Atmosphere The lowest layer is the troposphere, which extends from the surface to the bottom of the stratosphere. Three quarters of the atmosphere's mass resides within the troposphere, and is the layer within which the Earth's terrestrial weather develops. The depth of this layer varies between 17 km at the equator to 7 km at the poles. The stratosphere, extending from the top of the troposphere to the bottom of the mesosphere, contains the ozone layer. The ozone layer ranges in altitude between 15 and 35 km, and is where most of the ultraviolet radiation from the Sun is absorbed. The
Layer by Layer Layer by Layer The Layer by Layer method is a method of solving the 3x3x3 Rubik's Cube. Many beginners' methods use this approach, but it also forms the basis of the CFOP speedcubing technique. The Layer by Layer Method was pioneered by David Singmaster in his 1980 book "Notes on Rubik's "Magic Cube"". The same idea was adopted by James G. Nourse in his "The Simple Solution to Rubik's Cube" which became the bestselling book of 1981, and similar approaches could be found in Don Taylor's "Mastering Rubik's Cube" and Cyril Östrop's "Solving the Cube" from the same era. It