Menu

Flag of Scotland has a blue background

The famous Blue Marble photograph of Earth, taken by NASA's Apollo 17

The sky of the rising the summer the lake in Surat Thani Lake, Thailand

Blue is one of the colors of the rainbow that people can see. It is one of the primary colors (colors that can be mixed with other colors) of light, along with red and green. Apart from indigo and violet, it has the shortest wavelength of colors in the rainbow (about 470 nanometers).

Blue paint can be made by mixing magenta and cyan paint.

Blue is the color of the Earth's sky and sea. Earth looks blue when seen from outer space by astronauts.