To the human eye the surface of Mercury looks brown-greyish. But on a spectral image showing how much of the sun's energy is reflected off the surface in various lengthwave, Mercury has several area's that appear dark blue.
To the human eye the surface of Mercury looks brown-greyish. But on a spectral image showing how much of the sun's energy is reflected off the surface in various lengthwave, Mercury has several area's that appear dark blue.