Ray system they have been identified on Mars in infrared images taken from orbit by "2001 Mars Odyssey"s thermal imager. Rays appear at visible, and in some cases infrared wavelengths, when ejecta are made of material with different reflectivity (i.e., albedo) or thermal properties from the surface on which they are deposited. Typically, visible rays have a higher albedo than the surrounding surface. More rarely an impact will excavate low albedo material, for example basaltic-lava deposits on the lunar maria. Thermal rays, as seen on Mars, are especially apparent at night when slopes and shadows do not influence the infrared energy emitted
Cloud albedo if all other factors are the same. Addition of cloud nuclei by pollution can lead to an increase in solar radiation reflected by clouds. Increasing aerosol concentration and aerosol density increases cloud droplet concentration, decreases cloud droplet size, and increases cloud albedo. In macrophysically identical clouds, a cloud with few larger drops will have a lower albedo than a cloud with more smaller drops. The cloud albedo increases with the total water content or depth of the cloud and with the solar zenith angle. The variation of albedo with zenith angle is most rapid when the sun is near the