 million miles).