The outermost portion of the Earth's atmosphere. Extremely tenuous, it lies above the ionosphere from a height of about 500 km, to the edge of interplanetary space. Since the mean free path is much gr
eater than the atmospheric scale height, the atoms or molecules never collide with each other.
Frontal expansion on a level surface (not necessary lowland); Less restricted by topography; Widening of the tongue (lateral expansion is less than for piedmont); Lobe or fan formed where the lower po
rtion of the glacier leaves the confining wall of a valley and extends on to a less restricted and more level surface (WGMS 1970, 1998); Lobe or fan formed where the lower portion of the glacier leaves the confining wall of a valley and extends on to a less restricted and more level surface. Lateral extension markedly less than for piedmont. (WGMS 1977)
The fan of glacier ice formed when a valley glacier or outlet glacier flows beyond its constricting valley walls onto lowland terrain and expands laterally.
The deduction based on the observational fact that the greater the distance to a galaxy, the greater the redshift in its spectral lines (Doppler effect). The observations strongly indicate that galaxi
es appear to be moving away from us with speeds proportional to their distance. This is in agreement with the overall expansion of the Universe.