NASA Photos From Mars Curiosity Rover Reveal Red Planet is Also Green and Purple

NASA's Curiosity Mars rover is seen at the site from which it reached down to drill into a rock target called 'Buckskin' on lower Mount Sharp in this low-angle self-portrait taken August 5, 2015 and released August 19, 2015. Reuters

NASA's rover has been roaming around Mars since 2012, but the photos it sent back to Earth this week just changed the view. Long known as the Red Planet, it turns out Mars has some other colors to show off. Through special lenses on its camera-eyes, the rover sent back photos of purple contrasting with green tracking one mineral in particular: hematite.

The cameras on Curiosity take photographs at different wavelengths of lights. Since rocks reflect and absorb light differently, the camera (specifically the Mast Camera) can determine what type of minerals make-up Mars' surface.

Scientists noticed the variations in rocks from spectrometer observations from orbit years ago and have been planning to tackle the Vera Rubin Ridge on the lower part of Mount Sharp since. "This is the juiciest part of the traverse," said Jeffrey Johnson, a planetary geologist of Johns Hopkins University's applied physics laboratory.

Since Curiosity's landing in 2012, it has found simple organic compounds (though it is unclear if they were formed from human contamination or are native to Mars), evidence of water, and photographs from points of interest such as Mount Sharp, the Murray Buttes, Hidden Valley, Yellowknife Bay Formation, and Rocknest.

The latest images from the rover are showing a different perspective of what Mars looks like—and what it may have looked like in the past.

This pair of images from the Mast Camera (Mastcam) on NASA's Curiosity rover illustrates how special filters are used to scout terrain ahead for variations in the local bedrock. NASA

Hematite is typically a red color which blends with the rest of the surface as evident in the full color photograph. It usually forms in the presence of water, tacking on more evidence that ancient Martian times had conditions favorable for life. Though the rover found evidence that Mars once had conditions favorable to life in the first year of its journey, the presence of hematite hints at a changing and varied past for those conditions. And by using the special lenses on the cameras, scientists can pinpoint the areas that could be further investigated, said Johnson.

Collecting data on these rocks can answer questions about factors of the water that may have once passed through, such as its acidity, according to Johnson. Those answers could tell scientists what types of lifeforms would have been able to survive and potentially thrive. And the Mast Camera on the rover provides an excellent vantage point for gathering such intel. "It's like if you're flying in a plane and you're looking down in a canyon or rocks or fields or something," said Johnson. "It's always going to look a little different when you take your bike through it."

I see your true colors, and that's why I love you, Mars.💜 The purple hue indicates hematite below the dust.

— Curiosity Rover (@MarsCuriosity) November 1, 2017

Other substances the rover has detected on the surface have been different types of salts, gypsum, volcanic rocks, and rocks that have clearly been weathered for long periods of times, said Johnson. Further south of the ridge, where the rover will cross next, is more claylike.

"All of the minerals that we see tell a story," he said. "And sometimes that story is really complicated."