The human eye and brain have self-adjusting mechanisms in completely new environments, such as on other planets, in terms of both color and intensity.
The human brain is remarkably adept at adjusting to different lighting conditions. For instance, when wearing tinted sunglasses, a person initially perceives the colors vividly; however, after a while, these colors begin to appear “normal” again. This phenomenon also occurs naturally as people age. The lenses of older individuals tend to yellow compared to their younger years. Nevertheless, they do not perceive colors in the same way, as the brain compensates for these differences.
NASA’s Curiosity rover takes a selfie on Mars. (Image: NASA/JPL-Caltech)
So how will the brain adjust colors in a completely new environment? Experts share insights on how colors may appear on other planets.
A similar mechanism that helps adjust yellowed lenses and tinted sunglasses may also function when astronauts reach another planet, according to research by Michael Webster, a cognitive vision scientist at the University of Nevada. Depending on the predominant colors in the new environment, astronauts’ brains will recalibrate to perceive them in a more neutral way.
“My prediction is that when people arrive on Mars, the planet will no longer appear red in their eyes over time,” Webster states. Instead, the Martian terrain will start to look browner or grayer, and the reddish soil of Mars will seem greener—not blue like Earth, but significantly less orange than what humans currently see.
However, not all extraterrestrial skies will appear greener over time. This depends on the dominant colors of the light passing through the atmosphere compared to the predominant colors of the landscape. Because blue is the opposite of orange on the color wheel, cooler tones may become more pronounced as the astronauts’ brains lean towards neutrality. But if astronauts visit an exoplanet with purple foliage and a yellow sky, the brain may adjust differently.
The human “filter” is not limited to color; it also adjusts intensity. On a planet with a limited natural color palette, the brain will become attuned to very subtle changes in hue. Over time, astronauts will perceive paler colors becoming more vibrant and vice versa.
<pWhat would happen if, instead of waiting for the eyes and brains of astronauts to adapt to the new planet, humans invented an automatic filter device for that environment? Derya Akkaynak, an engineer and oceanographer at the University of Haifa, along with her colleagues at the lab, is researching a similar issue. However, her research is conducted in marine environments rather than outer space.
Theoretically, if the atmospheric and oceanic composition of an exoplanet is known, one can predict how light will interact there. Experts could then use this information to create algorithmic filters to “correct” the colors of the environment. This filter could be integrated into the visor of a space suit.
Before humans actually reach another planet, it is impossible to know exactly how the adjustment of the extraterrestrial color palette will unfold. However, deep-sea research could provide approximate results. Akkaynak has descended as deep as 30 meters underwater, deep enough to filter out red light. “Everything looks yellow instead of blue, perhaps because I am trying to compensate for the lack of red. But overall, the sight is truly surreal,” Akkaynak told Live Science on September 27.
