NASA has a habit of sharing raw images directly from orbiting spacecraft and rovers on Mars. The Red Planet is a completely different environment from Earth, and people naturally look for some of the same phenomena in the atmosphere on Mars as we see them here on Earth. One example of this is an image that NASA recently shared from the Mars Perseverance Rear Left Left Avoidance camera known as Hazcam.
Running across the top left of the image, as shown below, you can see what appears to be a rainbow in the sky over the surface of Mars. However, it looks like it can be deceptive. The official Perseverance Mars Rover Twitter page shared the photo, indicating that several people who saw it asked if it was a rainbow.
The Perseverance Team explains that it is not a rainbow because rainbows are not possible on the Red Planet. A rainbow is created when light is reflected from the round droplets of water in Earth’s atmosphere. However, there is not enough water on Mars to condense, and the planet is too cold to have liquid water in the atmosphere.
The least interesting explanation for what appears in the photo is lens flare. Lens flare is a phenomenon in which light is scattered or glowed in the lens system, usually in response to bright light that creates an unwanted defect within an image. In this case, the lens flare is very similar to a rainbow.
The Tenacity Rover has been on the surface of Mars for several months and is currently conducting its scientific investigations in an effort to find evidence of past life on Mars. The rover has also recently put the Ingenuity helicopter on the surface of Mars in preparation for its flight in the coming days.