Atmosphere of Earth and balloons, and too low to permit orbital spacecraft. The mesosphere is mainly accessed by sounding rockets and rocket-powered aircraft. The stratosphere is the second-lowest layer of Earth's atmosphere. It lies above the troposphere and is separated from it by the tropopause. This layer extends from the top of the troposphere at roughly above Earth's surface to the stratopause at an altitude of about . The atmospheric pressure at the top of the stratosphere is roughly 1/1000 the pressure at sea level. It contains the ozone layer, which is the part of Earth's atmosphere that contains relatively high concentrations of
Layer by Layer starts by making a cross on one face with the edge pieces, then putting the corners into position between the edges. By then the layer should be solved. Third, the four edge pieces of the middle layer are solved. At this point the first two layers are solved. Fourth, a cross of the opposite color is made on the last layer. Fifth, the last layer edges are permutated (swapped around). Sixth, the last layer corners are permutated. Finally, the last layer corners are oriented. Most Layer by Layer beginners' methods solve the first two layers using the same technique. However,