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
The Layer Monument skull is the commonest of all "memento mori" symbols in funerary art. It was also defined as the philosophical vessel ("Vas Philosophorum") in Renaissance-era alchemy. The role of the Quaternity in religious symbolism is discussed in depth in the writings of the Swiss psychologist Carl Gustav Jung. In essence, the Layer monument's four figurines represent spiritual entities which agree with Jung's analytical psychology, that the psyche moves toward individuation in fours (made up of pairs of opposites). The Layer Monument The Layer monument is an early 17th-century polychrome marble mural monument (320 × 350 cm) erected to the memory of