Earlier this year, NASA’s MESSENGER mission continued to take photos of Mercury right up until it crashed into the planet. This enhanced image of the usually grey-looking planet shows how color doesn’t quite capture the diversity of the planet’s make up.

Here’s what the yellow, blues, and bright spots and lines mean according to the European Space Agency:

The darker regions exhibit low-reflectance material, particularly for light at redder wavelengths. As a result, these regions take on a bluer cast.

The criss-crossing streaks across the disc of the planet show up in shades of light blue, grey and white. These regions take on a light blue hue for a different reason: their youthfulness. As material is exposed to the harsh space environment around Mercury it darkens, but these pale ‘rays’ are formed from material excavated from beneath the planet’s surface and sent flying during comparatively recent impacts. For this reason, they have retained their youthful glow.

The yellowish, tan-coloured regions are “intermediate terrain”. Mercury also hosts brighter and smoother terrain known as high-reflectance red plains. One example can be seen towards the upper right, where there is a prominent patch that is roughly circular. This is the Caloris basin, an impact crater thought to have been created by an asteroid collision during the Solar System’s early days.

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Image credit: NASA / JHU Applied Physics Lab / Carnegie Inst. Washington


Contact the author at katharine@io9.com.

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