By combining images taken through different filters in the visible and infrared, the MESSENGER data allow Mercury to be seen in a variety of high-resolution color views not previously possible. MESSENGER's eyes can see far beyond the color range of the human eye, and the colors seen in the accompanying image are somewhat different from what a human would see.
Bailey, D., Bailey, S. & Hufford, M. (1996) Copperheads Smell Like Cucumbers. [Audio] Retrieved from the Library of Congress, https://www.loc.gov/item/cmns001450/. Bailey, Dave, Sherman Bailey, and Mary Hufford.
All cucurbits produce a group of chemicals called cucurbitacins, which causes the bitter taste in cucumbers. The higher the concentration of cucurbitacins, the more bitter the taste. The bitterness is due to high levels of cucurbitacins that was triggered by environmental stress. These environmental stresses can include high temperatures, wide temperature swings, or too little water.