Fact Check: Did NASA's Perseverance Rover Photograph a Mars Rainbow?

NASA's Mars Perseverance rover has been on the Red Planet for nearly 50 days, and in that time, the robot has sent back thousands of images of the distant world.

The images have proved popular on social media, where they have been shared along with hoax photos and other examples of Mars misinformation.

One recent example is a photo—or several photos—of what some have claimed is a rainbow captured in the Martian sky by Perseverance. It has spread through Twitter, and the term "Mars rainbow" is also being searched for on Google, according to Google Trends data. The photos can be seen below.

In Focus

Mars lens flare

A photo of the lens flare on Mars that looks like a rainbow in the sky, acquired from Perseverance April 4.
Launch Slideshow 3 PHOTOS

The Claim

On April 5, Twitter account @ScienceIsNew shared photos of Mars taken by the Perseverance rover that showed a multicolored arc over the horizon.

It added the caption: "Breaking: Perseverance rover has captured rainbow on Red Planet 'Mars.'"

The account is followed by over 46,000 people and the post received hundreds of retweets and around 1,300 likes.

BREAKING: Perseverance Rover has captured rainbow on Red Planet 'Mars' pic.twitter.com/9BWVbXZiff

— Science & Nature (@ScienceIsNew) April 5, 2021

That same day, an unofficial fan account of the Perseverance rover, @PercyRover, tweeted the same photo along with the caption: "And so the Martian God said unto the Mars rovers of the land called Jezero, 'I set this rainbow in the clouds, and it shall be for a sign of my promise that Mars is a better planet than Venus.'"

The post was subsequently shared by several other users and liked over 1,200 times.

The Facts

On April 6, the official NASA Perseverance Twitter account provided an explanation for the photo, which does show what looks like a rainbow in the Martian sky.

The NASA account said the multicolored arc was not a rainbow, but rather a lens flare, which is caused by light hitting the camera lens at a certain angle.

In addition, the space agency said that rainbows cannot exist on Mars, given the planet's dry and cold atmosphere.

It wrote: "Many have asked: Is that a rainbow on Mars? No. Rainbows aren't possible here.

"Rainbows are created by light reflected off of round water droplets, but there isn't enough water here to condense, and it's too cold for liquid water in the atmosphere. This arc is a lens flare."

This is not to say there is no water in Mars' atmosphere, however. NASA's website says that the planet's atmosphere consists mostly of carbon dioxide and "some water vapor."

But even if, theoretically, there was enough vapor to produce a rainbow, the average temperature on Mars is -81 degrees Fahrenheit and the pressure is very low, so the vapor would not be able to form the round water droplets necessary for a rainbow to occur, according to lumenlearning.com.

The Ruling

False.

The Perseverance rover did not capture a rainbow on the surface of Mars. By NASA's explanation, the colored arc seen in the photos is a result of the way the light hit the camera lens.

False: The claim is demonstrably false. Primary source evidence proves the claim to be false.
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