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
Albedo 0.39 light it receives that is reflected back into space. The album title refers to the average albedo value of the planet Earth as it was in 1976. From the explanation on the back of the LP cover : ""The reflecting power of a planet or other non-luminous body. A perfect reflector would have an Albedo of 100%. The Earth's Albedo is 39%, or 0.39"". As with "Heaven and Hell", it was performed at the Royal Albert Hall in 1977. The album reached #18 on the UK Album Charts. In 2011 the album was included along with "Heaven and Hell" and