NASA reveals the mystery of the “rainbow” on Mars

NASA’s Aeronautics and Space Administration has cleared up a mysterious rainbow-like optical phenomenon in a recent photograph of Mars.

On Sunday, April 4, 2021, NASA released a fresh photograph of Mars taken by the Perseverance rover. Many drew attention to the unusual “rainbow” clearly visible in the picture. The snapshot gained viral popularity on social networks and was vividly discussed by enthusiasts.

Now NASA has provided an explanation on the official Twitter page, which is run on behalf of Perseverance:

Many people ask: is it a rainbow on Mars? No. A rainbow is not possible here. The rainbow is created by light reflected from round water droplets, but there is not enough water for condensation, and it is also too cold for liquid water in the atmosphere. This arc is a lens flare.

The photo was taken with the left rear camera to prevent hazards, so this optical effect is not surprising. The microblog Perseverance on behalf of the rover also notes:

I have sun visors on the front Hazcam cameras that were considered critical (they are needed to move forward and I usually drive forward). Sun visors were not considered necessary on the rear Hazcam cameras, so you can see stray light artifacts in the image.