14 DAY TRIAL // Earth's land is covered by the green of the plants, but NASA researchers warn that this is linked to the conditions on the Earth and plants on extra-solar planets could confer them green, yellow or red-dominant hues.
Astronomers believe plants on other planets reflect mostly other colors than green. "We can identify the strongest candidate wavelengths of light for the dominant color of photosynthesis on another planet," said Nancy Kiang, lead author of the study and a biometeorologist at NASA's Goddard Institute for Space Studies, New York.
"This work broadens our understanding of how life may be detected on Earth-like planets around other stars, while simultaneously improving our understanding of life on Earth," said Carl Pilcher, director of the NAI at NASA Ames.
Kiang's team measured what the star light would be at the surface of Earth-like planets whose atmospheric chemistry is linked to the stars they orbit, based on computer simulations. Linked to how light is impacted by different atmospheres, scientists assessed which colors would be the best for photosynthesis on other planets and each planet could possess different dominant colors for photosynthesis.
In some cases, the dominant photosynthesis could be even made on infrared. "This work will help guide designs for future space telescopes that will study extrasolar planets, to see if they are habitable, and could have alien plants," said Victoria Meadows, head of the VPL.
The team wants to detect habitable planets around other stars and how these planets could look for future planet-finding missions.
On Earth, organisms living in different environments absorb the light waves that are the most available. For example, bacteria types living in murky waters, with little visible light, employ infrared light for photosynthesis.
Chlorophyll, found in most plants, absorbs blue and red light and less green light, that's why it is green. Earth's atmosphere filters differently the sunlight's colors, so our planet's red light particles reach the surface more than blue or green light particles, and chlorophyll is more adapted for this.
But photosynthesis on extrasolar planets is not necessarily similar to that on Earth. "It makes one appreciate how life on Earth is so intimately adapted to the special qualities of our home planet and Sun," said Kiang.