Scientists, including biometeorologist Nancy Kiang of NASA’s Goddard Institute for Space Studies, suggest that the color of alien life depends on the type of star or their planet’s climate.
Plant life is probably more common because starlight is very useful and a very stable source of energy for life. For example, on Earth, phytoplankton (microbial plants) are abundant and provide the basis for “a large part of the ocean food chain, half of the oxygen in our atmosphere, and ultimately most of the Earth” (“Breakthrough”).
While studying plants on Earth, scientists have discovered something: At first, plants seem to be inefficient because they reflect light in the highest form of energy production, green light. The maximum amount of sunlight reaching the surface of our planet falls on the green band. However, photosynthesis uses particles of light (photons) and not just energy. The photon peak is in the red range. This is because red light penetrates the atmosphere more easily than blue light, which is scattered primarily by atmospheric ozone (which is why the sky appears blue and the sun red at sunset – the light has to travel through the atmosphere more than the midday sun, and only the least scattered light red).
But the blue light, although somewhat diffused by our atmosphere, still reaches the earth sufficiently to be useful to plants; Photosynthesis depends on photons, with more powerful photons being more efficient—blue photons are more powerful than red photons. Although there is a limit to how much energy a plant can consume. For most terrestrial plants it is sufficient to focus on a peak in the red range.
By the way, while the Sun emits more light energy in the green band, on the surface it appears yellow to us because, as mentioned above, some of the blue light is scattered by the atmosphere. From space, the Sun appears white, but this is how our eyes are designed — when the entire spectrum hits, especially from a bright source, our eyes perceive the source as white, even if it is not completely white.
Using this information about photosynthesis, Nancy Kiang and her fellow scientists hypothesized what color life would prefer in an alien environment. For example, F-type stars are hot blue stars that emit more blue photons than any other color, and certainly much more than the Sun. On a planet orbiting such a star, any plant-like organisms that find the chemistry of photosynthesis as useful as terrestrial plants, might want to focus on absorbing blue cells. Since these wavelengths are of little use (inefficient to use them), they reflect red and orange colors.
Around cooler, fainter, red M-type stars, there is so little light that plants need all the particles they can get to avoid reflecting the light back (black plants are a Gothic planet!). Although plant life primarily uses infrared-absorbing chlorophyll (scientists have discovered two types of infrared-absorbing chlorophyll on Earth), such plants may want to absorb as much heat as possible. Or for a planet orbiting a gas giant far from the central sun or a habitable moon with a thick atmosphere (reflecting more blue wavelengths than our atmosphere), plants on such a planet would also need to use all available light. (Note: single M-type red dwarfs are more common in our galaxy, not doubles.)
What does this mean for intelligent cultures? Each part of their spectrum can easily have different cultural meanings or cultural or theological metaphors. Think about what yellow means to us: warmth, light, day, energy – it’s a positive color. Red is associated with blood and often means life, and spilled blood, sacrifice or death. Blue is the color of coolness, water and sky. And, of course, green for food, sustenance, fertility, tranquility and life.
Around different stars, these colors can easily take on different meanings. Around a hot blue star, blue should not be the color of coolness. The sky could very well be blue, the sun would have a bright blue patch – this could be interesting. Imagine if our skies were yellow? Our yellow sun is this bright part of a bright spot in a yellow sky. We may not be able to define the Sun’s boundaries precisely, so we may not first recognize it as an autonomous body revolving around the Earth, but instead simply as a luminary moving across the sky. This is also possible for some planets orbiting a blue star.
On a planet with black plants, black represents life to a primitive wisdom mind. And if black is food, sustenance, fertility and therefore life, what about the black night sky?
What about a planet that has both blue water and blue plants? The color blue varies greatly. Perhaps some representatives of the animal world also have blue pigment (for example, to combine with vegetation). However, because blue light contains so many high-energy photons, Ms. Kiang opined.
Speaking of red stars, M class stars have more flare than the Sun and are more intense. This causes problems for life as the flares flood the planets with strong radiation. However, life is resilient, “life always finds a way”, and not only are there small life forms that can survive in outer space on Earth, but water is a good shield – life forms 9 to 10 meters below the surface are protected. from the flames, while still receiving enough life-giving photons.
Since the laws of physics and chemistry are universal, it is reasonable to assume that there are universal laws of biology based on physics and chemistry. Not all systems of life can detect photosynthesis, since there are a lot of chemical and physical changes in the laws of the world, the changes can be so different that some organisms may not "catch" You even need to find photosynthesis, or find another form of photosynthesis that is not needed or necessary for the biological system of the Earth. However, chlorophyll is a wonderful molecule; it is a very useful substance that produces energy for life, so it seems that it will be popular among living things in the universe (although, again, this does not exclude other factors).
