Blue Marble

The Blue Marble

The Blue Marble is a photograph of Earth taken on December 7, 1972, by one of the astronauts aboard the Apollo 17 spacecraft on its way to the Moon. Viewed from around 29,400 kilometers from Earth's surface, a cropped, rotated, and processed version has become one of the most reproduced images in history.

Marble

Marble is a metamorphic rock consisting of carbonate minerals (most commonly calcite (CaCO3) or dolomite (CaMg(CO3)2) that have recrystallized under the influence of heat and pressure. It has a crystalline texture, and is typically not foliated (layered), although there are exceptions.

Blue

Blue is one of the three primary colours in the RGB (additive) colour model, as well as in the RYB colour model. It lies between violet and cyan on the spectrum of visible light. The term blue generally describes colours perceived by humans observing light with a dominant wavelength between approximately 450 and 495 nanometres. The clear daytime sky and the deep sea appear blue because of an optical effect known as Rayleigh scattering. An optical effect called the Tyndall effect explains blue eyes. Distant objects appear more blue because of another optical effect called aerial perspective.

blue

Adjective

1. Of a blue hue.
2. Depressed, melancholic, sad.

Noun

1. The colour of the clear sky or the deep sea; the colour midway between green and violet in the visible spectrum and one of the primary additive colours.
2. Anything coloured blue, especially to distinguish it from similar objects differing only in colour.

marble

Noun

1. A metamorphic rock of crystalline limestone. .mw-parser-output .defdate{font-size:smaller}
2. A small ball used in games, originally of marble but now usually of glass or ceramic.

Verb

1. To cause (something to have) the streaked or swirled appearance of certain types of marble, for example by mixing viscous ingredients incompletely, or by applying paint or other colorants unevenly.
2. To get or have the streaked or swirled appearance of certain types of marble, for example due to the incomplete mixing of viscous ingredients, or the uneven application of paint or other colorants.