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.
The Earth at different points in its orbit. Earth's orbit is the trajectory along which Earth travels around the Sun. The average distance between the Earth and the Sun is 149.60 million km (92.96 million mi), and one complete orbit takes 365.256 days (1 sidereal year), during which time Earth has traveled 940 million km (584 million mi). Earth's orbit has an eccentricity of 0.0167. As seen from Earth, the planet's orbital prograde motion makes the Sun appear to move with respect to other stars at a rate of about 1Â° (or a Sun or Moon diameter every 12 hours) eastward per solar day.