A sky with two suns is one of the most common images to demonstrate to the rotunda in a sci-fi is a global landscape outside our solar system. But how could be influenced the hypothetical life on a planet if it has two suns instead of just one?
Photosynthesis, which can harness sunlight for biological applications, is a direct or indirect basis on which rests most of life on Earth. It is the energy source for plants and, therefore, indirectly for the animals at the top of the food chain. With multiple light sources usable, life elsewhere in the cosmos may have been adapted for use in light of all suns, or there may be other specialized beings to use the light of either sun. This latter option may be the most likely on planets where some of the surface is illuminated by only one sun for long periods of time.
If a planet is in a system with two or more stars, would potentially several sources of energy to perform photosynthesis. The temperature of a star determines its color and, therefore, the color of the light used for photosynthesis. Depending on the colors of the stellar light, the plants may have evolved very differently.
Jack O’Malley-James and Jane Greaves of the University of St Andrews, John Raven of the University of Dundee and Charles Cockell of the Open University (Open University), all of the United Kingdom, have evaluated the potential photosynthetic life on systems multi-star with different combinations of Sun-like stars and red dwarfs.
Red dwarf stars are the most common in our galaxy and are often present in systems of more than one star. Red dwarfs are very long lived and tend to have a stable activity, two best qualities for all plausible scenario of life.
As for Sun-like stars are also quite abundant and is already known about the existence of planets orbiting some of them.
More than 25 percent of Sun-like stars and about 50 percent of red dwarfs are multi-star systems.
In the simulations conducted by the research team, the Earth-like planets orbiting two stars very close to each other or do some of them when the separation between the two is great. The team also examined combinations of these scenarios, with two stars very close to each other and third a lot more away from them.
The results of the simulations suggest that planets may harbor plant multi-star systems with features far more exotic than those possessed by ordinary plants that are known on Earth.
For example, plants illuminated by dim red dwarfs may be very dark, definable as black, in order to absorb the entire range of wavelengths of visible light in order to maximize available light. They may also use infrared or ultraviolet light to perform photosynthesis.
For two stars orbiting planets like ours, the harmful radiation of the intense solar flares might have led to plants that have developed their own sunscreens to block harmful UV emissions.
The plant on a planet similar to Earth but with two or three suns, could be black or gray, according to results of simulations.
Many plants on Earth are green because of chlorophyll, which harnesses the energy from the sun to produce sugars that are used in metabolism. On planets in other solar systems, it is likely that plants have different pigments, suitable for absorbing the wavelengths available in their worlds.
On the other hand, plants of the Earth have an efficiency that is not the maximum possible, since a certain amount of wasted light, green. The plant would be ideal for a black molecule that absorbs all light that received. And this could be the case for a system of photosynthesis evolved into a planet suitable for life but environmental conditions ‘exotic’ where evolution had reached the state of maximum efficiency.
This would imply that the plants were completely black. Professor Robert Blankenship of Washington University in St. Louis, Missouri, USA, and contributor to NASA, produced, along with other scientists, two studies on the types of signals should be sought to detect possible life forms qualified as ‘vegetable’ based on photosynthesis. In this line of research also has examined the question of which aspect of these other worlds could present as a result of the presence in them of such life forms.
