images

Earth's limb at sunrise

by

Nasa/Novapix

Reference

t-nua10-00002

Date

2006-09-25

Uppermost layers of the atmosphere appear dark blue due to molecular scattering of solar rays. Beneath the blue is a white layer within which a thin, stratified layer of  suspended scattering material can be identified. The greyish-red band is residue of the Mt. Pinatubo eruption of June, 1991, comprised of a  combination of ash and sulfuric acid particles at an altitude of 20 to 27  kilometers above the Earth. The boundary between the grey-red and lighter colored red is the lower stratosphere. The clouds visible are cirrus at 40,000 ft altitude. Below the stratosphere the lower atmosphere appears darker red because of scattering by dust, water vapor, and smoke.